Reverse osmosis seawater desalination concentrated water softening and concentrating system
By introducing a seawater desalination subsystem, a concentrated seawater softening subsystem, and a concentrated brine concentration subsystem into the reverse osmosis seawater desalination system, and combining energy recovery and sodium ion exchange, the problems of high equipment investment and poor stability in concentrated seawater treatment are solved, achieving efficient concentrated brine concentration and high freshwater recovery rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2026-04-03
AI Technical Summary
Existing reverse osmosis seawater desalination technologies suffer from high equipment investment, poor stability, and significant loss of monovalent salts in concentrated seawater treatment. In particular, nanofiltration and ultra-high pressure reverse osmosis processes are inadequate in treating divalent salts and scaling.
A reverse osmosis seawater desalination concentrate softening and concentration system is adopted, including a seawater desalination subsystem, a concentrated seawater softening subsystem, and a concentrated brine concentration subsystem. It utilizes reverse osmosis membranes and energy recovery devices under conventional operating pressure, combined with a sodium ion exchanger, to achieve the softening and concentration of concentrated brine, avoiding the use of high-pressure equipment.
It significantly improves the concentration efficiency of reverse osmosis membrane elements under normal operating pressure, with a freshwater recovery rate of up to 75%, greatly enhancing the economy and stability of the system and reducing equipment investment and operation and maintenance costs.
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Figure CN224077205U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of seawater desalination equipment, and in particular to a reverse osmosis seawater desalination concentrate softening and concentration system. Background Technology
[0002] Reverse osmosis seawater desalination technology uses reverse osmosis membranes to desalinate seawater into fresh water while simultaneously producing concentrated seawater. It is an important way for coastal areas to solve the problem of water shortage. In order to protect the marine ecological environment, especially in enclosed sea areas with poor diffusion conditions, there are strict management regulations or discharge standards for the discharge of concentrated seawater, and the comprehensive utilization of concentrated seawater is encouraged.
[0003] In order to improve the comprehensive utilization efficiency of concentrated seawater and reduce the construction scale, investment and operation and maintenance costs of concentrated seawater comprehensive utilization projects, processes or combinations of processes such as nanofiltration and ultra-high pressure reverse osmosis are usually used to further separate or concentrate the concentrated seawater to a high concentration state where the salts are close to saturation.
[0004] Nanofiltration can separate divalent and monovalent salts, but due to the principle of solution charge balance and the separation characteristics of nanofiltration membranes, a considerable proportion of monovalent salts are still removed along with the divalent salts. This represents a significant raw material loss for industries utilizing monovalent salts, such as chlor-alkali production or bromine extraction. Furthermore, nanofiltration does not solve the scaling problem of calcium and magnesium salts during the comprehensive utilization of concentrated seawater; it merely transfers the problems of the reverse osmosis process to the nanofiltration stage. Ultra-high pressure reverse osmosis can concentrate concentrated brine, but its operating pressure reaches as high as 12 MPa. This places extremely high pressure resistance requirements on equipment such as reverse osmosis membranes, membrane housings, high-pressure pumps, energy recovery devices, pipelines, valves, and instruments, resulting in high equipment investment and low system stability.
[0005] In view of the above, this utility model is hereby proposed. Utility Model Content
[0006] The purpose of this invention is to provide a reverse osmosis seawater desalination concentrate softening and concentration system. Using the reverse osmosis seawater desalination concentrate softening and concentration system described in this invention, high-concentration brine can be obtained under the operating pressure of conventional seawater desalination systems. This can significantly improve the concentration efficiency of reverse osmosis membrane elements, achieve a high freshwater recovery rate, and greatly enhance the economy and stability of the system.
[0007] This utility model provides a reverse osmosis seawater desalination concentrate softening and concentration system, which includes a seawater desalination subsystem, a concentrated seawater softening subsystem, and a concentrated brine concentration subsystem.
[0008] The seawater desalination subsystem includes a seawater tank, a first feedwater pump, a first security filter, a first high-pressure pump, a first energy recovery device, an energy recovery booster pump, and a first reverse osmosis membrane device.
