Produced water diversion reverse osmosis system and process

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a produced water diversion reverse osmosis system and a produced water diversion reverse osmosis process, reverse pressure formed by a blind plate is utilized to reduce osmosis driving force of a front-end membrane element, concentration polarization and compaction effect generated in a long-term operation process of the front-end membrane element are reduced, and flux uniformity of a first-stage reverse osmosis pressure container is optimized; the second-stage reverse osmosis unit B is used for carrying out secondary treatment on the water produced at the rear end of the first-stage reverse osmosis so as to improve the water quality of the produced water; the produced water subjected to secondary treatment of the second-stage reverse osmosis unit A and the second-stage reverse osmosis unit B is directly collected, the concentrated water produced by the second-stage reverse osmosis unit A flows back to an inlet of the second-stage reverse osmosis unit B, and the concentrated water produced by the second-stage reverse osmosis unit B flows back to an inlet of the first-stage reverse osmosis unit, so that the water inlet salinity and the operation energy consumption are reduced, and the total recovery rate of the reverse osmosis system is improved.

Description

Technical Field

[0001] This application belongs to the technical field of water treatment, and particularly relates to a water production split reverse osmosis system and process. Background Art

[0002] Due to advantages such as low energy consumption, strong adaptability, and high operation stability, reverse osmosis technology has become one of the core technologies in the field of seawater desalination. However, in a complex water environment, the water quality of the produced water by the traditional single-stage reverse osmosis process is usually poor, and the system recovery rate is limited. The membrane elements are extremely vulnerable to concentration polarization, resulting in a relatively low operation efficiency of the system. Compared with the single-stage reverse osmosis process, the two-stage reverse osmosis process significantly improves the system performance by adding a second-stage reverse osmosis to deeply treat the low-salt produced water of the first-stage reverse osmosis. In addition, the two-stage reverse osmosis process can effectively improve the system recovery rate and reduce the concentrated water discharge by optimizing the pressure distribution and reflux design, thereby reducing the water production energy consumption of the reverse osmosis system.

[0003] In the existing two-stage reverse osmosis process, the water flux of the front-end membrane elements in the first-stage reverse osmosis pressure vessel is usually higher than that of the rear-end membrane elements. This easily leads to uneven flux distribution in the membrane module, causing concentration polarization and compaction effects in the front-end membrane elements, affecting the separation performance of the front-end membrane elements, significantly shortening their service life and increasing their replacement frequency. At the same time, the uneven operation pressure and energy distribution often result in relatively high system operation energy consumption. In addition, the treatment path of the traditional two-stage reverse osmosis process is relatively single and cannot perform split treatment on the produced water with different water qualities of the first-stage reverse osmosis, making it difficult to finely optimize the terminal produced water quality. These problems not only limit the application of the two-stage reverse osmosis process in large / super-large seawater desalination projects but also increase the operation and maintenance costs of the reverse osmosis system. Summary of the Invention

[0004] To overcome the deficiencies of the existing process technology, the present invention proposes a water production split reverse osmosis system and process to improve the total recovery rate of the reverse osmosis system. The technical solution is as follows: A water production split reverse osmosis system includes a first-stage reverse osmosis unit, a second-stage reverse osmosis unit A, and a second-stage reverse osmosis unit B; The first-stage reverse osmosis unit includes a high-pressure pump 1 and a reverse osmosis pressure vessel 1; a blind plate is provided inside the reverse osmosis pressure vessel 1; one end of the high-pressure pump 1 is connected to the water inlet pipe, and the other end is connected to the reverse osmosis pressure vessel 1; The water production port of the reverse osmosis pressure vessel 1 is connected to the reverse osmosis pressure vessel 2 of the second-stage reverse osmosis unit A and the terminal water production unit, and the concentrated water port of the first-stage reverse osmosis pressure vessel 1 is connected to the high-pressure pump 2; The second - stage reverse osmosis unit A includes reverse osmosis pressure vessel two and reverse osmosis pressure vessel three; the water production port of the reverse osmosis pressure vessel two is connected to the terminal water production unit, and the concentrated water port is connected to the reverse osmosis pressure vessel three. The water production port of the reverse osmosis pressure vessel three is connected to the terminal water production unit, and the concentrated water port is connected to the water inlet of high - pressure pump two. The second - stage reverse osmosis unit B includes reverse osmosis pressure vessel four and reverse osmosis pressure vessel five; the water inlet of the reverse osmosis pressure vessel four is connected to high - pressure pump two, the water production port is connected to the terminal water production unit, and the concentrated water port is connected to the reverse osmosis pressure vessel five; the water production port of the reverse osmosis pressure vessel five is connected to the terminal water production unit, and the concentrated water port is connected to the water inlet of high - pressure pump one.

