A membrane concentration device for seawater resource recovery

Abstract

This invention provides a membrane concentration device for seawater resource recovery, relating to the field of seawater treatment technology. It addresses the problems of high salinity in the concentrated brine produced after membrane concentration, which directly impacts the marine ecosystem; and the gradual decline in membrane performance and lifespan under prolonged operation and high salinity / pressure environments, requiring frequent replacements and increasing costs and maintenance workload. The device includes an ultrafiltration unit, a nanofiltration unit, and a multi-stage reverse osmosis membrane concentration unit. The ultrafiltration unit is used to treat seawater by removing suspended solids and colloids. The permeate outlet of the final membrane module is connected to the inlet of the first-stage membrane module via a return pipe. This invention employs a three-stage treatment process—ultrafiltration, nanofiltration, and CFRO—to progressively improve accuracy: ultrafiltration removes large particulate impurities, nanofiltration removes divalent ions to prevent scaling, and CFRO achieves high-concentration salt concentration and resource separation. Low-concentration permeate is returned to avoid waste. Furthermore, it can transform high-salinity wastewater into industrial raw materials, reducing environmental burden and industrial costs.

Description

Technical Field

[0001] This utility model belongs to the field of seawater treatment technology, and more specifically, it relates to a membrane concentration device for seawater resource utilization. Background Technology

[0002] With the increasing severity of water scarcity, seawater, as a vast potential water resource, has attracted widespread attention for its resource utilization. Simultaneously, industrial development generates large amounts of high-salinity wastewater, necessitating efficient treatment and resource recovery technologies. Membrane concentration technology has emerged in this context. Continuous advancements in membrane technology, such as reverse osmosis and nanofiltration, have gradually improved the performance and stability of membranes, providing technical support for the application of membrane concentration in seawater resource recovery. For example, reverse osmosis membranes can more effectively filter and desalinate seawater while gradually reducing energy consumption, making them more economically competitive. Therefore, a membrane concentration device for seawater resource recovery is needed to improve resource separation efficiency and membrane lifespan.

[0003] Existing membrane concentration devices for seawater resource recovery produce highly saline brine after concentration. Direct discharge of this brine can impact marine ecosystems, causing localized salinity anomalies, endangering marine life, and disrupting the ecological balance. Furthermore, prolonged operation under high salinity and pressure conditions gradually degrades membrane performance, shortens its lifespan, and necessitates frequent replacements, increasing costs and maintenance workload. Utility Model Content

[0004] To address the aforementioned technical problems, this utility model provides a membrane concentration device for seawater resource recovery. This device solves the problems of existing membrane concentration methods producing high-salinity brine, which, if directly discharged, can affect the marine ecosystem, causing localized salinity anomalies, endangering marine life, and disrupting the ecological balance. Furthermore, the membrane's performance gradually declines and its lifespan shortens under prolonged operation and high-salinity, high-pressure environments, requiring frequent replacements and increasing costs and maintenance workload.

[0005] This utility model relates to a membrane concentration device for seawater resource recovery, achieved through the following specific technical means:

[0006] A membrane concentration device for seawater resource recovery includes an ultrafiltration unit, a nanofiltration unit, and a multi-stage reverse osmosis membrane concentration unit.

[0007] The ultrafiltration unit is used to treat seawater by ultrafiltration to remove suspended solids and colloids from the seawater and obtain ultrafiltration permeate.

[0008] The nanofiltration unit is connected to the permeate outlet of the ultrafiltration unit and is used to perform nanofiltration treatment on the ultrafiltration permeate to remove divalent ions (calcium ions, magnesium ions and silicon ions) to obtain nanofiltration permeate.

[0009] The multi-stage reverse osmosis membrane concentration unit is connected to the permeate outlet of the nanofiltration unit and is used to perform multi-stage reverse osmosis membrane series concentration treatment on the nanofiltration permeate to obtain CFRO permeate and CFRO concentrate.

