Spiral wound separation membrane assembly and preparation method thereof

Abstract

The present invention provides a spirally wound separation membrane module and a method for preparing the same. The spirally wound separation membrane module according to one embodiment of the present invention comprises: an outflow tube; a filter assembly wound on the outflow tube in a spirally wound manner; and a fusion portion, in which a part or all of a heat-fusion line wound in a manner of surrounding the outer surface of the filter assembly in the length direction of the outflow tube is melted, so as to be fused and fixed to the filter assembly. Accordingly, the spirally wound separation membrane module and the method for preparing the same can significantly reduce the defect rate and process time, and can also show an environmentally friendly effect even when it is disposed of after use.

Description

Technical Field

[0001] The present invention relates to a spirally wound separation membrane component, and more particularly to a spirally wound separation membrane component and a preparation method thereof. Background Art

[0002] Separation membranes are classified into microfiltration membranes (MF), ultrafiltration membranes (UF), nanofiltration membranes (NF) and reverse osmosis (RO) membranes according to the pore size.

[0003] In order to apply the above separation membrane to industrial-scale liquid separation, a relatively large membrane area is required. The device unit integrating a large membrane area into a compact size is called a separation membrane module. Currently, various membrane module types have been developed, such as flat-plate modules, tubular modules, hollow fiber modules, and spiral wound modules. In particular, the recently commercialized permeation membrane modules mainly use spiral wound modules.

[0004] The spirally wound component performs a packaging process by winding predetermined fibers on the outer surface. In the past, the packaging process was performed by spraying a mixture of epoxy resin and curing agent while winding the fibers. However, the epoxy resin and curing agent were scattered and poor curing often occurred, which increased the defect rate. In addition, since the curing time was very long, the process time was also too long. In addition, since a mixed solution of epoxy resin and curing agent was used, there was also a very environmentally unfriendly problem in the disposal after use.

[0005] Therefore, there is an urgent need to study packaging process conditions, materials therefor, and spirally wound separation membrane modules that can significantly reduce the defect rate and process time while also being environmentally friendly during post-use disposal. Summary of the invention

[0006] Technical issues

[0007] The present invention is developed in view of the above problems, and its purpose is to provide a spirally wound separation membrane component and a preparation method thereof that can significantly reduce the defect rate and process time and can also show environmental protection effects when disposed of after use.

[0008] Solutions to the problem

[0009] In order to solve the above-mentioned technical problems, the present invention provides a spirally wound separation membrane assembly, which includes: an outflow tube; a filter assembly wound on the outflow tube in a spiral winding manner; and a welding portion, in which a part or all of the heat-melting line wound in a manner of surrounding the outer surface of the filter assembly in the length direction of the outflow tube is melted to be fused and fixed to the filter assembly.

[0010] According to an embodiment of the present invention, the filter assembly may include: a separation membrane bent to form at least one blade; an inner spacer arranged inside the blade; and an outer spacer arranged outside the blade.

[0011] In addition, the inner spacer may include a mesh sheet, and the outer spacer may include a tricot filter channel.

[0012] In addition, the heat-fusion line may include supporting fibers and a heat-fusion polymer formed on the surface of the supporting fibers and having a lower melting point or softening point than the supporting fibers.

[0013] Furthermore, the supporting fibers may include at least one selected from the group consisting of polyethylene terephthalate fibers, glass fibers, and carbon fibers, and the thermal fusion polymer may include at least one selected from the group consisting of polyethylene terephthalate and polyolefin polymers.

[0014] Furthermore, the heat-fused wire may be wound in one to four layers so as to surround the outer surface of the filter assembly in the longitudinal direction of the outflow pipe.

[0015] Furthermore, the heat-fused thread may be further wound in one or more layers at both ends of the outflow pipe in the length direction on the outer surface of the filter assembly.

[0016] Furthermore, the heat fusion thread may be wound around the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. In this case, the heat fusion thread may be wound around 290 to 320 times per unit length of 1 m per layer.

[0017] In addition, the above-mentioned heat fusion wire may be a core-sheath type heat fusion wire including the supporting fiber and the heat fusion polymer in a weight ratio of 20:80 to 80:20.

