Low-energy-consumption parallel-reverse-flow stage-effect high-power membrane concentration system and switching method thereof

Abstract

The invention discloses a low-energy-consumption parallel-reverse-flow stage-effect high-power membrane concentration system and a switching method thereof, and aims to overcome the defects of high energy consumption and high risk of an existing concentration mode. The device comprises a plurality of reverse osmosis membrane assemblies, each reverse osmosis membrane assembly is provided with a high-pressure side and a low-pressure side, each reverse osmosis membrane assembly is provided with a high-pressure side connector I, a high-pressure side connector II, a low-pressure side connector I and a low-pressure side connector II, and the high-pressure sides of the adjacent reverse osmosis membrane assemblies are connected in series through a pipeline. To-be-concentrated liquid sequentially passes through the high-pressure sides of all the effect reverse osmosis membrane assemblies, low-salt water is generated on the low-pressure sides, connectors of the adjacent low-pressure sides are communicated through a pipeline, the low-salt water sequentially passes through the low-pressure sides of all the effect reverse osmosis membrane assemblies, and a plurality of switch valves are arranged on the pipeline. And the switch valve is periodically switched to enable low-salt water to pass through each effect reverse osmosis membrane assembly along a downstream direction or a countercurrent direction. The reverse osmosis membrane assemblies are connected in series, and corresponding pipelines and switch valves are arranged, so that the energy consumption is reduced, and the pressure required by reverse osmosis is reduced.

Description

Technical Field

[0001] The invention relates to the field of reverse osmosis, and more specifically to a low-energy consumption forward and reverse current graded high-efficiency membrane concentration system and a switching method thereof. Background Art

[0002] Reverse osmosis is a selective permeation separation technology that overcomes the osmotic pressure on both sides of the membrane by external pressure driving force, intercepts the solutes to be retained on the outside of the membrane by utilizing the characteristics of the semipermeable membrane, and allows the solvent to pass through the membrane. In the field of membrane concentration, the commonly used membrane technology is ultra-high pressure membrane concentration, such as UHPRO, DTRO / STRO and other special ultra-high pressure membranes. Under an operating pressure of 120 bar, the final concentrate concentration of the membrane concentration can reach 100,000-150,000 mg / L. However, due to the high pressure risk and high energy consumption brought by ultra-high pressure, the operating energy consumption is high and the cost is high. Even with ultra-high pressure membrane concentration, it is difficult to achieve the effect of thermal concentration, such as MVR and other processes. Moreover, the amount of concentrated liquid after membrane concentration is still large, and the subsequent thermal evaporation and crystallization processes are highly required, and the construction and operation costs are very high. Summary of the invention

[0003] The present invention overcomes the shortcomings of the existing concentration methods, such as high energy consumption and high risk, and provides a low-energy consumption forward and reverse current graded high-efficiency membrane concentration system, which can reduce energy consumption and reduce the driving force required for reverse osmosis.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: A variable-effect high-multiple membrane concentration system comprises a plurality of reverse osmosis membrane assemblies, wherein the reverse osmosis membrane assemblies are provided with a high-pressure side and a low-pressure side, and the reverse osmosis membrane assemblies are provided with a high-pressure side interface I, a high-pressure side interface II, a low-pressure side interface I and a low-pressure side interface II, the high-pressure sides of adjacent reverse osmosis membrane assemblies are connected in series through pipelines, the liquid to be concentrated passes through the high-pressure side of each effect reverse osmosis membrane assembly in turn and produces low-salt water on the low-pressure side, the interfaces of adjacent low-pressure sides are connected through pipelines, and the low-salt water passes through the low-pressure side of each effect reverse osmosis membrane assembly in turn, wherein the pipelines are provided with a plurality of switch valves, and the switch valves are periodically switched to allow the low-salt water produced by reverse osmosis to pass through each effect reverse osmosis membrane assembly in downstream or upstream direction.

[0005] The system comprises a plurality of reverse osmosis membrane modules arranged in series, and the liquid to be concentrated flows to each reverse osmosis membrane module step by step, and the low-salt water is separated by the reverse osmosis membrane, and the concentrated water is concentrated step by step.

[0006] In order to reduce energy consumption and improve safety, a structure of multiple-effect reverse osmosis membrane modules connected in series is set up to perform reverse osmosis with a smaller driving force. The osmotic pressure difference between the high-pressure side and the low-pressure side of the same-effect reverse osmosis membrane module is reduced, thereby reducing the corresponding reverse osmosis driving resistance.