[0005] Preferably, the first - stage reverse osmosis unit includes an energy recovery system. The water inlets of the energy recovery system are respectively connected to the concentrated water port of the reverse osmosis pressure vessel one and the water inlet pipe, and its water outlets are respectively connected to high - pressure pump three and the discharge unit. High - pressure pump three is connected to the water inlet of the reverse osmosis pressure vessel one.

[0006] Preferably, the reverse osmosis pressure vessel one internally contains multiple serially - connected membrane element containers. Assuming the number of membrane element containers is n, when n is odd, a blind plate is added at the concentrated water port of the ((n + 1) / 2) - th membrane element container; when n is even, a blind plate is added at the concentrated water port of the ((n + 1) / 2) - th or n / 2 - th membrane element container; the blind plate includes any one of an 8 - shaped blind plate, a plug plate, and a gasket ring.

[0007] Preferably, the reverse osmosis pressure vessel one includes a front end and a rear end. The front end includes the unit from the first membrane element container to the membrane element container where the blind plate is provided; the rear end includes the unit from the membrane element container connected to the membrane element container with the blind plate to the last membrane element container; the front end is connected to the reverse osmosis pressure vessel two and the terminal water production unit, and the rear end is connected to the water inlet of high - pressure pump two and the water inlet of the energy recovery system.

[0008] Preferably, the reverse osmosis pressure vessel two, reverse osmosis pressure vessel three, reverse osmosis pressure vessel four, and reverse osmosis pressure vessel five all adopt a multi - stage configuration, with the number of stages being 2 - 3; each stage internally contains multiple membrane element containers arranged in a standard matrix, and the number of membrane element containers is 7 - 8.

[0009] Preferably, only a detection unit is provided at the water production port and the concentrated water port of the reverse osmosis pressure vessel one, reverse osmosis pressure vessel two, reverse osmosis pressure vessel three, reverse osmosis pressure vessel four, and reverse osmosis pressure vessel five.

[0010] Preferably, a pressure-resistant spiral-wound reverse osmosis membrane element is selected for the first reverse osmosis pressure vessel, and low-pressure high-flux spiral-wound reverse osmosis membrane elements are selected for the second, third, fourth, and fifth reverse osmosis pressure vessels to promote the uniform distribution of the flux in the reverse osmosis system.

[0011] A water production diversion reverse osmosis process includes the following steps: The water inlet of the first reverse osmosis pressure vessel is pumped in by the first high-pressure pump. The blind plate in the first reverse osmosis pressure vessel divides it into a front end and a rear end. The front end is connected to the water production outlet, and the rear end is connected to the concentrated water outlet; the produced water enters the second reverse osmosis pressure vessel of the second-stage reverse osmosis unit A for treatment. The concentrated water after treatment is desalinated again by the third reverse osmosis pressure vessel. The desalinated produced water is jointly transported to the terminal water production unit for mixing with the produced water of the fourth reverse osmosis pressure vessel of the second-stage reverse osmosis unit B. The concentrated water produced by the third reverse osmosis pressure vessel is then returned to the water inlet end of the first reverse osmosis pressure vessel of the first stage; The concentrated water of the first reverse osmosis pressure vessel is pumped into the fourth reverse osmosis pressure vessel by the second high-pressure pump. After being desalinated again by the fourth reverse osmosis pressure vessel, the produced water is sent to the terminal water production unit. The concentrated water of the fourth reverse osmosis pressure vessel is desalinated again by the fifth reverse osmosis pressure vessel, and the produced water is sent to the terminal water production unit, and the concentrated water is returned to the water inlet end of the first high-pressure pump.