[0018] In addition, the present invention also provides a method for preparing a spirally wound separation membrane assembly, which comprises the following steps: winding a heat-melt wire on a filter assembly spirally wound on an outlet pipe in a manner that surrounds the outer surface of the filter assembly in the length direction of the outlet pipe; performing heat treatment so that part or all of the heat-melt wire is melted; and forming a welded portion that is welded and fixed to the filter assembly by solidifying the melted heat-melt wire.

[0019] According to an embodiment of the present invention, the heat treatment step may be performed at 100° C. to 250° C. for 30 seconds to 2 minutes.

[0020] Furthermore, the above-mentioned curing may be performed for 3 minutes to 20 minutes.

[0021] Effects of the Invention

[0022] According to the present invention, the spirally wound separation membrane module and the preparation method thereof can significantly reduce the defect rate and process time, while also showing an environmentally friendly effect even when disposed of after use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a cross-sectional schematic diagram of an outflow pipe and a filter assembly provided in a spirally wound separation membrane module according to one embodiment of the present invention,

[0024] Figure 2 is a perspective view of a spirally wound separation membrane module according to one embodiment of the present invention,

[0025] Figure 3 are photographs showing a spirally wound separation membrane module before and after heat treatment according to an embodiment of the present invention, and

[0026] Figure 4 FIG. 1 is a SEM (scanning electron microscope) image of a welded portion provided in a spirally wound separation membrane module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that a person skilled in the art can easily implement the present invention. The present invention can be implemented in a variety of different embodiments and is not limited to the embodiments described in this specification. In order to clearly illustrate the present invention, parts not related to the description are omitted in the accompanying drawings, and the same reference numerals are given to the same or similar structural elements throughout the specification.

[0028] like Figure 1 and Figure 2As shown, the spirally wound separation membrane assembly 1000 according to the present invention includes: an outflow pipe 100; a filter assembly 200, which is spirally wound on the above-mentioned outflow pipe 100; and a welding part 300, in which a part or all of the heat-melting line wound in a manner of surrounding the outer surface of the filter assembly 200 in the length direction of the outflow pipe 100 is melted to be fused and fixed to the filter assembly 200.

[0029] First, the outflow pipe 100 may be composed of a hollow pipe member, either one of the two ends or both ends of the hollow pipe member are open, and the hollow pipe member includes at least one hole for introducing produced water.

[0030] Any known outflow pipe applicable to the spirally wound separation membrane module can be used without limitation, and is not particularly limited in the present invention.

[0031] Next, the filter assembly 200 will be described.

[0032] The filter assembly 200 includes a separation membrane 210 bent to form at least one blade; an inner spacer 220 disposed inside the blade; and an outer spacer 230 disposed outside the blade.

[0033] Referring to the raw water treatment process through the spiral wound separation membrane module 1000, the inflow water passes through the separation membrane 210 through the inner spacer 220, and dissolved salts and organic matter are removed during the process of passing through the separation membrane 210, and is separated into pure water. The separated water flows along the outer spacer 230, and the separated water is collected in the outflow pipe 100 located in the center and discharged to the outside of the spiral wound separation membrane module 1000.

[0034] As the separation membrane 210 , any separation membrane generally applicable to a spiral-wound separation membrane module in the art may be used without limitation, and therefore, there is no particular limitation thereto in the present invention.

[0035] In addition, the inner spacer 220 serves to form a flow path inside the blade. Specifically, the inner spacer 220 is arranged inside the blade formed by the bending of the separation membrane 210, thereby serving as an inflow water flow path (feed channel) to greatly improve the formation of the flow path inside the blade.

[0036] As the inner spacer 220 , any inner spacer generally applicable to a spiral-wound separation membrane module in the art may be used without limitation, and preferably, may include a mesh.

[0037] As the mesh sheet, any mesh sheet that can be used as an inner spacer of the filter assembly can be used without limitation. Preferably, polypropylene, polyethylene, or a polyolefin copolymer obtained by mixing polypropylene and polyethylene in a certain ratio can be used as the material of the mesh sheet.