[0007] The present application adjusts the flow direction on the low-pressure side by setting a switch valve to adjust the flow direction, and the flow direction includes downstream and upstream. Among them, downstream is the step-by-step transmission from the first-effect reverse osmosis membrane assembly to the end reverse osmosis membrane assembly, and upstream is the step-by-step transmission from the end reverse osmosis membrane assembly to the first-effect reverse osmosis membrane assembly. For the reverse osmosis membrane assembly, the downstream mode is that low salt water flows from the low-pressure side interface Ⅰ to the low-pressure side interface Ⅱ; the upstream mode is that low salt water flows from the low-pressure side interface Ⅱ to the low-pressure side interface Ⅰ. This can reduce the degradation of the membrane of the reverse osmosis membrane assembly, play a role similar to backwashing, use instead of washing, reduce the number of maintenance times in a forward and reverse alternating manner, extend the maintenance and cleaning cycle, and reduce the osmotic pressure difference required for reverse osmosis in this way, reducing energy consumption.

[0008] Preferably, the high-pressure side interface I and the high-pressure side interface II of the adjacent reverse osmosis membrane assembly are connected through the first tube, the low-pressure side interface I and the low-pressure side interface II of the adjacent reverse osmosis membrane assembly are connected through the second tube, the first tube and the second tube are connected through the third tube, the second tube and the third tube are provided with a switch valve, the third tube is connected to the downstream position of the switch of the second tube, and the high-pressure side interface I of the first-effect reverse osmosis membrane assembly is directly connected to the water to be concentrated. In the downstream mode, the first tube is connected to the second tube through the third tube, and the switch valve 7 on the second tube disconnects the low-pressure side interface I and the low-pressure side interface II, so that the concentrated water concentrated by the previous reverse osmosis membrane assembly enters the high-pressure side and the low-pressure side of the next reverse osmosis membrane assembly at the same time. This structure can reduce the pressure difference between the high-pressure side and the low-pressure side, thereby reducing the driving pressure required for ion reverse osmosis. In the countercurrent mode, the third tube is closed and the second tube is opened, and the concentrated water and the low-salt water flow in opposite directions. During the reverse osmosis process, the concentrated water closer to the front has a lower ion concentration, and the low-salt water closer to the front has a larger accumulated water volume and a lower ion concentration. This structure is also reasonable and can reduce the ion concentration difference on both sides of the reverse osmosis membrane.

[0009] Preferably, the low-pressure side interface II of the n-th effect reverse osmosis membrane assembly is also connected to the first pipe connected to the high-pressure side interface I of the n-1-th effect reverse osmosis membrane assembly through a fourth pipe, and a switch valve is provided on the fourth pipe, n≥2, and the low-pressure side interface I or low-pressure side interface II of the first effect reverse osmosis membrane assembly is connected to the outlet of the system. This structure is used in the downstream mode to merge the low-salt water obtained by each effect reverse osmosis membrane assembly into the concentrated water inlet of the previous effect reverse osmosis membrane assembly, thereby further diluting the concentrated water of the previous effect, thereby reducing the ion concentration difference on both sides of the membrane and reducing the corresponding resistance.

[0010] Preferably, the low-pressure side interface II of the last reverse osmosis membrane assembly is also connected to a fifth tube, which is connected to the first tube connected to the adjacent reverse osmosis membrane assembly, and a switch valve is provided on the fifth tube. This structure has the same function as the aforementioned fourth tube, and is used to supplement concentrated water in the countercurrent to reduce resistance.

[0011] As a preference, a forward osmosis membrane assembly is also included, the liquid to be concentrated is connected to the low-pressure side of the forward osmosis membrane assembly, and the high-pressure side interface II of the reverse osmosis membrane assembly at the end is connected to the high-pressure side of the forward osmosis membrane assembly. The water in the liquid to be concentrated is extracted through the forward osmosis membrane to increase its concentration.

[0012] As a preference, a supplementary reverse osmosis membrane assembly is also included, and the low-pressure side interface I and the low-pressure side interface II of the first-effect reverse osmosis membrane assembly are respectively connected to the supplementary reverse osmosis membrane assembly through pipelines, and the pipelines are provided with switch valves, and the concentrated water of the supplementary reverse osmosis membrane assembly is connected to the water inlet pipe of the liquid to be concentrated. The structure is used to further concentrate the low-salt water obtained from the first-effect reverse osmosis membrane assembly, and the low-salt water is led out, and the concentrated water is incorporated into the substitute concentrated liquid.