[0012] Preferably, the concentrated water outlet of the first reverse osmosis pressure vessel is connected to an energy recovery system. The liquid in the inlet pipeline is mixed with the concentrated water outlet of the first reverse osmosis pressure vessel in the energy recovery system. Part of the concentrated water formed after mixing enters the water inlet end of the first reverse osmosis pressure vessel through the third high-pressure pump of the energy recovery system, and the other part is discharged through the discharge unit.

[0013] Preferably, a part of the inlet pipe enters the first reverse osmosis pressure vessel through the first high-pressure pump. Under the physical blocking effect of the blind plate, the flow path of the produced water of the front-end membrane elements in the first reverse osmosis pressure vessel changes, thereby promoting the diversion of the produced water between the front end and the rear end. Among them, by moving the position of the blind plate, the diversion ratio of the produced water between the front end and the rear end of the first reverse osmosis pressure vessel can be easily adjusted; Under the action of the blind plate for water production diversion, the high-quality produced water at the front end enters the second-stage reverse osmosis unit A through the bypass.

[0014] Compared with the prior art, the beneficial effects of this application are as follows: (1) Compared with the traditional two-stage reverse osmosis process, in the present invention, by installing a blind plate in the first-stage reverse osmosis pressure vessel, the osmotic driving force of the front-end membrane elements is reduced by the back pressure formed by the blind plate, thereby effectively slowing down the concentration polarization and compaction effects generated by the front-end membrane elements during long-term operation, and reducing the membrane pollution and scaling problems, and prolonging the service life of the front-end membrane elements; (2) In the traditional two-stage reverse osmosis process, the high flux of the membrane elements at the front end of the first-stage reverse osmosis often reduces the driving force of the membrane elements at the rear end, resulting in insufficient utilization of the rear-end membrane elements. In the present invention, by adding a blind plate inside the pressure vessel of the first-stage reverse osmosis membrane module, the blind plate is used to limit the water production at the front end, which can effectively promote the water flow to the rear-end membrane elements, thereby redistributing the pressure and flow rate inside the pressure vessel, enhancing the water production of the rear-end membrane elements, promoting the uniform distribution of the flux inside the pressure vessel, and improving the overall operation efficiency of the reverse osmosis system; (3) Compared with the traditional two-stage reverse osmosis process, in the present invention, by adding a blind plate, the water production of different water qualities in the first-stage reverse osmosis membrane module can be effectively shunted. The water production of lower water quality at the rear end is re-treated through the conventional second-stage reverse osmosis B, while the water production of high water quality at the front end enters the second-stage reverse osmosis A for fine treatment through a bypass, and the water quality of the terminal mixed water production of the system is flexibly adjusted by using the water production of high water quality; (4) In the present invention, the back pressure formed by the blind plate drives the water production at the front end of the first-stage reverse osmosis pressure vessel to be transmitted to the second-stage reverse osmosis A, effectively reducing the number of high-pressure pumps for the water production at the rear end of the second-stage reverse osmosis, which is beneficial to reducing the operation energy consumption and plant power consumption of the system; (5) Different from the traditional series two-stage reverse osmosis process, the present invention adds a second-stage reverse osmosis A that operates in parallel with the second-stage reverse osmosis B, and uses the second-stage reverse osmosis A to finely treat the high-quality water production at the front end of the first-stage reverse osmosis pressure vessel; among them, the concentrated water (with water quality higher than the water production at the rear end of the first-stage reverse osmosis pressure vessel) after the second-stage treatment of the second-stage reverse osmosis is returned to the water inlet end of the second-stage reverse osmosis B, effectively reducing the salt concentration of the water inlet of the second-stage reverse osmosis B and improving the recovery rate of the system. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the present application; Figure 2 It is a schematic diagram of the blind plate installation position; Figure 3 It is a schematic diagram of the blind plate structure.