[0038] The inner spacer 220 may have an average gap of 6 mm2 to 20 mm2, preferably, an average gap of 9 mm2 to 17 mm2, so as to smoothly form a flow path. If the gap is less than 6 mm2, the formation of the flow path may be hindered, and if the gap exceeds 20 mm2, the separation membrane may be deformed and scaled during high-pressure operation.

[0039] In addition, the average thickness of the inner spacer 220 may be 0.2 mm to 3 mm, preferably 0.2 mm to 2.0 mm. If the average thickness of the inner spacer 220 is less than 0.2 mm, sufficient flow paths cannot be ensured, and if the average thickness of the inner spacer 220 exceeds 3 mm, the effective membrane area per unit volume is reduced, which may affect the performance of the module.

[0040] The above-mentioned external spacer 230 is arranged outside the blade to form an external flow path of the blade. Specifically, the above-mentioned external spacer 230 is arranged outside the blade. When there are more than two blades, it is arranged between the blades, thereby playing the role of a permeate water flow path (permeate spacer).

[0041] As the above-mentioned outer spacer 230, any outer spacer generally applicable to spiral-wound separation membrane modules in the art may be used without limitation, and preferably, may include a warp knitted fabric filter channel.

[0042] As for the above-mentioned tricot filter channel, any tricot can be used as an outer spacer of a filter assembly without restriction. Preferably, it can be formed by one or more resins selected from the group consisting of polypropylene, polyethylene, poly-4-methylpentene, propylene-α-olefin crystalline copolymer, polyethylene terephthalate, polybutylene terephthalate, polyamide and polycarbonate, or polyester modified by copolymerizing nylon, polypropylene or epoxy resin in polyethylene terephthalate resin (low melting polyethylene terephthalate, LMP).

[0043] Next, the above-mentioned welded portion 300 will be described.

[0044] As described above, the welded portion 300 is formed by partially or entirely melting a heat-welded wire wound around the outer surface of the filter assembly 200 in the longitudinal direction of the outflow pipe 100 to be fused and fixed to the filter assembly 200 .

[0045] Therefore, part or all of the above-mentioned heat-melting line may include a heat-melting polymer, and preferably, it can be a core-sheath type heat-melting line including supporting fibers and a heat-melting polymer, wherein the heat-melting polymer is formed on the surface of the above-mentioned supporting fibers and has a lower melting point or softening point than the above-mentioned supporting fibers.

[0046] At this time, as the above-mentioned supporting fiber, any fiber commonly used in the art can be used without limitation, and preferably, it can include one or more selected from the group consisting of polyethylene terephthalate fiber, glass fiber and carbon fiber.

[0047] In addition, the above-mentioned supporting fiber can be a monofilament or a multifilament formed by a fiber bundle. When the above-mentioned supporting fiber is a multifilament, the above-mentioned multifilament can solely include one selected from the group consisting of the above-mentioned polyethylene terephthalate fiber, glass fiber and carbon fiber, or can be a composite including two or more selected from the group consisting of polyethylene terephthalate fiber, glass fiber and carbon fiber.

[0048] In addition, as the above-mentioned heat-melting polymer, any heat-melting polymer can be used without limitation as long as it has a lower melting point or softening point than the above-mentioned supporting fibers, and preferably, it can include one or more selected from the group consisting of polyethylene terephthalate and polyolefin polymers.

[0049] In addition, the heat-fusion line may be formed by twisting fibers containing a heat-fusion polymer to the supporting fibers, or may be formed by coating the surface of the supporting fibers with a heat-fusion polymer, but is not limited thereto.

[0050] In addition, the heat-melting wire may include the support fiber and the heat-melting polymer in a weight ratio of 20:80 to 80:20, and preferably, the support fiber and the heat-melting polymer may be included in a weight ratio of 25:75 to 75:25. If the weight ratio of the support fiber and the heat-melting polymer is less than 20:80, the durability of the spiral-wound separation membrane module may be reduced, for example, defects may occur under high pressure conditions, etc. If the weight ratio of the support fiber and the heat-melting polymer exceeds 80:20, the heat-melting wire may not be fixed to the outer surface of the filter assembly, and the durability of the spiral-wound separation membrane module may be reduced, for example, defects may occur, etc.

