A large-scale membrane seawater desalination pretreatment process system

Abstract

The utility model discloses a large -scale membrane method seawater desalination pretreatment process system, including the filter pool of air flotation, intermediate water pool and macromolecular micropore filter material filter that set gradually, the filter pool of air flotation includes filter pool of air flotation body, is provided with filter material layer in the middle part of filter pool of air flotation body, in the filter material layer below, forms the filter area in the filter material layer above in filter pool of air flotation body, forms the area after filtering, the area after filtering is connected with intermediate water pool through intermediate water delivery pipe, and intermediate water pool and macromolecular micropore filter material filter are connected through intermediate water output pipe. The utility model greatly reduces the land area of conventional process, and the investment operating cost is reduced, and seawater removes algae, oil, suspended solids and the like in seawater in the filter pool of air flotation first, and the water collection is to the intermediate water pool, and then enters macromolecular micropore filter material filter, and further removes suspended solids, and the turbidity of effluent reaches the water requirement of seawater reverse osmosis and the like membrane method seawater desalination equipment.

Description

Technical Field

[0001] This utility model belongs to the field of seawater treatment technology, specifically relating to a large-scale membrane-based seawater desalination pretreatment process system. Background Technology

[0002] Membrane-based seawater desalination, such as reverse osmosis, is a common desalination process. It has strict requirements on the turbidity of the influent, therefore pretreatment is necessary before membrane desalination. Existing pretreatment solutions, such as "air flotation tank + gravity filter + pressure filter or membrane filtration," have the following problems: 1. The effluent quality of traditional air flotation tanks is unstable; 2. Mechanical filtration has a slow filtration rate and a large footprint; gravity filter effluent turbidity is generally below 3 NTU, which cannot meet the turbidity requirements of reverse osmosis influent (below 1 NTU); 3. Membrane filtration has high investment and operating costs, high self-consumption rate, and internal pressure ultrafiltration membranes have high influent turbidity requirements (below 5 NTU), requiring an additional filtration stage beforehand, and the influence of water temperature needs to be considered. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a large-scale membrane-based seawater desalination pretreatment process system, which solves the problems of existing pretreatment process systems being complicated, having unstable effluent quality, large footprint, and high cost, and achieves a seawater desalination pretreatment process with low operating cost, small footprint, and good treatment effect.

[0004] According to the technical solution of this utility model, this utility model provides a large-scale membrane-based seawater desalination pretreatment process system, including an air flotation filter, an intermediate water tank, and a polymer microporous filter media arranged sequentially; the air flotation filter includes an air flotation filter body, and a filter media layer is arranged in the middle of the air flotation filter body; in the air flotation filter body, an air flotation area is formed above the filter media layer, and a filtered area is formed below the filter media layer; the filtered area is connected to the intermediate water tank through an intermediate water delivery pipe, and the intermediate water tank and the polymer microporous filter media are connected through an intermediate water output pipe.

[0005] In some embodiments, a backwash water pipe is provided above the intermediate water delivery pipe in the filtered area of ​​the air flotation filter body. The backwash water pipe is connected to the intermediate water tank through the backwash water delivery pipe, and a backwash water delivery pump is provided on the backwash water delivery pipe.

[0006] In some implementations, the backwash water pipe is provided with multiple backwash water outlets, which are distributed below the filter media layer.

[0007] In some embodiments, a backflush air pipe is also provided above the intermediate water delivery pipe in the filtered area of ​​the air flotation filter body, and the backflush air pipe is connected to a blower.

[0008] In some embodiments, the backflush pipe is provided with multiple backflush air outlets, which are distributed below the filter media layer.

[0009] In some embodiments, the flotation filter also includes a coagulation tank and a flocculation tank; the upstream side of the coagulation tank is connected to a seawater input pipe, the downstream side of the coagulation tank is connected to the upstream side of the flocculation tank, and the downstream side of the flocculation tank is connected to the upstream side of the flotation filter body.

