Knitting method of efficient and energy-saving type bubble-free aeration membrane

Abstract

The invention provides a weaving method of an efficient and energy-saving type bubble-free aeration membrane, and belongs to the technical field of sewage purification treatment. The weaving method comprises the following steps: dividing the hollow fiber membrane filaments into three strands, namely a first strand of hollow fiber membrane filaments, a second strand of hollow fiber membrane filaments and a third strand of hollow fiber membrane filaments; the first strand of hollow fiber membrane yarn, the second strand of hollow fiber membrane yarn and the third strand of hollow fiber membrane yarn are woven in a staggered mode to form a braid-shaped structure till the tail ends of the hollow fiber membrane yarn are woven, and a hollow fiber membrane yarn bundle is formed; fixing the two ends of the obtained multiple strands of hollow fiber membrane tows, combining into a whole row, and packaging the whole row of hollow fiber membrane tows into a membrane. According to the efficient and energy-saving type bubble-free aeration membrane assembly, the weaving mode is adopted, the filling density is higher, the specific surface area is larger, and the occupied area can be saved; the gas-liquid contact area can be effectively increased, and the gas consumption of a sewage treatment system is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of sewage purification and treatment, in particular to a weaving method of a high-efficiency and energy-saving bubble-free aeration membrane. Background Art

[0002] Aeration is a method of bringing air and water into strong contact, with the purpose of dissolving oxygen in the air into the water, or expelling unwanted gases and volatile substances in the water into the air. In the aerobic biological treatment of wastewater, effective air-water contact must be generated and maintained, and sufficient dissolved oxygen should be maintained in the water as oxygen is continuously consumed by biological oxidation. Aeration equipment is widely used in sewage treatment for this purpose. Currently, small-aperture aeration or blast aeration is commonly used, and the oxygen utilization rate is low.

[0003] Bubbleless aeration is a technology widely used in fields such as sewage treatment and aquaculture. Its main purpose is to provide sufficient dissolved oxygen into the water. Bubbleless aeration technology uses special hollow fiber membranes or other breathable and hydrophobic membranes to transfer oxygen directly into the water without producing visible bubbles. This aeration method has the advantages of high oxygen transfer efficiency, low energy consumption, and reduced volatile organic compound emissions.

[0004] The hollow fiber membrane used in bubble-free aeration is relatively thin, generally between 0.5-0.9mm. In order to increase the surface area of ​​the membrane assembly, enhance oxygen mass transfer, and improve the stability of the biofilm, the hollow fiber membrane usually needs to be woven before use. At present, the commonly used multi-layer weaving method is that each layer is woven into a sheet by multiple hollow fiber membranes, and then encapsulated in a membrane shell for use. The above weaving method has a high manufacturing cost and is more complicated to weave, which may cause uneven oxygen distribution during use. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a weaving method for an efficient and energy-saving bubble-free aeration membrane. The technical solution includes making a membrane assembly by cross-weaving three hollow fiber membrane filaments, which can enhance the strength of the hollow fiber membrane filaments while increasing the contact area between the polymer membrane and the microorganisms. Compared with the conventional weaving method, it saves about 30% of gas and improves the biodegradation rate. The membrane assembly prepared by the present invention has a simple structure, is easy to maintain, and has more uniform aeration.

[0006] The present invention provides a method for weaving a high-efficiency and energy-saving bubble-free aeration membrane, comprising the following steps:

[0007] (1) providing hollow fiber membranes and dividing them into three strands, namely, a first strand of hollow fiber membranes, a second strand of hollow fiber membranes, and a third strand of hollow fiber membranes;

[0008] (2) interlacing and braiding the first strand of hollow fiber membrane filaments, the second strand of hollow fiber membrane filaments and the third strand of hollow fiber membrane filaments to form a braided structure until the ends of the hollow fiber membrane filaments are braided to form a hollow fiber membrane bundle;

[0009] (3) After fixing both ends of the multiple strands of hollow fiber membrane bundles obtained in step (2), the strands are combined into a whole row, and then the whole row of hollow fiber membrane bundles is packaged into membranes.

[0010] Wherein, in the step (1), the number of hollow fiber membrane fibers contained in each share is the same, and the number of hollow fiber membrane fibers contained in each share can be adjusted according to actual needs and performance parameters of the hollow fiber membrane fibers.

[0011] Wherein, in the step (1), each hollow fiber membrane fiber contains at least one hollow fiber membrane fiber.

[0012] Wherein, in the step (1), the hollow fiber membrane is a hydrophobic polyolefin membrane.

[0013] Wherein, in the step (1), the outer diameter of the hollow fiber membrane is 0.1 to 0.9 mm.

