A high recovery tubular membrane filtration system

Abstract

The utility model provides a kind of high recovery rate tubular membrane filtration system, it is related to water purification process field, solve the problem that existing tubular membrane filtration system recovery rate is low, membrane pollution is serious, cleaning wastewater treatment cost is high and operation cooperativity is poor, better guarantee water resource utilization rate and membrane component service life.It includes membrane component, water inlet pipeline, water production pipeline, auxiliary system, valve, PLC control system and water quality sensor;Membrane component is tubular structure and can be multiple groups parallel;System is realized high recovery rate and low pollution operation by substandard water backflow, standard water reuse and multiple system cooperation.The system structure is simple, low in cost, applicable to industrial wastewater treatment, circulating water reuse and the like scene.

Description

Technical Field

[0001] This utility model relates to the field of water purification technology, and in particular to a high recovery rate tubular membrane filtration system. Background Technology

[0002] In the application of tubular membrane filtration systems, existing systems have many technical defects: First, the recovery rate is low. Substandard water produced after raw water filtration is often directly discharged, and the cleaning process consumes a large amount of fresh water, resulting in an overall system recovery rate of less than 85%, leading to serious water waste. Second, membrane modules are easily fouled and damaged. Raw water is not pretreated with high precision (conventional pre-filtration precision >20μm), and large particulate pollutants easily wear down the membrane surface. Moreover, the "concentration polarization" phenomenon causes organic matter and colloids to adhere, reducing membrane flux by 30-50% and shortening the lifespan to only 2-3 years. At the same time, the membrane module structure is not strong enough and is prone to deformation under long-term pressure. Third, the cleaning cost is high. Chemical cleaning effluent contains acid and alkali agents, requiring separate treatment facilities. Furthermore, physical and chemical cleaning have poor synergy, making it impossible to target specific pollutants and even posing a risk of mixing of the two cleaning agents. Fourth, the operational coordination is insufficient. Pipeline switching relies on manual intervention, lacks real-time water quality monitoring and automatic control, and is difficult to switch online when multiple membrane modules are connected in parallel, easily leading to water production interruptions and failing to meet the requirements of high-efficiency filtration. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a high-recovery-rate tubular membrane filtration system, which solves the technical problems of low recovery rate, serious membrane fouling, high cleaning cost, insufficient component strength, and poor operational coordination in existing tubular membrane filtration systems. By optimizing the pipeline structure, strengthening membrane component protection, and implementing automatic control, it achieves efficient filtration of raw water and recycling of water resources.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A high-recovery-rate tubular membrane filtration system includes: The membrane module is located at the core of the filtration process. The membrane module has a tubular structure and multiple units can be connected in parallel. The lower end of the membrane module is equipped with a lower side port and a bottom port, and the upper end is equipped with an upper port and an upper side port. The inner cavity of the membrane module is supplied with raw water and cleaning water. The water inlet pipeline includes a water inlet pipe, a main water inlet pipe, a pre-filter, and a water inlet pump. The water inlet pipe is connected to the lower port of the membrane module. The main water inlet pipe is connected to the front end of the water inlet pipe. The pre-filter is fixed on the water inlet pipe and located behind the connection point between the main water inlet pipe and the discharge pipe. The water inlet pump is fixed on the water inlet pipe and located between the pre-filter and the membrane module. The permeate pipeline includes a permeate pipe and a permeate main pipe. The permeate pipe is connected to the upper port of the membrane module, and the permeate main pipe is connected to the rear end of the permeate pipe. The auxiliary system includes a discharge pipe, a backwashing system, a chemical cleaning system, an air scrubbing system, and a wastewater pipe. The discharge pipe is connected to the upper port of the membrane module. The backwashing system includes a clean water tank, a backwashing dosing system, a backwashing pipe, and a backwashing pump. The backwashing pipe is connected to the product water pipe. The chemical cleaning system includes a chemical cleaning water tank, a chemical cleaning dosing system, a chemical cleaning pipe, and a chemical cleaning pump. The chemical cleaning pipe is connected to the inlet water pipe. The air scrubbing system includes an air compressor, a compressed air storage tank, and an air scrubbing pipe. The air scrubbing pipe is connected to the lower port of the membrane module. The wastewater pipe is connected to the rear end of the discharge pipe. Valves, several valves are fixed on the inlet pipe, product water pipe, discharge pipe, backwash pipe, chemical cleaning pipe and air scrubbing pipe respectively, and are used to control the opening and closing of each pipeline and the switching of media.

