A membrane filtration device

Abstract

The present invention discloses a membrane filtration device, comprising a sealed tank, a water inlet provided on the sealed tank, a first water outlet and a concentrated water outlet, a water inlet pump connected to the water inlet, a water outlet pump connected to the first water outlet, and an immersed curtain membrane assembly provided in the sealed tank; the immersed curtain membrane assembly comprises a membrane bundle, an upper membrane tube, a lower membrane tube, an upper mounting bracket, a lower mounting bracket, a second water outlet provided on the upper membrane tube and / or the lower membrane tube, and a water collector respectively connected to the first water outlet and the second water outlet; the upper mounting bracket and the lower mounting bracket are both fixedly connected to the sealed tank; at least one of the upper membrane tube and the lower membrane tube is a movable membrane tube, which is movably connected to the corresponding mounting bracket, and a limiter is provided on the movable membrane tube to prevent the two from completely separating, and the limiter is located on the side of the corresponding mounting bracket away from the membrane bundle. The membrane filtration device of the present invention has a high membrane flux, can prevent debris from accumulating at the end of the membrane curtain, and has good system operation stability.

Description

Technical Field

[0001] The invention relates to a membrane filtration device. Background Art

[0002] Hollow fiber membranes generally adopt two structures: curtain membrane and column membrane.

[0003] Curtain membranes are typically constructed as submerged membrane cassettes placed within a membrane tank. The filtration process relies on the suction force of the water production pump to create a transmembrane pressure differential. Because the membrane filtration system is open, this structure struggles to achieve high pressure differentials, resulting in low membrane flux. Furthermore, in-situ restorative chemical cleaning within the membrane tank is difficult to achieve.

[0004] Column membranes are generally made into membrane columns with cast ends and installed side by side on the membrane frame; the filtration area of ​​a single membrane column used in large-scale water treatment equipment is generally 50-75m 2 The filtration pressure is generally around 1 bar. Column membrane filtration systems are closed systems. Their disadvantages include a small filtration area per column and low membrane filament loading efficiency. The closed structure, cast at both ends, makes it difficult to thoroughly clean the hollow fiber membranes and is prone to clogging with debris at the base of the membranes. Summary of the Invention

[0005] The purpose of the present invention is to provide a membrane filtration device that can have a higher filtration pressure and a higher membrane flux; can avoid the accumulation of debris at the end of the membrane curtain, is easier to clean, and has better stability in system operation.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A membrane filtration device comprises a sealed tank, a water inlet, a first water outlet and a concentrate outlet provided on the sealed tank, a water inlet pump connected to the water inlet, a water outlet pump connected to the first water outlet, and a submerged curtain membrane assembly provided in the sealed tank;

[0008] The submerged curtain membrane module includes a membrane bundle, an upper membrane tube for fixedly connecting the upper end of the membrane bundle, a lower membrane tube for fixedly connecting the lower end of the membrane bundle, an upper mounting bracket for mounting the upper membrane tube, a lower mounting bracket for mounting the lower membrane tube, a second water outlet opened on the upper membrane tube and / or the lower membrane tube, and a water collector respectively connected to the first water outlet and the second water outlet;

[0009] The upper mounting bracket and the lower mounting bracket are both fixedly connected in the sealed tank;

[0010] At least one of the upper membrane tube and the lower membrane tube is a movable membrane tube, which is movably connected to the corresponding mounting bracket. The movable membrane tube is provided with a limiting member for preventing the two from completely separating, and the limiting member is located on the side of the corresponding mounting bracket away from the membrane bundle.

[0011] Preferably, when the upper membrane tube is a movable membrane tube, the upper mounting bracket includes an upper through hole through which the upper membrane tube can pass upward, and the limiting member is an upper limiting ring arranged on the upper outer side of the upper membrane tube and used to prevent the upper membrane tube from completely passing through the upper through hole downward.

[0012] Preferably, when the lower membrane tube is a movable membrane tube, the lower mounting bracket includes a lower through hole through which the lower membrane tube can pass downward, and the limiting member is a lower limiting ring arranged on the lower outer side of the lower membrane tube and used to prevent the lower membrane tube from completely passing through the lower through hole upward.

[0013] Preferably, the sealed can comprises a conical bottom that gradually contracts in a downward direction, and a drain outlet opened at the bottom end of the conical bottom.

[0014] Preferably, the device further comprises an aeration port opened at the lower end of the sealed tank and an exhaust port opened at the upper end of the sealed tank.