[0010] The multi-stage reverse osmosis membrane concentration unit is a CFRO system, including a multi-stage membrane module series structure, a permeate recirculation structure, and an RO membrane module. The RO membrane module is used to reverse osmosis treat the nanofiltration permeate to obtain RO permeate and RO brine. The RO brine enters the multi-stage membrane module series structure for progressive concentration, where each stage of the membrane module further concentrates the brine. The downstream membrane module achieves high salt concentration at a lower osmotic pressure by sacrificing the desalination rate. The permeate (low-concentration brine) of the CFRO system is recirculated back to the front end for further concentration treatment. The permeate recirculation structure is a recirculation pipe, and the permeate outlet of the last stage membrane module is connected to the inlet of the first stage membrane module through the recirculation pipe.

[0011] In at least some embodiments, the ultrafiltration unit uses a hollow fiber ultrafiltration membrane or a flat sheet ultrafiltration membrane with a pore size of 0.01-0.1 μm.

[0012] In at least some embodiments, the return pipe is equipped with a booster pump and a flow regulating valve.

[0013] In at least some embodiments, in the multi-stage membrane module series structure, the desalination rate of the later membrane module is lower than that of the earlier membrane module.

[0014] In at least some embodiments, the CFRO permeate can be used as external drainage or recycled water for replenishing circulating water, and the CFRO concentrate can be transported to industrial users via pipelines as a "liquid salt" raw material.

[0015] In at least some embodiments, the nanofiltration unit employs a spiral wound nanofiltration membrane or a hollow fiber nanofiltration membrane.

[0016] In at least some embodiments, the multi-stage reverse osmosis membrane concentration unit further includes:

[0017] Raw water pump, used to pump nanofiltration permeate into the membrane system;

[0018] The concentrate discharge structure, after volume reduction, produces CFRO concentrate (high-concentration brine) as the final product discharged from the system.

[0019] Compared with the prior art, the membrane concentration device for seawater resource recovery of this utility model has the following beneficial effects:

[0020] The combination of ultrafiltration and nanofiltration units with multi-stage reverse osmosis membrane concentration units facilitates the gradual improvement of seawater treatment precision through a three-stage treatment chain: ultrafiltration (pretreatment) → nanofiltration (ion separation) → CFRO (deep concentration). Ultrafiltration removes large particulate impurities, nanofiltration targets and removes divalent ions, reducing the risk of subsequent membrane fouling, and CFRO achieves high-level salt concentration and resource separation. Furthermore, the RO brine is concentrated through multiple membrane stages, with each stage further increasing the salt concentration, ultimately producing high-concentration concentrate. Low-concentration permeate is returned to the front end for reprocessing, avoiding resource waste caused by single-treatment and discharge. The 0.01-0.1μm membrane pore size can effectively separate micron-sized particles, retain dissolved salts, and does not affect subsequent ion separation.

[0021] The combination of a permeate recirculation structure and a concentrate discharge structure facilitates the conversion of high-salinity wastewater generated by traditional membrane treatment into industrial raw materials, avoiding the environmental burden caused by direct discharge. Furthermore, the linkage between seawater treatment and industrial production reduces raw material costs for industrial users. By installing a booster pump and flow regulating valve on the permeate recirculation pipeline of the CFRO system, the pressure and flow rate of the recirculated brine are controlled, preventing treatment interruptions due to insufficient recirculation pressure, ensuring continuous operation, and allowing parameters to be adjusted in real time according to fluctuations in influent water quality (such as changes in seawater salinity) to adapt to different operating conditions. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the present invention.

[0023] Figure 2 This is a schematic diagram of the multi-stage reverse osmosis membrane concentration system of this utility model.

[0024] Figure 3 This is a schematic diagram of the water production and reflux structure of this utility model.

[0025] Figure 4 This is a schematic diagram of the ultrafiltration water production process of this utility model.

[0026] In the diagram, the correspondence between component names and drawing numbers is as follows:

[0027] 1. Ultrafiltration unit; 101. Ultrafiltration permeate; 2. Nanofiltration unit; 201. Nanofiltration permeate; 3. Multi-stage reverse osmosis membrane concentration unit; 301. CFRO permeate; 302. CFRO concentrate; 303. Raw water pump; 304. RO membrane module; 305. Multi-stage membrane module series structure; 306. Permeate reflux structure; 3061. Booster pump; 3062. Flow regulating valve; 3063. Reflux pipeline; 307. Concentrate discharge structure. Detailed Implementation

[0028] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0029] As attached Figure 1 To be continued Figure 4 As shown:

[0030] Example 1: This utility model provides a membrane concentration device for seawater resource utilization, including an ultrafiltration unit 1, a nanofiltration unit 2, and a multi-stage reverse osmosis membrane concentration unit 3;

[0031] Ultrafiltration unit 1 is used to ultrafiltration seawater to remove suspended solids and colloids from the seawater and obtain ultrafiltration permeate 101;

[0032] Nanofiltration unit 2 is connected to the product water outlet of ultrafiltration unit 1 and is used to perform nanofiltration treatment on ultrafiltration product water 101 to remove divalent ions such as calcium ions, magnesium ions and silicon ions to obtain nanofiltration product water 201.