[0005] Furthermore, the valve on the water inlet pipe is a two-way switching valve, which is respectively connected to the main water inlet pipe and the chemical cleaning pipe. The valve core of the two-way switching valve is made of nitrile rubber, which is used to selectively accept the raw water from the main water inlet pipe or the cleaning water from the chemical cleaning pipe, and has acid and alkali corrosion resistance and sealing and leak-proof performance.

[0006] Furthermore, the valve on the water production pipe is a multi-directional distribution valve, which is respectively connected to the main water production pipe, the purified water tank, and the chemical cleaning water tank. The valve body of the multi-directional distribution valve is equipped with a flow sensor, which is used to distribute the qualified water filtered by the membrane module to the main water production pipe, the purified water tank, or the chemical cleaning water tank, and to monitor the flow of each branch in real time.

[0007] Furthermore, the valve on the discharge pipe is a bidirectional flow guide valve, which is respectively connected to the front end of the inlet pipe and the wastewater pipe. The outlet end of the bidirectional flow guide valve is equipped with a rubber flap check structure, which is used to guide the substandard water discharged from the membrane module to the front end of the inlet pipe or to guide the cleaning tailwater to the wastewater pipe.

[0008] Furthermore, the air scrubbing system is equipped with an interlock valve on the air scrubbing pipe. The interlock valve is electrically connected to the backwash pump of the backwash system. The opening delay time of the interlock valve is synchronized with the start time of the backwash pump, which is used to control the air scrubbing system to operate alone or in coordination with the backwash system.

[0009] Furthermore, the pre-filter has a filtration accuracy of 5-10μm, is made of 304 stainless steel, and has a washable stainless steel woven mesh filter element inside. The filter element has fluororubber sealing rings at both ends to intercept large particulate pollutants in the raw water and the returned substandard water.

[0010] Furthermore, the backwashing dosing system includes a metering pump and a reagent storage tank. The reagent storage tank stores a citric acid solution with a concentration of 0.5-1%. The outlet of the metering pump is connected to the backwashing pipe. The flow rate of the metering pump is adjustable from 0 to 20 L / h, and the reagent injection amount can be adjusted according to the degree of fouling of the membrane module.

[0011] Furthermore, the chemical cleaning dosing system includes dual-channel metering pumps and two reagent storage tanks. One reagent storage tank stores a NaOH solution with a concentration of 0.8-1.2%, and the other reagent storage tank stores a citric acid solution with a concentration of 1-1.5%. The outlets of both metering pumps are connected to the chemical cleaning pipe. The dual-channel metering pumps are equipped with an interlock function to prevent the two reagents from being injected simultaneously.

[0012] Furthermore, the membrane module is a PVDF tubular membrane with an inner diameter of 8-20 mm and a wall thickness of 1.5-3 mm.

[0013] Furthermore, it also includes a PLC control system and a water quality sensor. The water quality sensor is fixed on the product water pipe and is used to detect the turbidity and TDS value of the qualified water. The PLC control system is electrically connected to the inlet pump, backwash pump, chemical cleaning pump, air compressor, all valves and water quality sensor respectively. It can automatically control the start and stop of each pump and the switching of valves according to the feedback data of the water quality sensor, so as to realize the unattended automatic operation of the filtration, backwashing and chemical cleaning processes.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The recovery rate is significantly improved. Substandard water is returned to the front end of the inlet pipe through the discharge pipe, mixed with the raw water and filtered again. The backwashing system and chemical cleaning system both use qualified water as the water source, avoiding the consumption of fresh water and the direct discharge of wastewater. The system has a high recovery rate.

[0015] 2. Extended membrane module lifespan: The pre-filter intercepts large particulate pollutants, reducing physical wear on the membrane module; PVDF material is resistant to acid and alkali corrosion, and the outer wall reinforcing ribs enhance structural strength; the air scrubbing system and backwashing system work together, and the chemical cleaning system switches agents precisely to remove various pollutants, preventing a continuous decline in membrane flux and extending the membrane module lifespan.