[0015] Preferably, the device further comprises a water inlet tank connected to the water inlet, and the water inlet pump is connected between the water inlet tank and the sealing tank.

[0016] Preferably, the device further comprises a water production tank communicated with the first water production port, and the water production pump is communicated between the water production tank and the sealing tank.

[0017] More preferably, the device further comprises a backwash pipeline connected between the water production tank and the first water production port, and a backwash pump connected to the backwash pipeline.

[0018] Preferably, the membrane bundle is a homogeneous hollow fiber membrane, or a lining-reinforced hollow fiber membrane, or an alloy hollow fiber membrane, or a porous hollow fiber membrane.

[0019] Preferably, the membrane bundle is an ultrafiltration membrane, a microfiltration membrane, a nanofiltration membrane, or a reverse osmosis membrane.

[0020] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: a membrane filtration device of the present invention, by providing a sealing tank, a water inlet pump connected to the water inlet of the sealing tank, and a water production pump connected to the water production outlet of the sealing tank, enables the system to have a higher filtration pressure and a higher membrane flux; at least one end of the membrane bundle is movably arranged in the corresponding mounting bracket, and during the filtration and aeration process, the membrane bundle can keep floating up and down, so that the debris in the membrane pool cannot accumulate at the end of the membrane curtain, which can ensure the long-term stable operation of the system; at the same time, it also reduces the aeration volume during aeration, thereby reducing the operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attachment Figure 1 It is a structural schematic diagram of the device of the present invention;

[0022] Attachment Figure 2 It is a structural diagram of the sealed tank;

[0023] Attachment Figure 3 Schematic diagram of the installation structure of the membrane bundle, upper membrane tube and lower membrane tube.

[0024] Among them: 1. Sealing tank; 2. Water inlet; 3. First water outlet; 4. Concentrate outlet; 5. Water inlet pump; 6. Water production pump; 7. Membrane fiber bundle; 8. Upper membrane tube; 9. Lower membrane tube; 10. Upper mounting bracket; 11. Lower mounting bracket; 12. Second water outlet; 13. Water collector; 14. Limiting piece; 15. Sleeve; 16. Conical bottom; 17. Drain outlet; 18. Aeration outlet; 19. Exhaust outlet; 20. Water inlet tank; 21. Water production tank; 22. Backwash pipeline; 23. Backwash pump. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0026] See also Figure 1-3 As shown, the membrane filtration device comprises a sealed tank 1, a water inlet 2, a first water outlet 3, and a concentrate outlet 4 provided on the sealed tank 1, a water inlet pump 5 connected to the water inlet 2, a water production pump 6 connected to the first water production outlet 3, and a submerged curtain membrane assembly disposed in the sealed tank 1. The water inlet pump 5 and the water production pump 6 are both disposed outside the sealed tank 1.

[0027] In this embodiment, the membrane filtration device further includes a water inlet tank 20 connected to the water inlet 2 and a water production tank 21 connected to the first water production port 3. A water inlet pump 5 is connected between the water inlet tank 20 and the sealed tank 1, and a water production pump 6 is connected between the water production tank 21 and the sealed tank 1.

[0028] This arrangement creates a positive pressure outside the submerged curtain membrane module when the inlet pump 5 is operating, while a vacuum suction force is created inside the module when the product water pump 6 is operating. During normal operation, when at least one of the inlet pump 5 or product water pump 6 is powered on, a large transmembrane pressure differential is achieved, enabling the system to achieve higher filtration pressures and membrane flux.

[0029] The membrane filtration device further includes a backwash line 22 connected between the water production tank 21 and the first water production port 3, and a backwash pump 23 connected to the backwash line 22. During normal operation, the backwash pump 23 is turned off, and the water produced by the sealed tank 1 is pumped into the water production tank 21 by the water production pump 6. When the submerged curtain membrane assembly in the sealed tank 1 needs to be cleaned, the water production pump 6 is turned off, and the backwash pump 23 pumps the water produced in the water production tank 21 into the sealed tank 1 to perform reverse cleaning on the submerged curtain membrane assembly therein.

[0030] See also Figure 2-3 As shown, the submerged curtain membrane module comprises a membrane bundle 7, an upper membrane tube 8 for fixedly connecting the upper end of the membrane bundle 7, a lower membrane tube 9 for fixedly connecting the lower end of the membrane bundle 7, an upper mounting bracket 10 for mounting the upper membrane tube 8, a lower mounting bracket 11 for mounting the lower membrane tube 9, a second water outlet 12 provided on the upper membrane tube 8 and / or the lower membrane tube 9, and a water collector 13 connected to the first water outlet 3 and the second water outlet 12, respectively. In this embodiment, the second water outlet 12 is provided at the top of the upper membrane tube 8, while the lower membrane tube 9 is enclosed.

