Reverse osmosis device and seawater desalination system

Abstract

The application discloses a reverse osmosis device, at least comprising a filter core, wherein the filter core comprises a reverse osmosis main body, the reverse osmosis main body comprises a membrane shell, a first reverse osmosis component and a second reverse osmosis component which are installed in the membrane shell, the first reverse osmosis component comprises a first reverse osmosis water collecting pipe and a first reverse osmosis membrane which is wound around the outer periphery of the first reverse osmosis water collecting pipe, the second reverse osmosis component comprises a second reverse osmosis water collecting pipe and a second reverse osmosis membrane which is wound around the outer periphery of the second reverse osmosis water collecting pipe, the second reverse osmosis component is embedded in the first reverse osmosis water collecting pipe, the inlet of the first reverse osmosis membrane is connected with water, and the outlet of the second reverse osmosis water collecting pipe discharges clean water. The reverse osmosis device has the advantages of simple structure, compact layout and small floor area. The application further discloses a seawater desalination system.

Description

Technical Field

[0001] This invention relates to the field of seawater desalination technology, and in particular to a reverse osmosis device and a seawater desalination system. Background Technology

[0002] Seawater desalination, as a technology for increasing freshwater resources, offers reliable water supply and quality unaffected by geographical location, environmental conditions, climate, or social factors. Furthermore, its application is expanding due to the increasing maturity of desalination processes and cost reductions. In particular, the maturation of membrane manufacturing processes has broadened its application scope and driven the technological advancement of membrane-based seawater desalination. Additionally, market demands for high-quality water sources are a major driving force behind the rapid global development of membrane-based seawater desalination. However, membrane-based seawater desalination typically employs a multi-stage reverse osmosis membrane module series connection structure, which presents challenges due to its complex structure and large footprint. Summary of the Invention

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a reverse osmosis device and a seawater desalination system, which solves the problems of complex structure and large footprint of the reverse osmosis device.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A reverse osmosis device includes at least one filter element. The filter element includes a reverse osmosis body. The reverse osmosis body includes a membrane housing and a first reverse osmosis component and a second reverse osmosis component installed within the membrane housing. The first reverse osmosis component includes a primary reverse osmosis water collection pipe and a primary reverse osmosis membrane wound around its outer periphery. The second reverse osmosis component includes a secondary reverse osmosis water collection pipe and a secondary reverse osmosis membrane wound around its outer periphery. The second reverse osmosis component is embedded within the primary reverse osmosis water collection pipe. The inlet of the primary reverse osmosis membrane is connected to incoming water, and the outlet of the secondary reverse osmosis water collection pipe discharges purified water.

[0006] Furthermore, the filter element also includes a pre-scale inhibitor disposed at the inlet end of the membrane housing; the pre-scale inhibitor includes a scale inhibitor body, and a first mesh element and a second mesh element are respectively provided at both ends of the scale inhibitor body, the second mesh element being at least connected to the first-stage reverse osmosis membrane, and at least one barrier mesh element is provided inside the scale inhibitor body; the grid density of the first mesh element is greater than the grid density of the barrier mesh element and the second mesh element.

[0007] Furthermore, the filter element also includes a post-mineralization section disposed at the water outlet end of the membrane housing, wherein the post-mineralization section is provided with a mineralization jet that is connected to the secondary reverse osmosis water collection pipe.

[0008] Furthermore, the mineralizing jet ejector is an umbrella-shaped structure with a cavity, and the mineralizing jet ejector has multiple jet holes, the diameter of which is smaller than the diameter of the secondary reverse osmosis water collection pipe.

[0009] Furthermore, the number of filter elements is n, where 2≤n≤8; multiple filter elements are connected in series, and the primary reverse osmosis membrane, the secondary reverse osmosis membrane, and the secondary reverse osmosis water collection pipe of adjacent filter elements are all connected in a one-to-one correspondence.

[0010] The present invention also provides a seawater desalination system, including a seawater desalination module, wherein the seawater desalination module includes a pretreatment unit, a fine filtration unit and a reverse osmosis unit connected in sequence, and the reverse osmosis unit includes the reverse osmosis device as described above.

[0011] Furthermore, the seawater desalination system also includes a chlorine generation module for preparing sodium hypochlorite solution by electrolysis of seawater; the outlet of the chlorine generation module is connected to the inlet of the seawater desalination module.

[0012] Furthermore, the seawater desalination system also includes a seawater inlet pump; the seawater inlet pump is connected to both the inlet of the chlorine generation module and the inlet of the seawater desalination module. The chlorine generation module includes a sodium hypochlorite storage tank, the outlet of the chlorine generation module is connected to the inlet of the sodium hypochlorite storage tank, and the outlet of the sodium hypochlorite storage tank is connected to the inlet of the seawater desalination module via a dosing pipe to add sodium hypochlorite solution to the inlet of the seawater desalination module; or, the seawater inlet pump is connected to the inlet of the chlorine generation module, and the outlet of the chlorine generation module is directly connected to the inlet of the seawater desalination module to input seawater into the inlet of the seawater desalination module.

