Modular design system of large reverse osmosis or nanofiltration membrane device and operation method of modular design system

Abstract

The invention provides a modular design system for a large reverse osmosis or nanofiltration membrane device and an operation method thereof, and the modular design system comprises a raw water pump, a security filter, a high-pressure pump, a first modular device group, a first inter-section pump, a second modular device group, a second inter-section pump and a third modular device group which are sequentially connected in series, and also comprises a cleaning unit device, a water outlet of the cleaning unit device is respectively connected to water inlets of membrane units in the first modular device group, the second modular device group and the third modular device group, and water outlets of membrane units in the first modular device group, the second modular device group and the third modular device group are connected to a water inlet of the cleaning unit device; the modularized membrane unit modules are arranged and form the modularized device group, so that the modularization and standardization of the membrane treatment system are realized, the design flow is simplified, the rapid assembly is facilitated, the equipment processing, mounting and debugging cost is reduced, and the continuous operation of the system in the cleaning process is ensured while the standardized efficient cleaning is realized.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering, and more particularly to a system for modular design of large-scale reverse osmosis or nanofiltration membrane devices and its operation method. Background Technology

[0002] Reverse osmosis and nanofiltration membrane technologies are becoming increasingly mature and are being widely applied in municipal water supply and drainage, wastewater reuse, chemical industry, metallurgy, and other fields. Large-scale reverse osmosis and nanofiltration membrane devices are also becoming more common. However, current membrane device design lacks a macro-level, holistic, and systematic approach. Most reverse osmosis and nanofiltration membrane devices are customized according to the specific conditions of the project. The number of membranes and the arrangement of membrane arrays are different for each system. There is no effective modular and standardized design. The arrangement and number of membranes between different sections of the system are inconsistent, which affects the economic efficiency of membrane technology to a certain extent. The design, processing, installation, commissioning, operation and maintenance require a lot of manpower and repetitive work. The design of large-scale reverse osmosis and nanofiltration membrane devices often follows the design methods of conventional small membrane devices. The scale of the device is expanded by connecting multiple sets in parallel in a rather crude way. Such design methods, devices and systems require a lot of manpower for design, equipment processing, installation and commissioning, are inconvenient to operate and manage, have high chemical and energy consumption for operation and cleaning, and the separation function of the membrane device is not fully utilized. Although the fouling of each membrane system component has distinct characteristics, such as the first few membranes in each stage, which have high operating pressure and low salt content at the point of entry into the membrane stack and high actual operating membrane flux, their fouling characteristics are inorganic fouling, and they are suitable for alkaline washing to restore membrane performance; the last few membranes in each stage, which have the highest concentration ratio, high salt content and low membrane flux, are mainly fouled by inorganic fouling such as scaling, and are suitable for acid washing to restore membrane performance; due to the lack of modular design, the arrangement and number of membranes in each stage are inconsistent, resulting in inconsistent optimal flow parameters for cleaning each stage of the membrane unit, making it impossible to conveniently and uniformly perform targeted and efficient cleaning of membrane system components with different fouling online; The membrane unit design does not utilize inter-stage pressurization to fully utilize the water production and separation functions of each membrane stage; often, energy recovery is not adopted to recover the pressure energy of the concentrate, resulting in high energy consumption of the membrane unit. Often, the designed cleaning devices have many specifications, or require temporary adjustments to cleaning parameters, or the cleaning devices designed for the project cannot effectively clean and restore the contaminated membrane system components. In some cases, membrane contamination even requires offline cleaning, which not only makes management and operation inconvenient, but also brings a lot of unnecessary human and financial investment.

[0003] Once the above-mentioned relatively outdated large-scale membrane device design schemes are implemented, it will be difficult to change the situation of high chemical and energy consumption, time-consuming and labor-intensive maintenance, and low efficiency of membrane fouling cleaning and recovery, even with the adoption of various optimization measures and methods in the later stages. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a modular design system for large-scale reverse osmosis or nanofiltration membrane devices. This system can solve the problems of high chemical and energy consumption and low membrane fouling cleaning and recovery efficiency caused by the lack of effective modular and standardized design in large-scale reverse osmosis or nanofiltration membrane devices.