[0031] In this embodiment, membrane bundle 7 is formed by a plurality of hollow fiber membranes, the upper end of which is cast in upper membrane tube 8, and the lower end of which is cast in lower membrane tube 9. Upper and lower mounting brackets 10 and 11 are both fixedly attached to sealed tank 1, with multiple evenly spaced and parallel membrane bundles 7 positioned between them. Water collector 13 is fixedly mounted above upper mounting bracket 10.

[0032] At least one of the upper membrane tube 8 and the lower membrane tube 9 is a movable membrane tube. The movable membrane tube is movably connected to the corresponding mounting bracket and is provided with a stopper 14 to prevent the two from completely separating. The stopper 14 is located on the side of the corresponding mounting bracket away from the membrane bundle 7.

[0033] In embodiment 1, the upper membrane tube 8 is a movable membrane tube, and the lower membrane tube 9 is fixedly mounted on the lower mounting bracket 11 .

[0034] In Example 2, the lower membrane tube 9 is a movable membrane tube, and the upper membrane tube 8 is fixedly arranged on the upper mounting bracket 10 .

[0035] In this embodiment, the upper membrane tube 8 and the lower membrane tube 9 are both movable membrane tubes.

[0036] The upper mounting bracket 10 includes an upper through-hole through which the upper membrane tube 8 passes upward. The stopper 14 is an upper stop ring disposed on the upper portion of the outer side of the upper membrane tube 8 and prevents the upper membrane tube 8 from completely passing through the upper through-hole. The diameter of the upper membrane tube 8 is smaller than the diameter of the upper through-hole, while the outer diameter of the upper stop ring is larger than the diameter of the upper through-hole. In this embodiment, the cross-sections of the upper membrane tube 8, the upper through-hole, and the upper stop ring are all square, with the side lengths of the squares being proportional to their diameters.

[0037] By this arrangement, it is possible to ensure that the upper film tube 8 floats up and down in the upper through hole and does not separate from the upper mounting bracket 10. The upper film tube 8 also has radial displacement during the up and down floating process, further avoiding the accumulation of debris.

[0038] See also Figure 3 As shown, the upper portion of the upper membrane tube 8 is fitted with a sleeve 15 , the second water outlet 12 is located at the top of the sleeve 15 , and the upper limit ring is located at the bottom of the sleeve 15 .

[0039] When the membrane bundle 7 is stretched upward, the bottom end height of the upper membrane tube 8 is lower than or equal to the bottom surface height of the upper mounting bracket 10. This arrangement can prevent the inner wall of the upper through hole from scratching the membrane bundle 7.

[0040] The lower mounting bracket 11 includes a lower through-hole through which the lower membrane tube 9 passes downward. The stopper 14 is a lower stop ring disposed on the lower outer portion of the lower membrane tube 9 to prevent the lower membrane tube 9 from completely passing upward through the lower through-hole. The diameter of the lower membrane tube 9 is smaller than that of the lower through-hole, while the outer diameter of the lower stop ring is larger than that of the lower through-hole. In this embodiment, the cross-sections of the lower membrane tube 9, the lower through-hole, and the lower stop ring are all oriented in a positive direction, and the ratio of the side lengths of the square is the same as the ratio of the diameters.

[0041] Through this arrangement, it is possible to ensure that the lower film tube 9 floats up and down in the lower through hole without being separated from the lower mounting bracket 11. The lower film tube 9 also has radial displacement during the up and down floating process, further avoiding the accumulation of debris.

[0042] See also Figure 3 As shown, the bottom end of the lower film tube 9 is closed, and the lower limiting ring protrudes from the side of the bottom end of the lower film tube 9.

[0043] When the membrane bundle 7 is tensioned downward, the top height of the lower membrane tube 9 is higher than or equal to the top surface height of the lower mounting bracket 11. Through this arrangement, the inner wall of the lower through hole can be prevented from scratching the membrane bundle 7.

[0044] In this embodiment, the distance between the upper limit ring and the lower limit member 14 is 30-200 mm greater than the distance between the upper mounting bracket 10 and the lower mounting bracket 11 to ensure that the upper membrane tube 8 and the lower membrane tube 9 have a free travel of 30-200 mm at the same time.