[0016] Water inlet pipe, 2 - High-pressure pump 1, 21 - High-pressure pump 2, 3 - Reverse osmosis pressure vessel 1, 4 - Energy recovery system, 41 - High-pressure pump 3, 5 - Reverse osmosis pressure vessel 2, 6 - Reverse osmosis pressure vessel 3, 7 - Terminal water production unit, 8 - Discharge unit, 9 - Reverse osmosis pressure vessel 4, 10 - Reverse osmosis pressure vessel 5; 38 - Blind plate, 381 - Solid round plate, 382 - Solid lifting handle, 383 - Hollow lifting ring. Detailed Embodiments

[0017] The technical solution of the present application will be described in detail below through specific embodiments and the accompanying drawings. It should be understood that the specific features in the embodiments of the present application are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. The specific technical features can be combined with each other.

[0018] A water production diversion reverse osmosis system includes a first-stage reverse osmosis unit, a second-stage reverse osmosis unit A, and a second-stage reverse osmosis unit B; the first-stage reverse osmosis unit includes a high-pressure pump 2 and a reverse osmosis pressure vessel 3; a blind plate 38 is provided inside the reverse osmosis pressure vessel 3; one end of the high-pressure pump 2 is connected to the water inlet pipe 1, and the other end is connected to the reverse osmosis pressure vessel 3; the reverse osmosis pressure vessel 3 includes a front end 30 and a rear end 39, the front end 30 includes a unit from the first membrane element container to the membrane element container provided with a blind plate; the rear end includes a unit from the membrane element container connected after the membrane element container provided with a blind plate to the last membrane element container; the front end is connected to the reverse osmosis pressure vessel 2 5 and the terminal water production unit 7, and the rear end is connected to the water inlet of the high-pressure pump 21 and the water inlet of the energy recovery system 4.

[0019] The water production outlet of the reverse osmosis pressure vessel 3 is connected to the reverse osmosis pressure vessel 2 5 of the second-stage reverse osmosis unit A and the terminal water production unit 7, and the concentrated water outlet of the first-stage reverse osmosis pressure vessel 3 is connected to the high-pressure pump 21; The second-stage reverse osmosis unit A includes a reverse osmosis pressure vessel 2 5 and a reverse osmosis pressure vessel 3 6; the water production outlet of the reverse osmosis pressure vessel 2 5 is connected to the terminal water production unit 7, and the concentrated water outlet is connected to the reverse osmosis pressure vessel 3 6. The water production outlet of the reverse osmosis pressure vessel 3 6 is connected to the terminal water production unit 7, and the concentrated water outlet is connected to the water inlet of the high-pressure pump 21.

[0020] The second-stage reverse osmosis unit B includes a reverse osmosis pressure vessel 4 9 and a reverse osmosis pressure vessel 5 10; the water inlet of the reverse osmosis pressure vessel 4 9 is connected to the high-pressure pump 21, the water production outlet is connected to the terminal water production unit 7, and the concentrated water outlet is connected to the reverse osmosis pressure vessel 5 10; the water production outlet of the reverse osmosis pressure vessel 5 10 is connected to the terminal water production unit 7, and the concentrated water outlet is connected to the water inlet of the high-pressure pump 2.

[0021] The first-stage reverse osmosis unit includes an energy recovery system 4. The water inlets of the energy recovery system 4 are respectively connected to the concentrated water outlet of the reverse osmosis pressure vessel 3 and the water inlet pipe 1, and its water outlets are respectively connected to the high-pressure pump 41 and the discharge unit 8. The high-pressure pump 41 is connected to the water inlet of the reverse osmosis pressure vessel 3.

[0022] The first reverse osmosis pressure vessel 3 contains multiple serially connected membrane element containers. Assuming the number of membrane element containers is n, when n is odd, a blind plate 38 is added at the concentrated water outlet of the (n - 1) / 2-th membrane element container; when n is even, a blind plate 38 is added at the concentrated water outlet of the n / 2-th membrane element container; the blind plate 38 includes any one of an 8-shaped blind plate, a plug plate, and a gasket ring. Figure 2 Among them, the first reverse osmosis pressure vessel 3 includes 7 membrane elements (31 - 37), a blind plate 38, the front end 30 of the first-stage reverse osmosis pressure vessel (including membrane elements 31 - 33), and the rear end 39 of the first-stage reverse osmosis pressure vessel (including membrane elements 34 - 37), and the blind plate 38 includes a solid circular plate 381, a solid lifting handle 382, and a hollow lifting ring 383.