[0051] On the other hand, the heat fusion wire may be wound in 1 to 4 layers so as to surround the outer surface of the filter assembly 200 in the length direction of the outflow pipe 100. Preferably, the heat fusion wire may be wound in 1 to 3 layers so as to surround the outer surface of the filter assembly 200 in the length direction of the outflow pipe 100. If the number of winding layers of the heat fusion wire exceeds 4 layers, problems may occur when installing in a housing due to an increase in the outer diameter, or workability may be reduced due to exceeding the standard weight, such as problems during installation, etc. If the heat fusion wire is not included, curing cannot be performed, so it may not be fixed to the outer surface, and the durability of the spirally wound separation membrane module may be reduced, such as defects.

[0052] In addition, the heat-melting wire may be further wound with one or more layers at both ends of the outflow pipe in the outer surface of the filter assembly in the length direction. If the heat-melting wire is not further wound with one or more layers at both ends of the outflow pipe in the length direction of the outer surface of the filter assembly, the problem of not being able to protect the internal original components during the high-pressure process may occur.

[0053] In addition, the heat fusion wire may be wound in a manner to surround the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. In this case, the heat fusion wire may be wound 290 to 320 times per unit length of 1 m per layer, and preferably, the heat fusion wire may be wound 300 to 310 times per unit length of 1 m per layer. If the number of times the heat fusion wire is wound per unit length of 1 m per layer is less than 290 times, the durability of the spirally wound separation membrane module may be reduced, for example, defects may occur under high pressure conditions, and if the number of times the heat fusion wire is wound per unit length of 1 m per layer is more than 320 times, problems may occur during installation on the housing due to an increase in the outer diameter, or problems may occur during installation due to exceeding the standard weight, resulting in reduced workability.

[0054] According to the present invention, the preparation method of the spirally wound separation membrane assembly includes the following steps: winding a heat-melting wire on a filter assembly spirally wound on an outflow pipe in a manner to surround the outer surface of the filter assembly in the length direction of the outflow pipe; performing heat treatment so that a part or all of the heat-melting wire is melted; and forming a fusion portion that is fused and fixed to the filter assembly by solidifying the molten heat-melting wire.

[0055] In the description of the method for producing a spirally wound separation membrane module, the same description as that of each configuration described in the above-mentioned spirally wound separation membrane module will be omitted.

[0056] The step of performing heat treatment so that a part or all of the heat-melting wire is melted may be performed at 100° C. to 250° C., preferably, at 120° C. to 220° C. for 30 seconds to 2 minutes, preferably, for 30 seconds to 1.5 minutes. If the temperature of the above heat treatment step is less than 100° C. or the heat treatment time is less than 30 seconds, there may be a problem that the welded portion cannot be fixed to the filter assembly at a desired level, and if the temperature of the above heat treatment step is greater than 250° C. or the heat treatment time exceeds 2 minutes, there may be problems such as an increase in defect rate or an increase in process time.

[0057] In addition, the curing can be performed for 3 minutes to 20 minutes, preferably, for 5 minutes to 15 minutes. If the curing time is less than 3 minutes, the welded portion may not be fixed to the filter assembly at a desired level, and if the curing time is more than 20 minutes, the process time may increase.

[0058] By performing the above-mentioned heat treatment step and the step of forming the welded portion, Figure 3 and Figure 4 The weld is formed as shown.

[0059] The spirally wound separation membrane module and the preparation method thereof according to the present invention can significantly reduce the defect rate and process time, and can also show environmental protection effects even when disposed of after use.

[0060] Modes for carrying out the invention

[0061] The present invention will be described in more detail by the following examples, but the following examples should not be construed as limiting the scope of the present invention but should be construed as helping to understand the present invention.

