Low-pressure high-power concentration device and method

Abstract

The invention provides a low-pressure high-power concentration device and a low-pressure high-power concentration method, and relates to the technical field of liquid concentration, the low-pressure high-power concentration device comprises: a first membrane concentration assembly, two ends of a feed liquid side of the first membrane concentration assembly are respectively provided with a raw water inlet and a concentrated product outlet, and the raw water inlet is connected with a first pump; the two ends of the feed liquid side of the second membrane concentration assembly are connected with a water outlet and a concentrated solution inlet of the penetrating fluid side of the first membrane concentration assembly through a diluent pipeline and a concentrated solution pipeline respectively, and a second pump is arranged on the diluent pipeline; the high-power concentration of the to-be-concentrated solution can be realized under low operation pressure.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid concentration, and more specifically, relates to a low-pressure high-multiple concentration device and method. Background Art

[0002] With the advancement of relevant policies on environmental protection and resource recycling in my country, the resource utilization of sewage will be the development direction of sewage treatment in my country in the future. The resource utilization of sewage mainly includes water recycling and salt recycling in high-salt wastewater. The difficulty lies in improving the purity and concentration of salt in wastewater. For example, in the wet recycling process of waste lithium batteries, the lithium-containing solution produced is about 2% to 3% lithium sulfate and about 3% to 4% sodium sulfate. The lithium sulfate needs to be concentrated 4 to 5 times before entering the lithium precipitation stage to recover lithium carbonate. At this time, the salt content is as high as more than 25%, and the osmotic pressure is above 130 bar; for example, after the stainless steel pickling wastewater is neutralized and the sludge is filtered, the filtered liquid NO3 - About 15g / L~30g / L, needs to be concentrated to more than 100g / L, at this time the calcium nitrate concentration is 26.5%, the osmotic pressure is about 120bar, and the water production is required to be NO3 - Less than 30mg / L. Commonly used concentration methods include membrane method and thermal method. Compared with thermal method, membrane method has significant advantages in equipment investment, energy consumption, operation and maintenance. Membrane methods include ultra-high pressure reverse osmosis, forward osmosis, membrane distillation and electrodialysis. The operating pressure of ultra-high pressure reverse osmosis is greater than 100bar, which means high energy consumption, high cost and high safety risk; the disadvantage of forward osmosis is that the extraction liquid is difficult to recycle; the disadvantage of membrane distillation is that the flux is small, and there is a risk of wetting of membrane elements; the disadvantage of electrodialysis is that it occupies a large area and has high power consumption. Therefore, it is of great significance to seek technology that can carry out high-concentration brine concentration at low operating pressure. Summary of the invention

[0003] The purpose of the present invention is to provide a low-pressure high-multiple concentration device and method to address the deficiencies in the prior art, so as to achieve high-multiple concentration of a liquid to be concentrated under low operating pressure.

[0004] In order to achieve the above object, the present invention provides a low-pressure high-power concentration device, which comprises:

[0005] A first membrane concentration assembly, wherein both ends of the feed liquid side of the first membrane concentration assembly are respectively provided with a raw water inlet and a concentrated product outlet, and the raw water inlet is connected to a first pump;

[0006] The second membrane concentration assembly, the two ends of the feed liquid side of the second membrane concentration assembly are connected to the water outlet and the concentrated liquid inlet of the permeate side of the first membrane concentration assembly through a diluent pipeline and a concentrated liquid pipeline respectively, and a second pump is arranged on the diluent pipeline.

[0007] Optionally, at least two of the first membrane concentration components are provided, and at least two of the first membrane concentration components are connected in sequence to form at least a two-stage arrangement, and the diluent pipeline is connected to the water outlets on the permeate sides of at least two of the first membrane concentration components through at least two first branch pipelines, and the concentrated liquid pipeline is connected to the concentrated liquid inlet on the permeate sides of at least two of the first membrane concentration components through at least two second branch pipelines.

[0008] Optionally, the raw water inlet is connected to a water inlet pipe, and the first pump is arranged on the water inlet pipe.

[0009] Optionally, a filter and a third pump are provided on the water inlet pipe upstream of the first pump.

[0010] Optionally, the first pump and the second pump are high-pressure pumps.

[0011] Optionally, the output pressure of the first pump and the second pump is no more than 7 MPa.

[0012] Optionally, the filter has a filtration accuracy of 10-100 microns.

[0013] Optionally, the first membrane concentration component is a hollow fiber membrane component, and the second membrane concentration component is a spiral reverse osmosis membrane component.