[0009] The concentrated seawater softening subsystem includes a sodium ion exchanger;
[0010] The concentrated brine concentration subsystem includes a concentrated brine tank, a second feed water pump, a second security filter, a second high-pressure pump, a second energy recovery device, a second reverse osmosis membrane device, an inter-stage booster pump, and a third reverse osmosis membrane device.
[0011] Furthermore, the seawater tank contains seawater; wherein, the output end of the seawater tank is connected to the input end of the first water supply pump, and the output end of the first water supply pump is connected to the input end of the first security filter, and the seawater is pumped by the first water supply pump and delivered to the first security filter.
[0012] Furthermore, the first output end of the first security filter is connected to the input end of the first high-pressure pump, and the output end of the first high-pressure pump is connected to the input end of the first reverse osmosis membrane device. The first high-pressure pump draws seawater filtered by the first security filter and delivers it to the first reverse osmosis membrane device.
[0013] Furthermore, the first output end of the first reverse osmosis membrane device is connected to a freshwater collection device to collect the freshwater produced after treatment by the first reverse osmosis membrane device.
[0014] Furthermore, the first reverse osmosis membrane device is provided with at least two 7-core pressure vessels; and each pressure vessel is filled with 7 high desalination rate seawater desalination reverse osmosis membrane elements.
[0015] Furthermore, the second output end of the first security filter is connected to the first input end of the first energy recovery device, the first output end of the first energy recovery device is connected to the input end of the energy recovery booster pump, and the output end of the energy recovery booster pump is connected to the input end of the first reverse osmosis membrane device.
[0016] Furthermore, the second output end of the first reverse osmosis membrane device is connected to the second input end of the first energy recovery device, and the concentrated seawater obtained after being treated by the first reverse osmosis membrane device is supplied to the first energy recovery device.
[0017] Furthermore, the second output end of the first energy recovery device is connected to the input end of the sodium ion exchanger, and the concentrated seawater after energy recovery is transported to the sodium ion exchanger through the first energy recovery device.
[0018] Furthermore, the output end of the sodium ion exchanger is connected to the input end of the concentrated brine tank, and the concentrated brine obtained after softening by the sodium ion exchanger is supplied to the concentrated brine tank.
[0019] Furthermore, the concentrated brine tank contains concentrated brine; wherein, the output end of the concentrated brine tank is connected to the input end of the second water supply pump, and the output end of the second water supply pump is connected to the input end of the second security filter, and the concentrated brine is pumped by the second water supply pump and delivered to the second security filter.
[0020] Furthermore, the first output end of the second security filter is connected to the input end of the second high-pressure pump, and the output end of the second high-pressure pump is connected to the input end of the second reverse osmosis membrane device. The concentrated brine filtered by the second security filter is pumped by the second high-pressure pump and transported to the second reverse osmosis membrane device.
[0021] Furthermore, the first output end of the second reverse osmosis membrane device is connected to the input end of the inter-stage booster pump, and the output end of the inter-stage booster pump is connected to the input end of the third reverse osmosis membrane device. The concentrated brine obtained after being processed by the second reverse osmosis membrane device is drawn by the inter-stage booster pump and sent to the third reverse osmosis membrane device.
[0022] Furthermore, the second output terminal of the second security filter is connected to the first input terminal of the second energy recovery device, and the first output terminal of the second energy recovery device is connected to the input terminal of the second reverse osmosis membrane device.
[0023] Furthermore, the first output end of the third reverse osmosis membrane device is connected to the second input end of the second energy recovery device, and the high-concentration brine obtained after being processed by the third reverse osmosis membrane device is supplied to the second energy recovery device.
[0024] Furthermore, the second output terminal of the second energy recovery device is connected to a high-concentration brine collection device to collect the high-concentration brine after energy recovery.
[0025] Furthermore, the second reverse osmosis membrane device is provided with at least two 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate.
[0026] Furthermore, the third reverse osmosis membrane device is provided with at least two 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate.