[0005] Therefore, the present invention adopts the following technical solution: A modular design system for a large-scale reverse osmosis or nanofiltration membrane device includes a raw water pump, a security filter, a high-pressure pump, a first modular device group, a first inter-stage pump, a second modular device group, a second inter-stage pump, and a third modular device group connected in series. It also includes a cleaning unit device. The outlet of the cleaning unit device is connected to the inlet of each membrane unit in the first, second, and third modular device groups, respectively. The outlet of each membrane unit module in the first, second, and third modular device groups is connected to the inlet of the cleaning unit device.

[0006] Based on the above technical solutions, the present invention may also employ the following further technical solutions, or systematically combine these further technical solutions: The first modular device group, the second modular device group, and the third modular device group each include a plurality of membrane unit modules connected in parallel.

[0007] The membrane unit module includes a cleaning fluid inlet valve, an inlet valve, a membrane unit device, a cleaning fluid outlet valve, a concentrate discharge valve, a permeate discharge valve, and a permeate outlet valve. The outlets of the cleaning fluid inlet valve and the inlet valve are connected in parallel and then connected in series with the inlet of the membrane unit device. The inlets of the cleaning fluid outlet valve and the concentrate discharge valve are connected in parallel and then connected in series with the concentrate outlet of the membrane unit device. The permeate discharge valve and the permeate outlet valve are connected in series, and their inlets are connected in series with the permeate outlet of the membrane unit device.

[0008] The membrane unit module in the first modular device group and the second modular device also includes a concentrate valve. The concentrate valve is connected in parallel with the cleaning fluid outlet valve and the concentrate discharge valve, and the inlet of the three valves is connected in series with the concentrate outlet of the membrane unit device. The concentrate discharge valve is only opened when the system is running and closed when cleaning.

[0009] A first pressure transmitter and a first flow meter are connected in series between the cleaning fluid inlet valve, the outlet of the inlet valve and the inlet of the membrane unit. A second pressure transmitter and a second flow meter are connected in series between the cleaning fluid outlet valve, the concentrate discharge valve, the inlet of the concentrate valve and the concentrate outlet of the membrane unit. A conductivity meter and a third flow meter are connected in series between the inlet of the product water discharge valve and the product water outlet valve and the product water outlet of the membrane unit.

[0010] The cleaning unit includes a cleaning water tank, a cleaning water pump, and a cleaning filter. The cleaning water pump and the cleaning filter are connected in series between the cleaning liquid outlet of the cleaning water tank and the inlet of the cleaning liquid inlet valve. A first cleaning valve is connected between the inlet of the cleaning water pump and the cleaning liquid outlet of the cleaning water tank. A circulating water valve is connected between the outlet of the cleaning water pump and the upper inlet and outlet of the cleaning water tank. A second cleaning valve is connected between the outlet of the cleaning filter and the inlet of the cleaning liquid inlet valve. The inlet and outlet of the cleaning water tank are also connected to inlet and outlet valves.

[0011] The concentrated water discharge valve is used to discharge a portion of the concentrated water, and the outlet of the concentrated water discharge valve is connected to the concentrated water drainage ditch. The product water discharge valve is used to discharge substandard product water, and the outlet of the product water discharge valve is connected to the wastewater drainage ditch.