[0014] The present invention also provides a low-pressure high-multiple concentration method, using the above-mentioned low-pressure high-multiple concentration device, the method comprises:

[0015] The liquid to be concentrated is input into the feed liquid side of the first membrane concentration module through the first pump for concentration, and the first produced water is produced on the permeate side of the first membrane concentration module;

[0016] The first produced water is input into the second membrane concentration module for concentration to produce second produced water and concentrated liquid;

[0017] The concentrated liquid is returned to the permeate side of the first membrane concentration module to mix with the first produced water to form a diluent;

[0018] Continuously inputting the diluted liquid into the second membrane concentration module for concentration;

[0019] The feed liquid side and the permeate liquid side of the first membrane concentration component are respectively kept as the to-be-concentrated liquid and the diluent, and the concentrated product is continuously produced.

[0020] Optionally, at least two of the first membrane concentration assemblies are provided, and at least two of the first membrane concentration assemblies are connected in sequence to form at least a two-stage arrangement. The diluent pipeline is connected to the water outlets on the permeate sides of at least two of the first membrane concentration assemblies through at least two first branch pipelines, and the concentrated liquid pipeline is connected to the concentrated liquid inlet on the permeate sides of at least two of the first membrane concentration assemblies through at least two second branch pipelines. The concentrated liquid is sequentially input into the at least two first membrane concentration assemblies through the first pump, and at least two-stage concentration is performed.

[0021] The present invention provides a low-pressure high-fold concentration device and method, which have the following beneficial effects: the low-pressure high-fold concentration device comprises a first membrane concentration component and a second membrane concentration component, the first produced water produced by the first membrane concentration component is cyclically connected with the second membrane concentration component, the first produced water is concentrated by the second membrane concentration component to produce second produced water and concentrated liquid, the second produced water can be discharged as a purified product, and the concentrated liquid is continuously refluxed to the permeate side of the first membrane concentration component to continuously mix with the diluent, such mixing makes the salt concentration of the permeate side of the first membrane concentration component higher than that of the first produced water directly produced by the first membrane concentration component, can reduce the osmotic pressure difference between the two sides of the membrane of the first membrane concentration component, thereby reducing its operating pressure and breaking through the osmotic pressure limit, similarly, for the second membrane concentration component, since its feed liquid side is a diluent, the salt concentration is also lower than the concentration of the liquid to be concentrated, so that the osmotic pressure difference between the two sides of the membrane of the second membrane concentration component is also lower, so that its operating pressure is also lower, so the first pump and the second pump are both operated at a lower operating pressure, and the first membrane concentration component can continuously produce a highly concentrated concentrated product.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0024] Figure 1 A schematic structural diagram of a low-pressure high-multiple concentration device according to Embodiment 1 of the present invention is shown.

[0025] Figure 2 A flow chart of a low-pressure high-multiple concentration method according to Embodiment 1 of the present invention is shown.

[0026] Figure 3 A schematic structural diagram of a low-pressure high-multiple concentration device according to the second embodiment of the present invention is shown.

[0027] Description of reference numerals:

[0028] 1. The first membrane concentration component; 2. The first pump; 3. The second membrane concentration component; 4. The diluent pipeline; 5. The concentrate pipeline; 6. The second pump; 7. The water inlet pipe; 8. The filter; 9. The third pump; 10. The first membrane concentration component of the first stage; 11. The first membrane concentration component of the second stage. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0030] Embodiment 1

[0031] like Figure 1 As shown, the present invention provides a low-pressure high-multiple concentration device, which includes:

[0032] A first membrane concentration module 1, wherein both ends of the feed liquid side of the first membrane concentration module 1 are respectively provided with a raw water inlet and a concentrated product outlet, and the raw water inlet is connected to a first pump 2;

[0033] The second membrane concentration assembly 3 has two ends on the feed liquid side connected to the water outlet and the concentrate inlet of the permeate side of the first membrane concentration assembly 1 through a diluent pipeline 4 and a concentrate pipeline 5 respectively, and a second pump 6 is provided on the diluent pipeline 4.