[0013] Furthermore, the pretreatment unit includes a pretreatment filter and a reducing agent addition point. The inlet of the pretreatment filter is connected to the seawater to be desalinated, and the reducing agent addition point is located between the pretreatment filter and the fine filtration unit.

[0014] Furthermore, the reverse osmosis unit also includes a reverse osmosis feed water pump, a reverse osmosis security filter, and a high-pressure pump connected in sequence. The inlet of the reverse osmosis feed water pump is connected to the outlet of the fine filtration unit, and the outlet of the high-pressure pump is connected to the inlet of the reverse osmosis device.

[0015] The beneficial effects of this invention are as follows: the first reverse osmosis component and the second reverse osmosis component are integrated into one membrane housing, and the second reverse osmosis component is embedded in the first-stage reverse osmosis water collection pipe of the first reverse osmosis component. Seawater enters the filter element through the inlet of the first-stage reverse osmosis membrane. After being filtered by the first-stage reverse osmosis membrane, the seawater enters the second-stage reverse osmosis membrane through the first-stage reverse osmosis water collection pipe and is finally discharged from the filter element through the outlet of the second-stage reverse osmosis water collection pipe. This achieves two-stage reverse osmosis filtration of seawater, which more effectively removes various impurities from the seawater. It solves the problem of the original multiple reverse osmosis membrane components being set up separately, with a complex structure and a large footprint. This device has a simple structure and a compact and reasonable layout. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the first filter element of a reverse osmosis device according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 Side view of the front scale inhibitor section in the middle;

[0019] Figure 3 yes Figure 1 Side view of the post-mineralized section in the middle;

[0020] Figure 4 yes Figure 1 A schematic diagram of the decomposition process;

[0021] Figure 5 yes Figure 4 A schematic diagram of the mineralization jet injector in the image;

[0022] Figure 6 This is a schematic diagram of the structure of the 2nd to nth filter element of a reverse osmosis device according to an embodiment of the present invention;

[0023] Figure 7 yes Figure 6 Side view of the post-mineralized section in the middle;

[0024] Figure 8 yes Figure 6 A schematic diagram of the decomposition process;

[0025] Figure 9 This is a schematic diagram of the structure of the first filter element of a reverse osmosis device according to another embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of the structure of the 2nd to nth filter element of the reverse osmosis device according to another embodiment of the present invention;

[0027] Figure 11 This is a schematic diagram of the reverse osmosis device of the present invention, which has two filter elements connected together.

[0028] Figure 12 This is a process flow diagram of a seawater desalination system according to an embodiment of the present invention;

[0029] Figure 13 This is a process flow diagram of a seawater desalination system according to another embodiment of the present invention;

[0030] Figure 14 This is a process flow diagram showing the connection between the seawater intake pump and the seawater desalination module;

[0031] Figure 15 This is a process flow diagram showing the connection between the seawater inlet pump and the chlorine generation module.

[0032] In the picture:

[0033] A. Seawater intake pump;

[0034] B. Seawater desalination module; B1. Seawater desalination section;

[0035] 10. Pre-treatment unit; 11. Pre-treatment filter;

[0036] 20. Fine filtration unit; 21. Fine filtration security filter; 22. Fine filtration feed pump; 23. Fine filtration device; 24. Water storage tank;

[0037] 30. Reverse osmosis unit; 301. Reverse osmosis feed pump; 302. Reverse osmosis security filter; 303. High-pressure pump; 304. Reverse osmosis device; 3. Filter element; 31. Reverse osmosis main body; 311. Membrane housing; 312. First reverse osmosis assembly; 312a. First-stage reverse osmosis water collection pipe; 312b. First-stage reverse osmosis membrane; 313. Second reverse osmosis assembly; 313a. Second-stage reverse osmosis water collection pipe; 313b. Second-stage reverse osmosis membrane; 32. Pre-scale inhibitor; 321. Scale inhibitor body; 322. First mesh element; 323. Second mesh element; 324. Barrier mesh element; 33. Post-mineralization unit; 331. Mineralization jet; 34. Sealing ring;

[0038] 40. Energy recovery unit; 41. Energy recovery device; 42. Booster pump;

[0039] C. Chlorine production module; C1. Electrolytic chlorine production section;

[0040] 51. Chlorine filter; 52. Electrolytic cell; 53. Sodium hypochlorite storage tank; 54. Dosing pump; 55. Cooling unit; 551. Heat exchanger; 552. Cooling water pump; 56. Pickling unit; 561. Acid unloading pump; 562. Acid storage tank; 563. Acid mist absorber; 564. Pickling tank; 565. Pickling pump. Detailed Implementation

[0041] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," etc., 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. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0043] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of description and simplification, 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 the present invention.