[0012] In the first modular device group: the inlets of several water inlet valves are connected to the outlet of the high-pressure pump, the inlets of several cleaning fluid inlet valves are connected to the outlet of the cleaning filter, the outlets of several cleaning fluid outlet valves are connected to the cleaning fluid inlet of the cleaning water tank, the outlets of several concentrate valves are connected to the inlet of the first interstage pump, and the produced water from several product water outlet valves is collected through a product water pipeline. In the second modular device group: the inlets of several water inlet valves are connected to the outlet of the first interstage pump, the inlets of several cleaning fluid inlet valves are connected to the outlet of the cleaning filter, the outlets of several cleaning fluid outlet valves are connected to the cleaning fluid inlet of the cleaning water tank, the outlets of several concentrate valves are connected to the inlet of the second interstage pump, and the product water from several product outlet valves is collected through product water pipes; In the third modular device group: the inlets of several water inlet valves are connected to the outlet of the second interstage pump, the inlets of several cleaning fluid inlet valves are connected to the outlet of the cleaning filter, the outlets of several cleaning fluid outlet valves are connected to the cleaning fluid inlet of the cleaning water tank, and the produced water from several water outlet valves is collected through a water production pipeline.

[0013] The membrane unit module also includes a concentrate valve, which is connected in parallel with the cleaning fluid outlet valve and the concentrate discharge valve, and the inlets of the three are connected in series with the concentrate outlet of the membrane unit device. A pressure-exchange capacity recovery device is provided between the outlet of the security filter and the outlet of the concentrate valve of the third modular device group.

[0014] The purpose of this invention is also to overcome the shortcomings of the prior art and provide a system operation method for a modularly designed large-scale reverse osmosis or nanofiltration membrane device. This method can solve the problems of high chemical and energy consumption and low membrane fouling cleaning and recovery efficiency caused by the lack of effective modular and standardized design of large-scale reverse osmosis or nanofiltration membrane devices.

[0015] Therefore, the present invention adopts the following technical solution: An operation method for a modularly designed system of a large-scale reverse osmosis or nanofiltration membrane device includes the following steps: 1. Raw water is pumped to a security filter for pretreatment. 2. After being pressurized by a high-pressure pump, the pretreated water enters the first modular unit group, which consists of multiple membrane unit modules; 3. The concentrate from the first modular unit group is pressurized by the first interstage pump and then enters the second modular unit group. The concentrate from the second modular unit group is pressurized by the second interstage pump and then enters the third modular unit group. IV. The produced water from the first modular unit group, the second modular unit group, and the third modular unit group is collected and output. 5. When cleaning is required, chemical cleaning is performed on any membrane unit module through the cleaning unit device. The cleaning solution enters the membrane unit device through the cleaning solution inlet valve and returns to the cleaning unit device through the cleaning solution outlet valve.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: setting up modular membrane unit modules and assembling them into modular device groups realizes the modularization and standardization of membrane treatment systems, simplifies the design process, facilitates rapid assembly, reduces equipment processing, installation and commissioning costs, achieves standardized and efficient cleaning while ensuring continuous operation of the system during the cleaning process. Attached Figure Description

[0017] Figures 1-4 These are schematic diagrams of different embodiments of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote elements with the same or similar functions throughout. However, it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present invention. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0020] The present invention provides a modular design system for a large-scale reverse osmosis or nanofiltration membrane device, comprising a raw water pump 1, a security filter 2, a high-pressure pump 3, a first modular device group 4, a first inter-stage pump 5, a second modular device group 6, a second inter-stage pump 7, and a third modular device group 8 connected in series. It also includes a cleaning unit device 9, the outlet of which is connected to the inlet of each membrane unit in the first modular device group 4, the second modular device group 6, and the third modular device group 8, and the outlet of each membrane unit module in the first modular device group 4, the second modular device group 6, and the third modular device group 8 is connected to the inlet of the cleaning unit device 9.

[0021] The first modular device group 4, the second modular device group 6, and the third modular device group 8 each include several parallel membrane unit modules 10.

[0022] The recovery rate of the reverse osmosis system is between 40% and 85%. When the recovery rate is close to 40%, the membrane unit devices are preferably connected in parallel. When the recovery rate is close to 85%, the ratio of the number of membrane unit modules 10 in the first modular device group 4, the second modular device group 6, and the third modular device group 8 is preferably 4:2:1.