[0033] The multi-stage reverse osmosis membrane concentration unit 3 is connected to the permeate outlet of the nanofiltration unit 2 and is used to perform multi-stage reverse osmosis membrane series concentration treatment on the nanofiltration permeate 201 to obtain CFRO permeate 301 and CFRO concentrate 302.

[0034] The multi-stage reverse osmosis membrane concentration unit 3 is a CFRO system, including a multi-stage membrane module series structure 305, a permeate return structure 306, and an RO membrane module 304. The RO membrane module 304 is used to reverse osmosis treat the nanofiltration permeate 201 to obtain RO permeate and RO brine. The RO brine enters the multi-stage membrane module series structure 305 for progressive concentration, where each stage of the membrane module further concentrates the brine. The downstream membrane module achieves high salt concentration at a lower osmotic pressure by sacrificing the desalination rate. The low-concentration brine of the CFRO system is returned to the front end for re-concentration treatment. The permeate return structure 306 is a return pipe 3063, and the permeate outlet of the final membrane module is connected to the inlet of the first-stage membrane module through the return pipe 3063. Specifically, through a three-stage treatment chain of ultrafiltration pretreatment → nanofiltration ion separation → CFRO deep concentration, the seawater treatment precision is gradually improved. Ultrafiltration removes large particulate impurities, nanofiltration targets and removes divalent ions, reducing the risk of subsequent membrane scaling, and CFRO achieves high salt concentration and resource separation.

[0035] The multi-stage reverse osmosis membrane concentration unit 3 also includes:

[0036] Raw water pump 303 is used to pump nanofiltration permeate 201 into the membrane system;

[0037] The concentrate discharge structure 307 produces CFRO concentrate 302, a high-concentration brine, which is the final product discharged by the system after the reduction process. Specifically, the RO brine is concentrated through multiple membrane stages, and the salt concentration is further increased through each membrane stage to finally produce high-concentration concentrate. The low-concentration permeate is returned to the front end for reprocessing, avoiding the waste of resources caused by single-treatment and discharge.

[0038] In the multi-stage membrane module series structure 305, the desalination rate of the downstream membrane module is lower than that of the upstream membrane module. The ultrafiltration unit 1 adopts a hollow fiber ultrafiltration membrane or a flat sheet ultrafiltration membrane with a pore size of 0.01-0.1μm. Specifically, the pore size of the membrane of 0.01-0.1μm can effectively separate micron-sized particles, retain dissolved salts, and does not affect the subsequent ion separation.

[0039] Example 2: Based on Example 1, as follows Figure 2 As shown, nanofiltration unit 2 uses spiral wound nanofiltration membrane or hollow fiber nanofiltration membrane. CFRO permeate 301 can be used as external drainage or recycled water for circulating water replenishment. CFRO concentrate 302 is transported to industrial users as "liquid salt" raw material through pipelines. Specifically, it transforms high-salt wastewater generated by traditional membrane treatment into industrial raw materials, avoiding the environmental burden caused by direct discharge. Furthermore, seawater treatment is linked with industrial production, reducing the raw material costs for industrial users.

[0040] The return pipe 3063 is equipped with a booster pump 3061 and a flow regulating valve 3062. Specifically, the booster pump 3061 and the flow regulating valve 3062 installed on the product water return pipe 3063 of the CFRO system control the pressure and flow rate of the return brine, avoid treatment interruption due to insufficient return pressure, ensure continuous operation, and adjust parameters in real time according to fluctuations in influent water quality, such as changes in seawater salinity, to adapt to different operating conditions.