[0013] As preferably, it also includes a boosting component, the boosting component is arranged on a front pressure-compensating container on one side of the high-pressure side interface I of the reverse osmosis membrane assembly and a rear pressure-compensating container on one side of the high-pressure side interface II, the first tube connected between the front pressure-compensating container and the high-pressure side interface I is communicated through a first switching valve, the first tube connected between the rear pressure-compensating container and the high-pressure side interface II is communicated through a second switching valve, the first switching valve and the second switching valve are also connected to a sixth tube, the pressure-compensating container increases the liquid pressure through volume change, and the concentrated water flow direction of the reverse osmosis membrane assembly is adjusted by switching the first switching valve and the second switching valve, the first switching valve and the second switching valve are two-position four-way valves, the first interface of the first switching valve is connected to the previous effect reverse osmosis membrane assembly, the second interface of the first switching valve is connected to the front pressure-compensating container, the third interface of the first switching valve is connected to the high-pressure side interface I of the reverse osmosis membrane assembly, the fourth interface of the first switching valve is connected to the sixth tube, the first interface of the second switching valve is connected to the high-pressure side interface II of the reverse osmosis membrane assembly, the second interface of the second switching valve is connected to the rear pressure-compensating container, the third interface of the second switching valve is connected to the next effect reverse osmosis membrane assembly, and the fourth interface of the second switching valve is connected to the sixth tube; The first switching valve has two valve positions. In the first valve position, the first interface of the first switching valve is connected to the fourth interface of the first switching valve, and the second interface of the first switching valve is connected to the third interface of the first switching valve; in the second valve position, the first interface of the first switching valve is connected to the second interface of the first switching valve, and the third interface of the first switching valve is connected to the fourth interface of the first switching valve; The second switching valve has two valve positions. In the first valve position, the first interface of the second switching valve is connected to the third interface of the second switching valve, and the second interface of the second switching valve is connected to the fourth interface of the second switching valve; in the second valve position, the first interface of the second switching valve is connected to the second interface of the second switching valve, and the third interface of the second switching valve is connected to the fourth interface of the second switching valve.

[0014] The functions of the booster assembly include pressure replenishment and switching the high-pressure side and the low-pressure side of the reverse osmosis membrane assembly in the forward and reverse flow. Pressure replenishment can improve the reverse osmosis efficiency of each effect reverse osmosis membrane assembly. Switching in the forward and reverse flow can reduce the degradation of the membrane of the reverse osmosis membrane assembly.

[0015] Through the above structure, the high-pressure side is also switched between forward and reverse flow, which further reduces the maintenance times and prolongs the maintenance and cleaning cycles.

[0016] A variable-level high-efficiency membrane concentration system and a switching method thereof, comprising the variable-level high-efficiency membrane concentration system as described above, The low-pressure side of the system switches to downstream flow in the following manner: the switch valves on the third pipe and the fourth pipe are opened, and the switch valves on the second pipe and the fifth pipe are closed; The low-pressure side of the system switches to reverse flow in the following manner: the switch valves on the third pipe and the fourth pipe are closed, and the switch valves on the second pipe and the fifth pipe are opened; A first threshold and a second threshold are set, and the switching method of the concentration system includes: Step 1, monitoring the water outlet rate of the low-pressure side of the first-effect reverse osmosis membrane assembly; Step 2: When the water outflow rate is lower than the first threshold, switch the system to forward and reverse flow state; Step 3: When the water outlet rate is lower than the second threshold, the system is cleaned; Repeat steps 1 to 3.

[0017] Preferably, the supplementary reverse osmosis membrane assembly described above is also included, and the switch valves connected to the low-pressure side interface I and the low-pressure side interface II are switched mutually exclusively according to the downstream or upstream flow of the system, so that the low-salt water passes through the first-stage reverse osmosis membrane assembly.

[0018] Preferably, the boosting component mentioned above is also included, and the flow direction through the high-pressure side of the reverse osmosis membrane component is adjusted by switching the two-position four-way valve. The two-position four-way valve is switched periodically, and the period is set to the filling time of the front pressure-compensating container or the rear pressure-compensating container. The front pressure-compensating container and the rear pressure-compensating container are pressurized by alternating volume changes according to the liquid level.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) By connecting multiple-effect reverse osmosis membrane modules in series to form a low-pressure high-multiple membrane concentration system, the reverse osmosis ion permeation pressure difference between the high-pressure side and the low-pressure side of each stage is reduced, thereby reducing the reverse osmosis operation driving pressure and concentration difficulty, achieving multi-stage high-multiple membrane concentration at a lower pressure, while reducing energy consumption and improving safety; (2) By switching between forward and reverse flow, the number of maintenance times can be reduced and the maintenance cycle can be extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a reverse osmosis membrane module of the present invention; Figure 2 is a schematic diagram of the present invention; Figure 3 It is a schematic diagram of the low-pressure side downstream of the present invention; Figure 4 It is a low-pressure side counterflow schematic diagram of the present invention; Figure 5 is a schematic diagram of embodiment 1 of the present invention; Figure 6 is a schematic diagram of the downstream of the high pressure side of the reverse osmosis membrane assembly in Example 2 of the present invention; Figure 7 It is a schematic diagram of the countercurrent on the high pressure side of the reverse osmosis membrane assembly in Example 2 of the present invention. DETAILED DESCRIPTION

[0021] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0025] In the present disclosure, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present disclosure can be determined according to specific circumstances, and they cannot be understood as limitations on the present disclosure.