[0023] The membrane unit module 10 includes a cleaning fluid inlet valve 11, an inlet valve 13, a membrane unit device 18, a cleaning fluid outlet valve 16, a concentrate discharge valve 14, a permeate discharge valve 15, and a permeate outlet valve 17. The outlets of the cleaning fluid inlet valve 11 and the inlet valve 13 are connected in parallel and then connected in series with the inlet of the membrane unit device 18. The inlets of the cleaning fluid outlet valve 16 and the concentrate discharge valve 14 are connected in parallel and then connected in series with the concentrate outlet of the membrane unit device 18. The permeate discharge valve 15 and the permeate outlet valve 17 are connected in series and their inlets are connected in series with the permeate outlet of the membrane unit device 18.

[0024] The membrane unit module 10 in the first modular device group 4 and the second modular device 6 also includes a concentrate valve 12. The concentrate valve 12 is connected in parallel with the cleaning fluid outlet valve 16 and the concentrate discharge valve 14, and the inlet of the three is connected in series with the concentrate outlet of the membrane unit device 18. The concentrate discharge valve 14 is only opened when the system is running and closed when cleaning.

[0025] A first pressure transmitter 19 and a first flow meter 20 are connected in series between the outlet of the cleaning fluid inlet valve 11 and the outlet of the membrane unit 18. A second pressure transmitter 21 and a second flow meter 22 are connected in series between the inlet of the cleaning fluid outlet valve 16, the concentrate discharge valve 14, and the concentrate valve 12 and the concentrate outlet of the membrane unit 18. A conductivity meter 23 and a third flow meter 24 are connected in series between the inlet of the product water discharge valve 15 and the product water outlet valve 17 and the product water outlet of the membrane unit 18.

[0026] The cleaning unit device 9 includes a cleaning water tank 91, a cleaning water pump 92, and a cleaning filter 93. The cleaning water pump 92 and the cleaning filter 93 are connected in series between the cleaning liquid outlet of the cleaning water tank 91 and the inlet of the cleaning liquid inlet valve 11. A first cleaning valve 94 is connected between the inlet of the cleaning water pump 92 and the cleaning liquid outlet of the cleaning water tank 91. A circulating water valve 95 is connected between the outlet of the cleaning water pump 92 and the upper inlet and outlet of the cleaning water tank 91. A second cleaning valve 96 is connected between the outlet of the cleaning filter 93 and the inlet of the cleaning liquid inlet valve 11. The inlet and outlet of the cleaning water tank 91 are also connected to inlet and outlet valves 97.

[0027] The concentrate discharge valve 14 is used to discharge part of the concentrate. The outlet of the concentrate discharge valve 14 is connected to the concentrate drainage ditch 25. The product water discharge valve 15 is used to discharge unqualified product water. The outlet of the product water discharge valve is connected to the wastewater drainage ditch 26.

[0028] In the first modular device group 4: the inlets of several inlet valves 13 are connected to the outlet of the high-pressure pump 3, the inlets of several cleaning fluid inlet valves 11 are connected to the outlet of the cleaning filter 93, the outlets of several cleaning fluid outlet valves 16 are connected to the cleaning fluid inlet of the cleaning water tank 91, the outlets of several concentrate valves 12 are connected to the inlet of the first interstage pump 5, and the produced water from several product water outlet valves 17 is collected through the product water pipeline. In the second modular device group 6: the inlets of several inlet valves 13 are connected to the outlet of the first interstage pump 5, the inlets of several cleaning fluid inlet valves 11 are connected to the outlet of the cleaning filter 93, the outlets of several cleaning fluid outlet valves 16 are connected to the cleaning fluid inlet of the cleaning water tank 91, the outlets of several concentrate valves 12 are connected to the inlet of the second interstage pump 7, and the produced water from several producing outlet valves 17 is collected through the produced water pipeline. In the third modular device group 8: the inlets of several inlet valves 13 are connected to the outlet of the second interstage pump 7, the inlets of several cleaning fluid inlet valves 11 are connected to the outlet of the cleaning filter 93, the outlets of several cleaning fluid outlet valves 16 are connected to the cleaning fluid inlet of the cleaning water tank 91, and the produced water from several produced water outlet valves 17 is collected through the produced water pipeline.