[0027] Furthermore, the second output end of the second reverse osmosis membrane device and the second output end of the third reverse osmosis membrane device are both connected to the seawater clear water tank, so that the brine obtained after being treated by the second reverse osmosis membrane device and the third reverse osmosis membrane device is returned to the seawater clear water tank.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] The reverse osmosis seawater desalination concentrate softening and concentration system of this invention can produce high-concentration brine with 4 times the salt content of seawater under the operating pressure (8MPa) of conventional seawater desalination systems. It does not require nanofiltration membranes, ultra-high pressure (12MPa) reverse osmosis membranes and matching ultra-high pressure equipment. The freshwater recovery rate is as high as 75%, which is much higher than that of conventional seawater desalination systems (40-50%), and can greatly improve the economy and stability of the system. Attached Figure Description
[0030] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0031] Figure 1 A schematic diagram of the reverse osmosis seawater desalination concentrate softening and concentration system provided by this utility model.
[0032] Among them, 1 is the seawater desalination subsystem, 10 is the seawater clear water tank, 11 is the first feed water pump, 12 is the first security filter, 13 is the first high-pressure pump, 14 is the first reverse osmosis membrane device, 15 is the first energy recovery device, and 16 is the energy recovery booster pump; 2 is the concentrated seawater softening subsystem, 20 is the sodium ion exchanger; 3 is the concentrated brine concentration subsystem, 30 is the concentrated brine tank, 31 is the second feed water pump, 32 is the second security filter, 33 is the second high-pressure pump, 34 is the second reverse osmosis membrane device, 35 is the third reverse osmosis membrane device, 36 is the second energy recovery device, and 37 is the inter-stage booster pump. Detailed Implementation
[0033] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0034] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device 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 utility model.
[0035] In the description of this utility model, it should be noted that the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0036] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0037] Firstly, such as Figure 1 As shown, this utility model provides a reverse osmosis seawater desalination concentrate softening and concentration system, which includes a seawater desalination subsystem 1, a concentrated seawater softening subsystem 2, and a concentrated brine concentration subsystem 3.
[0038] like Figure 1 As shown, the seawater desalination subsystem 1 includes a seawater clear water tank 10, a first feed water pump 11, a first security filter 12, a first high-pressure pump 13, a first energy recovery device 15, an energy recovery booster pump 16, and a first reverse osmosis membrane device 14.
[0039] like Figure 1 As shown, the concentrated seawater softening subsystem 2 includes a sodium ion exchanger 20.
[0040] like Figure 1 As shown, the concentrated brine concentration subsystem 3 includes a concentrated brine tank 30, a second feed water pump 31, a second security filter 32, a second high-pressure pump 33, a second energy recovery device 36, a second reverse osmosis membrane device 34, an inter-stage booster pump 37, and a third reverse osmosis membrane device 35.
[0041] In this invention, the reverse osmosis seawater desalination concentrate softening and concentration system described herein can produce high-concentration brine under the operating pressure of a conventional seawater desalination system. This significantly improves the concentration efficiency of the reverse osmosis membrane element, results in a high freshwater recovery rate, and greatly enhances the system's economy and stability. As an optional implementation, the seawater clear water tank 10 contains seawater.
[0042] As an optional implementation, the total dissolved solids (TDS) of the seawater is C, and the flow rate of the seawater is F.
[0043] As an optional implementation method, C = 25000~40000 mg / L, for example, it can be 25000 mg / L, 30000 mg / L, 35000 mg / L, 40000 mg / L, etc.
[0044] As an optional implementation method, such as Figure 1 As shown, the output end of the seawater clean water tank 10 is connected to the input end of the first water supply pump 11, and the output end of the first water supply pump 11 is connected to the input end of the first security filter 12. The first water supply pump 11 draws seawater clean water and delivers it to the first security filter 12.
[0045] As an optional implementation method, such as Figure 1 As shown, the first output end of the first security filter 12 is connected to the input end of the first high-pressure pump 13, and the output end of the first high-pressure pump 13 is connected to the input end of the first reverse osmosis membrane device 14. The first high-pressure pump 13 draws seawater filtered by the first security filter 12 and delivers it to the first reverse osmosis membrane device 14.
[0046] As an optional implementation method, such as Figure 1 As shown, the first output end of the first reverse osmosis membrane device 14 is connected to a freshwater collection device to collect the freshwater produced after treatment by the first reverse osmosis membrane device 14.