[0044] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0045] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0046] A reverse osmosis device 304, such as Figure 1As shown, it includes at least one filter element 3. The filter element 3 includes a reverse osmosis body 31. The reverse osmosis body 31 includes a membrane housing 311 and a first reverse osmosis component 312 and a second reverse osmosis component 313 installed in the membrane housing 311. The first reverse osmosis component 312 includes a primary reverse osmosis water collection pipe 312a and a primary reverse osmosis membrane 312b wound around its outer periphery. The second reverse osmosis component 313 includes a secondary reverse osmosis water collection pipe 313a and a secondary reverse osmosis membrane 313b wound around its outer periphery. The second reverse osmosis component 313 is embedded in the primary reverse osmosis water collection pipe 312a. The inlet of the primary reverse osmosis membrane 312b is connected to the incoming water, and the outlet of the secondary reverse osmosis water collection pipe 313a discharges purified water.

[0047] In this embodiment, the first reverse osmosis component 312 and the second reverse osmosis component 313 are integrated into a single membrane housing 311. The second reverse osmosis component 313 is embedded in the first-stage reverse osmosis water collection pipe 312a of the first reverse osmosis component 312. Seawater enters the filter element 3 through the inlet of the first-stage reverse osmosis membrane 312b. After being filtered by the first-stage reverse osmosis membrane 312b, the seawater enters the second-stage reverse osmosis membrane 313b through the first-stage reverse osmosis water collection pipe 312a for further filtration. Finally, the seawater is discharged from the filter element 3 through the outlet of the second-stage reverse osmosis water collection pipe 313a. This achieves two-stage reverse osmosis filtration of seawater, more effectively removing various impurities from the seawater. It solves the problem of the original multiple reverse osmosis membrane components being separately installed, resulting in a complex structure and a large footprint. This device has a simple structure and a compact and reasonable layout. The reverse osmosis device 304 is mainly used to filter and remove salt, microorganisms, suspended matter, colloidal substances, and heavy metal ions.

[0048] Furthermore, such as Figures 1 to 4 As shown, the filter element 3 also includes a pre-scale inhibitor 32 disposed at the inlet end of the membrane housing 311; the pre-scale inhibitor 32 includes an inhibitor body 321 (with built-in scale inhibitor), and the two ends of the inhibitor body 321 are respectively provided with a first mesh element 322 and a second mesh element 323. The second mesh element 323 is at least connected to the first-stage reverse osmosis membrane 312b, so that seawater can enter the first-stage reverse osmosis membrane 312b for first-stage reverse osmosis filtration after being filtered by the pre-scale inhibitor 32; the inhibitor body 321 is provided with at least one barrier mesh element 324, through which the scale inhibitor is arranged in layers, so that the scale inhibitor is evenly distributed inside the inhibitor body 321, effectively ensuring the full release of the scale inhibitor; the grid density of the first mesh element 322 is greater than that of the barrier mesh element 324 and the second mesh element 323, that is, the outermost inlet end uses a denser grid to wrap the scale inhibitor, ensuring water passage while preventing scale inhibitor leakage. The pre-scale inhibitor 32 is mainly used to remove mineral deposits formed by metal ions such as calcium and magnesium.

[0049] Furthermore, such as Figures 1 to 5As shown, filter element 3 also includes a post-mineralization section 33 located at the outlet end of membrane housing 311. The post-mineralization section 33 contains a mineralization jet injector 331 connected to the secondary reverse osmosis water collection pipe 313a. The post-mineralization section 33 replenishes the minerals and trace elements in the fresh water, improving the drinking taste. The mineralization jet injector 331 disperses the fresh water discharged from the secondary reverse osmosis water collection pipe 313a, ensuring the fresh water is evenly dispersed and fully contacts the post-mineralization section 33, thus improving the mineralization effect. If used for industrial applications, such as as steam conversion water, the post-mineralization section 33 can be omitted.

[0050] Furthermore, such as Figure 5 As shown, the mineralizing jet ejector 331 is an umbrella-shaped structure with a cavity. The mineralizing jet ejector 331 has multiple jet holes, and the diameter of the jet holes is smaller than the diameter of the secondary reverse osmosis water collection pipe 313a. This structure can effectively ensure that the flow rate of the purified water is increased and fully contacted with the post-mineralization section 33. In addition, the impact velocity is large, which can achieve effective mineralization.

[0051] Furthermore, such as Figures 9 to 11 As shown, the number of filter elements 3 is n, where 2 ≤ n ≤ 8. Multiple filter elements 3 are connected in series. The primary reverse osmosis membrane 312b, secondary reverse osmosis membrane 313b, and secondary reverse osmosis water collection pipe 313a of adjacent filter elements 3 are all connected in a one-to-one correspondence. That is, the outlet of the primary reverse osmosis membrane 312b of the previous filter element 3 is connected to the inlet of the secondary reverse osmosis membrane 313b of the next filter element 3, the outlet of the secondary reverse osmosis membrane 313b of the previous filter element 3 is connected to the inlet of the secondary reverse osmosis membrane 313b of the next filter element 3, and the outlet of the secondary reverse osmosis water collection pipe 313a of the previous filter element 3 is connected to the inlet of the secondary reverse osmosis water collection pipe 313a of the next filter element 3. This allows water from the same functional chambers of each filter element 3 to be connected through multiple filter elements 3 connected in series. Figures 9 to 11 The proposal and Figures 1 to 8 The unique structure involves extending the membrane housing 311 of each filter element 3 at its tail end, adding a sleeve-like structure. This structure, via a rubber ring, adapts to the next filter element 3. This increases the stability of the filter element 3 within the membrane housing 311, forming a... Figure 11 The structure.