[0029] Membrane unit module 10 also includes a concentrate valve 12, which is connected in parallel with cleaning fluid outlet valve 16 and concentrate discharge valve 14, and the inlets of the three are connected in series with the concentrate outlet of membrane unit device 18. A pressure-exchange capacity recovery device 27 is installed between the outlet of the security filter 2 and the outlet of the concentrate valve 12 of the third modular unit group 8.

[0030] like Figure 2 As shown, the concentrate at the very end of the block membrane treatment system can be equipped with a pressure-exchange energy recovery device. This device uses the concentrate pressure to boost the pressure of the raw water at the outlet of the security filter, adjusts it to the same pressure as the outlet of the high-pressure pump, and then connects it directly to the pipeline at the outlet of the high-pressure pump, allowing it to enter the main inlet pipeline of the membrane system. This recovers the pressure energy of the concentrate and reduces the flow rate of the high-pressure water pumped in by the high-pressure pump, thereby reducing energy consumption.

[0031] The present invention provides a method for operating a modularly designed system for a large-scale reverse osmosis or nanofiltration membrane device, comprising the following steps: 1. Raw water is pumped to the security filter 2 for pretreatment via raw water pump 1; 2. After being pressurized by high-pressure pump 2, the pretreated water enters the first modular device group 4, which consists of multiple membrane unit modules 10. 3. The concentrate from the first modular unit 4 is pressurized by the first interstage pump 5 and then enters the second modular unit 6. The concentrate from the second modular unit 6 is pressurized by the second interstage pump 7 and then enters the third modular unit 8. IV. Water production collection and output from the first modular unit group 4, the second modular unit group 6, and the third modular unit group 8; 5. When cleaning is required, chemical cleaning is performed on any membrane unit module 10 through the cleaning unit device 9. The cleaning solution enters the membrane unit device 18 through the cleaning solution inlet valve 11 and returns to the cleaning unit device through the cleaning solution outlet valve 16.

[0032] The aforementioned membrane unit devices have a uniform membrane arrangement, and uniform size and position of inlet, concentrate outlet, product water outlet, concentrate discharge outlet, product water discharge outlet, cleaning fluid inlet, and cleaning fluid return outlet. They are also equipped with corresponding uniform automatic valve pipelines, uniform pressure, flow, conductivity and other test probes, transmitters and other instruments, and all other uniform membrane unit device specifications.

[0033] The modular design method, devices, and systems, along with their associated valve and piping systems, enable all or part of the membrane unit units to operate in any of the first, second, or third stages of the system, or in a cleaning or shutdown state.

[0034] The aforementioned cleaning unit device 9 can be equipped with multiple high-pressure pumps or high-pressure pump groups, which can be combined in series with pumps of different head and flow rates. The small-head pumps are driven by frequency converters to reduce the power of the frequency converters, thereby reducing energy consumption and investment in frequency converters. The large-head pumps operate at the power frequency and are made to work at their highest efficiency point to reduce system energy consumption. Intelligent control is achieved through a matching instrumentation and control system and a matching electrical system to monitor and subsequently optimize operating parameters through data acquisition and analysis. Considering the overall operation, it can be composed of one or more sets of parallel devices and systems to facilitate the adjustment of its production capacity.

[0035] The modular membrane unit device, with its modular and standardized design, integrates membrane components with consistent fouling characteristics into a single module. This facilitates targeted and effective cleaning and restoration operations using a standardized cleaning device after operation.

[0036] By implementing measures such as setting up inter-stage pumps for cascade pressurization based on salinity and recovering pressure energy from the concentrated water from the final stage, the desalination and water production performance of the membrane can be fully utilized, the system's pressure energy can be fully exploited, and power consumption can be saved.