[0026] A variable-level high-efficiency membrane concentration system, Figure 1 , Figure 2As shown, it includes several reverse osmosis membrane modules 1, and the reverse osmosis membrane modules 1 are provided with a high-pressure side and a low-pressure side. High-salt water is separated from the solvent to the low-pressure side through reverse osmosis under high pressure on the high-pressure side, and the concentration on the high-pressure side is increased.

[0027] Ginseng Figure 1 As shown, the reverse osmosis membrane assembly 1 is provided with a high-pressure side interface Ⅰ2, a high-pressure side interface Ⅱ3, a low-pressure side interface Ⅰ4 and a low-pressure side interface Ⅱ5, a total of four interfaces.

[0028] The high-pressure sides of adjacent reverse osmosis membrane assemblies 1 are connected in series through pipelines, and the liquid to be concentrated passes through the high-pressure side of each effect reverse osmosis membrane assembly 1 in turn. The interfaces of adjacent low-pressure sides are connected through pipelines, and low-salt water passes through the low-pressure side of each effect reverse osmosis membrane assembly 1 in turn.

[0029] The specific series connection method is as follows: Ginseng Figure 1 As shown, the high-pressure side interface I2 and the high-pressure side interface II3 of the adjacent reverse osmosis membrane assembly 1 are connected through the first pipe 9, the low-pressure side interface I4 and the low-pressure side interface II5 of the adjacent reverse osmosis membrane assembly 1 are connected through the second pipe 10, the first pipe 9 and the second pipe 10 are connected through the third pipe 11, and the second pipe 10 and the third pipe 11 are both provided with a switch valve 7, and the third pipe 11 is connected to the downstream position of the switch valve 7 of the second pipe 10. In the downstream mode, the first pipe 9 is connected to the second pipe 10 through the third pipe 11, and the switch valve 7 on the second pipe 10 disconnects the low-pressure side interface I4 and the low-pressure side interface II5, so that the concentrated water concentrated by the previous reverse osmosis membrane assembly 1 enters the high-pressure side and the low-pressure side of the next reverse osmosis membrane assembly 1 at the same time. This structure can reduce the pressure difference between the high-pressure side and the low-pressure side, thereby reducing the driving pressure required for ion reverse osmosis. In the countercurrent mode, the third tube 11 is closed and the second tube 10 is opened. The concentrated water and the low-salt water flow in opposite directions. In the reverse osmosis process, the concentrated water closer to the front has a lower ion concentration, and the low-salt water closer to the front has a larger accumulated water volume and a lower ion concentration. This structure is also reasonable and can reduce the ion concentration difference on both sides of the reverse osmosis membrane. The high-pressure side interface Ⅰ2 of the first effect is directly connected to the water to be concentrated.

[0030] The low-pressure side interface II5 of the n-th effect reverse osmosis membrane assembly 1 is also connected to the first tube 9 connected to the high-pressure side interface I2 of the n-1-th effect reverse osmosis membrane assembly 1 through the fourth tube 12. The fourth tube 12 is provided with a switch valve 7, n≥2. This structure is used in the downstream mode to merge the low-salt water obtained by each effect reverse osmosis membrane assembly 1 into the concentrated water inlet of the previous effect reverse osmosis membrane assembly 1, thereby further diluting the concentrated water of the previous effect, thereby reducing the reverse osmosis ion osmotic pressure difference on both sides of the membrane and reducing the corresponding reverse osmosis operation driving force. The low-pressure side interface II5 or the low-pressure side interface I4 of the first effect reverse osmosis membrane assembly sends out the low-salt water.

[0031] The low-pressure side interface II5 of the last reverse osmosis membrane assembly 1 is also connected to a fifth pipe 13, which is connected to the first pipe 9 connected to the adjacent reverse osmosis membrane assembly 1, and a switch valve 7 is provided on the fifth pipe 13. This structure has the same function as the aforementioned fourth pipe 12, and is used to supplement concentrated water in the countercurrent to reduce resistance.

[0032] Wherein, a plurality of switch valves 7 are arranged on the pipeline, and the switch valves 7 are periodically switched to allow the low-salt water to pass through each effect reverse osmosis membrane assembly 1 in a downstream or upstream direction.

[0033] The switching mode of the switch valve 7 is: The low-pressure side of the system switches to downstream in the following manner: the switch valves 7 on the third pipe 11 and the fourth pipe 12 are opened, and the switch valves 7 on the second pipe 10 and the fifth pipe 13 are closed; Figure 3 shown.

[0034] The low-pressure side of the system switches to reverse flow in the following manner: the switch valves 7 on the third pipe 11 and the fourth pipe 12 are closed, and the switch valves 7 on the second pipe 10 and the fifth pipe 13 are opened; Figure 4 shown.

[0035] A first threshold and a second threshold are set, and the switching method of the concentration system includes: Step 1, monitoring the water outlet rate of the low-pressure side of the first-effect reverse osmosis membrane assembly 1; Step 2: When the water outflow rate is lower than the first threshold, switch the system to forward and reverse flow state; Step 3: When the water outlet rate is lower than the second threshold, the system is cleaned; Repeat steps 1 to 3.