[0023] The second reverse osmosis pressure vessel 5, the third reverse osmosis pressure vessel 6, the fourth reverse osmosis pressure vessel 9, and the fifth reverse osmosis pressure vessel 10 all adopt a multi-stage configuration, with the number of stages being 2 - 3; each stage internally contains multiple membrane element containers arranged in a standard matrix, and the number of membrane element containers is 7 - 8.

[0024] At the product water outlet and concentrated water outlet of the first reverse osmosis pressure vessel 3, the second reverse osmosis pressure vessel 5, the third reverse osmosis pressure vessel 6, the fourth reverse osmosis pressure vessel 9, and the fifth reverse osmosis pressure vessel 10, a detection unit and a switching valve are provided. The detection unit (such as a concentration detector) is used to detect whether the outlet liquid meets the standard. If it does not meet the standard, it needs to be repaired or replaced in time, and the switching valve is opened or closed according to the detection result.

[0025] The first reverse osmosis pressure vessel 3 selects a pressure-resistant spiral wound reverse osmosis membrane element, and the second reverse osmosis pressure vessel 5, the third reverse osmosis pressure vessel 6, the fourth reverse osmosis pressure vessel 9, and the fifth reverse osmosis pressure vessel 10 select a low-pressure high-flux spiral wound reverse osmosis membrane element to promote the uniform distribution of the flux of the reverse osmosis system.

[0026] The present invention proposes a new process for split-flow reverse osmosis for water production. The process flow will be described in detail below through embodiments and drawings. Obviously, the described embodiments are only partial embodiments of the present invention and do not represent all embodiments.

[0027] Embodiment 1 shows a new process for split-flow reverse osmosis for water production. The new process adopted in this embodiment has been applied to a super-large seawater desalination project in the Middle East. This process mainly involves a two-stage reverse osmosis system, which mainly includes a first-stage reverse osmosis unit, a second-stage reverse osmosis unit A, and a second-stage reverse osmosis unit B, as Figure 1 shown. The first-stage reverse osmosis unit mainly includes a high-pressure pump 2, a first reverse osmosis pressure vessel 3, an energy recovery system 4, and an energy recovery system high-pressure pump 41. Among them, the first reverse osmosis pressure vessel 3 is composed of 7 membrane elements arranged in a standard matrix, and the blind plate 38 is located between membrane elements 33 and 34 (Figure 2 ), that is, a blind plate 38 is installed between the 3rd and 4th membrane elements, and the blind plate insertion structure is as Figure 3 shown. Among them, the front-end 30 and rear-end 39 membrane elements of the first reverse osmosis pressure vessel 3 both use 820V-440 type spiral wound reverse osmosis membrane elements with a pressure resistance of 820V.

[0028] The second-stage reverse osmosis includes two subsystems A and B. Both A and B are two-stage reverse osmosis systems, which mainly include the second reverse osmosis pressure vessel 5, the third reverse osmosis pressure vessel 6, the fourth reverse osmosis pressure vessel 9, and the fifth reverse osmosis pressure vessel 10. Each stage of the reverse osmosis pressure vessel contains 7 membrane elements arranged in a standard matrix, and all use 720D-440 type low-pressure high-flux membranes.

[0029] Part of the water inlet pipe 1 enters the first reverse osmosis pressure vessel 3 through the first high-pressure pump 2. Under the physical blocking effect of the blind plate 38, the water production flow path of the front-end 30 membrane elements of the first reverse osmosis pressure vessel 3 changes, thereby promoting the water production diversion between the front-end 30 and the rear-end 39. Among them, the position of the blind plate insertion plate 38 can be flexibly moved by lifting the hollow hanging ring 383 of the blind plate 38, so as to easily adjust the water production diversion ratio between the front-end 30 and the rear-end 39 of the pressure vessel 3.