[0062] Example 1

[0063] First, on the 8-inch diameter outlet pipe, Figure 1 The structure shown is prepared by winding a filter assembly to prepare a spirally wound component, and the above-mentioned filter assembly is prepared as follows: 23 blades are formed by bending a separation membrane formed by stacking membranes (polyamide membranes) sequentially in a step-like structure with a step pitch of 5 mm, so that a mesh sheet of polyethylene and polypropylene composite materials as an inner spacer is arranged in the separation membrane, and a warp knitted fabric as an outer spacer is arranged in the area between the formed blades.

[0064] Afterwards, the heat-melting wire is wound into one layer on the spirally wound component in a manner to surround the outer surface of the filter assembly in the length direction of the outflow pipe, and the heat-melting wire is wound into two layers on the outer surface of the filter assembly at both ends in the length direction of the outflow pipe, and then heat-treated at 120°C for 1 minute using a 2000W hot air blower, and waited for 10 minutes at room temperature to allow the molten heat-melting polymer to solidify to form a fusion portion that is fused and fixed to the filter assembly, thereby preparing a spirally wound separation membrane component.

[0065] At this time, as the above-mentioned heat-melting wire, a core-sheath type heat-melting wire containing a supporting fiber made of polyethylene terephthalate and a polyolefin heat-melting polymer with a melting point of 100° C. in a weight ratio of 50:50 was used, and the above-mentioned heat-melting wire was wound 305 times per unit length of 1 m per layer.

[0066] Examples 2 to 17 and Comparative Examples 1 to 2

[0067] The spirally wound separation membrane components shown in Tables 1 to 4 were prepared in the same manner as in Example 1 except for changing the number of wound heat-melt wire layers, the number of heat-melt wire layers wound on both ends, the twist number of the heat-melt wires, the weight ratio of the supporting fiber and the heat-melt polymer, the heat treatment temperature and time, the curing time, etc.

[0068] Comparative Example 3

[0069] A spirally wound separation membrane assembly is prepared in the same manner as in Example 1, except that the glass fiber in contact with the mixed solution of epoxy resin and curing agent is wound around the spirally wound assembly in a manner that surrounds the outer surface of the filter assembly in the length direction of the outflow pipe instead of the welding portion, and the assembly is cured in a curing chamber at 60°C for 6 hours.

[0070] Comparative Example 4

[0071] A spirally wound separation membrane module was prepared in the same manner as in Comparative Example 3 except that the curing was performed in a curing chamber at 60° C. for 1 minute.

[0072] Experimental example

[0073] The spirally wound separation membrane modules prepared according to Examples and Comparative Examples were evaluated for the following items, and the results are shown in Tables 1 to 4 below.

[0074] 1. Defect rate evaluation

[0075] The defect rate of the spiral wound separation membrane modules according to the examples and comparative examples was evaluated. Specifically, for the spiral wound separation membrane modules prepared according to the examples and comparative examples, 15 people with more than 10 years of experience in the relevant field evaluated the defect rate by vision and touch. At this time, after calculating the average value with 10 points as the full score, the defect rate was evaluated as follows: 8 points or more: ○, 4 points or more and less than 8 points: △, less than 4 points: ×.

[0076] 2. High-pressure durability evaluation

[0077] The high-pressure durability was evaluated as follows: when operating under 600 psi, if there was no problem, it was evaluated as ○, and if there was any problem such as channeling phenomenon where the internal original member protruded, it was evaluated as ×.

[0078] 3. Flow rate and removal rate evaluation

[0079] For concentrated water (2000 mg / L, NaCl), the flow rate and removal rate were evaluated by LTT-1 (Long Term Tester) under the conditions of 225 psi pressure, 25°C temperature and 15% recovery rate (recovery = (production water flow rate / inlet water flow rate) × 100 (%)).

[0080] 4. Differential pressure evaluation

[0081] For concentrate water (2000 mg / L NaCl), the differential pressure at each water flow rate was measured while increasing the concentrate flow rate through LTT-1 (Long Term Tester) under a pressure condition of 225 psi.

[0082] 5. Workability evaluation

[0083] The workability was evaluated as follows: ○ if there was no problem when mounting the housing, and × if any problem occurred such as exceeding the outer diameter and standard weight.