[0016] 3. Reduced operating costs: The amount of chemical cleaning effluent discharged is reduced, thus decreasing the investment and operating costs of wastewater treatment facilities; qualified water replaces fresh water as the cleaning water source, reducing the cost of fresh water procurement; the interlocking of dual metering pumps avoids waste of chemicals and equipment corrosion, further controlling operating costs.

[0017] 4. Improved ease of operation and stability: The PLC control system, combined with water quality sensors, enables fully automated operation without manual intervention; the design of multi-directional distribution valve flow monitoring, bidirectional flow guide valve check structure, and linkage valve timing synchronization ensures stable system operation, adapts to different water quality scenarios, and has a wide range of applications. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a diagram of the overall system structure. Figure 2 This is a structural diagram of a multi-membrane module parallel system; The system includes: membrane module 1, inlet pipe 2, main inlet pipe 21, pre-filter 22, inlet pump 23, product water pipe 3, main product water pipe 31, discharge pipe 4, backwash system 5, clean water tank 51, backwash dosing system 52, backwash dosing pipe 53, backwash pipe 54, backwash pump 55, chemical cleaning system 6, chemical cleaning tank 61, chemical cleaning dosing system 62, chemical cleaning dosing pipe 63, chemical cleaning pipe 64, chemical cleaning pump 65, valve 7, air scrubbing system 8, air compressor 81, compressed air storage tank 82, air scrubbing pipe 83, and wastewater pipe 9. Detailed Implementation

[0019] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0020] Example 1 like Figure 1 , 2 As shown, a high-recovery-rate tubular membrane filtration system includes a membrane module 1, an inlet water pipeline, a product water pipeline, an auxiliary system, a valve 7, a PLC control system 10, and a water quality sensor 32.

[0021] Membrane module 1 uses a PVDF tubular membrane with an inner diameter of 15mm and a wall thickness of 2mm. The outer wall is provided with reinforcing ribs 11 along the axial direction (80mm spacing, 3mm height), which are integrally formed with the membrane module 1. Membrane module 1 is configured with 3 sets connected in parallel (single set water production capacity 1.2m³ / h, total water production capacity 3.6m³ / h). Figure 2 As shown, each membrane module 1 has a DN50 304 stainless steel short pipe (100mm in length) welded to its lower end, a DN25 304 stainless steel short pipe (80mm in length) welded to its bottom end, a DN50 304 stainless steel short pipe (100mm in length) welded to its upper end, and a DN40 304 stainless steel short pipe (80mm in length) welded to its upper side. Each short pipe is connected to the corresponding pipeline through a flange, and the flange gasket is made of nitrile rubber (water-resistant and corrosion-resistant).

[0022] In the water inlet pipeline, inlet pipe 2 is a DN50 304 stainless steel pipe, and main inlet pipe 21 is a DN80 304 stainless steel pipe. Figure 1As shown, the pre-filter 22 is connected to the front end of the inlet pipe 2 via a three-way connector; the two-way switching valve on the inlet pipe 2 is a 2W-160-15 type 304 stainless steel solenoid valve with a nitrile rubber core; the pre-filter 22 is a 304 stainless steel cartridge filter with a filtration accuracy of 8μm and a processing capacity of 5m³ / h. The inner filter element is a 100-mesh stainless steel woven mesh (removable and washable, backwashed once every 7 days with qualified water at a flow rate of 3m³ / h for 5 minutes), and fluororubber sealing rings (2mm thick) at both ends of the filter element. The pre-filter 22 is connected to the inlet pipe 2 via a flange and is located after the connection point between the main inlet pipe 21 and the outlet pipe 4; the inlet pump 23 is an ISW80-160 type horizontal centrifugal pump with a flow rate of 5m³ / h, a head of 25m, and a power of 1.5kW. It is connected to the inlet pipe 2 via a flange and is located between the pre-filter 22 and the membrane module 1.