[0030] Under the water production diversion effect of the blind plate 38, the high-quality water produced at the front-end 30 enters the second-stage reverse osmosis A through a bypass. At the same time, the addition of the blind plate insertion plate 38 causes the pressure in the water production pipe of the front-end 30 membrane elements of the first reverse osmosis pressure vessel 3 to increase to form a back pressure, thereby reducing the osmotic driving force of the front-end 30 membrane elements. This not only reduces the potential impact of concentration polarization on the front-end 30 membrane elements, but also slows down the compaction effect of the front-end 30 membrane elements under high-temperature and high-pressure operating conditions.

[0031] In addition, the back pressure in the water production pipe at the front-end 30 of the first reverse osmosis pressure vessel 3 directly drives the corresponding high-quality water production to be transmitted to the second reverse osmosis pressure vessel 5. The concentrated water produced by the second reverse osmosis pressure vessel 5 is desalinated again by the third reverse osmosis pressure vessel 6. The water produced after desalination by the third reverse osmosis pressure vessel 6 is sent to the terminal water production unit 7 to be mixed with the water produced by the second reverse osmosis pressure vessel 5, while the concentrated water produced by the third reverse osmosis pressure vessel 6 (with a water quality higher than the water produced at the rear-end 39 of the first reverse osmosis pressure vessel 3) is returned to the water inlet end of the second-stage reverse osmosis unit B to reduce the inlet salinity of the second-stage reverse osmosis unit B and improve the system recovery rate.

[0032] The blind plate 38 effectively promotes the water flow to be transmitted to the membrane elements at the rear end 39 by restricting the water production at the front end 30 of the first reverse osmosis pressure vessel 3, redistributes the pressure and flow rate inside the first reverse osmosis pressure vessel 3, significantly enhances the water production of the membrane elements at the rear end 39, and improves the flux uniformity of the pressure vessel 3. The part of the produced water with lower water quality at the rear end 39 of the first reverse osmosis pressure vessel 3 is directly sent to the terminal water production unit 7, and the other part is mixed with the concentrated water of the third reverse osmosis pressure vessel 6 and enters the second reverse osmosis pressure vessel 5 through the second high-pressure pump 21 for desalination. The concentrated water produced by the second reverse osmosis pressure vessel 5 is subjected to advanced treatment through the third reverse osmosis pressure vessel 6. The produced water desalinated by the third reverse osmosis pressure vessel is mixed with the produced water of the second reverse osmosis pressure vessel 5 and then jointly sent to the terminal water production unit 7, while the concentrated water produced by the third reverse osmosis pressure vessel 6 is returned to the water inlet end of the first-stage reverse osmosis unit to reduce the total inlet salinity and operating energy consumption, thereby improving the total recovery rate of the reverse osmosis system.

[0033] After the water inlet pipe 1 is mixed with the concentrated water of the third reverse osmosis pressure vessel 6, a part passes through the energy recovery system 4 and is mixed with the concentrated water produced by the first reverse osmosis pressure vessel 3 inside the energy recovery system 4. A part of the concentrated water formed after mixing enters the water inlet end of the first reverse osmosis pressure vessel 3 through the high-pressure pump three 41 of the energy recovery system, and the other part is discharged through the discharge unit 8.

[0034] Under the conditions of a water temperature of 30 °C and an inlet salinity of 40,000 ppm, in the traditional two-stage reverse osmosis process of Comparative Example 1, each of the first-stage reverse osmosis and the second-stage reverse osmosis includes 20 reverse osmosis frames, and the plant power consumption is relatively high (2.411 kWh / m 3 ). The present invention effectively realizes the water flow diversion between the front end 30 and the rear end 39 of the first reverse osmosis pressure vessel 3 by installing the blind plate 38 inside the first reverse osmosis pressure vessel 3, and the diversion ratio is flexibly adjustable. The design of the water flow diversion of the blind plate 38 not only effectively reduces the number of reverse osmosis configuration frames in the second stage by 10, but also generates a pressure of about 10 kg in the water production pipeline at the front end 30, so as to promote the water production to pass through the second-stage reverse osmosis A without an additional high-pressure pump. In Example 1, the number of the second high-pressure pumps 21 for the water production at the rear end 39 is reduced by 30 - 50%, and the plant power consumption is only 2.033 kWh / m 3 , reducing by about 0.19 - 0.38 kWh / m 3 . In addition, compared with the traditional two-stage reverse osmosis process and the traditional two-stage reverse osmosis process with separate water production by quality, the present invention effectively improves the total recovery rate (38.86%) of the seawater desalination plant through the synergistic effect of the water flow diversion of the blind plate 38 and the bypass design of the second-stage reverse osmosis A, laying a solid foundation for its application in large-scale seawater desalination plants.