[0010] In some embodiments, the coagulation tank and the flocculation tank are side by side and adjacent to each other at the same height. The coagulation tank and the flocculation tank are connected only through a first connecting channel. The inlet of the first connecting channel is located at the top of the coagulation tank, and the outlet of the first connecting channel is located at the bottom of the flocculation tank. A coagulation tank agitator is installed in the coagulation tank, and a flocculation tank agitator is installed in the flocculation tank. A coagulation tank drain pipe is connected to the bottom of the coagulation tank, and a flocculation tank drain pipe is connected to the bottom of the flocculation tank. The flocculation tank and the air flotation filter tank are connected only through a second connecting channel. The inlet of the second connecting channel is located at the top of the flocculation tank.

[0011] In some embodiments, a dissolved air input pipe is provided on the upstream side of the air flotation filter body, a sludge scraper is provided above the air flotation area, a sludge discharge tank is provided on one side of the air flotation filter body, an industrial water pipe is provided directly above the sludge discharge tank, and a sludge discharge pipe is connected to the bottom of the sludge discharge tank.

[0012] In some embodiments, a transition water tank is provided between the main body of the air flotation filter tank and the intermediate water tank. The filtered area of ​​the main body of the air flotation filter tank is connected to the bottom of the transition water tank through an intermediate water delivery pipe. The transition water tank and the main body of the air flotation filter tank form a communicating vessel structure. The side wall of the transition water tank near the main body of the air flotation filter tank is higher than the main body of the air flotation filter tank. The side wall of the transition water tank near the intermediate water tank forms the entrance of the intermediate water tank at a height lower than the main body of the air flotation filter tank.

[0013] In some embodiments, a clean water tank is also included. The polymer microporous filter media and the clean water tank are connected by a clean water delivery pipe, and the clean water tank is connected to the reverse osmosis system through a clean water output pipe.

[0014] Compared with the prior art, the beneficial technical effects of this utility model are as follows: This invention innovatively employs a "flotation filter + polymer microporous filter" for pretreatment in a large-scale membrane-based seawater desalination process. This effectively removes suspended solids, algae, and oil, significantly reducing the footprint and investment / operating costs compared to conventional processes. In this system, seawater first undergoes flotation filtration to remove algae, oil, and suspended solids. The effluent is then collected in an intermediate tank and further filtered by the polymer microporous filter to remove more suspended solids. The resulting effluent turbidity meets the influent requirements for membrane-based seawater desalination equipment such as reverse osmosis. Compared to traditional flotation devices, the flotation filter adds a filtration zone with a filter media layer. The flotated material rises to the surface to form a scum layer, while the clean water flows downwards into the filter media layer for filtration, achieving mud-water separation and thus improving the removal efficiency of suspended solids. The polymer microporous filter media in the filter has both filtration and adsorption functions. It can remove suspended solids and algae, and has a high filtration rate, high turbidity removal rate, and low self-water rate (≤1%). The filter media is cleaned by stirring and rinsing with raw water, without the need for air source or chemical agents. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure provided by this utility model.

[0016] Explanation of reference numerals in the attached figures: 1. Air flotation filter; 2. Intermediate water tank; 3. Polymer microporous filter media; 4. Filter media layer; 5. Intermediate water delivery pipe; 6. Intermediate water output pipe; 7. Backwash water pipe; 8. Backwash water delivery pipe; 9. Backwash water delivery pump; 10. Backflush air pipe; 11. Blower; 12. Coagulation tank; 13. Flocculation tank; 14. Seawater input pipe; 15. Contact zone; 16. First connecting channel; 17. Coagulation tank agitator; 18. Flocculation tank agitator; 19. Coagulation tank drain pipe; 20. Flocculation tank drain pipe; 21. Second connecting channel; 22. Dissolved air input pipe; 23. Sludge scraper; 24. Sludge discharge tank; 25. Industrial water pipe; 26. Sludge discharge pipe; 27. Transition water tank; 28. Clear water tank; 29. ​​Clear water delivery pipe; 30. Clear water output pipe; 31. Wastewater collection tank. Detailed Implementation

[0017] This utility model provides a large-scale membrane-based seawater desalination pretreatment process system, or in other words, a pretreatment process system for membrane-based seawater desalination. It mainly aims to solve the problems of existing pretreatment process systems, such as complexity, unstable effluent quality, large footprint, and high cost, and to achieve a seawater desalination pretreatment process with low operating costs, small footprint, and good treatment effect.