[0023] In the product water pipeline, product water pipe 3 is a DN40 304 stainless steel pipe, and the main product water pipe 31 is a DN65 304 stainless steel pipe. Figure 1 As shown, it is connected to the rear end of the product water pipe 3 via a four-way connector; the multi-directional distribution valve on the product water pipe 3 is a Q941F-16 type 304 stainless steel valve with a built-in turbine flow sensor (range 0-10m³ / h, accuracy ±2%); the purified water tank 51 is made of PE material with a volume of 500L, and the chemical cleaning water tank 61 is made of PE material with a volume of 300L, both connected to the four-way connector of the product water pipe 3 via DN40 PE pipes; the water quality sensor 32 is a TDS-100 type, fixed on the product water pipe 3 near the membrane module 1, with a detection accuracy of ±2%, and the data is transmitted to the PLC control system 10 via RS485 communication.

[0024] In the auxiliary system, discharge pipe 4 is a DN50 304 stainless steel pipe, such as Figure 1As shown, the short pipe at the upper port of membrane module 1 is connected to the front end of inlet pipe 2 via a tee connector (the connection point is located between inlet main pipe 21 and pre-filter 22); the bidirectional flow guide valve on discharge pipe 4 is an H41X-16 type 304 stainless steel valve, and the outlet check valve structure is a rubber flap type; wastewater pipe 9 is a DN65 304 stainless steel pipe, connected to the rear end of discharge pipe 4 via a tee connector; in backwashing system 5, backwash pipe 54 is a DN40 304 stainless steel pipe, connected to the four-way connector of product water pipe 3, backwash pump 55 is an ISW65-125 type horizontal centrifugal pump (flow rate 2m³ / h, head 18m, power 0.75kW), and backwash dosing system 52 includes a JWM-10 type metering pump (flow rate 0-20L / h) and a 50L PE material reagent storage tank (storing 0.8% citric acid solution). In the chemical cleaning system 6, the chemical cleaning pipe 64 is a DN50 304 stainless steel pipe connected to the tee fitting of the inlet pipe 2. The chemical cleaning pump 65 is an ISW80-160 horizontal centrifugal pump (the same model as the inlet pump 23). The chemical cleaning dosing system 62 includes a JWM-15 dual-channel metering pump (flow rate 0-15L / h) and two 50L PE material reagent storage tanks (containing 1.0% NaOH solution and 1.2% citric acid solution respectively). The dual-channel metering pump is interlocked through the PLC control system 10. In the air scrubbing system 8, the air compressor 81 is a V-0.6 / 8 type (discharge capacity 0.6m³ / min, working pressure 0.8MPa), the compressed air storage tank 82 is made of 304 stainless steel (volume 0.3m³), and the air scrubbing pipe 83 is a DN25 304 stainless steel pipe. Figure 2 As shown, the short pipe at the bottom port of each membrane module 1 is connected by a branch pipe. The linkage valve 84 on the air wiping pipe 83 is a 2W-200-20 type 304 stainless steel solenoid valve, which is synchronously started and stopped with the backwash pump 55 through a PLC control system.

[0025] All valves 7 are 2W-160-15 type 304 stainless steel solenoid valves with a response time of <0.5s; the PLC control system 10 is an S7-200SMART type, equipped with a 16-point input / 16-point output module, with preset control logic: when the water quality sensor 32 detects that the turbidity of the qualified water is >1NTU, the backflow valve of the discharge pipe 4 is automatically opened to guide the non-qualified water to the front end of the inlet pipe 2; after the membrane module 1 has been running continuously for 8 hours, it automatically switches to the backwash + air scrubbing process; the alkaline washing process is automatically started every 24 hours, and the acid washing process is automatically started every 96 hours.

[0026] The working principle of this embodiment is as follows: Before construction, three sets of parallel membrane modules are assembled according to the water production requirements, such as... Figure 1Connect all pipes and valves 7 as shown, and adjust the parameters of the PLC control system 10; during the filtration stage, raw water (turbidity 8 NTU) from the main inlet pipe 21 flows in through the inlet pipe 2, the pre-filter 22 intercepts large particulate pollutants larger than 8 μm, and the inlet pump 23 starts (outlet pressure 0.25 MPa), delivering the pretreated raw water to the lower port of the membrane module 1; Figure 2 As shown, raw water flows inside the membrane module 1. Water that meets the standards (turbidity < 1 NTU) passes through the membrane and enters the product water pipe 3 from the upper side opening. The water quality sensor 32 monitors the water quality in real time. 70% of the water that meets the standards is transported to the subsequent industrial circulating water system through the product water main pipe 31, and 30% of the water that meets the standards is distributed to the clean water tank 51 and the chemical cleaning water tank 61 in a 1:1 ratio. Water that does not meet the standards (turbidity > 1 NTU) enters the discharge pipe 4 from the upper port of the membrane module 1, and is guided to the front end of the inlet pipe 2 by the bidirectional flow guide valve. After mixing with the raw water, it is filtered again.