[0036] It also includes a forward osmosis membrane assembly 6, the liquid to be concentrated is connected to the low-pressure side of the forward osmosis membrane assembly 6, and the high-pressure side interface II3 of the reverse osmosis membrane assembly 1 at the end is connected to the high-pressure side of the forward osmosis membrane assembly 6. The water in the concentrated liquid is extracted through the forward osmosis membrane to increase its concentration.

[0037] It also includes a supplementary reverse osmosis membrane assembly 8. The low-pressure side interface Ⅰ4 and the low-pressure side interface Ⅱ5 of the first-effect reverse osmosis membrane assembly 1 are connected to the supplementary reverse osmosis membrane assembly 8 through pipelines. The pipelines are provided with switch valves 7. The concentrated water of the supplementary reverse osmosis membrane assembly 8 is connected to the water inlet pipe of the liquid to be concentrated. The structure is used to further concentrate the low-salt water obtained from the first-effect reverse osmosis membrane assembly 1, and the low-salt water is exported and the concentrated water is incorporated into the liquid to be concentrated. The development valve connected to the low-pressure side interface Ⅰ4 and the low-pressure side interface Ⅱ5 is mutually exclusive switched according to the downstream or upstream of the system, so that the low-salt water passes through the first-stage reverse osmosis membrane assembly 1.

[0038] The system comprises a plurality of reverse osmosis membrane modules 1 arranged in series, and the liquid to be concentrated flows to each reverse osmosis membrane module 1 step by step, and the low-salt water is separated by the reverse osmosis membrane, and the concentrated water is concentrated step by step.

[0039] In order to reduce energy consumption and improve safety, reverse osmosis is performed at a lower pressure, and a structure of multiple-effect reverse osmosis membrane modules 1 connected in series is set up to reduce the reverse osmosis osmosis pressure difference between the high-pressure side and the low-pressure side in the same effect reverse osmosis membrane module 1, thereby reducing the corresponding reverse osmosis operation driving force.

[0040] The present application adjusts the flow direction on the low-pressure side by setting a switch valve 7 to adjust the flow direction, and the flow direction includes downstream and upstream. The downstream is transmitted step by step from the first-effect reverse osmosis membrane assembly 1 to the end reverse osmosis membrane assembly 1, and the upstream is transmitted step by step from the end reverse osmosis membrane assembly 1 to the first-effect reverse osmosis membrane assembly 1.

[0041] During the transfer process, the flow direction is opposite on the low-pressure side of each reverse osmosis membrane assembly 1. This can reduce the degradation of the membrane of the reverse osmosis membrane assembly 1, play a role similar to backwashing, use instead of washing, and reduce the maintenance times by alternating forward and reverse flow, and extend the cleaning and maintenance cycle.

[0042] Embodiment 1: The number of reverse osmosis membrane modules 1 is five.

[0043] Ginseng Figure 5 As shown, take this quantity as an example: The high-salinity wastewater is connected to the low-pressure side interface 621 of the forward osmosis membrane assembly 6, and enters the high-pressure side interface 111 of the first reverse osmosis membrane assembly from the low-pressure side interface 622 on the other side through a pipeline, and the pipeline has a valve V0.

[0044] The first reverse osmosis membrane assembly a, the second reverse osmosis membrane assembly b, the third reverse osmosis membrane assembly c, the fourth reverse osmosis membrane assembly d, and the fifth reverse osmosis membrane assembly e are connected in series through the high-pressure side interface. Specifically, the high-pressure side interface 112 of the first reverse osmosis membrane assembly a is connected to the high-pressure side interface 211 of the second reverse osmosis membrane assembly b, the high-pressure side interface 212 of the second reverse osmosis membrane assembly b is connected to the high-pressure side interface 311 of the third reverse osmosis membrane assembly c, the high-pressure side interface 312 of the third reverse osmosis membrane assembly c is connected to the high-pressure side interface 411 of the fourth reverse osmosis membrane assembly d, the high-pressure side interface 412 of the fourth reverse osmosis membrane assembly d is connected to the high-pressure side interface 511 of the fifth reverse osmosis membrane assembly e, and the high-pressure side interface 512 of the fifth reverse osmosis membrane assembly e is connected to the high-pressure side interface 612 of the forward osmosis membrane assembly 6, and the high-pressure side interface 611 of the forward osmosis membrane assembly 6 is discharged as the final concentrated liquid.