[0018] Please see Figure 1This utility model discloses a large-scale membrane-based seawater desalination pretreatment system, mainly comprising a flotation filter tank 1, an intermediate water tank 2, and a polymer microporous filter media 3 arranged sequentially. The flotation filter tank 1 includes a main body with a filter media layer 4, specifically sea sand, in its middle section. Above the filter media layer 4, a flotation zone (or flotation separation zone) is formed within the flotation filter tank body. Similar to existing flotation devices, scum forms above the flotation zone, separating impurities from the seawater. Below the filter media layer 4, a filtered zone is formed. Due to the presence of the filter media layer 4, the seawater entering the filtered zone has a high degree of cleanliness and is free of large solid impurities. The filtered zone is connected to the intermediate water tank 2 via an intermediate water delivery pipe 5, allowing the flotated and filtered seawater to enter the intermediate water tank 2. The intermediate water tank 2 and the polymer microporous filter media 3 are connected via an intermediate water output pipe 6, enabling the seawater from the intermediate water tank 2 to be further filtered by the polymer microporous filter media 3. The water output from the polymer microporous filter 3 is pre-treated water, which can be temporarily stored in the clean water tank or directly fed into the subsequent membrane seawater desalination equipment.

[0019] In a preferred embodiment, in the post-filtration area of ​​the air flotation filter body, a backwash water pipe 7 is also provided above the intermediate water delivery pipe 5. The backwash water pipe 7 is connected to the intermediate water tank 2 via a backwash water delivery pipe 8. A backwash water delivery pump 9 is provided on the backwash water delivery pipe 8, so that the water in the intermediate water tank 2 can be used to backwash the filter media layer 4, causing impurities falling into the filter media layer 4 to detach from the filter media layer 4. Regular backwashing can ensure the filtration effect. Furthermore, the backwash water pipe 7 is provided with multiple backwash water outlets, which are distributed below the filter media layer 4, so that backwash water can be output upwards relatively evenly to backwash all parts of the filter media layer 4.

[0020] In a preferred embodiment, a backflush air pipe 10 is further provided above the intermediate water delivery pipe 5 in the filtered area of ​​the flotation filter body, and the backflush air pipe 10 is connected to a blower 11. The backflush air pipe 10 introduces gas (such as air) into the filtered area. The gas rises, carrying impurities away from the filter media layer 4, thus cleaning the filter media layer 4. Furthermore, the backflush air pipe 10 is provided with multiple backflush air outlets, which are distributed below the filter media layer 4, thereby enabling relatively uniform upward output of backflush air to backflush various parts of the filter media layer 4.

[0021] More specifically, such as Figure 1In the illustrated embodiment, in the filtered area of ​​the air flotation filter body, a backflush air pipe 10, a backwash water pipe 7, and an intermediate water delivery pipe 5 are simultaneously provided (of course, components related to the backflush air pipe 10 and the backwash water pipe 7 as described above are also provided); the backflush air pipe 10, the backwash water pipe 7, and the intermediate water delivery pipe 5 all have a relatively long section located within the air flotation filter body, and the portions located within the air flotation filter body are all distributed with through holes (the backflush air pipe 10 and the backwash water pipe 7 can also be provided with nozzle-like components). The portions located within the air flotation filter body are, for example, in the form of coils, so that the through holes (or nozzle-like components) are more evenly distributed below the filter media layer 4, and the through holes (or nozzle-like components) face upwards; the backflush air pipe 10 is located above the backwash water pipe 7 or the backflush air pipe 10 and the backwash water pipe 7 are at similar heights, and the intermediate water delivery pipe 5 is located below the backflush air pipe 10 and the backwash water pipe 7. In this design, backwashing and backflushing processes are performed simultaneously, resulting in better cleaning of the filter media layer 4 and facilitating the removal of impurities from the filter media layer 4 into the surface scum for treatment. Furthermore, the backwashing and backflushing processes are located above the intermediate water delivery pipe 5, ensuring unobstructed water flow. The distributed perforations or nozzles in the backflushing air pipe 10 and backwash water pipe 7 enhance the cleaning effect. The intermediate water delivery pipe 5 also uses multiple distributed perforations as inlets, resulting in lower suction and flow rates compared to a single inlet, thus preventing the intake of lighter solid impurities. Additionally, a gap exists between the intermediate water delivery pipe 5 and the bottom of the flotation filter body, allowing small amounts of solid impurities penetrating the filter media layer 4 to settle at the bottom without entering the intermediate water delivery pipe 5. Moreover, a drain pipe is installed at the bottom of the flotation filter body for periodic waste discharge or water drainage during thorough cleaning and maintenance; this drain pipe is connected, for example, to the wastewater collection tank 31.