[0045] This arrangement allows the membrane bundle 7 to float up and down and left and right during the filtration and aeration process, preventing debris from the sealed tank 1 from accumulating at the ends of the membrane curtain. This ensures long-term stable operation of the system, requiring only regular air-water washing and online cleaning. Furthermore, since debris is prevented from accumulating at the ends of the membrane curtain, the aeration volume can be reduced, lowering operating costs. During operation, the aeration volume is only 60-70% of that of conventional membrane curtains, reducing operating costs by 25-30%.

[0046] The sealed tank 1 includes a tapered bottom 16 that tapers downward and a drain port 17 at the bottom of the tapered bottom 16. This arrangement ensures that all wastewater in the sealed tank 1 is completely drained, thereby enabling thorough in-situ restorative chemical cleaning of the submerged curtain membrane module.

[0047] The membrane filtration device further comprises an aeration port 18 provided at the lower end of the sealed tank 1 and an exhaust port 19 provided at the upper end of the sealed tank 1 .

[0048] The membrane filtration device further includes a first pressure gauge mounted on the sealed tank 1, a second pressure gauge mounted on the water inlet pipeline (the pipeline connecting the water inlet tank 20 and the sealed tank 1), and a third pressure gauge mounted on the produced water pipeline (the pipeline connecting the produced water tank 21 and the sealed tank 1, distinct from the backwash pipeline 22). The pressure gauges enable real-time monitoring of the pressure in the corresponding pipelines.

[0049] The membrane bundle 7 is a homogeneous hollow fiber membrane, a liner-reinforced hollow fiber membrane, an alloy hollow fiber membrane, or a porous hollow fiber membrane.

[0050] The membrane bundle 7 is an ultrafiltration membrane, a microfiltration membrane, a nanofiltration membrane, or a reverse osmosis membrane.

[0051] The medium filtered by the above-mentioned membrane filtration device can be sewage, surface water, groundwater, process water, seawater, brackish water, chemical fluid, biomass fluid, or beverage.

[0052] In the submerged curtain membrane module, the packing area of ​​the membrane bundle 7 is 100-10000m 2 between.

[0053] In the above membrane filtration device, the number of sealed tanks 1 can be configured as needed, preferably between 1 and 200.

[0054] The membrane filtration device of the present invention has the following advantages:

[0055] Highly intensive, saving space and floor space: Compared with traditional open hollow fiber curtain membrane equipment, closed hollow fiber curtain membrane filtration equipment has a high membrane fiber packing density, improved membrane flux, high equipment efficiency, and can save up to 50% of floor space; compared with traditional column ultrafiltration membrane rack equipment, closed hollow fiber curtain ultrafiltration membrane filtration equipment can save up to 30% of floor space;

[0056] Saving investment: In sewage treatment plant upgrading and reconstruction projects, existing aerobic tanks can be used as high-concentration activated sludge aerobic tanks, or secondary sedimentation tanks can be converted into high-concentration activated sludge aerobic tanks, eliminating the need for new membrane tanks. The use of the external closed membrane filtration equipment of the present invention significantly reduces the need for additional air volume, thereby significantly saving investment in upgrading projects and shortening the construction period of upgrading and reconstruction projects.

[0057] Reduce operating costs: Compared with traditional structures, closed hollow fiber curtain membrane filtration equipment can save aeration volume; it is easier to achieve full automatic operation mode, which can significantly save labor costs;

[0058] Improve the membrane's ability to resist fouling and clogging, and extend the service life of the membrane fibers: Closed hollow fiber curtain membrane filtration equipment can achieve thorough in-situ restorative chemical cleaning, improve the membrane's ability to resist fouling and clogging, and extend the service life of the membrane fibers.

[0059] Example 1: Domestic sewage treatment in a certain village, a closed hollow fiber curtain membrane filtration device is used in conjunction with an A2O integrated device at the front end; a single sealed tank 1 is filled with 497 square meters of membrane fibers, and each device has five sealed tanks 1, operating in fully automatic mode. One device can treat 1000m3 of rural domestic sewage per day. 3 / sky.