[0035] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A water production diversion reverse osmosis system, characterized in that: It includes a first-stage reverse osmosis unit, a second-stage reverse osmosis unit A and a second-stage reverse osmosis unit B; The first-stage reverse osmosis unit comprises a high-pressure pump (2) and a reverse osmosis pressure vessel (3); a blind plate (38) is provided inside the reverse osmosis pressure vessel (3); one end of the high-pressure pump (2) is connected to the water inlet pipe (1), and the other end is connected to the reverse osmosis pressure vessel (3); The water production port of the reverse osmosis pressure vessel 1 (3) is connected to the reverse osmosis pressure vessel 2 (5) of the second-stage reverse osmosis unit A and the terminal water production unit (7), and the concentrated water port of the first-stage reverse osmosis pressure vessel 1 (3) is connected to the high-pressure pump 2 (21); The second-stage reverse osmosis unit A comprises a reverse osmosis pressure vessel 2 (5) and a reverse osmosis pressure vessel 3 (6); the water outlet of the reverse osmosis pressure vessel 2 (5) is connected to the terminal water outlet (7), and the concentrate outlet is connected to the reverse osmosis pressure vessel 3 (6); the water outlet of the reverse osmosis pressure vessel 3 (6) is connected to the terminal water outlet (7), and the concentrate outlet is connected to the water inlet of the high-pressure pump 2 (21); The second-stage reverse osmosis unit B comprises a reverse osmosis pressure vessel four (9) and a reverse osmosis pressure vessel five (10); the water inlet of the reverse osmosis pressure vessel four (9) is connected to the high-pressure pump two (21), the water outlet is connected to the terminal water production unit (7), and the concentrate outlet is connected to the reverse osmosis pressure vessel five (10); the water outlet of the reverse osmosis pressure vessel five (10) is connected to the terminal water production unit (7), and the concentrate outlet is connected to the water inlet of the high-pressure pump one (2).

2. A water production diversion reverse osmosis system according to claim 1, characterized in that: The first-stage reverse osmosis unit comprises an energy recovery system (4), the water inlet of the energy recovery system (4) being respectively connected to the concentrate outlet of the reverse osmosis pressure vessel (3) and the water inlet pipe (1), and the water outlet of the energy recovery system (4) being respectively connected to the high-pressure pump (41) and the discharge unit (8), the high-pressure pump (41) being connected to the water inlet of the reverse osmosis pressure vessel (3).

3. A water production diversion reverse osmosis system according to claim 1, characterized in that: The reverse osmosis pressure vessel (3) contains a plurality of membrane element containers connected in series. Assuming that the number of membrane element containers is n, when n is an odd number, a blind plate (38) is added at the concentrate outlet of the (n+1) / 2th membrane element container; when n is an even number, a blind plate (38) is added at the concentrate outlet of the (n+1) / 2th or n / 2th membrane element container; the blind plate (38) includes any one of an 8-shaped blind plate, an insert plate, and a gasket.

4. A water production diversion reverse osmosis system according to claim 1, characterized in that: The reverse osmosis pressure vessel (3) comprises a front end (30) and a rear end (39), wherein the front end (30) comprises a unit from a first membrane element container to a membrane element container provided with a blind plate; the rear end comprises a unit from a membrane element container connected to the membrane element container provided with a blind plate to a last membrane element container; the front end is connected to the reverse osmosis pressure vessel (5) and the terminal water production unit (7), and the rear end is connected to a water inlet of a high-pressure pump (21) and a water inlet of an energy recovery system (4).