[0047] It is important to note that the seawater is filtered through the first security filter to remove residual suspended solids, colloids, microorganisms, and other impurities from the pretreated water, thus protecting the subsequent high-pressure pump and reverse osmosis membrane. Then, it is pumped by the first high-pressure pump to the first reverse osmosis membrane unit. In this unit, some water molecules and a very small amount of salt ions pass through the reverse osmosis membrane to the low-pressure side, forming freshwater, which is collected by the freshwater collection device. Meanwhile, the portion of seawater that does not pass through the reverse osmosis membrane has its salt content concentrated due to the reduced water content, forming concentrated seawater.
[0048] As an optional implementation, the total dissolved solids (TDS) of the freshwater product is <500 mg / L, and the flow rate of the freshwater product is 3 / 4 F.
[0049] As an optional implementation, according to the material balance CF+C×1 / 2F=X×3 / 4F+500×3 / 4F, the total dissolved solids (TDS) of the concentrated seawater is between (2C-500) and 2C, and the flow rate of the concentrated seawater is 3 / 4F.
[0050] As an optional implementation, the first reverse osmosis membrane device 14 is provided with at least two 7-core pressure vessels, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, etc.
[0051] As an optional implementation, each of the pressure vessels is filled with seven high-desalination-rate seawater desalination reverse osmosis membrane elements.
[0052] As an optional implementation method, such as Figure 1 As shown, the second output terminal of the first security filter 12 is connected to the first input terminal of the first energy recovery device 15, the first output terminal of the first energy recovery device 15 is connected to the input terminal of the energy recovery booster pump 16, and the output terminal of the energy recovery booster pump 16 is connected to the input terminal of the first reverse osmosis membrane device 14.
[0053] As an optional implementation method, such as Figure 1 As shown, the second output end of the first reverse osmosis membrane device 14 is connected to the second input end of the first energy recovery device 15, and the concentrated seawater obtained after being treated by the first reverse osmosis membrane device 14 is supplied to the first energy recovery device 15.
[0054] It is important to note that in the first energy recovery device, the high-pressure concentrated seawater discharged from the first reverse osmosis membrane device exchanges pressure with the low-pressure feed water, recovering the hydraulic energy of the high-pressure concentrated seawater and transferring it to the low-pressure feed water (original seawater), thereby significantly reducing the energy consumption of the high-pressure pump. The energy recovery booster pump compensates for pressure losses during the energy recovery process (such as pipeline friction and device efficiency losses), ensuring that the pressure remains stable at the target value.
[0055] As an optional implementation method, such as Figure 1 As shown, the second output end of the first energy recovery device 15 is connected to the input end of the sodium ion exchanger 20, and the concentrated seawater after energy recovery is transported to the sodium ion exchanger 20 through the first energy recovery device 15.
[0056] As an optional implementation method, such as Figure 1 As shown, the output end of the sodium ion exchanger 20 is connected to the input end of the concentrated brine tank 30, and the concentrated brine obtained after being softened by the sodium ion exchanger 20 is supplied to the concentrated brine tank 30.
[0057] It is important to note that during the softening process of concentrated seawater through a sodium ion exchanger, sodium-type cation exchange resin is used to remove calcium from the water. 2+ Mg 2+ Plasma and Na on resin + This exchange process reduces the hardness (Ca) of the concentrated brine. 2+ Mg 2+ The concentration of plasma is used to prevent equipment blockage or efficiency reduction due to scaling or precipitation in subsequent processes.
[0058] As an optional implementation method, such as Figure 1 As shown, the concentrated brine tank 30 contains concentrated brine.
[0059] As an optional implementation, the total solids in the concentrated brine are mainly monovalent salts, the total dissolved solids (TDS) of the concentrated brine is (2 ± 1%)C, and the flow rate of the concentrated brine is 3 / 4F.
[0060] As an optional implementation method, such as Figure 1 As shown, the output end of the concentrated brine tank 30 is connected to the input end of the second water supply pump 31, and the output end of the second water supply pump 31 is connected to the input end of the second security filter 32. The concentrated brine is pumped by the second water supply pump 31 and transported to the second security filter 32.