[0027] Air-water synergistic backwashing stage (every 8 hours): The inlet pump 23 stops, and the PLC control system 10 simultaneously starts the backwash pump 55 and the air compressor 81. The linkage valve 84 opens, and the water in the purified water tank 51 is mixed with the 0.8% citric acid solution injected by the backwash dosing system 52 (the concentration of the reagent after mixing is 0.5%). The mixture enters the upper port of the membrane module 1 through the backwash pipe 54 and the product water pipe 3. At the same time, compressed air enters the bottom port of the membrane module 1 through the air scrubbing pipe 83. The air and water work synergistically in the inner cavity of the membrane module 1 (lasting for 2 minutes) to remove pollutants from the membrane surface. If the backwash water meets the standard (turbidity < 1 NTU), it enters the product water pipe 3. If it does not meet the standard, it is returned through the discharge pipe 4.

[0028] Chemical cleaning stage: Alkaline washing (once every 24 hours), valve 7 of the main inlet pipe 21 is closed, valve 7 of the chemical cleaning pipe 64 is opened, and the chemical cleaning pump 65 is started (outlet pressure 0.3MPa). 1.0% NaOH solution enters the membrane module 1 through the inlet pipe 2 and is circulated for 35 minutes (to remove organic contaminants). The cleaning effluent is discharged through the discharge pipe 4 to the wastewater pipe 9, enters the neutralization tank, and is adjusted to pH 6-9 before being discharged. Acid washing (once every 96 hours), the process is the same as alkaline washing, but the chemical is replaced with 1.2% citric acid solution, and is cleaned for 45 minutes (to remove inorganic precipitates). After cleaning, the membrane module is rinsed with qualified water from the product water pipe 3 for 13 minutes to avoid chemical residue. After cleaning, the PLC control system automatically switches back to the filtration stage and repeats the above process.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A high-recovery-rate tubular membrane filtration system, characterized in that, include: Membrane module (1) is located at the core of the filtration process. Membrane module (1) is a tubular structure and multiple units can be connected in parallel. The lower end of membrane module (1) is provided with a lower side port and a bottom port, and the upper end is provided with an upper port and an upper side port. The inner cavity of membrane module (1) is supplied with raw water and cleaning water. The water inlet pipeline includes an inlet pipe (2), a main inlet pipe (21), a pre-filter (22), and an inlet pump (23). The inlet pipe (2) is connected to the lower opening of the membrane module (1). The main inlet pipe (21) is connected to the front end of the inlet pipe (2). The pre-filter (22) is fixed on the inlet pipe (2) and located behind the connection point between the main inlet pipe (21) and the discharge pipe (4). The inlet pump (23) is fixed on the inlet pipe (2) and located between the pre-filter (22) and the membrane module (1). The water production pipeline includes a water production pipe (3) and a water production main pipe (31). The water production pipe (3) is connected to the upper port of the membrane module (1), and the water production main pipe (31) is connected to the rear end of the water production pipe (3). The auxiliary system includes a discharge pipe (4), a backwashing system (5), a chemical cleaning system (6), an air scrubbing system (8), and a wastewater pipe (9). The discharge pipe (4) is connected to the upper port of the membrane module (1). The backwashing system (5) includes a clean water tank (51), a backwashing dosing system (52), a backwashing pipe (54), and a backwashing pump (55). The backwashing pipe (54) is connected to the product water pipe (3). The chemical cleaning system (6) includes a chemical cleaning tank (61), a chemical cleaning dosing system (62), a chemical cleaning pipe (64), and a chemical cleaning pump (65). The chemical cleaning pipe (64) is connected to the inlet water pipe (2). The air scrubbing system (8) includes an air compressor (81), a compressed air storage tank (82), and an air scrubbing pipe (83). The air scrubbing pipe (83) is connected to the bottom port of the membrane module (1). The wastewater pipe (9) is connected to the rear end of the discharge pipe (4). Valves (7) are fixed on the water inlet pipe (2), water production pipe (3), discharge pipe (4), backwash pipe (54), chemical cleaning pipe (64) and air scrubbing pipe (83) respectively, and are used to control the opening and closing of each pipeline and the switching of media.