[0045] The first reverse osmosis membrane assembly a, the second reverse osmosis membrane assembly b, the third reverse osmosis membrane assembly c, the fourth reverse osmosis membrane assembly d, and the fifth reverse osmosis membrane assembly e are connected in series through the low-pressure side interface. Specifically, the low-pressure side interface 122 of the first reverse osmosis membrane assembly a is connected to the low-pressure side interface 221 of the second reverse osmosis membrane assembly b through the valve V14, the low-pressure side interface 222 of the second reverse osmosis membrane assembly b is connected to the low-pressure side interface 321 of the third reverse osmosis membrane assembly c through the valve V13, the low-pressure side interface 322 of the third reverse osmosis membrane assembly c is connected to the low-pressure side interface 421 of the fourth reverse osmosis membrane assembly d through the valve V12, and the low-pressure side interface 422 of the fourth reverse osmosis membrane assembly d is connected to the low-pressure side interface 521 of the fifth reverse osmosis membrane assembly e through the valve V11.

[0046] The low-pressure side interface 522 is connected to the high-pressure side interface 511 through a pipeline, and a valve V10 is provided on the pipeline.

[0047] The low-pressure side interface 522 is connected to the high-pressure side interface 312 through a pipeline, and a valve V9 is provided on the pipeline.

[0048] The low-pressure side interface 422 is connected to the high-pressure side interface 212 through a pipeline, and a valve V7 is provided on the pipeline.

[0049] The low-pressure side interface 322 is connected to the high-pressure side interface 112 through a pipeline, and a valve V5 is provided on the pipeline.

[0050] The low-pressure side interface 222 is connected to the high-pressure side interface 111 through a pipeline, and a valve V3 is provided on the pipeline.

[0051] The high-pressure side interface 112 and the low-pressure side interface 221 are connected, and a valve V2 is provided on the pipeline.

[0052] The high-pressure side interface 212 is connected to the low-pressure side interface 321 , and a valve V4 is provided on the pipeline.

[0053] The high-pressure side interface 312 is connected to the low-pressure side interface 421, and a valve V6 is provided on the pipeline.

[0054] The high-pressure side interface 412 is connected to the low-pressure side interface 521, and a valve V8 is provided on the pipeline.

[0055] The low-pressure side interfaces 121 and 122 of the first reverse osmosis membrane assembly a discharge low-salt water through pipelines, and valves V1 and V15 are provided on the two pipelines. The pipelines are respectively connected to the supplementary reverse osmosis membrane assembly 8, the concentrated water outlet of the supplementary reverse osmosis membrane assembly 8 is connected to the low-pressure side interface 621, and the low-salt water outlet is connected to the low-salt water outlet to enter the next process.

[0056] When switching to downstream: open valve V0, valve V2, valve V4, valve V5, valve V8, valve V9, valve V7, valve V5, valve V3, valve V1, and close the remaining valves.

[0057] When switching to reverse flow: open valve V0, valve V10, valve V11, valve V12, valve V13, valve V14, valve V15, and close the rest.

[0058] Embodiment 2: Ginseng Figure 6 , Figure 7 As shown, in some embodiments, a boosting component is further included, and the boosting component is arranged on a front pressure-compensating container 15 on the side of the high-pressure side interface Ⅰ2 of the reverse osmosis membrane assembly 1 and a rear pressure-compensating container 16 on the side of the high-pressure side interface Ⅱ3. The front pressure-compensating container 15 and the first pipe 9 connected to the high-pressure side interface Ⅰ2 are communicated through a first switching valve 17, and the rear pressure-compensating container 16 and the first pipe 9 connected to the high-pressure side interface Ⅱ3 are communicated through a second switching valve 18. The first switching valve 17 and the second switching valve 18 are also connected to a sixth pipe 14. The pressure-compensating container increases the liquid pressure through volume changes, and the concentrated water flow of the reverse osmosis membrane assembly 1 is adjusted by switching the first switching valve 17 and the second switching valve 18. The first switching valve 17 and the second switching valve 18 are two-position four-way valves. The first interface 171 of the first switching valve is connected to the previous effect reverse osmosis membrane assembly 1, the second interface 172 of the first switching valve is connected to the front pressure compensation container 15, the third interface 173 of the first switching valve is connected to the high-pressure side interface Ⅰ2 of the reverse osmosis membrane assembly 1, the fourth interface 174 of the first switching valve is connected to the sixth pipe 14, the first interface 181 of the second switching valve is connected to the high-pressure side interface Ⅱ3 of the reverse osmosis membrane assembly 1, the second interface 182 of the second switching valve is connected to the rear pressure compensation container 16, the third interface 183 of the second switching valve is connected to the next effect reverse osmosis membrane assembly 1, and the fourth interface 184 of the second switching valve is connected to the sixth pipe 14.

[0059] The first switching valve 17 has two valve positions. In the first valve position 19, the first interface 171 of the first switching valve is connected to the fourth interface 174 of the first switching valve, and the second interface 172 of the first switching valve is connected to the third interface 173 of the first switching valve. In the second valve position 20, the first interface 171 of the first switching valve is connected to the second interface 172 of the first switching valve, and the third interface 173 of the first switching valve is connected to the fourth interface 174 of the first switching valve.