[0052] Specifically, such as Figure 1 and Figure 4 As shown, the filter element 3 is the first filter element 3 directly connected to seawater. The outer periphery of the second mesh element 323 of the pre-scale inhibitor 32 is provided with a grid, allowing the pre-scale inhibitor 32 to communicate with the first-stage reverse osmosis membrane 312b. Seawater can pass through the pre-scale inhibitor 32 and then enter the first-stage reverse osmosis membrane 312b for filtration. Figure 6 and Figure 8As shown, the filter element 3 is the second to nth filter element 3 connected in sequence with the first filter element 3. Adjacent filter elements 3 are connected by a pipeline passing through the post-mineralization section 33 of the adjacent preceding filter element 3 and the pre-scale inhibition section 32 of the following filter element 3, so as to realize the water connection between the same functional chambers of each filter element 3.

[0053] In the above embodiment, the operation process of the reverse osmosis device 304 is as follows:

[0054] The reverse osmosis unit 304 is used in a seawater desalination system. The reverse osmosis unit 304 includes at least one filter element 3, which integrates pre-scale inhibition, two-stage reverse osmosis filtration, and post-mineralization functions. Pre-treated seawater first passes through the pre-scale inhibition section 32, where the scale inhibitor is slowly released into the raw seawater. It then enters the membrane housing 311 and is filtered by the first-stage reverse osmosis membrane 312b. After filtration, it passes through the first-stage reverse osmosis collection pipe 312a and enters the next stage, the second-stage reverse osmosis membrane 313b. Unfiltered seawater enters the second to nth stage filter elements 3 for further filtration, and is finally discharged at the nth stage filter element 3 as first-stage reverse osmosis wastewater. The seawater filtered by the first-stage reverse osmosis membrane 312b is used as the raw water for the second-stage reverse osmosis membrane 313b for secondary filtration. The water after secondary filtration is collected through the second-stage reverse osmosis collection pipe 313a. At this stage, the effluent is almost ion-free. Unfiltered water from the second-stage reverse osmosis membrane 313b enters the second to nth stage filter elements 3 for further filtration. Similarly, in this embodiment, the water in the same functional chambers of the filter element 3 is connected in series through multiple filter elements 3. In order to be compatible with the membrane housing 311, the membrane element mentioned in this embodiment is fixed to the membrane housing 311 by a sealing ring 34, which also prevents water from flowing between the filter elements.

[0055] In the field of seawater desalination, the membrane housing 311 typically contains 1-8 filter elements 3. To meet the requirements of normal operating conditions, the integrated filter element 3 mentioned in this embodiment will have the first (e.g., Figures 1 to 4 (as shown) and 2 to n (as shown) Figures 6 to 8 (As shown) The structure of filter element 3 is differentiated. Along the reverse osmosis water flow direction, as... Figure 1 As shown, the inlet of the first filter element 3 only allows pre-treated seawater to enter the first-stage reverse osmosis membrane 312b area for filtration; as Figure 1 , Figure 6 and Figure 11 As shown, starting from the second filter element 3, the outlet of the first-stage reverse osmosis membrane 312b region of the previous filter element 3 (corresponding to the discharge of raw water and first-stage reverse osmosis wastewater i), the outlet of the second-stage reverse osmosis membrane 313b region (corresponding to the discharge of first-stage reverse osmosis permeate, i.e., second-stage reverse osmosis raw water and wastewater j), and the outlet of the second-stage reverse osmosis water collection pipe 313a (corresponding to the discharge of second-stage reverse osmosis permeate k) are connected to the inlet of the corresponding functional chamber of the next adjacent filter element 3. The various stages of the structure are sealed with rubber rings. If a single filter element 3 membrane housing 311 is used, then only the design of this application is employed. Figure 1 The first filter element 3 structure is shown.

[0056] To further explain, the seawater inlet of the first filter element 3 is pressurized by the high-pressure pump 303 to complete the first-stage reverse osmosis filtration. The second-stage reverse osmosis, which is embedded within the first-stage reverse osmosis membrane, requires the pressure after the first-stage reverse osmosis membrane 312b as the second-stage reverse osmosis filtration pressure. To ensure that the second-stage reverse osmosis effluent meets the requirements, a negative pressure pump or vacuum pump (not shown) can be installed at the outlet of the second-stage reverse osmosis permeate pipe 313a of the nth filter element 3, depending on different operating conditions, to increase the transmembrane pressure difference of the second-stage reverse osmosis membrane 313b. Furthermore, the desalination rate of the selected second-stage reverse osmosis membrane 313b is generally higher than that of the first-stage reverse osmosis membrane 312b.

[0057] The present invention also provides a seawater desalination system, such as Figure 12 and Figure 14 As shown, it includes a seawater desalination module B, which includes a pretreatment unit 10, a fine filtration unit 20 and a reverse osmosis unit 30 connected in sequence. The reverse osmosis unit 30 includes a reverse osmosis device 304 as described above.