5. A water production diversion reverse osmosis system according to claim 1, characterized in that: Reverse osmosis pressure vessel 2 (5), reverse osmosis pressure vessel 3 (6), reverse osmosis pressure vessel 4 (9), and reverse osmosis pressure vessel 5 (10) are all configured in multiple sections, with 2-3 sections in number; each section contains multiple membrane element containers arranged in a standard matrix, with 7-8 membrane element containers in number.

6. A water production diversion reverse osmosis system according to claim 1, characterized in that: The water outlet and the concentrated water outlet of the reverse osmosis pressure vessel 1 (3), the reverse osmosis pressure vessel 2 (5), the reverse osmosis pressure vessel 3 (6), the reverse osmosis pressure vessel 4 (9) and the reverse osmosis pressure vessel 5 (10) are only provided with detection units.

7. A water production diversion reverse osmosis system according to claim 1, characterized in that: The reverse osmosis pressure vessel 1 (3) uses a pressure-resistant spiral reverse osmosis membrane element, and the reverse osmosis pressure vessel 2 (5), the reverse osmosis pressure vessel 3 (6), the reverse osmosis pressure vessel 4 (9), and the reverse osmosis pressure vessel 5 (10) use a low-pressure high-flux spiral reverse osmosis membrane element to promote uniform flux distribution of the reverse osmosis system.

8. A water production diversion reverse osmosis process, characterized in that: The following steps are involved: The inlet water of the first-stage reverse osmosis pressure vessel 1 (3) is pumped in by the high-pressure pump 1 (2). The blind plate in the reverse osmosis pressure vessel 1 (3) divides it into a front end (30) and a rear end (39). The front end (30) is connected to the water outlet and the rear end is connected to the concentrate outlet. The produced water enters the reverse osmosis pressure vessel 2 (5) of the second-stage reverse osmosis unit A for treatment. The treated concentrate is desalinated again by the reverse osmosis pressure vessel 3 (6). The desalinated produced water and the produced water of the reverse osmosis pressure vessel 4 (9) of the second-stage reverse osmosis unit B are transported to the terminal water production unit (7) for mixing. The concentrate produced by the reverse osmosis pressure vessel 3 (6) flows back to the inlet end of the first-stage reverse osmosis pressure vessel 1 (3). The concentrated water from the reverse osmosis pressure vessel 1 (3) is pumped into the reverse osmosis pressure vessel 4 (9) by the high-pressure pump 2 (21), and after being desalinated again by the reverse osmosis pressure vessel 4 (9), the produced water is sent to the terminal water production unit (7). The concentrated water from the reverse osmosis pressure vessel 4 (9) is desalinated again by the reverse osmosis pressure vessel 5 (10), and the produced water is sent to the terminal water production unit (7), and the concentrated water flows back to the water inlet end of the high-pressure pump 1 (2).

9. A water production diversion reverse osmosis process according to claim 8, characterized in that: The concentrate outlet of the reverse osmosis pressure vessel (3) is connected to the energy recovery system (4). The liquid in the water inlet pipe is mixed with the concentrate outlet of the reverse osmosis pressure vessel (3) in the energy recovery system (4). A portion of the concentrate formed after mixing enters the water inlet end of the reverse osmosis pressure vessel (3) through the energy recovery system high-pressure pump (41), and the other portion is discharged through the discharge unit (8).

10. A water production diversion reverse osmosis process according to claim 8, characterized in that: A portion of the water inlet pipe (1) enters the reverse osmosis pressure vessel (3) through the high-pressure pump (2). Under the physical blocking effect of the blind plate (38), the water production flow path of the membrane element at the front end (30) of the reverse osmosis pressure vessel (3) changes, thereby promoting the water production diversion between the front end (30) and the rear end (39). The water production diversion ratio between the front end (30) and the rear end (39) of the reverse osmosis pressure vessel (3) can be easily adjusted by moving the position of the blind plate (38). Under the action of the blind plate (38) to divert the produced water, the high-quality produced water from the front end (30) enters the second-stage reverse osmosis unit A through the bypass.

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