[0034] Specifically, in order to achieve high concentration of the liquid to be concentrated under low operating pressure, the low-pressure high-concentration device provided by the present invention comprises a first membrane concentration component 1 and a second membrane concentration component 3. The first produced water produced by the first membrane concentration component 1 is circulated and connected to the second membrane concentration component 3. The first produced water is concentrated by the second membrane concentration component 3 to produce second produced water and concentrated liquid. The second produced water can be discharged as a purified product, and the concentrated liquid is continuously refluxed to the permeate side of the first membrane concentration component 1 to be continuously mixed with the diluent. Such mixing makes the permeate side of the first membrane concentration component 1 The salt concentration is higher than that of the first produced water directly produced by the first membrane concentration component 1, which can reduce the osmotic pressure difference on both sides of the membrane of the first membrane concentration component 1, thereby reducing its operating pressure and breaking through the osmotic pressure limit. Similarly, for the second membrane concentration component 3, since its feed liquid side is a diluent, the salt concentration is also lower than the concentration of the liquid to be concentrated, so that the osmotic pressure difference on both sides of the membrane of the second membrane concentration component 3 is also lower, so that its operating pressure is also smaller, so the first pump 2 and the second pump 6 are both operated at a lower operating pressure, and the first membrane concentration component 1 can continuously produce a highly concentrated concentrated product.

[0035] In this embodiment, the raw water inlet is connected to a water inlet pipe 7 , and the first pump 2 is disposed on the water inlet pipe 7 .

[0036] Specifically, the raw water inlet is used to input the liquid to be concentrated to the feed liquid side of the first membrane concentration assembly 1 , and the liquid to be concentrated is pumped in by the first pump 2 .

[0037] In this embodiment, a filter 8 and a third pump 9 are provided on the water inlet pipe 7 upstream of the first pump 2 .

[0038] Specifically, the third pump 9 can extract the liquid to be concentrated and input it into the filter 8 for filtration. The filtered liquid to be concentrated is pressurized by the first pump 2 and then pumped into the feed liquid side of the first membrane concentration assembly 1 to meet the membrane concentration working pressure of the first membrane concentration unit.

[0039] In this embodiment, the membrane concentration working pressure of the first membrane concentration unit is 3.5-9.0 MPa.

[0040] Furthermore, in order to ensure the smooth operation of the low-pressure high-multiple concentration device, the concentration of the liquid to be concentrated can be controlled to be low according to the working pressure of the first pump 2. The working pressure required for the initial concentration of the liquid to be concentrated in the first membrane concentration component 1 meets the working pressure of the first pump 2. Then, as the low-pressure high-multiple concentration device is operated, the concentrated liquid produced by the second membrane concentration component 3 continuously flows back to the permeate side of the first membrane concentration component 1, so that the concentration of the permeate side of the first membrane concentration component 1 increases, and the osmotic pressure difference between the two sides of the membrane of the first membrane concentration component 1 decreases. At this time, the concentration of the liquid to be concentrated can be increased without changing the working pressure of the first pump 2 until the expected processing capacity is reached; under the operating pressure of conventional seawater desalination, the low-pressure high-multiple concentration device can increase the traditional spiral reverse osmosis concentration limit from 7% to 14%, or even higher.

[0041] In this embodiment, the first pump 2 and the second pump 6 are high-pressure pumps.

[0042] Specifically, the working pressure of the first pump 2 and the second pump 6 can meet the membrane concentration pressure requirements of the first membrane concentration assembly 1 and the second membrane concentration assembly 3. A high-pressure pump is used, and the third pump 9 is an ordinary booster pump to transport the liquid to be concentrated and pass it through the filter 8.

[0043] In this embodiment, the output pressure of the first pump 2 and the second pump 6 is no greater than 7 MPa.

[0044] Specifically, in order to maintain the concentration of the liquid to be concentrated at a low working pressure, the output pressure of the first pump 2 and the second pump 6 can be a conventional operating pressure, that is, not greater than 7 MPa.

[0045] In this embodiment, the filtering accuracy of the filter 8 is 10-100 microns.

[0046] Specifically, the filter 8 may be a core filter 8 or a precision filter 8 .

[0047] In this embodiment, the first membrane concentration module 1 is a hollow fiber membrane module, and the second membrane concentration module 3 is a spiral reverse osmosis membrane module.

[0048] In other embodiments, the first membrane concentration module 1 may also be a spiral membrane module.

[0049] In this embodiment, the component to be concentrated in the concentrated liquid is NaCl; the highly concentrated brine passes through the hollow fiber membrane module, and its permeate enters the spiral reverse osmosis membrane module to produce a concentrated liquid, which is refluxed to become a diluent. The diluent continuously enters the spiral reverse osmosis membrane module through a high-pressure pump, and is concentrated under normal operating pressure (≦7Mpa). The spiral reverse osmosis concentrated liquid is circulated and reused in the hollow fiber membrane module, the concentrating capacity of the hollow fiber membrane module is improved, and a high-fold concentrated product is continuously produced, and the spiral reverse osmosis membrane module produces water for external discharge.