[0058] Furthermore, such as Figure 12 and Figure 15 As shown, the seawater desalination system also includes a chlorine generation module C, which is used to electrolyze seawater to prepare sodium hypochlorite solution; the outlet of the chlorine generation module C is connected to the inlet of the seawater desalination module B to inject the sodium hypochlorite solution into the inlet of the seawater desalination module B to remove hydrogen sulfide from the incoming seawater.

[0059] Furthermore, the seawater desalination system also includes an inlet seawater pump A; such as Figure 12 As shown, the seawater pump A is connected to the inlet of both the chlorination module C and the desalination module B. The chlorination module C includes a sodium hypochlorite storage tank 53. The outlet of the chlorination module C is connected to the inlet of the sodium hypochlorite storage tank 53. The outlet of the sodium hypochlorite storage tank 53 is connected to the inlet of the desalination module B via a dosing pipe to add sodium hypochlorite solution to the inlet of the desalination module B; or, as... Figure 13 As shown, the seawater pump A is connected to the chlorine generation module C, and the outlet of the chlorine generation module C is directly connected to the inlet of the seawater desalination module B to input seawater into the inlet of the seawater desalination module B.

[0060] The varying quality of seawater globally means that desalination systems are largely "custom-designed," requiring local systems to be tailored to the specific influent water conditions. In some regions, excessive hydrogen sulfide levels result in acidic influent water, which, in humid environments, readily reacts electrochemically with steel equipment, causing corrosion to steel or other metal-based collection and transportation systems and equipment. Specifically, for example... Figure 12 As shown, seawater pump A pumps seawater into the inlet of seawater desalination module B. The sodium hypochlorite solution prepared by chlorination module C is stored in sodium hypochlorite storage tank 53. The sodium hypochlorite solution is then added to the inlet of seawater desalination module B through a dosing pipe to mix with the seawater. The sodium hypochlorite oxidizes the sulfide in the seawater into elemental sulfur. When the concentration of sodium hypochlorite is high, the elemental sulfur can be further oxidized to sodium sulfate. This solves the problem of high hydrogen sulfide content in seawater in some areas, which easily leads to hydrogen sulfide corrosion of equipment and causes irreversible negative impacts on the entire seawater desalination system. This embodiment combines the electrolytic seawater chlorination module C with the seawater desalination module B, using the effective chlorine generated by electrolytic chlorination to oxidize the hydrogen sulfide in the inlet of the seawater desalination system, further expanding the application range of the chlorination module C and simultaneously reducing the limitations of the seawater desalination system. For example, Figure 13 As shown, when the required seawater flow rate is low, the effluent from the chlorination module C can be directly treated and then enter the seawater desalination system. That is, the seawater pump A does not need to be directly connected to the inlet of the seawater desalination module B.

[0061] This embodiment can solve the problem of excessive hydrogen sulfide content in the feed water of membrane-based seawater desalination systems. Because hydrogen sulfide dissolves in water, making the solution acidic, it causes corrosion in the system's main components, including steel or reactive metal gathering and transportation systems and equipment. The corrosion principle is as follows:

[0062] H2S→HS - +H + →S 2- +2H +

[0063] Fe-2e - →Fe 2+

[0064] 2H + +2e - →H2↑

[0065] xFe + yH₂S → Fe x S y +yH2

[0066] Sodium hypochlorite is produced by the pre-chlorination module C to degrade hydrogen sulfide, thereby eliminating the corrosion of metal equipment and materials by hydrogen sulfide solution. Electrolysis can also degrade hydrogen sulfide in seawater. The corrosion prevention principle is as follows:

[0067] Anode plate: 2Cl - →Cl2↑+2e - S 2- →S↓+2e -

[0068] Cathode plate: 2H₂O + 2e- →H₂↑+2OH⁻ - M n+ Cations in seawater +ne - →M

[0069] The reaction occurs in seawater: Cl₂ + 2OH⁻ - →ClO - +Cl - +H2O

[0070] The residual chlorine produced will undergo a redox reaction with hydrogen sulfide in the water:

[0071] H₂S + NaClO = NaCl + S↓ + H₂O

[0072] S + 4NaClO = Na₂SO₄ + NaCl

[0073] The above reaction achieves the effect of removing hydrogen sulfide from seawater, as described in this invention.

[0074] Among them, such as Figure 12 , Figure 13 and Figure 15 As shown, the chlorine production module C includes a chlorine filter 51 connected to the seawater inlet pump A. After filtration, the chlorine enters the electrolytic chlorine production section C1, which includes an electrolytic cell 52, a sodium hypochlorite storage tank 53, a dosing pump 54, a cooling unit 55 consisting of a heat exchanger 551, a cooling water pump 552, and supporting electrical equipment (not shown), and an acid washing unit 56 consisting of an acid unloading pump 561, an acid storage tank 562, an acid mist absorber 563, an acid washing tank 564, and an acid washing pump 565. The electrolytic cell 52 is not limited in form; a suitable plate-and-mesh electrolytic cell 52 or a tube-plate electrolytic cell 52 can be selected according to the actual situation.