[0037] For systems with severe membrane fouling and high cleaning frequency, an additional membrane unit can be added as a backup module. During cleaning, other membrane units operate, and after cleaning is completed, it is put into operation. During operation, the modules of the membrane units that need cleaning are shut down for online cleaning, which can improve the operating efficiency of the membrane system.

[0038] The membrane unit features a modular design, consisting of modules with consistent membrane arrangement and quantity. This provides a good foundation for standardization in the cleaning system. The cleaning system offers excellent surface flow rates for the modular membrane units and allows for the design and configuration of membrane unit types (such as acid washing and alkaline washing) and quantities according to system scale, making cleaning more effective and convenient.

[0039] This modular and standardized design method facilitates the AI-driven industrial management of future water treatment membrane technologies.

[0040] Specific embodiments of the present invention are as follows: (1) The influent flow rate is 950 m3 / h, and the raw water contains NaCl with a concentration of 508.5 ppm.

[0041] (2) The reverse osmosis system uses DuPont BW30-400 membrane elements and has a three-stage design: 4*(20*6)+2*(20*6)+1*(20*6), with a total recovery rate of 87.5%. Interstage pump 1 is pressurized by 0.28MPa and interstage pump 2 is pressurized by 0.3MPa.

[0042] (3) Pollution factor 0.85, simulation results are as follows: (4) The main parameters for segment operation are as follows: The recovery rate and flow rate of the three-stage membrane are relatively uniform, which fully utilizes the separation function of the three-stage membrane.

[0043] (5) Cleaning unit, main performance parameters: cleaning flow rate * pressure = 240 m³ / h * 0.28 MPa, The optimal cleaning parameters are achieved by cleaning a membrane unit with 20 membrane housings, with an influent flow rate of approximately 12 m³ / h for each housing. This cleaning unit provides the above-mentioned optimal cleaning flow conditions for all membrane units within the system, which is precisely the beneficial effect resulting from the design concept of this invention.

[0044] (6) Based on a pump efficiency of 75%, the energy consumption per ton of water is 0.53 kWh / m3, which is relatively ideal. It makes full use of the inter-stage pressure and the separation and desalination performance of the membrane. Of course, the energy consumption is also related to the number and performance of the membrane.

[0045] Figure 2 This is a schematic diagram of an implementation scheme for a modular design method, device, and system using a pressure-exchange energy recovery device, as one embodiment of the design method of the present invention.

[0046] The energy-saving benefits of the pressure exchange energy recovery device described in the specific embodiments above are calculated and explained below: The third-stage concentrate of the membrane system, at a pressure of 118.7 m³ / h * 1.14 MPa, passes through an energy recovery device with a rated flow rate of 120 m³ / h (pressure loss approximately 0.10 MPa, maintaining a constant flow rate). This device recovers the pressure energy of the third-stage concentrate. The output of the energy recovery device is 118.7 m³ / h * 1.04 MPa higher than the raw water pressure. This energy is then combined with the outlet pipe of the high-pressure pump and enters the membrane system, reducing the corresponding output of the high-pressure pump. The power saved is: W = Q * p / 3.67 / 0.8 = 118.7 * 1.04 / 3.67 / 0.75 = 44.8494 kW.

[0047] Based on 8000 working hours per year and an electricity price of 0.7 yuan / kWh, the annual electricity cost savings are: E = 43.2592 * 8000 * 0.7 / 10000 = 251,157 yuan.

[0048] The modular design of this invention concentrates the membrane system concentrate in one place, which facilitates the implementation of pressure energy recovery technology and has considerable economic benefits.

[0049] Figure 3 This is a schematic diagram of another embodiment of the modular design method, device, and system of the present invention. As shown in the figure, the No. 8 membrane unit device (with 11 interfaces and automatic valves) is completely interchangeable and can be interchanged with any of the No. 1-7 membrane unit devices as needed. It can be connected to any of the first, second, or third sections of the device and system for operation.