[0050] like Figure 2 As shown, the present invention also provides a low-pressure high-multiple concentration method, using the above-mentioned low-pressure high-multiple concentration device, the method comprises:

[0051] The liquid to be concentrated is input to the feed liquid side of the first membrane concentration module 1 through the first pump 2 for concentration, and the first produced water is produced on the permeate side of the first membrane concentration module 1;

[0052] The first produced water is input into the second membrane concentration module 3 for concentration to produce second produced water and concentrated liquid;

[0053] The concentrated liquid is returned to the permeate side of the first membrane concentration module 1 to be mixed with the first produced water to form a diluent;

[0054] Continuously inputting the diluted liquid into the second membrane concentration module 3 for concentration;

[0055] The feed liquid side and the permeate liquid side of the first membrane concentration module 1 are kept as the liquid to be concentrated and the diluent respectively, and the concentrated product is continuously produced.

[0056] In summary, when the low-pressure high-multiple concentration method provided by the present invention is used, the low-pressure high-multiple concentration device is used to prepare a concentrated liquid to be a high-concentration brine (TDS 7%) as an example: the liquid to be concentrated is first pumped into the filter 8 by the third pump 9, and the liquid to be concentrated after being filtered by the core filter 8 is pumped into the hollow fiber membrane module with a working pressure of 7Mpa by the second pump 6 at an operating pressure of 7Mpa; the highly concentrated brine is concentrated by the hollow fiber membrane module to produce a concentrated product with a salt content of 13.99%; in this process, the first produced water produced by the permeate side of the hollow fiber membrane module enters the spiral reverse osmosis membrane module for concentration, and the produced concentrated liquid NaCl concentration is 7%, and the concentrated liquid is refluxed to the permeate side of the hollow fiber membrane module to form a diluent and continuously input into the spiral reverse osmosis membrane module through the second pump 6, and the diluent salt content is 3.5%. The diluent enters the spiral reverse osmosis membrane module through the second pump 6, and the operating pressure is also 7Mpa to achieve concentration, and the concentrated liquid is circulated back to the hollow fiber membrane module, and the hollow fiber membrane module continuously produces a concentrated product with a NaCl concentration of 13.99%, and the second produced water TDS 0.01% of the spiral reverse osmosis membrane module is discharged.

[0057] Embodiment 2

[0058] like Figure 3 As shown, the difference between this embodiment and the first embodiment is that:

[0059] In this embodiment, at least two first membrane concentration components 1 are provided, and at least two first membrane concentration components 1 are connected in sequence to form at least a two-stage arrangement. The diluent pipeline 4 is connected to the water outlets on the permeate side of at least two first membrane concentration components 1 through at least two first branch pipelines, and the concentrated liquid pipeline 5 is connected to the concentrated liquid inlet on the permeate side of at least two first membrane concentration components 1 through at least two second branch pipelines.

[0060] Specifically, the working pressure of the first membrane concentration assembly 1 is 3.5-9.0 MPa, and at least two first membrane concentration assemblies 1 form at least a two-stage arrangement, which is set according to different influent salt concentrations and concentration requirements.

[0061] The low-pressure high-multiple concentration method in this embodiment is different from that in the first embodiment in that:

[0062] In this embodiment, at least two first membrane concentration modules 1 are provided, and at least two first membrane concentration modules 1 are connected in sequence to form at least a two-stage arrangement. The diluent pipeline 4 is connected to the water outlets on the permeate side of at least two first membrane concentration modules 1 through at least two first branch pipelines, and the concentrated liquid pipeline 5 is connected to the concentrated liquid inlet on the permeate side of at least two first membrane concentration modules 1 through at least two second branch pipelines. The concentrated liquid is sequentially input into at least two first membrane concentration modules 1 through the first pump 2, and at least two-stage concentration is performed.