[0075] The basic principle of chlorine production by electrolysis of seawater is that when a certain voltage is applied to an electrode plate made of special materials in seawater, the following electrolysis reaction will occur on the surface of the electrode plate.

[0076] Anode plate: 2Cl - →Cl2↑+2e -

[0077] Cathode plate: 2H₂O + 2e - →H₂↑+2OH⁻ -

[0078] The reaction occurs in seawater: Cl₂ + 2OH⁻ - →ClO - +Cl - +H2O

[0079] ClO produced in the above electrolysis reaction -Both Cl2 and Cl2 exist in the electrolyzed seawater and have oxidizing and bactericidal capabilities; they are collectively referred to as available chlorine.

[0080] The basic process for producing chlorine from seawater via electrolysis is as follows: seawater inlet → seawater pump → chlorine filter → electrolytic cell → sodium hypochlorite storage tank → dosing pump → circulating water. Simultaneously with the production of sodium hypochlorite through seawater electrolysis, hydrogen sulfide in the seawater can also be electrolytically decomposed.

[0081] Furthermore, such as Figures 12 to 14 As shown, the pretreatment unit 10 includes a pretreatment filter 11 and a reducing agent addition point. The inlet of the pretreatment filter 11 is connected to the seawater to be desalinated, and the reducing agent addition point is located between the pretreatment filter 11 and the fine filtration unit 20. To prevent the effective chlorine concentration in the seawater entering the seawater desalination module B from being too high, a reducing agent can be added for reaction neutralization. It is worth mentioning that the sodium hypochlorite solution produced after electrolysis in the chlorine production module C can be used not only to oxidize hydrogen sulfide in the raw seawater but also as circulating cooling water for the plant area.

[0082] Furthermore, such as Figure 14 As shown, the fine filtration unit 20 includes a fine filtration security filter 21, a fine filtration water supply pump 22, a fine filtration device 23, and a water storage tank 24 connected in sequence; wherein, the inlet end of the fine filtration security filter 21 is connected to the outlet end of the pretreatment filter 11, the fine filtration device 23 is an ultrafiltration or nanofiltration device, and the water storage tank 24 is used to store seawater after ultrafiltration or nanofiltration.

[0083] Furthermore, such as Figure 14 As shown, the reverse osmosis unit 30 also includes a reverse osmosis feed water pump 301, a reverse osmosis security filter 302, and a high-pressure pump 303 connected in sequence. The inlet end of the reverse osmosis feed water pump 301 is connected to the outlet end of the fine filtration unit 20, that is, connected to the water storage tank 24. The outlet end of the high-pressure pump 303 is connected to the inlet end of the reverse osmosis device 304, so as to pump the ultrafiltration or nanofiltration seawater into the reverse osmosis unit 30, and pressurize it through the high-pressure pump 303 to complete the first stage of reverse osmosis filtration.

[0084] Furthermore, such as Figure 14 As shown, the seawater desalination system also includes an energy recovery unit 40 connected to the concentrated seawater outlet of the reverse osmosis unit 30. The energy recovery unit 40 includes a booster pump 42 and an energy recovery device 41. The concentrated water after desalination in the reverse osmosis unit 30 passes through the energy recovery device 41 and the booster pump 42 before returning to the membrane of the reverse osmosis unit 30 for energy recovery. The energy-recovered reverse osmosis concentrated water can be discharged from the seawater desalination module B or returned to the inlet of the chlorination module C for concentrated seawater electrolysis.

[0085] It should be noted that the connections between the various components are made through pipes, such as... Figure 11 As shown, adjacent filter elements 3 are connected by pipes to the same functional components.

[0086] Specifically, such as Figure 12 As shown, the working process of the seawater desalination system is as follows:

[0087] After pretreatment, the seawater is pumped by seawater pump A and sent to the chlorine generation module C and the seawater desalination module B respectively. Before entering the electrolytic chlorine generation section C1, it is filtered by a higher-precision electrolytic chlorine generation filter 51. After filtration, the seawater to be electrolyzed is electrolyzed in an electrolytic cell 52 made of DSA anode and Hastelloy cathode to generate available chlorine, which then enters the sodium hypochlorite storage tank 53. Simultaneously, the seawater to be desalinated is oxidized by sodium hypochlorite in the sodium hypochlorite storage tank 53, and then filtered by the pretreatment filter 11 to remove solid sulfur and other particulate matter from the seawater. To prevent the available chlorine concentration in the seawater entering the seawater desalination module B from being too high, a reducing agent can be added to neutralize the reaction before it enters the seawater desalination section B1. It is worth mentioning that the sodium hypochlorite solution produced by electrolysis in the chlorine generation module C can be used not only to oxidize hydrogen sulfide in the raw seawater, but also as circulating cooling water for the plant area.