2. The high recovery rate tubular membrane filtration system as described in claim 1, characterized in that, The valve (7) on the water inlet pipe (2) is a two-way switching valve, which is connected to the main water inlet pipe (21) and the chemical cleaning pipe (64) respectively. The valve core of the two-way switching valve is made of nitrile rubber, which is used to selectively accept the raw water from the main water inlet pipe (21) or the cleaning water from the chemical cleaning pipe (64), and has acid and alkali corrosion resistance and sealing and leak prevention performance.

3. The high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, The valve (7) on the water production pipe (3) is a multi-directional distribution valve, which is connected to the main water production pipe (31), the purified water tank (51) and the chemical cleaning water tank (61) respectively. The valve body of the multi-directional distribution valve is equipped with a flow sensor, which is used to distribute the qualified water filtered by the membrane module (1) to the main water production pipe (31), the purified water tank (51) or the chemical cleaning water tank (61), and monitor the flow of each branch in real time.

4. The high recovery rate tubular membrane filtration system as described in claim 1, characterized in that, The valve (7) on the discharge pipe (4) is a bidirectional flow guide valve, which is connected to the front end of the inlet pipe (2) and the wastewater pipe (9) respectively. The outlet end of the bidirectional flow guide valve is equipped with a rubber flap check structure, which is used to guide the substandard water discharged from the membrane module (1) to the front end of the inlet pipe (2) or the cleaning tail water to the wastewater pipe (9).

5. A high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, The air scrubbing system (8) is equipped with an interlock valve on the air scrubbing pipe (83). The interlock valve is electrically connected to the backwash pump (55) of the backwash system (5). The opening delay time of the interlock valve is synchronized with the start time of the backwash pump (55) to control the air scrubbing system (8) to operate alone or in coordination with the backwash system (5).

6. The high recovery rate tubular membrane filtration system as described in claim 1, characterized in that, The pre-filter (22) has a filtration accuracy of 5-10μm and is made of 304 stainless steel. The pre-filter (22) has a washable stainless steel woven mesh filter element in its inner cavity and fluororubber sealing rings at both ends of the filter element to intercept large particulate pollutants in the raw water and the returned substandard water.

7. A high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, The backwashing dosing system (52) includes a metering pump and a reagent storage tank. The reagent storage tank stores a citric acid solution with a concentration of 0.5-1%. The outlet of the metering pump is connected to the backwashing pipe (54). The flow rate of the metering pump is adjustable from 0 to 20 L / h. The amount of reagent injected can be adjusted according to the degree of fouling of the membrane module (1).

8. A high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, The chemical cleaning dosing system (62) includes a dual-channel metering pump and two reagent storage tanks. One reagent storage tank stores a NaOH solution with a concentration of 0.8-1.2%, and the other reagent storage tank stores a citric acid solution with a concentration of 1-1.5%. The outlets of both metering pumps are connected to the chemical cleaning pipe (64). The dual-channel metering pumps are equipped with an interlock function to prevent the two reagents from being injected at the same time.

9. A high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, The membrane module (1) is a PVDF tubular membrane with an inner diameter of 8-20 mm and a wall thickness of 1.5-3 mm.

10. A high-recovery-rate tubular membrane filtration system as described in claim 1, characterized in that, It also includes a PLC control system and a water quality sensor. The water quality sensor is fixed on the water production pipe (3) and is used to detect the turbidity and TDS value of the qualified water. The PLC control system is electrically connected to the water inlet pump (23), backwash pump (55), chemical cleaning pump (65), air compressor (81), all valves (7) and water quality sensor (32). It can automatically control the start and stop of each pump and the switching of valves (7) according to the feedback data of the water quality sensor, so as to realize the unattended automatic operation of the filtration, backwashing and chemical cleaning process.

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