[0014] Among them, in step (2), the step of interlacing and weaving to form a braided structure:

[0015] S1: select three straw ropes, namely the first strand of hollow fiber membrane yarn, the second strand of hollow fiber membrane yarn and the third strand of hollow fiber membrane yarn;

[0016] S2: Perform the first winding, with the first strand of hollow fiber membrane as the middle rope body, the second strand of hollow fiber membrane and the third strand of hollow fiber membrane respectively located on both sides of the first strand of hollow fiber membrane, the second strand of hollow fiber membrane passes through the surface of the first strand of hollow fiber membrane, and the second strand of hollow fiber membrane and the first strand of hollow fiber membrane have an overlapping portion, the third strand of hollow fiber membrane passes through the surface of the second strand of hollow fiber membrane, the third strand of hollow fiber membrane is located between the first strand of hollow fiber membrane and the second strand of hollow fiber membrane, and the third strand of hollow fiber membrane and the second strand of hollow fiber membrane have an overlapping portion;

[0017] S3: performing secondary winding, in which the third strand of hollow fiber membrane is used as the middle rope body, the first strand of hollow fiber membrane and the second strand of hollow fiber membrane are respectively located on both sides of the third strand of hollow fiber membrane, the first strand of hollow fiber membrane passes through the surface of the third strand of hollow fiber membrane, and the first strand of hollow fiber membrane and the third strand of hollow fiber membrane have an overlapping portion, the second strand of hollow fiber membrane passes through the surface of the first strand of hollow fiber membrane, the second strand of hollow fiber membrane is located between the first strand of hollow fiber membrane and the third strand of hollow fiber membrane, and the second strand of hollow fiber membrane overlaps the first strand of hollow fiber membrane;

[0018] S4: performing a third winding, at which time the second strand of hollow fiber membrane yarn is used as the middle rope body, the third strand of hollow fiber membrane yarn and the first strand of hollow fiber membrane yarn are respectively located on both sides of the second strand of hollow fiber membrane yarn, the third strand of hollow fiber membrane yarn passes through the surface of the second strand of hollow fiber membrane yarn, and the third strand of hollow fiber membrane yarn and the second strand of hollow fiber membrane yarn have an overlapping portion, the first strand of hollow fiber membrane yarn passes through the surface of the third strand of hollow fiber membrane yarn, the first strand of hollow fiber membrane yarn is located between the second strand of hollow fiber membrane yarn and the third strand of hollow fiber membrane yarn, and the first strand of hollow fiber membrane yarn and the third strand of hollow fiber membrane yarn have an overlapping portion;

[0019] S5: The second step, the third step and the fourth step performed in sequence are regarded as one cycle, and repeated for several cycles.

[0020] Among them, in the step (2), the step of interlacing and weaving to form a braided structure is as follows: the left strand of hollow fiber membrane is placed on the middle strand of hollow fiber membrane, and then the right strand of hollow fiber membrane is placed on the new middle strand of hollow fiber membrane, and then the new left strand of hollow fiber membrane is placed on the new middle strand of hollow fiber membrane. Continue weaving according to the above steps.

[0021] Wherein, in step (2), when weaving to the end of the hollow fiber membrane filament, the end of the hollow fiber membrane filament is fixed with a rope or glue to prevent the woven hollow fiber membrane filament from unraveling.

[0022] By adopting the above weaving method, a high-efficiency and energy-saving bubble-free aeration membrane component is prepared, comprising: a membrane shell and a membrane sheet, wherein the membrane shell comprises an upper membrane shell and a lower membrane shell, the upper membrane shell is provided with an air inlet, the air inlet is connected to the air inlet pipe, and is used to provide the membrane component with the gas required for aeration, and the number of the membrane shell air outlets is 0 to 3; the lower membrane shell is provided with an air outlet, the air outlet is connected to the exhaust pipe, and is used to remove the excess gas in the membrane wire; the membrane sheet is the high-efficiency and energy-saving bubble-free aeration membrane; the two ends of the membrane sheet are respectively encapsulated in the upper membrane shell and the lower membrane shell, and the two ports of the hollow fiber membrane wire are connected with the membrane shell cavity to ensure that the gas is input into the membrane wire through the upper membrane shell, and the excess gas in the membrane wire is discharged through the lower membrane shell, and the membrane sheet can be arranged in a single row or multiple rows; the number of the air inlets is ≥1;

[0023] The above technical solution of the present invention has the following advantages compared with the prior art:

[0024] The present invention adopts the cross-weaving method of hollow fiber membrane filaments to prepare the high-efficiency and energy-saving bubble-free aeration membrane, which has the following advantages: first, the packing density is higher and the specific surface area of ​​the membrane assembly is larger, which can save floor space and enhance the contact area between the hollow fiber membrane filaments and microorganisms, promote the growth of biofilm on the surface of the braided membrane tube, improve the pollutant degradation efficiency, and further save the aeration volume; second, it is convenient to maintain and the aeration is more uniform. After a single membrane filament is damaged, the overall equipment will not fail, and the service life of the equipment can be effectively extended; third, the number of overlapping parts of the membrane filaments is increased, which increases the aeration resistance of the membrane filaments and reduces the rate of bubble aeration. Compared with the conventional weaving method, the aeration volume is further saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is a schematic diagram of the membrane assembly of the present invention.