[0088] Among them, such as Figure 15 As shown, the working process of the chlorination module C is as follows: seawater enters the electrolysis cell 52 after being filtered by the chlorination filter 51 through the seawater inlet pump A. After electrolysis, the seawater enters the sodium hypochlorite storage tank 53, and finally, the chlorinated seawater is transported to the dosing point by the dosing pump 54. This process is supplemented by a cooling unit 55 and an acid washing unit 56. The cooling unit 55 is used to cool the system rectifier (not shown in this invention). The water source is taken from the self-made chlorination filter 51 and pumped to the heat exchanger 551 by the cooling water pump 552. The cooled water undergoes heat exchange in the rectifier, which plays a role in system protection. After the electrolytic cell 52 has been running for a period of time, the pickling unit 56 is started to clean the scale on the plates of the electrolytic cell 52. After the concentrated hydrochloric acid or similar cleaning agent arrives, it is unloaded into the acid storage tank 562 by the acid unloading pump 561. The pickling agent in the acid storage tank 562 can generally flow into the pickling tank 564 by gravity. After a certain concentration of pickling agent is prepared, the agent is pumped into the electrolytic cell 52 by the pickling pump 565 to clean the plates. During this process, the acid mist in the acid storage tank 562 and the pickling tank 564 is treated by the acid mist absorber 563, and the absorbed pickling agent is returned to the pickling tank 564.

[0089] like Figure 14As shown, the working process of seawater desalination module B is as follows: After adding sodium hypochlorite solution from sodium hypochlorite storage tank 53 to the influent of seawater desalination module B, it is pumped into the system through influent seawater pump A. After pretreatment by pretreatment unit 10 to remove excess sulfur and residual chlorine, the seawater passes through fine filtration security filter 21 and then through fine filtration feed water pump 22 into fine filtration device 23 for fine filtration. The salinity of the seawater after fine filtration is still relatively high, but large particulate solid impurities are basically removed. This part of the water is stored in storage tank 24. After fine filtration, the seawater enters reverse osmosis security filter 302 through reverse osmosis feed water pump 301, and then through high-pressure pump 303 into reverse osmosis device 304 for seawater desalination. The concentrated water after desalination is returned to the membrane of reverse osmosis device 304 through energy recovery device 41 and booster pump 42 for energy recovery. The reverse osmosis concentrated water after energy recovery can be discharged from seawater desalination module B or returned to the influent of chlorination module C for electrolysis of concentrated seawater.

[0090] In the chlorine generation module C mentioned above, the sodium hypochlorite storage tank 53 can be eliminated. When the required seawater desalination flow rate is low, the effluent from the chlorine generation module C can be directly used as the influent for the seawater desalination module B.

[0091] To further demonstrate the feasibility of this seawater desalination system, a laboratory simulation experiment was conducted, using sodium sulfide instead of hydrogen sulfide. The results showed that NaClO can desalinate hydrogen sulfide at room temperature. 2- Oxidation eventually transforms it into stable SO4. 2- A NaClO concentration of 3 mg / L or higher can reduce the concentration of Na2S in the seawater solution used in desalination projects, thereby reducing the S concentration. 2- Eliminate to a safe range <0.01 mg / L. A NaClO dosage of 7 mg / L will reduce the Na2S concentration in the desalination project's seawater solution. 2- Oxidized to SO4 2- The highest efficiency was achieved by controlling the concentration at a low level of 2.25 × 10⁻⁶. 3 mg / L.

[0092] The beneficial effects of this invention are:

[0093] (1) The first reverse osmosis component 312 and the second reverse osmosis component 313 are integrated in a membrane housing 311, and the second reverse osmosis component 313 is embedded in the first-stage reverse osmosis water collection pipe 312a of the first reverse osmosis component 312. Seawater enters the filter element 3 through the inlet of the first-stage reverse osmosis membrane 312b. After being filtered by the first-stage reverse osmosis membrane 312b, the seawater enters the second-stage reverse osmosis membrane 313b through the first-stage reverse osmosis water collection pipe 312a for filtration. Finally, the filter element 3 is discharged through the outlet of the second-stage reverse osmosis water collection pipe 313a. This achieves dual-stage reverse osmosis filtration of seawater, which more effectively removes various impurities in seawater. It solves the problem of the original multiple reverse osmosis membrane components being set up separately, with a complex structure and a large footprint. This device has a simple structure and a compact and reasonable layout.

[0094] (2) The sodium hypochlorite solution prepared by the chlorine production module C is added to the inlet of the seawater desalination module B and mixed with seawater or used directly as the source water for desalination. The sodium hypochlorite oxidizes the sulfide in the seawater into elemental sulfur. When the concentration of sodium hypochlorite is high, the elemental sulfur can be further oxidized to generate sodium sulfate. This solves the problem that the hydrogen sulfide content in the seawater in some areas is high, and the equipment is prone to hydrogen sulfide corrosion, which causes irreversible negative impacts on the entire seawater desalination system. In this embodiment, the electrolytic seawater chlorine production module C is combined with the seawater desalination module B. The effective chlorine generated by electrolytic chlorine production is used to oxidize the hydrogen sulfide in the inlet water of the seawater desalination system, further expanding the application range of the chlorine production module C and simultaneously reducing the limited range of the seawater desalination system.