[0063] In this embodiment, when the low-pressure high-fold concentration method provided by the present invention is used, the above-mentioned low-pressure high-fold concentration device is used, and the liquid to be concentrated is a high-concentration salt water (TDS 7%) as an example: the liquid to be concentrated is firstly pumped into the filter 8 by the third pump 9, and the liquid to be concentrated after being filtered by the core filter 8 is pumped into the feed liquid side of the first membrane concentration component 10 of the first stage by the second pump 6, and the working pressure of the first membrane concentration component 10 of the first stage is 6Mpa, and the first membrane concentration component 10 of the first stage can produce a first-stage concentrated product with a salt content of 12%, and then the first-stage concentrated product enters the feed liquid side of the second-stage first membrane concentration component 11, and the working pressure of the second-stage first membrane concentration component 11 is 7Mpa. The first membrane concentration component 1 adopts a hollow fiber membrane component, and the high-concentration salt water can produce a high-concentration secondary concentrated product with a salt content of 16% after being concentrated by the second-stage first membrane concentration component 11; in this process, the first stage The first produced water on the permeate side of the first membrane concentration module 10 and the second-level first membrane concentration module 11 enters the spiral reverse osmosis membrane module for concentration under the action of the second pump 6. The produced concentrated liquid has a NaCl concentration of 6.93%. The concentrated liquid flows back to the permeate side of the two hollow fiber membrane modules to become a diluent. The diluent has a salt content of 3.5%. The diluent enters the spiral reverse osmosis membrane module through the second pump 6. The operating pressure is also 7Mpa to achieve concentration. The concentrated liquid is circulated back to the hollow fiber membrane module. The second-level first membrane concentration module 11 continuously produces a high-multiple secondary concentrated product with a NaCl concentration of 16%, i.e., the final concentrated product. The second produced water of the spiral reverse osmosis membrane module has a TDS of 0.07% and is discharged.

[0064] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A low-pressure high-power concentration device, characterized in that: The device includes: A first membrane concentration assembly, wherein both ends of the feed liquid side of the first membrane concentration assembly are respectively provided with a raw water inlet and a concentrated product outlet, and the raw water inlet is connected to a first pump; The second membrane concentration assembly, the two ends of the feed liquid side of the second membrane concentration assembly are connected to the water outlet and the concentrated liquid inlet of the permeate side of the first membrane concentration assembly through a diluent pipeline and a concentrated liquid pipeline respectively, and a second pump is arranged on the diluent pipeline.

2. The low-pressure high-power concentration device according to claim 1, characterized in that: At least two of the first membrane concentration components are provided, and at least two of the first membrane concentration components are connected in sequence to form at least a two-stage arrangement. The diluent pipeline is connected to the water outlets on the permeate sides of at least two of the first membrane concentration components through at least two first branch pipelines, and the concentrated liquid pipeline is connected to the concentrated liquid inlet on the permeate sides of at least two of the first membrane concentration components through at least two second branch pipelines.

3. The low-pressure high-power concentration device according to claim 1, characterized in that: The raw water inlet is connected to a water inlet pipe, and the first pump is arranged on the water inlet pipe.

4. The low-pressure high-power concentration device according to claim 3, characterized in that: A filter and a third pump are arranged on the water inlet pipe upstream of the first pump.

5. The low-pressure high-power concentration device according to claim 4, characterized in that: The first pump and the second pump are high-pressure pumps.

6. The low-pressure high-power concentration device according to claim 5, characterized in that: The output pressure of the first pump and the second pump is no more than 7 MPa.

7. The low-pressure high-power concentration device according to claim 4, characterized in that: The filtering accuracy of the filter is 10-100 microns.

8. The low-pressure high-power concentration device according to claim 1, characterized in that: The first membrane concentration component is a hollow fiber membrane component, and the second membrane concentration component is a spiral reverse osmosis membrane component.

9. A low-pressure high-multiple concentration method, using the low-pressure high-multiple concentration device according to any one of claims 1 to 8, characterized in that: The method includes: The liquid to be concentrated is input into the feed liquid side of the first membrane concentration module through the first pump for concentration, and the first produced water is produced on the permeate side of the first membrane concentration module; The first produced water is input into the second membrane concentration module for concentration to produce second produced water and concentrated liquid; The concentrated liquid is returned to the permeate side of the first membrane concentration module to mix with the first produced water to form a diluent; Continuously inputting the diluted liquid into the second membrane concentration module for concentration; The feed liquid side and the permeate liquid side of the first membrane concentration component are respectively kept as the to-be-concentrated liquid and the diluent, and the concentrated product is continuously produced.

10. The low-pressure high-multiple concentration method according to claim 9, characterized in that: At least two of the first membrane concentration modules are provided, and at least two of the first membrane concentration modules are connected in sequence to form at least a two-stage arrangement. The diluent pipeline is connected to the water outlets on the permeate sides of at least two of the first membrane concentration modules through at least two first branch pipelines, and the concentrated liquid pipeline is connected to the concentrated liquid inlet on the permeate sides of at least two of the first membrane concentration modules through at least two second branch pipelines. The concentrated liquid is sequentially input into the at least two first membrane concentration modules through the first pump, and at least two-stage concentration is performed.

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