[0022] In a preferred embodiment, the flotation filter 1 further includes a coagulation tank 12 and a flocculation tank 13. The upstream side of the coagulation tank 12 is connected to a seawater inlet pipe 14, and the downstream side of the coagulation tank 12 is connected to the upstream side of the flocculation tank 13; the downstream side of the flocculation tank 13 is connected to the upstream side of the flotation filter body. Seawater first enters the coagulation tank 12. During the pretreatment process, a coagulant is added to the coagulation tank 12 to coagulate. The coagulant's role is to coagulate, bridge, and trap small colloids, suspended solids, and even large organic molecules in the water, forming larger suspended particles so that they can combine with the flocculant to form larger flocculent suspended solids for removal during sedimentation filtration. Then, the seawater enters the flocculation tank 13, where a flocculant is added to flocculate. The flocculant's role is to capture small particles in the water, forming larger flocculent suspended solids, accelerating the coagulation speed of the coagulant, and facilitating more thorough removal in the subsequent filtration process.

[0023] Furthermore, such as Figure 1As shown, the coagulation tank 12 and the flocculation tank 13 are adjacent to each other and at the same height. They are connected only by a first connecting channel 16, with the inlet of the first connecting channel 16 located at the top of the coagulation tank 12 and the outlet at the bottom of the flocculation tank 13. A coagulation tank agitator 17 is installed in the coagulation tank 12, and a flocculation tank agitator 18 is installed in the flocculation tank 13. A coagulation tank drain pipe 19 is connected to the bottom of the coagulation tank 12, and a flocculation tank drain pipe 20 is connected to the bottom of the flocculation tank 13. The flocculation tank 13 and the air flotation filter body are connected only by a second connecting channel 21, with the inlet of the second connecting channel 21 located at the top of the flocculation tank 13. In this design, both the first connecting channel 16 and the second connecting channel 21 are horizontally S-shaped, thus extending the reaction time. The coagulation tank drain pipe 19 and the flocculation tank drain pipe 20 are both connected to the sewage collection tank 31. The coagulation tank drain pipe 19 and the flocculation tank drain pipe 20 can discharge the impurities deposited at the bottom of the tank during the treatment process, and can also be used to empty the corresponding tanks during maintenance and cleaning.

[0024] In a specific embodiment, a dissolved air input pipe 22 is provided on the upstream side of the dissolved air flotation filter body, and this part with the dissolved air input pipe 22 is called the contact area 15. A sludge scraper 23 is provided above the flotation area, and a sludge discharge tank 24 is provided on one side of the flotation filter body. An industrial water pipe 25 is also provided directly above the sludge discharge tank 24, and a sludge discharge pipe 26 is connected to the bottom of the sludge discharge tank 24. The industrial water pipe 25 can deliver industrial water downward to the sludge discharge tank 24 for flushing, so that the scum can be discharged through the sludge discharge pipe 26. The sludge discharge pipe 26 is connected, for example, to a sewage collection tank 31.

[0025] In a preferred embodiment, such as Figure 1As shown, a transition water tank 27 is provided between the main body of the air flotation filter tank and the intermediate water tank 2. The filtered area of ​​the main body of the air flotation filter tank is connected to the bottom of the transition water tank 27 through the intermediate water delivery pipe 5. The transition water tank 27 and the main body of the air flotation filter tank form a communicating vessel structure. The side wall of the transition water tank 27 near the main body of the air flotation filter tank is higher than the main body of the air flotation filter tank. The side wall of the transition water tank 27 near the intermediate water tank 2 forms the entrance of the intermediate water tank at a height lower than the main body of the air flotation filter tank. In this scheme, the water transport process from the intermediate water transport pipe 5 to the transition water tank 27 is realized through the principle of communicating vessels, without the need for a pump (of course, in some other embodiments, a pump can be installed in the intermediate water transport pipe 5 without forming a communicating vessel structure). The flow rate is relatively slow and the disturbance in the tank is small. According to the principle of communicating vessels, the liquid level of the transition water tank 27 and the main body of the air flotation filter will tend to be level, but the structural design makes the highest liquid level of the transition water tank 27 slightly lower than the liquid level of the main body of the air flotation filter, thereby providing continuous power for the water flow. At the same time, due to this structural design, it is possible to prevent the water in the intermediate water tank 2 from flowing back into the main body of the air flotation filter without the need for setting and controlling valves, ensuring that the intermediate water tank 2 is more stable. For example, when the main body of the air flotation filter is under maintenance and venting, the intermediate water tank 2 will not be affected. Optionally, the volume of the intermediate water tank 2 is relatively large (e.g., larger than the main body of the air flotation filter), while the volume of the transition water tank 27 is small (e.g., smaller than the main body of the air flotation filter).