[0095] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, which are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A reverse osmosis device, characterized in that, The system includes at least one filter element (3), which includes a reverse osmosis body (31). The reverse osmosis body (31) includes a membrane housing (311) and a first reverse osmosis component (312) and a second reverse osmosis component (313) installed in the membrane housing (311). The first reverse osmosis component (312) includes a primary reverse osmosis water collection pipe (312a) and a primary reverse osmosis membrane (312b) wound around its outer periphery. The second reverse osmosis component (313) includes a secondary reverse osmosis water collection pipe (313a) and a secondary reverse osmosis membrane (313b) wound around its outer periphery. The second reverse osmosis component (313) is embedded in the primary reverse osmosis water collection pipe (312a). The inlet of the primary reverse osmosis membrane (312b) is connected to incoming water, and the outlet of the secondary reverse osmosis water collection pipe (313a) discharges purified water. The number of filter elements (3) is n, 2≤n≤8; multiple filter elements (3) are directly connected in series. The outlet of the primary reverse osmosis membrane (312b) of the previous filter element (3) is connected to the inlet of the primary reverse osmosis membrane (312b) of the next filter element (3), the outlet of the secondary reverse osmosis membrane (313b) of the previous filter element (3) is connected to the inlet of the secondary reverse osmosis membrane (313b) of the next filter element (3), and the outlet of the secondary reverse osmosis water collection pipe (313a) of the previous filter element (3) is connected to the inlet of the secondary reverse osmosis water collection pipe (313a) of the next filter element (3), so as to realize that the water of the same functional chamber of each filter element (3) is connected through multiple filter elements (3) in series.

2. The reverse osmosis device as described in claim 1, characterized in that, The filter element (3) further includes a pre-scale inhibitor (32) disposed at the inlet end of the membrane housing (311); the pre-scale inhibitor (32) includes an inhibitor body (321), the inhibitor body (321) contains an inhibitor, the two ends of the inhibitor body (321) are respectively provided with a first mesh element (322) and a second mesh element (323), the second mesh element (323) is at least connected to the first-stage reverse osmosis membrane (312b), the inhibitor body (321) contains at least one barrier mesh element (324), the inhibitor is arranged in layers through the barrier mesh element (324), so that the inhibitor is evenly distributed inside the inhibitor body (321); the grid density of the first mesh element (322) is greater than the grid density of the barrier mesh element (324) and the second mesh element (323).

3. The reverse osmosis device as described in claim 1, characterized in that, The filter element (3) also includes a post-mineralization section (33) disposed at the water outlet end of the membrane housing (311), and the post-mineralization section (33) is provided with a mineralization jet (331) connected to the secondary reverse osmosis water collection pipe (313a).

4. The reverse osmosis device as described in claim 3, characterized in that, The mineralizing jet ejector (331) is an umbrella-shaped structure with a cavity. The mineralizing jet ejector (331) has multiple jet holes, and the diameter of the jet holes is smaller than the diameter of the secondary reverse osmosis water collection pipe (313a).

5. A seawater desalination system, characterized in that, The system includes a seawater desalination module (B), which includes a pretreatment unit (10), a fine filtration unit (20), and a reverse osmosis unit (30) connected in sequence. The reverse osmosis unit (30) includes a reverse osmosis device (304) as described in any one of claims 1-4.

6. The seawater desalination system according to claim 5, characterized in that, The seawater desalination system also includes a chlorine generation module (C) for preparing sodium hypochlorite solution by electrolysis of seawater; the outlet of the chlorine generation module (C) is connected to the inlet of the seawater desalination module (B).

7. The seawater desalination system as described in claim 6, characterized in that, The seawater desalination system also includes a seawater inlet pump (A); the seawater inlet pump (A) is connected to the inlet of the chlorine generation module (C) and the inlet of the seawater desalination module (B). The chlorine generation module (C) includes a sodium hypochlorite storage tank (53). The outlet of the chlorine generation module (C) is connected to the inlet of the sodium hypochlorite storage tank (53). The outlet of the sodium hypochlorite storage tank (53) is connected to the inlet of the seawater desalination module (B) through a dosing pipe to add sodium hypochlorite solution to the inlet of the seawater desalination module (B); or, the seawater inlet pump (A) is connected to the inlet of the chlorine generation module (C), and the outlet of the chlorine generation module (C) is directly connected to the inlet of the seawater desalination module (B) to input seawater into the inlet of the seawater desalination module (B).

8. The seawater desalination system as described in claim 5, characterized in that, The pretreatment unit (10) includes a pretreatment filter (11) and a reducing agent addition point. The inlet of the pretreatment filter (11) is connected to the seawater to be desalinated, and the reducing agent addition point is located between the pretreatment filter (11) and the fine filtration unit (20).

9. The seawater desalination system as described in claim 5, characterized in that, The reverse osmosis unit (30) also includes a reverse osmosis feed water pump (301), a reverse osmosis security filter (302) and a high-pressure pump (303) connected in sequence. The inlet end of the reverse osmosis feed water pump (301) is connected to the outlet end of the fine filtration unit (20), and the outlet end of the high-pressure pump (303) is connected to the inlet end of the reverse osmosis device (304).

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