[0041] The specific usage and function of this embodiment are as follows:

[0042] This invention utilizes a three-stage treatment process—ultrafiltration pretreatment, nanofiltration ion separation, and CFRO deep concentration—to progressively improve seawater treatment precision. Ultrafiltration removes large particulate impurities, nanofiltration targets and removes divalent ions, mitigating the risk of subsequent membrane fouling, and CFRO achieves high-level salt concentration and resource separation. Furthermore, the RO brine is progressively concentrated through multiple membrane stages, with each stage further increasing the salt concentration, ultimately producing high-concentration concentrate. Low-concentration permeate is recycled back to the front end for reprocessing, avoiding resource waste caused by single-treatment discharge. The 0.01-0.1μm membrane pore size effectively separates micron-sized particles while retaining dissolved salts without affecting subsequent ion separation. It converts high-salt wastewater generated by traditional membrane treatment into industrial raw materials, avoiding the environmental burden caused by direct discharge. Moreover, the linkage between seawater treatment and industrial production reduces raw material costs for industrial users. Through CFRO… The system's product water return pipeline 3063 is equipped with a booster pump 3061 and a flow regulating valve 3062 to control the pressure and flow rate of the return brine, avoid treatment interruption due to insufficient return pressure, ensure continuous operation, and adjust parameters in real time according to fluctuations in influent water quality, such as changes in seawater salinity, to adapt to different operating conditions.

[0043] The following points should be noted in this article:

[0044] 1. The accompanying drawings of this utility model embodiment only involve the structure involved in this utility model embodiment; other structures can refer to general designs.

[0045] 2. Where there is no conflict, the embodiments of this utility model and the features in the embodiments can be combined with each other to obtain new embodiments.

[0046] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A membrane concentration device for seawater resource utilization, characterized by: It includes an ultrafiltration unit (1), a nanofiltration unit (2), and a multi-stage reverse osmosis membrane concentration unit (3). The ultrafiltration unit (1) is used to perform ultrafiltration on seawater to remove suspended solids and colloids from the seawater and obtain ultrafiltration permeate (101). The nanofiltration unit (2) is connected to the product water outlet of the ultrafiltration unit (1) and is used to perform nanofiltration treatment on the ultrafiltration product water (101) to remove divalent ions therein, thereby obtaining nanofiltration product water (201). The multi-stage reverse osmosis membrane concentration unit (3) is connected to the permeate outlet of the nanofiltration unit (2) and is used to perform multi-stage reverse osmosis membrane series concentration treatment on the nanofiltration permeate (201) to obtain CFRO permeate (301) and CFRO concentrate (302). The multi-stage reverse osmosis membrane concentration unit (3) is a CFRO system, including a multi-stage membrane module series structure (305), a permeate return structure (306), and an RO membrane module (304). The RO membrane module (304) is used to reverse osmosis treat the nanofiltration permeate (201) to obtain RO permeate and RO brine. The RO brine enters the multi-stage membrane module series structure (305) for stage-by-stage concentration, where each stage membrane module further concentrates the brine. The downstream membrane module achieves high salt concentration at a lower osmotic pressure by sacrificing the desalination rate. The permeate of the CFRO system is returned to the front end for re-concentration treatment. The permeate return structure (306) is a return pipe (3063), and the permeate outlet of the final membrane module is connected to the inlet of the first membrane module through the return pipe (3063).

2. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: The multi-stage reverse osmosis membrane concentration unit (3) also includes: Raw water pump (303) is used to pump nanofiltration permeate (201) into the membrane system; The concentrate discharge structure (307) produces CFRO concentrate (302) after reduction, which is the final product of the system discharge.

3. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: In the multi-stage membrane module series structure (305), the desalination rate of the downstream membrane module is lower than that of the upstream membrane module.

4. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: The ultrafiltration unit (1) uses a hollow fiber ultrafiltration membrane or a flat sheet ultrafiltration membrane with a pore size of 0.01-0.1 μm.

5. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: The nanofiltration unit (2) uses spiral wound nanofiltration membrane or hollow fiber nanofiltration membrane.

6. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: The CFRO permeate (301) can be used as external drainage or recycled water for replenishing circulating water, and the CFRO concentrate (302) can be transported to industrial users via pipeline as a "liquid salt" raw material.

7. The membrane concentration device for seawater resource recovery according to claim 1, characterized in that: The return pipe (3063) is equipped with a booster pump (3061) and a flow regulating valve (3062).

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