[0084] Table 1

[0085]

[0086] Table 2

[0087]

[0088] Table 3

[0089]

[0090] Table 4

[0091]

[0092] As can be seen from Tables 1 to 4 above, Examples 1, 5, 6, 9, 10 and 13, which all meet the conditions according to the present invention such as the number of layers of the hot-melt wires wound, the number of layers of the hot-melt wires wound on both ends, the number of twists of the hot-melt wires, the weight ratio of the supporting fiber and the hot-melt polymer, the heat treatment temperature and time, the curing time and the components for fixing the fibers in a manner of surrounding the outer surface of the filter assembly, show the same level of flow rate, removal rate and differential pressure as compared with Examples 2 to 4, 7, 8, 11, 12, 14 to 17 and Comparative Examples 1 to 4, which do not meet at least one of the above conditions, and have a significantly low defect rate and significantly excellent high-pressure durability and workability, and the process time is also very short.

[0093] As described above, one embodiment of the present invention is described, but the subject matter of the present invention is not limited to the embodiment presented in this specification. A technician in the field who understands the subject matter of the present invention can easily propose other embodiments within the scope of the same subject matter by adding, modifying, deleting, increasing, etc. the constituent elements, and these belong to the scope of the subject matter of the present invention.

Claims

1. A spirally wound separation membrane module, characterized in that: include: Outflow tube; A filter assembly is wound around the outlet pipe in a spiral winding manner; and The welded portion is formed by partially or entirely melting the heat-welded wire wound around the outer surface of the filter assembly in the length direction of the outflow pipe, fusing and fixing the heat-welded wire to the filter assembly, thereby preventing defects and reducing durability. The heat-fused wire is wound in one to four layers so as to surround the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. The heat fusion wire was wound around the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. At this time, the heat fusion wire was wound 290 to 320 times per unit length of 1 m per layer.

2. The spirally wound separation membrane assembly according to claim 1, characterized in that: The filter assembly comprises: A separation membrane is bent to form at least one leaf; an inner spacer disposed inside the blade; and An outer spacer is arranged outside the blade.

3. The spirally wound separation membrane assembly according to claim 2, characterized in that: The inner spacer comprises a mesh, The outer spacer includes a warp knit filter channel.

4. The spirally wound separation membrane module according to claim 1, characterized in that: The heat-fusion line includes supporting fibers and a heat-fusion polymer formed on surfaces of the supporting fibers and having a lower melting point or softening point than the supporting fibers.

5. The spirally wound separation membrane module according to claim 4, characterized in that: The supporting fibers include at least one selected from the group consisting of polyethylene terephthalate fibers, glass fibers, and carbon fibers. The heat-welding polymer includes at least one selected from the group consisting of polyethylene terephthalate and polyolefin polymers.

6. The spirally wound separation membrane module according to claim 5, characterized in that: The heat-fused wire is further wound in one or more layers at both ends of the outflow pipe in the length direction on the outer surface of the filter assembly.

7. The spirally wound separation membrane module according to claim 1, characterized in that: The heat fusion bond is a core-sheath type heat fusion bond including support fibers and a heat fusion polymer in a weight ratio of 20:80 to 80:

20.

8. A method for preparing a spirally wound separation membrane module, characterized in that: The steps include: A heat-melting wire is wound around the filter assembly spirally wound around the outflow pipe so as to surround the outer surface of the filter assembly in the longitudinal direction of the outflow pipe; Performing heat treatment so that part or all of the heat-fused connection is melted; and The melted heat-welded wire is solidified to form a weld and fixed to the filter assembly, thereby preventing the weld from being defective or having reduced durability. The heat-fused wire is wound in one to four layers so as to surround the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. The heat-fused wire was wound around the outer surface of the filter assembly in the longitudinal direction of the outflow pipe. At this time, the heat-fused wire was wound 290 to 320 times per unit length of 1 m per layer.

9. The method for preparing a spirally wound separation membrane module according to claim 8, characterized in that: The heat treatment step is performed at 100° C. to 250° C. for 30 seconds to 2 minutes.

10. The method for preparing a spirally wound separation membrane module according to claim 8, characterized in that: The curing is carried out for 3 to 20 minutes.

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