[0026] In a specific embodiment, a clear water tank 28 is also included. The polymer microporous filter media 3 and the clear water tank 28 are connected via a clear water delivery pipe 29, and the clear water tank 28 is connected to the reverse osmosis system via a clear water output pipe 30. The clear water tank 28 is used to collect the pretreated clear water. The clear water tank 28 acts as a buffer, ensuring that the shutdown and maintenance of upstream equipment does not affect the operation of downstream equipment, and vice versa, thus contributing to the overall treatment efficiency. The solution of this utility model is particularly suitable for large-scale membrane-based seawater desalination systems such as reverse osmosis systems.

[0027] As a supplementary explanation, the present invention also includes supporting pipelines, valves, instruments, and control systems to achieve the required operation and further realize automated control, which is achievable based on the existing technology and will not be elaborated here.

[0028] This utility model relates to a polymer microporous filter media, specifically a filter that uses polymer microporous materials as the filter media. More specifically, it uses polymer microporous suspended filter media particles as the filtration medium, enabling it to intercept and filter suspended solids, algae, colloids, and other substances in water at ultra-high flow rates (45–80 m / h). The filtration rate of this polymer microporous filter media is significantly higher than that of conventional filters (fine sand filtration 6–8 m / h; single-layer filter media filtration 8–10 m / h; double-layer filter media filtration 10–14 m / h; variable porosity filtration 18–21 m / h; fiber filtration 20–40 m / h). A single unit (e.g., DN5000 mm in diameter) can achieve an output of up to 1500 m³ / h. 3 / h; Under normal operating conditions, the turbidity reduction rate of this filter can reach over 98%. When the influent turbidity is ≤10 NTU, the effluent turbidity is ≤0.2 NTU; when the influent turbidity is ≤30 NTU, the effluent turbidity is ≤0.6 NTU. Routine cleaning of the filter media utilizes raw water agitation and rinsing, requiring no air source or chemical agents. Only when the effluent turbidity requirement is high, the filter media's dirt-holding capacity is significantly impacted, or the incoming water is particularly dirty, is it necessary to use acids, alkalis, or bactericides for deep cleaning and regeneration of the filter media; no coagulants or flocculants need to be added.

[0029] An air flotation tank (or air flotation device) is a tank that uses a large number of microbubbles to capture and adsorb fine particulate matter, causing it to float to the surface to achieve solid-liquid separation. Its working principle involves introducing air into the water to form microbubbles. These bubbles adhere to the fine suspended matter, forming a water-air-solid three-phase system. The suspended matter rises to the surface due to the buoyancy of the bubbles, forming foam or scum, thus separating the suspended matter from the water. This invention's air flotation filter tank, compared to traditional air flotation devices, adds a filtration zone below the air flotation separation zone. The filtration zone contains a filter media layer. The air-flotated matter floats to the surface, forming a scum layer, while clean water flows downwards into the filter media layer for filtration, achieving mud-water separation and improving the removal efficiency of suspended matter. The scum layer on the tank surface can be discharged with the backwash water during backwashing of the filter tank.

[0030] Among existing pretreatment methods, the following filtration methods can also be selected: Gravity filters are devices that filter based on the static pressure generated by the weight of the liquid itself. Pressure filters are filters that operate under specific pressure, usually with a sealed steel tank as the outer shell; they are also called mechanical filters. They are mainly used to filter impurities and particulate matter in the filter medium. Their working principle is that external pressure drives the medium through the filter medium, impurities are trapped on the filter, and clean medium flows out through the filter. Mechanical filtration refers to passing water through grids, screens, filter media, etc., to remove suspended impurities, as well as some organic matter and colloids in the water; the filter media generally uses fine sand, quartz sand, anthracite, etc. Membrane filtration uses continuous ultrafiltration (microfiltration) as a pretreatment for reverse osmosis to replace the traditional multi-stage filtration process, reducing the fouling pressure on the reverse osmosis membrane.