[0060] Example 2: A municipal wastewater treatment plant used an external MBR process to upgrade the existing A2O process for deep treatment. The existing secondary sedimentation tank was converted into a high-concentration sludge aerobic tank. The A2O biochemical effluent and secondary sedimentation tank wastewater were filtered and concentrated using an external MBR sealed tank 1. The filtered water passing through the MBR membrane was the treated water that met the standards. A total of eight closed hollow fiber curtain membrane filtration units were used; each sealed tank 1 was filled with 2121 square meters of membrane fibers, and each unit had six sealed tanks 1. The eight units were operated in a seven-in-one standby mode, with a daily water production of 30,000 m3. 3 / sky.

[0061] Example 3: A surface water treatment project at a paper mill uses three closed-loop ultrafiltration hollow fiber curtain membrane filtration devices. The treated water is used as production water for the factory. Each sealed tank 1 is filled with 2,121 square meters of membrane fibers, and each device has a total of six sealed tanks 1. The three devices are operated in a two-in-one standby mode, and the daily water production of the two devices is 20,000 m 3 / sky.

[0062] Example 4: A water reuse project in a printing and dyeing factory uses three closed ultrafiltration hollow fiber curtain membrane filtration equipment as the pre-treatment of RO; a single sealed tank 1 is filled with 1060 square meters of membrane fibers, and each equipment has a total of six sealed tanks 1; the three equipment adopts a two-in-one standby operation mode, and the daily water production of the two equipments is 10,000m 3 / sky.

[0063] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A membrane filtration device, characterized in that: It includes a sealed tank, a water inlet, a first water outlet and a concentrated water outlet opened on the sealed tank, a water inlet pump connected to the water inlet, a water production pump connected to the first water outlet, and an immersed curtain membrane assembly arranged in the sealed tank; The submerged curtain membrane module includes a membrane bundle, an upper membrane tube for fixedly connecting the upper end of the membrane bundle, a lower membrane tube for fixedly connecting the lower end of the membrane bundle, an upper mounting bracket for mounting the upper membrane tube, a lower mounting bracket for mounting the lower membrane tube, second water outlets opened on the upper membrane tube and the lower membrane tube, and a water collector respectively connected to the first water outlet and the second water outlet; The upper mounting bracket and the lower mounting bracket are both fixedly connected in the sealed tank; At least one of the upper membrane tube and the lower membrane tube is a movable membrane tube, and the movable membrane tube is movably connected to the corresponding mounting bracket. The movable membrane tube is provided with a limiting member for preventing the two from being completely separated, and the limiting member is located on a side of the corresponding mounting bracket away from the membrane bundle; When the upper membrane tube is a movable membrane tube, the upper mounting bracket includes an upper through hole through which the upper membrane tube can pass upward, and the limiting member is an upper limit ring provided on the upper outer portion of the upper membrane tube and used to prevent the upper membrane tube from completely passing downward through the upper through hole; When the lower membrane tube is a movable membrane tube, the lower mounting bracket includes a lower through hole through which the lower membrane tube can pass downward, and the limiting member is a lower limiting ring arranged on the lower outer portion of the lower membrane tube and used to prevent the lower membrane tube from completely passing through the lower through hole upward; During the filtration and aeration process, the membrane bundle can keep floating up and down; the upper membrane tube also has radial displacement during the floating process; the lower membrane tube also has radial displacement during the floating process.

2. A membrane filtration device according to claim 1, characterized in that: The sealed tank comprises a conical bottom which gradually contracts in a downward direction and a drain outlet which is opened at the bottom end of the conical bottom.

3. A membrane filtration device according to claim 1, characterized in that: The device further comprises an aeration port opened at the lower end of the sealed tank and an exhaust port opened at the upper end of the sealed tank.

4. A membrane filtration device according to claim 1, characterized in that: The device further comprises a water inlet tank communicated with the water inlet, and the water inlet pump is communicated between the water inlet tank and the sealing tank.

5. A membrane filtration device according to claim 1, characterized in that: The device further includes a water production tank communicated with the first water production port, and the water production pump is communicated between the water production tank and the sealing tank.

6. A membrane filtration device according to claim 5, characterized in that: The device further comprises a backwash pipeline connected between the water production tank and the first water production port, and a backwash pump connected to the backwash pipeline.

7. A membrane filtration device according to claim 1, characterized in that: The membrane bundle is a homogeneous hollow fiber membrane, or a lining-reinforced hollow fiber membrane, or an alloy hollow fiber membrane, or a porous hollow fiber membrane.

8. A membrane filtration device according to claim 1, characterized in that: The membrane bundle is an ultrafiltration membrane, a microfiltration membrane, a nanofiltration membrane, or a reverse osmosis membrane.

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