[0027] Figure 2 It is a braided hollow fiber membrane yarn described in the present invention.

[0028] In the figure, 1, diaphragm; 2, membrane shell; 3, rubber casting shell. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0030] Comparative Example 1

[0031] This embodiment provides a conventional bubble-free aeration membrane assembly, which is as follows:

[0032] S1 fiber arrangement: 1000 polypropylene hollow fiber membranes (outer diameter 0.4mm, inner diameter 0.2mm) are formed into membrane fiber bundles in a natural vertical manner; a total of 3 bundles are made, with a total of 3000 membrane fibers;

[0033] S2 fixation: tie the two ends of the three bundles of hollow fiber membranes with ropes, leaving 5 cm at the end of the membranes to prevent the membranes from spreading;

[0034] S3 packaging: Insert both ends of the membrane wire into the glue casting box, pour in epoxy resin potting glue, and after the glue solidifies, cut and install the components into membrane components.

[0035] Example 1

[0036] This embodiment provides a weaving method for an energy-efficient and bubble-free aeration membrane, comprising:

[0037] S1: 3000 polypropylene hollow fiber membrane yarns (outer diameter 0.4 mm, inner diameter 0.2 mm) are divided into 3000 strands, each strand contains 1 hollow fiber membrane yarn, and every three strands are woven;

[0038] S2 starts weaving: put the left strand of hollow fiber membrane on top of the middle strand of hollow fiber membrane, then put the right strand of hollow fiber membrane on top of the new middle strand of hollow fiber membrane, then put the new left strand of hollow fiber membrane on top of the new middle strand of hollow fiber membrane. Continue weaving according to the above steps until you reach the end of the hollow fiber membrane.

[0039] S3 fixation: When the hollow fiber membrane is woven to the end, use a rope to tie the end of the hollow fiber membrane to fix it, leaving 5 cm at the end of the membrane to prevent the woven hollow fiber membrane from spreading. In this way, a total of 1,000 membranes are woven, and then the woven membranes are divided into three bundles, such as Figure 1 shown.

[0040] S4 filament formation: Put three bundles of hollow fiber membrane filaments with both ends fixed into the glue casting box, pour in epoxy resin glue, and after the glue solidifies, cut and install the components into membrane components.

[0041] Example 2

[0042] This embodiment provides a weaving method for an energy-efficient and bubble-free aeration membrane, comprising:

[0043] S1: 3000 hollow fiber membranes are divided into 300 strands, each strand contains 10 hollow fiber membranes, and every three strands are woven;

[0044] S2 starts weaving: put the left strand of hollow fiber membrane on top of the middle strand of hollow fiber membrane, then put the right strand of hollow fiber membrane on top of the new middle strand of hollow fiber membrane, then put the new left strand of hollow fiber membrane on top of the new middle strand of hollow fiber membrane. Continue weaving according to the above steps until you reach the end of the hollow fiber membrane.

[0045] S3 fixation: When weaving to the end of the hollow fiber membrane, use a rope to tie and fix the end of the hollow fiber membrane, leaving 5cm at the end of the membrane to prevent the woven hollow fiber membrane from spreading.

[0046] S4 filament formation: Put three bundles of hollow fiber membrane filaments with both ends fixed into the glue casting box, pour in epoxy resin glue, and after the glue solidifies, cut and install the components into membrane components.

[0047] Furthermore, the hollow fiber membrane has an outer diameter of 0.4 mm and an inner diameter of 0.2 mm.