[0031] Air flotation (AF) is a commonly used technology in seawater desalination. This method is particularly suitable for removing particles with a relative density close to that of water, such as algal cells, oil, grease, or other light solid pollutants that cannot be effectively removed by sedimentation or filtration. AF tanks offer higher separation efficiency and effect than sedimentation tanks and can save on coagulant usage. Its working principle is: by introducing gas into the water, the air bubbles react with suspended particles or dissolved substances in the water, causing them to float to the surface, where they are then separated through centralized removal. However, after wastewater passes through conventional AF equipment, some suspended solids remain, such as colloidal COD components and residual macromolecular substances. To address this problem, this invention provides an AF filtration treatment device that improves the removal efficiency of suspended solids through AF and filtration.

[0032] The existing filtration process of "gravity filter + pressure filter or membrane filtration" has the following problems: 1) Gravity filters or pressure filters are mechanical filters, with slow filtration speed and large footprint; the turbidity of the effluent from gravity filters cannot meet the requirements of seawater reverse osmosis feed water, requiring an additional stage of filtration; 2) Membrane filtration has high investment and operating costs, high self-water consumption, and the influence of water temperature needs to be considered; 3) Conventional filtration and ultrafiltration equipment have strict requirements on the content of suspended solids in the influent, generally requiring fine sand filters to have suspended solids ≤5mg / L, quartz sand and dual-media filters to have suspended solids ≤20mg / L, and internal pressure ultrafiltration membranes to have turbidity <5NTU. The above treatment processes suffer from high investment and operating costs, high self-water consumption, slow filtration speed, large footprint, and strict requirements on the content of suspended solids in the influent. To address these problems, this utility model provides a polymer microporous filter media filter, which has high filtration speed, good effluent quality, and low cost.

[0033] In summary, the large-scale membrane seawater desalination pretreatment process system of this utility model innovatively adopts "air flotation filter + polymer microporous filter" for pretreatment, which can effectively remove suspended solids, algae, oil, etc., and compared with conventional processes, it greatly reduces the footprint, investment and operating costs, and achieves better treatment results.

[0034] In this process, seawater first undergoes an air flotation filtration tank to remove algae, oil, and suspended solids. The effluent is then collected in an intermediate tank and (via an intermediate pump) enters a high-polymer microporous filter media for further removal of suspended solids. The effluent turbidity meets the influent requirements for membrane-based seawater desalination equipment such as reverse osmosis. The pretreated product water can be collected in a clear water tank for subsequent reverse osmosis treatment. After a certain operating cycle, backwashing is performed using a backwash pump and blower; the scum on the tank surface is discharged along with the backwash water to a wastewater collection tank. Compared to traditional air flotation devices, the air flotation filtration tank adds a filtration zone with a filter media layer. The air-flotated material floats to the surface to form a scum layer, while the clear water flows downwards into the filter media layer for filtration, achieving mud-water separation and thus improving the removal efficiency of suspended solids. The polymer microporous filter media in this filter combines filtration and adsorption functions, effectively removing suspended solids and algae. It boasts high filtration speed, high turbidity removal rate, and low self-water usage (≤1%). Routine cleaning of the filter media utilizes raw water for agitation and rinsing, eliminating the need for air supply or chemical agents. The entire operation is automated via valves, instruments, and control systems, requiring no manual intervention.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; obviously, the described embodiments are some embodiments of this utility model, but not all embodiments; based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model; in the absence of conflict, the embodiments and features in the embodiments of this utility model can be combined with each other; modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions for some of the technical features, do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A large-scale membrane-based seawater desalination pretreatment process system, characterized in that, It includes an air flotation filter (1), an intermediate water tank (2), and a polymer microporous filter media (3) arranged in sequence; the air flotation filter (1) includes an air flotation filter body, and a filter media layer (4) is provided in the middle of the air flotation filter body; in the air flotation filter body, an air flotation area is formed above the filter media layer (4), and a filtered area is formed below the filter media layer (4); the filtered area is connected to the intermediate water tank (2) through an intermediate water delivery pipe (5), and the intermediate water tank (2) and the polymer microporous filter media (3) are connected through an intermediate water output pipe (6).