[0050] Figure 4 This is a schematic diagram of another embodiment of the design method of the present invention: a modular design method, device, and system. As shown in the figure, the membrane unit devices 1#-z# (all as shown) Figure 1-2 The configuration shown has 11 interfaces and automatic valves that are completely interchangeable, and any one of them can be connected to any of the first, second, or third sections of the device and system.

[0051] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use a system and its operation method for a modular design of a large reverse osmosis or nanofiltration membrane device according to this invention, and can achieve the positive effects described in this invention.

[0052] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "installed," "set," "equipped with," "connected," "connected," and "sleeve-in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral construction; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between parts of two mechanisms, elements, or systems. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] In the description of this invention, it should be understood that the terms "one end," "the other end," "outer side," "inner side," "horizontal," "end," "length," "outer end," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.

[0054] Furthermore, in practicing the claims of this invention, those skilled in the art can understand and influence variations to the disclosed embodiments through a study of the drawings, the disclosure, and the appended claims. Additionally, in the claims and description, words such as "comprising" and "containing" do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made in accordance with the present invention are covered by the scope of the claims of the present invention, and will not be listed here.

Claims

1. A modular design system for a large-scale reverse osmosis or nanofiltration membrane device, characterized in that, The system includes a raw water pump (1), a security filter (2), a high-pressure pump (3), a first modular device group (4), a first inter-stage pump (5), a second modular device group (6), a second inter-stage pump (7), and a third modular device group (8) connected in series. It also includes a cleaning unit device (9). The outlet of the cleaning unit device (9) is connected to the cleaning fluid inlet valve (11) of each membrane unit module (10) in the first modular device group (4), the second modular device group (6), and the third modular device group (8). The cleaning fluid outlet valve (16) of the membrane unit module (10) in the first modular device group (4), the second modular device group (6), and the third modular device group (8) is connected to the inlet of the cleaning unit device (9).

2. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 1, characterized in that, The first modular device group (4), the second modular device group (6), and the third modular device group (8) each include a plurality of parallel membrane unit modules (10).

3. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 2, characterized in that, The membrane unit module (10) includes a cleaning fluid inlet valve (11), an inlet valve (13), a membrane unit device (18), a cleaning fluid outlet valve (16), a concentrate discharge valve (14), a permeate discharge valve (15), and a permeate outlet valve (17). The outlets of the cleaning fluid inlet valve (11) and the inlet valve (13) are connected in parallel and connected to the inlet of the membrane unit device (18). The inlets of the cleaning fluid outlet valve (16) and the concentrate discharge valve (14) are connected in parallel and connected to the concentrate outlet of the membrane unit device (18). The inlets of the permeate discharge valve (15) and the permeate outlet valve (17) are connected in parallel and connected to the permeate outlet of the membrane unit device (18).

4. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 3, characterized in that, The membrane unit module (10) in the first modular device group (4) and the second modular device (6) further includes a concentrate valve (12). The concentrate valve (12) is connected in parallel with the cleaning fluid outlet valve (16) and the concentrate discharge valve (14), and the inlet of the three is connected in series with the concentrate outlet of the membrane unit device (18). The concentrate discharge valve (14) is only opened when the system is running and closed when cleaning.

5. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 4, characterized in that, A first pressure transmitter (19) and a first flow meter (20) are connected in series between the outlet of the cleaning fluid inlet valve (11) and the outlet of the inlet valve (13) and the inlet of the membrane unit device (18). A second pressure transmitter (21) and a second flow meter (22) are connected in series between the inlet of the cleaning fluid outlet valve (16), the concentrate discharge valve (14), and the concentrate valve (12) and the concentrate outlet of the membrane unit device (18). A conductivity meter (23) and a third flow meter (24) are connected in series between the inlet of the product water discharge valve (15) and the product water outlet valve (17) and the product water outlet of the membrane unit device (18).

6. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 4, characterized in that, The cleaning unit device (9) includes a cleaning water tank (91), a cleaning water pump (92), and a cleaning filter (93). The cleaning water pump (92) and the cleaning filter (93) are connected in series between the cleaning liquid outlet of the cleaning water tank (91) and the inlet of the cleaning liquid inlet valve (11). A first cleaning valve (94) is connected between the inlet of the cleaning water pump (92) and the cleaning liquid outlet of the cleaning water tank (91). A circulating water valve (95) is connected between the outlet of the cleaning water pump (92) and the upper inlet and outlet of the cleaning water tank (91). A second cleaning valve (96) is connected between the outlet of the cleaning filter (93) and the inlet of the cleaning liquid inlet valve (11). The inlet and outlet of the cleaning water tank (91) are also connected to inlet and outlet valves (97).

7. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 3, characterized in that, The concentrated water discharge valve (14) is used to discharge part of the concentrated water. The outlet of the concentrated water discharge valve (14) is connected to the concentrated water drainage ditch (25). The product water discharge valve (15) is used to discharge unqualified product water. The outlet of the product water discharge valve is connected to the wastewater drainage ditch (26).

8. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 6, characterized in that, In the first modular device group (4): the inlets of several water inlet valves (13) are connected to the outlet of the high pressure pump (3), the inlets of several cleaning fluid inlet valves (11) are connected to the outlet of the cleaning filter (93), the outlets of several cleaning fluid outlet valves (16) are connected to the cleaning fluid inlet of the cleaning water tank (91), the outlets of several concentrated water valves (12) are connected to the inlet of the first interstage pump (5), and the produced water of several produced water outlet valves (17) is collected through the produced water pipeline. In the second modular device group (6): the inlets of several water inlet valves (13) are connected to the outlet of the first interstage pump (5), the inlets of several cleaning fluid inlet valves (11) are connected to the outlet of the cleaning filter (93), the outlets of several cleaning fluid outlet valves (16) are connected to the cleaning fluid inlet of the cleaning water tank (91), the outlets of several concentrate valves (12) are connected to the inlet of the second interstage pump (7), and the water produced by several water production outlet valves (17) is collected through the water production pipeline; In the third modular device group (8): the inlets of several water inlet valves (13) are connected to the outlet of the second interstage pump (7), the inlets of several cleaning fluid inlet valves (11) are connected to the outlet of the cleaning filter (93), the outlets of several cleaning fluid outlet valves (16) are connected to the cleaning fluid inlet of the cleaning water tank (91), and the water produced by several water production outlet valves (17) is collected through water production pipes.

9. The system for modular design of a large-scale reverse osmosis or nanofiltration membrane device as described in claim 3, characterized in that, The membrane unit module (10) also includes a concentrate valve (12), which is connected in parallel with the cleaning fluid outlet valve (16) and the concentrate discharge valve (14), and the inlet of the three valves is connected in series with the concentrate outlet of the membrane unit device (18). A pressure-exchange capacity recovery device (27) is provided between the outlet of the security filter (2) and the outlet of the concentrate valve (12) of the third modular device group (8).

10. A method for operating a modularly designed system for a large-scale reverse osmosis or nanofiltration membrane device, characterized in that, Includes the following steps:

1. The raw water is pumped (1) to the security filter (2) for pretreatment; 2. After being pressurized by a high-pressure pump (2), the pretreated water enters the first modular device group (4) consisting of multiple membrane unit modules (10).

3. The concentrated water from the first modular unit (4) is pressurized by the first interstage pump (5) and then enters the second modular unit (6). The concentrated water from the second modular unit (6) is pressurized by the second interstage pump (7) and then enters the third modular unit (8). IV. Water collection and output from the first modular unit group (4), the second modular unit group (6), and the third modular unit group (8); 5. When cleaning is required, chemical cleaning is performed on any membrane unit module (10) through the cleaning unit device (9). The cleaning solution enters the membrane unit device (18) through the cleaning solution inlet valve (11) and returns to the cleaning unit device from the cleaning solution outlet valve (16).

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