[0061] As an optional implementation method, such as Figure 1 As shown, the first output end of the second security filter 32 is connected to the input end of the second high-pressure pump 33, and the output end of the second high-pressure pump 33 is connected to the input end of the second reverse osmosis membrane device 34. The concentrated brine filtered by the second security filter 32 is pumped by the second high-pressure pump 33 and transported to the second reverse osmosis membrane device 34.
[0062] As an optional implementation method, such as Figure 1 As shown, the first output end of the second reverse osmosis membrane device 34 is connected to the input end of the inter-stage booster pump 37, and the output end of the inter-stage booster pump 37 is connected to the input end of the third reverse osmosis membrane device 35. The concentrated brine obtained after being processed by the second reverse osmosis membrane device is drawn by the inter-stage booster pump 37 and sent to the third reverse osmosis membrane device 35.
[0063] It is important to note that the concentrated brine is filtered through the second security filter to remove residual suspended solids, colloids, microorganisms, and other impurities from the pretreated water, thus protecting the subsequent high-pressure pump and reverse osmosis membrane. It is then pumped to the second reverse osmosis membrane unit by the second high-pressure pump, where it undergoes its first concentration. Some water molecules and a small amount of salt ions in the concentrated brine pass through the reverse osmosis membrane and enter the low-pressure side, forming brine that flows back to the seawater clear water tank. The first concentrated brine that does not pass through the reverse osmosis membrane in the second unit is pumped to the third unit for a second concentration via an inter-stage booster pump. Similarly, some water molecules and some salt ions pass through the reverse osmosis membrane and enter the low-pressure side, forming brine that flows back to the seawater clear water tank. The highly concentrated brine that does not pass through the reverse osmosis membrane in the third unit is then transported to the energy recovery device.
[0064] It should be noted that an inter-stage booster pump is installed between the second and third reverse osmosis membrane units in the concentrated brine concentration subsystem. This allows the energy return booster pump to be eliminated simultaneously. This balances the inter-stage pressure of the reverse osmosis membrane units without increasing system investment, thereby improving the concentration efficiency of the reverse osmosis membrane elements and further reducing system operation and maintenance costs.
[0065] As an optional implementation method, such as Figure 1 As shown, the second output terminal of the second security filter 32 is connected to the first input terminal of the second energy recovery device 36, and the first output terminal of the second energy recovery device 36 is connected to the input terminal of the second reverse osmosis membrane device 34.
[0066] As an optional implementation method, such as Figure 1 As shown, the first output end of the third reverse osmosis membrane device 35 is connected to the second input end of the second energy recovery device 36, and the high-concentration brine obtained after being processed by the third reverse osmosis membrane device 35 is supplied to the second energy recovery device 36.
[0067] As an optional implementation method, such as Figure 1 As shown, the second output terminal of the second energy recovery device 36 is connected to the high-concentration brine collection device to collect the high-concentration brine after energy recovery.
[0068] As an optional implementation, the total solids in the high-concentration brine are mainly monovalent salts, the total dissolved solids (TDS) of the high-concentration brine is (4±5%)C, the flow rate of the high-concentration brine is 1 / 4F, and the high-concentration brine can be used for the comprehensive utilization of concentrated seawater in chlor-alkali industries or bromine extraction projects.
[0069] As an optional implementation, the second reverse osmosis membrane device 34 is provided with at least two 6-core pressure vessels, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, etc.
[0070] As an optional implementation, each of the pressure vessels is filled with 6 reverse osmosis membrane elements for brine concentration with a certain desalination rate.
[0071] As an optional implementation, the third reverse osmosis membrane device 35 is provided with at least two 6-core pressure vessels, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, etc.
[0072] As an optional implementation, each of the pressure vessels is filled with 6 reverse osmosis membrane elements for brine concentration with a certain desalination rate.
[0073] As an optional implementation method, such as Figure 1 As shown, the second output end of the second reverse osmosis membrane device 34 and the second output end of the third reverse osmosis membrane device 35 are both connected to the seawater clear water tank 10, and the brine obtained after being processed by the second reverse osmosis membrane device 34 and the third reverse osmosis membrane device 35 is returned to the seawater clear water tank 10.