[0060] The second switching valve 18 has two valve positions. In the first valve position 19, the first interface 181 of the second switching valve is connected to the third interface 183 of the second switching valve, and the second interface 182 of the second switching valve is connected to the fourth interface 184 of the second switching valve; in the second valve position 20, the first interface 181 of the second switching valve is connected to the second interface 182 of the second switching valve, and the third interface 183 of the second switching valve is connected to the fourth interface 184 of the second switching valve.

[0061] When downstream, the liquid enters the reverse osmosis membrane assembly 1 from the front pressure compensation container 15, and the concentrated brine obtained in the previous effect enters the rear pressure compensation container 16. The first switching valve 17 is in the first valve position 19, and the second switching valve 18 is in the first valve position 19.

[0062] On the contrary, in reverse flow, the liquid enters the reverse osmosis membrane assembly 1 from the rear pressure compensation container 16, and the concentrated brine obtained in the previous effect enters the front pressure compensation container 15. The first switching valve 17 is in the second valve position 20, and the second switching valve 18 is in the second valve position 20.

[0063] The first switching valve 17 and the second switching valve 18 are electromagnetic valves, and the valve positions are switched based on the front pressure compensation container 15 and the rear pressure compensation container 16 .

[0064] The boosting assembly is arranged outside a plurality of reverse osmosis membrane assemblies 1, or, a plurality of reverse osmosis membrane assemblies 1 from the back to the front are all provided with the boosting assembly, and the present application does not impose any limitation on this.

[0065] The flow direction through the high-pressure side of the reverse osmosis membrane assembly is adjusted by switching the two-position four-way valve. The two-position four-way valve is switched periodically, and the period is set to the filling time of the front pressure-compensating container 15 or the rear pressure-compensating container 16. The front pressure-compensating container 15 and the rear pressure-compensating container 16 are pressurized by alternating volume changes according to the liquid level.

[0066] The functions of the booster assembly include pressure replenishment and switching the high-pressure side and the low-pressure side of the reverse osmosis membrane assembly 1 in the forward and reverse flow. Pressure replenishment can improve the reverse osmosis efficiency of each effect reverse osmosis membrane assembly 1. Switching in the forward and reverse flow can reduce the degradation of the membrane of the reverse osmosis membrane assembly 1.

[0067] The boost component uses double breathing similar to that of birds, switching between forward and reverse flow while boosting.

[0068] Through the above structure, the high-pressure side is also switched between forward and reverse flow, which further reduces the number of maintenance times and prolongs the maintenance cycle.

[0069] The embodiments described above are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A variable-level high-efficiency membrane concentration system, characterized in that: The invention comprises a plurality of reverse osmosis membrane assemblies, wherein the reverse osmosis membrane assemblies are provided with a high-pressure side and a low-pressure side, and the reverse osmosis membrane assemblies are provided with a high-pressure side interface I, a high-pressure side interface II, a low-pressure side interface I and a low-pressure side interface II, the high-pressure sides of adjacent reverse osmosis membrane assemblies are connected in series through pipelines, the liquid to be concentrated passes through the high-pressure side of each effect reverse osmosis membrane assembly in turn and produces low-salt water on the low-pressure side, the interfaces of adjacent low-pressure sides are connected through pipelines, the low-salt water passes through the low-pressure side of each effect reverse osmosis membrane assembly in turn, wherein the pipelines are provided with a plurality of switch valves, and the switch valves are periodically switched to allow the low-salt water to pass through each effect reverse osmosis membrane assembly in downstream or upstream direction.

2. A variable-level high-efficiency membrane concentration system according to claim 1, characterized in that: The high-pressure side interface I and the high-pressure side interface II of adjacent reverse osmosis membrane assemblies are connected through a first pipe, the low-pressure side interface I and the low-pressure side interface II of adjacent reverse osmosis membrane assemblies are connected through a second pipe, the first pipe and the second pipe are connected through a third pipe, and switch valves are provided on the second pipe and the third pipe. The third pipe is arranged at the downstream position of the switch valve of the second pipe, and the high-pressure side interface I of the first-effect reverse osmosis membrane assembly is connected to the water to be concentrated.

3. A variable-level high-efficiency membrane concentration system according to claim 2, characterized in that: The low-pressure side interface II of the n-th effect reverse osmosis membrane assembly is also connected to the first pipe connected to the high-pressure side interface I of the n-1-th effect reverse osmosis membrane assembly through a fourth pipe. A switch valve is provided on the fourth pipeline. n≥2. The low-pressure side interface of the first effect reverse osmosis membrane assembly transports low-salt water.

4. A variable-level high-efficiency membrane concentration system according to claim 3, characterized in that: The low-pressure side interface II of the last reverse osmosis membrane assembly is also connected to a fifth pipe, the fifth pipe is connected to the first pipe connected to the adjacent reverse osmosis membrane assembly, and a switch valve is arranged on the fifth pipe.