[0048] The high-efficiency and energy-saving bubble-free aeration membrane assembly prepared in the above embodiment is used as follows:

[0049] A high-efficiency and energy-saving bubble-free aeration membrane module, such as Figure 2 As shown, it includes a membrane shell 2 and a membrane sheet 1, and the membrane shell includes an upper membrane shell and a lower membrane shell. The upper membrane shell is provided with an air inlet, and the air inlet is connected to the air inlet pipe for providing the membrane assembly with the gas required for aeration; the lower membrane shell is provided with an air outlet, and the exhaust port is connected to the exhaust pipe for removing excess gas in the membrane filaments, and the lower membrane shell is provided with two air outlets; the membrane sheet is made of a number of hollow fiber membrane bundles woven by the above-mentioned high-efficiency and energy-saving bubble-free aeration membrane weaving method, which are neatly arranged in parallel single sheets, and the two ends of the hollow fiber membrane bundles are respectively sealed in a rubber casting shell by sealant, and the membrane bundle is composed of three hollow fiber membrane filaments cross-woven; the two ends of the membrane sheet are respectively encapsulated in the upper and lower membrane shells, and the two ports of the hollow fiber membrane filaments are connected with the membrane shell cavity to ensure that the gas can be input into the membrane filaments through the upper membrane shell, and the excess gas inside the membrane filaments is discharged through the lower membrane shell. Under a certain pressure, different gases (hydrogen, oxygen or other gases, the specific gases that hollow fiber membranes selectively permeate are determined by the material and properties of the membranes) can be passed from the inside of the membranes through the membrane wall to the outside of the membranes, where they react with the biofilm, and each three strands are woven together to reduce the COD / NH in the sewage. 3 -N.

[0050] Application cases and data detection

[0051] The membrane components prepared in Example 1, Example 2 and Comparative Example 1 were placed vertically in three water tanks of the same size, and a blank control group was set up at the same time. No components were installed in the blank control group. All water tanks were provided with overflow ports and circulation pumps. The flow rate of the circulation pump was 50 ml / min to ensure that the wastewater was in a circulating state. At the same time, 50 L of water samples were taken at the same time and at the same place. The water samples were sewage in a conventional aerobic biochemical pool. 50 L of water samples were poured into each water tank. The upper end of the membrane component was used for air intake and the lower end for air outlet. The gas introduced was pure oxygen. The pressure of the component was maintained at a constant 50 kpa. After one week of stable operation, the COD and ammonia nitrogen contents in the water were detected. The results are shown in Table 1 below.

[0052] Table 1

[0053]

[0054] It can be seen from the experimental data in Table 1 that the COD removal efficiency of the bubble-free aeration using the weaving method of the present invention reaches more than 51%, and the ammonia nitrogen removal efficiency reaches 87.2%, which are significantly higher than those of comparative example 1 and the blank control group.

[0055] The high-efficiency and energy-saving bubble-free aeration membrane assembly prepared by the present invention can be used for sewage treatment in various scenarios, and according to the water quality, the number of hollow fiber membrane filaments per strand can be flexibly selected to prepare woven hollow fiber membranes of different thicknesses and different surface roughness. The high-efficiency and energy-saving bubble-free aeration membrane assembly prepared by the present invention adopts a weaving method, has a higher packing density, a larger specific surface area, and can save floor space; at the same time, compared with the conventional membrane aeration method, the bubble-free aeration membrane assembly prepared by the present invention can effectively increase the gas-liquid contact area, provide a good growth area for the biofilm, increase the resistance of the gas passage in the membrane filament, and reduce the gas consumption of the sewage treatment system.

[0056] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A weaving method for an energy-efficient and bubble-free aeration membrane, characterized in that: The following steps are involved: (1) dividing the hollow fiber membrane into three strands, namely, a first strand of hollow fiber membrane, a second strand of hollow fiber membrane and a third strand of hollow fiber membrane; (2) interlacing and braiding the first strand of hollow fiber membrane filaments, the second strand of hollow fiber membrane filaments and the third strand of hollow fiber membrane filaments to form a braided structure until the ends of the hollow fiber membrane filaments are braided to form a hollow fiber membrane bundle; (3) After fixing both ends of the multiple strands of hollow fiber membrane bundles obtained in step (2), the strands are combined into a whole row, and then the whole row of hollow fiber membrane bundles is packaged into membranes.

2. The weaving method according to claim 1, characterized in that: In the step (1), each strand contains the same number of hollow fiber membrane fibers.

3. The weaving method according to claim 1, characterized in that: In the step (1), each hollow fiber membrane fiber contains at least one hollow fiber membrane fiber.

4. The weaving method according to claim 1, characterized in that: In the step (1), the hollow fiber membrane is a hydrophobic polyolefin membrane.

5. The weaving method according to claim 1, characterized in that: In the step (1), the outer diameter of the hollow fiber membrane is 0.1 to 0.9 mm.

6. The weaving method according to claim 1, characterized in that: In the step (3), when the hollow fiber membrane is woven to the end, the end of the hollow fiber membrane is fixed with a rope or glue to prevent the woven hollow fiber membrane from unraveling.

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