[0074] As an optional implementation, the total solids in the brine are mainly monovalent salts, the total dissolved solids (TDS) of the brine is (1 ± 2%)C, and the flow rate of the brine is 1 / 2F.
[0075] Secondly, this utility model provides a method for softening concentrated water from reverse osmosis seawater desalination, wherein the method employs the reverse osmosis seawater desalination concentrated water softening and concentration system described in the first aspect, specifically including:
[0076] (1) Seawater desalination: The pretreated seawater (TDS is C, flow rate is F) is processed by the seawater desalination subsystem 1 to obtain freshwater product (TDS < 500 mg / L, flow rate is 3 / 4 F) and concentrated seawater (TDS is 2 C, flow rate is 3 / 4 F); (the freshwater product is collected directly, and the concentrated seawater is further softened in the next step);
[0077] (2) Concentrated seawater softening: After being processed by concentrated seawater softening subsystem 2, concentrated brine is obtained (the total dissolved solids are mainly monovalent salts, the TDS is 2C, and the flow rate is 3 / 4F); (the concentrated brine is then further concentrated in the next step);
[0078] (3) Concentration of concentrated brine: After being processed by the concentrated brine concentration subsystem 3, the concentrated brine is respectively obtained as high-concentration brine (the total dissolved solids are mainly monovalent salts, the TDS is 4C, and the flow rate is 1 / 4F) and brine (the total dissolved solids are mainly monovalent salts, the TDS is C, and the flow rate is 1 / 2F); (the high-concentration brine can be collected after energy recovery, and the brine is returned to the seawater clear water tank).
[0079] The present invention will be further illustrated by the following embodiments. Unless otherwise specified, the materials in the embodiments are prepared according to existing methods or purchased directly from the market.
[0080] Example 1
[0081] This embodiment provides a reverse osmosis seawater desalination concentrate softening and concentration system, which includes a seawater desalination subsystem, a concentrated seawater softening subsystem, and a concentrated brine concentration subsystem.
[0082] The seawater desalination subsystem includes a seawater clear water tank, a first feed water pump, a first security filter, a first high-pressure pump, a first energy recovery device, an energy recovery booster pump, and a first reverse osmosis membrane device; the concentrated seawater softening subsystem includes a sodium ion exchanger; and the concentrated brine concentrating subsystem includes a concentrated brine tank, a second feed water pump, a second security filter, a second high-pressure pump, a second energy recovery device, a second reverse osmosis membrane device, an inter-stage booster pump, and a third reverse osmosis membrane device.
[0083] The seawater tank contains seawater; the output of the seawater tank is connected to the input of the first water pump, and the output of the first water pump is connected to the input of the first security filter. The seawater is pumped by the first water pump and delivered to the first security filter.
[0084] The first output end of the first security filter is connected to the input end of the first high-pressure pump, and the output end of the first high-pressure pump is connected to the input end of the first reverse osmosis membrane device. The first high-pressure pump draws seawater filtered by the first security filter and delivers it to the first reverse osmosis membrane device. The first output end of the first reverse osmosis membrane device is connected to a freshwater collection device to collect the freshwater produced after treatment by the first reverse osmosis membrane device.
[0085] The first reverse osmosis membrane device is equipped with 75 seven-core pressure vessels; and each pressure vessel is filled with seven high-desalination-rate seawater desalination reverse osmosis membrane elements.
[0086] Specifically, the second output end of the first security filter is connected to the first input end of the first energy recovery device, the first output end of the first energy recovery device is connected to the input end of the energy recovery booster pump, and the output end of the energy recovery booster pump is connected to the input end of the first reverse osmosis membrane device; the second output end of the first reverse osmosis membrane device is connected to the second input end of the first energy recovery device, supplying concentrated seawater obtained after treatment by the first reverse osmosis membrane device to the first energy recovery device; and the second output end of the first energy recovery device is connected to the input end of the sodium ion exchanger, supplying the concentrated seawater after energy recovery to the sodium ion exchanger through the first energy recovery device.