5. The variable-level high-efficiency membrane concentration system according to claim 1 is characterized in that: It also includes a forward osmosis membrane assembly, the liquid to be concentrated is connected to the low-pressure side of the forward osmosis membrane assembly, and the high-pressure side interface II of the reverse osmosis membrane assembly at the end is connected to the high-pressure side of the forward osmosis membrane assembly.

6. A variable-level high-efficiency membrane concentration system according to claim 2, characterized in that: It also includes a supplementary reverse osmosis membrane assembly. The low-pressure side interface I and the low-pressure side interface II of the first-effect reverse osmosis membrane assembly are respectively connected to the supplementary reverse osmosis membrane assembly through pipelines. The pipelines are provided with switch valves, and the concentrated water of the supplementary reverse osmosis membrane assembly is connected to the water inlet pipe of the liquid to be concentrated.

7. The variable-level high-efficiency membrane concentration system according to claim 2 is characterized in that: It also includes a boosting component, which is arranged on a front pressure-compensating container on one side of the high-pressure side interface I of the reverse osmosis membrane assembly and a rear pressure-compensating container on one side of the high-pressure side interface II. The first tube connected to the front pressure-compensating container and the high-pressure side interface I is communicated through a first switching valve, and the first tube connected to the rear pressure-compensating container and the high-pressure side interface II is communicated through a second switching valve. The first switching valve and the second switching valve are also connected to a sixth tube. The pressure-compensating container increases the liquid pressure through volume change, and the concentrated water flow direction of the reverse osmosis membrane assembly is adjusted by switching the first switching valve and the second switching valve. The first switching valve and the second switching valve are two-position four-way valves. The first interface of the first switching valve is connected to the previous effect reverse osmosis membrane assembly, the second interface of the first switching valve is connected to the front pressure-compensating container, the third interface of the first switching valve is connected to the high-pressure side interface I of the reverse osmosis membrane assembly, the fourth interface of the first switching valve is connected to the sixth tube, the first interface of the second switching valve is connected to the high-pressure side interface II of the reverse osmosis membrane assembly, the second interface of the second switching valve is connected to the rear pressure-compensating container, the third interface of the second switching valve is connected to the next effect reverse osmosis membrane assembly, and the fourth interface of the second switching valve is connected to the sixth tube; The first switching valve has two valve positions. In the first valve position, the first interface of the first switching valve is connected to the fourth interface of the first switching valve, and the second interface of the first switching valve is connected to the third interface of the first switching valve; in the second valve position, the first interface of the first switching valve is connected to the second interface of the first switching valve, and the third interface of the first switching valve is connected to the fourth interface of the first switching valve; The second switching valve has two valve positions. In the first valve position, the first interface of the second switching valve is connected to the third interface of the second switching valve, and the second interface of the second switching valve is connected to the fourth interface of the second switching valve; in the second valve position, the first interface of the second switching valve is connected to the second interface of the second switching valve, and the third interface of the second switching valve is connected to the fourth interface of the second switching valve.

8. A switching method for a variable-level high-efficiency membrane concentration system, characterized in that: The method comprises the variable-level high-efficiency membrane concentration system as claimed in claim 4, The low-pressure side of the system switches to downstream in a manner that: the switch valves on the third pipe and the fourth pipe are opened, and the switch valves on the second pipe and the fifth pipe are closed; The low-pressure side of the system switches to reverse flow in the following manner: the switch valves on the third pipe and the fourth pipe are closed, and the switch valves on the second pipe and the fifth pipe are opened; A first threshold and a second threshold are set, and the switching method of the concentration system includes: Step 1, monitoring the water outlet rate of the low-pressure side of the first-effect reverse osmosis membrane assembly; Step 2: When the water outflow rate is lower than the first threshold, switch the system to forward and reverse flow state; Step 3: When the water output rate is lower than the second threshold, the system is cleaned; Repeat steps 1 to 3.

9. The switching method of a variable-level high-efficiency membrane concentration system according to claim 8 is characterized in that: It also includes a supplementary reverse osmosis membrane assembly, and the switch valves connected to the low-pressure side interface I and the low-pressure side interface II are switched mutually exclusively according to the downstream or upstream flow of the system, so that the low-salt water passes through the first-stage reverse osmosis membrane assembly.

10. The switching method of a variable-level high-efficiency membrane concentration system according to claim 8, characterized in that: It also includes a boosting component, which adjusts the flow direction through the high-pressure side of the reverse osmosis membrane component by switching a two-position four-way valve. The two-position four-way valve is switched periodically, and the period is set to the filling time of the front pressure-boosting container or the rear pressure-boosting container. The front pressure-boosting container and the rear pressure-boosting container are pressurized by alternating volume changes according to the liquid level.

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