2. The large-scale membrane seawater desalination pretreatment process system according to claim 1, characterized in that, In the filtered area of ​​the air flotation filter body, a backwash water pipe (7) is also provided above the intermediate water delivery pipe (5). The backwash water pipe (7) is connected to the intermediate water tank (2) through the backwash water delivery pipe (8). A backwash water delivery pump (9) is provided on the backwash water delivery pipe (8).

3. The large-scale membrane seawater desalination pretreatment process system according to claim 2, characterized in that, Multiple backwash water outlets are provided on the backwash water pipe (7), and the backwash water outlets are distributed below the filter media layer (4).

4. The large-scale membrane seawater desalination pretreatment process system according to claim 2, characterized in that, In the post-filtration area of ​​the air flotation filter body, a backflush air pipe (10) is also provided above the intermediate water delivery pipe (5), and the backflush air pipe (10) is connected to a blower (11).

5. The large-scale membrane seawater desalination pretreatment process system according to claim 4, characterized in that, Multiple backflush air outlets are provided on the backflush air pipe (10), and the backflush air outlets are distributed below the filter media layer (4).

6. The large-scale membrane-based seawater desalination pretreatment process system according to any one of claims 1 to 5, characterized in that, The air flotation filter (1) also includes a coagulation tank (12) and a flocculation tank (13); the upstream side of the coagulation tank (12) is connected to the seawater input pipe (14), the downstream side of the coagulation tank (12) is connected to the upstream side of the flocculation tank (13), and the downstream side of the flocculation tank (13) is connected to the upstream side of the air flotation filter body.

7. The large-scale membrane seawater desalination pretreatment process system according to claim 6, characterized in that, The coagulation tank (12) and the flocculation tank (13) are side by side and adjacent to each other at the same height. The coagulation tank (12) and the flocculation tank (13) are connected only through the first connecting channel (16). The inlet of the first connecting channel (16) is located at the top of the coagulation tank (12), and the outlet of the first connecting channel (16) is located at the bottom of the flocculation tank (13). A coagulation tank agitator (17) is installed in the coagulation tank (12), and a flocculation tank agitator (18) is installed in the flocculation tank (13). A coagulation tank drain pipe (19) is connected to the bottom of the coagulation tank (12), and a flocculation tank drain pipe (20) is connected to the bottom of the flocculation tank (13). The flocculation tank (13) and the air flotation filter body are connected only through the second connecting channel (21). The inlet of the second connecting channel (21) is located at the top of the flocculation tank (13).

8. The large-scale membrane-based seawater desalination pretreatment process system according to any one of claims 1 to 5, characterized in that, A dissolved air input pipe (22) is provided on the upstream side of the air flotation filter body, a sludge scraper (23) is provided above the air flotation area, a sludge discharge tank (24) is provided on one side of the air flotation filter body, an industrial water pipe (25) is provided directly above the sludge discharge tank (24), and a sludge discharge pipe (26) is connected to the bottom of the sludge discharge tank (24).

9. The large-scale membrane-based seawater desalination pretreatment process system according to any one of claims 1 to 5, characterized in that, A transition water tank (27) is provided between the main body of the air flotation filter tank and the intermediate water tank (2). The filtered area of ​​the main body of the air flotation filter tank is connected to the bottom of the transition water tank (27) through the intermediate water delivery pipe (5). The transition water tank (27) and the main body of the air flotation filter tank form a communicating vessel structure. The side wall of the transition water tank (27) near the main body of the air flotation filter tank is higher than the main body of the air flotation filter tank. The side wall of the transition water tank (27) near the intermediate water tank (2) forms the entrance of the intermediate water tank at a height lower than the main body of the air flotation filter tank.

10. The large-scale membrane-based seawater desalination pretreatment process system according to any one of claims 1 to 5, characterized in that, It also includes a clean water tank (28), a polymer microporous filter media (3), and the clean water tank (28) are connected by a clean water delivery pipe (29), and the clean water tank (28) is connected to the reverse osmosis system through a clean water output pipe (30).

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