[0087] The output end of the sodium ion exchanger is connected to the input end of the concentrated brine tank, supplying the concentrated brine softened by the sodium ion exchanger to the concentrated brine tank; and the concentrated brine tank contains concentrated brine; wherein the output end of the concentrated brine tank is connected to the input end of the second water supply pump, and the output end of the second water supply pump is connected to the input end of the second security filter, so that the concentrated brine is pumped by the second water supply pump and transported to the second security filter.
[0088] The first output end of the second security filter is connected to the input end of the second high-pressure pump, and the output end of the second high-pressure pump is connected to the input end of the second reverse osmosis membrane device. The concentrated brine filtered by the second security filter is pumped by the second high-pressure pump and delivered to the second reverse osmosis membrane device. The first output end of the second reverse osmosis membrane device is connected to the input end of the inter-stage booster pump, and the output end of the inter-stage booster pump is connected to the input end of the third reverse osmosis membrane device. The concentrated brine obtained after treatment by the second reverse osmosis membrane device is pumped by the inter-stage booster pump and delivered to the third reverse osmosis membrane device.
[0089] The second output end of the second security filter is connected to the first input end of the second energy recovery device, and the first output end of the second energy recovery device is connected to the input end of the second reverse osmosis membrane device. The first output end of the third reverse osmosis membrane device is connected to the second input end of the second energy recovery device, and the high-concentration brine obtained after treatment by the third reverse osmosis membrane device is supplied to the second energy recovery device. The second output end of the second energy recovery device is connected to the high-concentration brine collection device to collect the high-concentration brine after energy recovery.
[0090] The second reverse osmosis membrane device is provided with at least 24 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate; and the third reverse osmosis membrane device is provided with at least 11 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate.
[0091] The second output end of the second reverse osmosis membrane device and the second output end of the third reverse osmosis membrane device are both connected to the seawater clear water tank, and the brine obtained after being processed by the second reverse osmosis membrane device and the third reverse osmosis membrane device is returned to the seawater clear water tank.
[0092] Example 2
[0093] This embodiment provides a method for softening concentrated water from reverse osmosis seawater desalination. The method uses the reverse osmosis seawater desalination concentrated water softening and concentration system provided in Embodiment 1, and specifically includes:
[0094] (1) Seawater desalination: Under an operating pressure of 8 MPa, the pretreated seawater (TDS = C = 35000 mg / L, flow rate F = 10000 m³ / L) was desalinated. 3 / d), after treatment by the seawater desalination subsystem, freshwater product (TDS < 500 mg / L, flow rate 3 / 4F = 7500 m³ / d) is obtained. 3 / d) and concentrated seawater (TDS = 2C = 70000 mg / L, flow rate = 3 / 4F = 7500 m 3 / d); wherein, the freshwater is directly collected (freshwater recovery rate is 75%), and the concentrated seawater continues to undergo the next step of softening;
[0095] (2) Concentrated seawater softening: After being treated by the concentrated seawater softening subsystem, concentrated brine is obtained (the total dissolved solids are mainly monovalent salts, TDS is 2C = 70000 mg / L, and the flow rate is 3 / 4F = 7500 m³ / L). 3 / d); wherein the concentrated brine is further concentrated in the next step;
[0096] (3) Concentration of concentrated brine: Under an operating pressure of 8 MPa, the concentrated brine is processed by the concentrated brine concentration subsystem to obtain high-concentration brine (the total dissolved solids are mainly monovalent salts, TDS is 4C = 140000 mg / L, and the flow rate is 1 / 4F = 2500 m³ / L). 3 / d)) and brine (total dissolved solids are mainly monovalent salts, TDS is C = 35000 mg / L, flow rate is 1 / 2F); wherein, the high-concentration brine can be collected after energy recovery, and the brine is returned to the seawater clear water tank.
[0097] 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 the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A reverse osmosis seawater desalination concentrate softening and concentration system, characterized in that, The reverse osmosis seawater desalination concentrate softening and concentration system includes a seawater desalination subsystem, a concentrated seawater softening subsystem, and a concentrated brine concentration subsystem. The seawater desalination subsystem includes a seawater tank, a first feedwater pump, a first security filter, a first high-pressure pump, a first energy recovery device, an energy recovery booster pump, and a first reverse osmosis membrane device. The concentrated seawater softening subsystem includes a sodium ion exchanger; The concentrated brine concentration subsystem includes a concentrated brine tank, a second feed water pump, a second security filter, a second high-pressure pump, a second energy recovery device, a second reverse osmosis membrane device, an inter-stage booster pump, and a third reverse osmosis membrane device.
2. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The seawater tank contains seawater; the output end of the seawater tank is connected to the input end of the first water pump, and the output end of the first water pump is connected to the input end of the first security filter. The seawater is pumped by the first water pump and delivered to the first security filter.
3. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The first output end of the first security filter is connected to the input end of the first high-pressure pump, and the output end of the first high-pressure pump is connected to the input end of the first reverse osmosis membrane device. The first high-pressure pump draws seawater filtered by the first security filter and delivers it to the first reverse osmosis membrane device. Furthermore, the first output end of the first reverse osmosis membrane device is connected to a freshwater collection device to collect the freshwater produced after treatment by the first reverse osmosis membrane device.
4. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1 or 3, characterized in that, The first reverse osmosis membrane device is provided with at least two 7-core pressure vessels; and each pressure vessel is filled with 7 high desalination seawater desalination reverse osmosis membrane elements.
5. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The second output terminal of the first security filter is connected to the first input terminal of the first energy recovery device, the first output terminal of the first energy recovery device is connected to the input terminal of the energy recovery booster pump, and the output terminal of the energy recovery booster pump is connected to the input terminal of the first reverse osmosis membrane device. Furthermore, the second output end of the first reverse osmosis membrane device is connected to the second input end of the first energy recovery device, and the concentrated seawater obtained after being treated by the first reverse osmosis membrane device is supplied to the first energy recovery device. Furthermore, the second output end of the first energy recovery device is connected to the input end of the sodium ion exchanger, and the concentrated seawater after energy recovery is transported to the sodium ion exchanger through the first energy recovery device.
6. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The output end of the sodium ion exchanger is connected to the input end of the concentrated brine tank, and the concentrated brine obtained after being softened by the sodium ion exchanger is supplied to the concentrated brine tank. The concentrated brine tank contains concentrated brine; the output end of the concentrated brine tank is connected to the input end of the second water supply pump, and the output end of the second water supply pump is connected to the input end of the second security filter. The concentrated brine is pumped by the second water supply pump and delivered to the second security filter.
7. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The first output end of the second security filter is connected to the input end of the second high-pressure pump, and the output end of the second high-pressure pump is connected to the input end of the second reverse osmosis membrane device. The concentrated brine filtered by the second security filter is pumped by the second high-pressure pump and transported to the second reverse osmosis membrane device. Furthermore, the first output end of the second reverse osmosis membrane device is connected to the input end of the inter-stage booster pump, and the output end of the inter-stage booster pump is connected to the input end of the third reverse osmosis membrane device. The concentrated brine obtained after being processed by the second reverse osmosis membrane device is drawn by the inter-stage booster pump and sent to the third reverse osmosis membrane device.
8. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The second output terminal of the second security filter is connected to the first input terminal of the second energy recovery device, and the first output terminal of the second energy recovery device is connected to the input terminal of the second reverse osmosis membrane device. Furthermore, the first output end of the third reverse osmosis membrane device is connected to the second input end of the second energy recovery device, and the high-concentration brine obtained after being processed by the third reverse osmosis membrane device is supplied to the second energy recovery device; Furthermore, the second output terminal of the second energy recovery device is connected to a high-concentration brine collection device to collect the high-concentration brine after energy recovery.
9. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1 or 7, characterized in that, The second reverse osmosis membrane device is provided with at least two 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate. And / or, the third reverse osmosis membrane device is provided with at least two 6-core pressure vessels; and each pressure vessel is filled with 6 brine concentration reverse osmosis membrane elements with a certain desalination rate.
10. The reverse osmosis seawater desalination concentrate softening and concentration system according to claim 1, characterized in that, The second output end of the second reverse osmosis membrane device and the second output end of the third reverse osmosis membrane device are both connected to the seawater clear water tank, and the brine obtained after being processed by the second reverse osmosis membrane device and the third reverse osmosis membrane device is returned to the seawater clear water tank.