CN111943398A - Method and device for inhibiting membrane scaling in brackish water desalination treatment - Google Patents

Method and device for inhibiting membrane scaling in brackish water desalination treatment Download PDF

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Publication number
CN111943398A
CN111943398A CN202010823173.9A CN202010823173A CN111943398A CN 111943398 A CN111943398 A CN 111943398A CN 202010823173 A CN202010823173 A CN 202010823173A CN 111943398 A CN111943398 A CN 111943398A
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reverse osmosis
membrane
brackish water
water
inhibiting
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Chinese (zh)
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王胜
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Shandong Sunway Saline Alkali Soil Technology Co Ltd
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Shandong Sunway Saline Alkali Soil Technology Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/08—Prevention of membrane fouling or of concentration polarisation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/16—Use of chemical agents
    • B01D2321/162—Use of acids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/20—By influencing the flow
    • B01D2321/2033—By influencing the flow dynamically
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis

Abstract

The invention discloses a method for inhibiting membrane scaling in brackish water desalination treatment, which comprises the steps of pretreating brackish water → adding chemicals to eliminate residual chlorine → security filtration → adding security filtration and pipelines → pumping scale inhibitor → pumping hydrochloric acid. The invention also comprises an electromagnetic directional valve, two inlets of the electromagnetic directional valve are respectively communicated with the scale inhibitor storage tank and the hydrochloric acid storage tank through anti-corrosion water pipes, and an outlet of the electromagnetic directional valve is communicated with a pulse pump; the reverse osmosis membrane component is arranged at the outer side of the outer security filtering filter element, the support rod is fixedly connected with a spiral pipeline, and the surface of the spiral pipeline is provided with micropores; the scale inhibitor is injected into the spiral pipeline and directly reaches the surface of the reverse osmosis membrane component to form a scale inhibitor layer structure, so that the inhibition effect of membrane scaling is improved; and hydrochloric acid can be injected within a specified time by using the reversing electromagnetic valve, so that the scale on the scaled surface can be removed, the scale formation of the membrane can be further inhibited, and the service time of the reverse osmosis membrane is prolonged.

Description

Method and device for inhibiting membrane scaling in brackish water desalination treatment
Technical Field
The invention relates to the technical field of brackish water desalination, in particular to a method for inhibiting membrane scaling in brackish water desalination treatment, and particularly relates to a device for inhibiting membrane scaling in brackish water desalination treatment.
Background
Brackish water is water with alkalinity greater than hardness and contains a large amount of neutral salts, and the pH value is greater than 7. Bitter water in China is mainly distributed in coastal areas in the north and east. The method for desalting the bitter water comprises the following steps:
the distillation method is a process of boiling and evaporating brackish water or seawater and condensing steam into fresh water. The distillation method is the most early brackish water desalination method, and has the main advantages of simple structure, easy operation and good quality of obtained fresh water. There are many types of distillation methods, such as multiple effect evaporation, multi-stage flash evaporation, vapor compression distillation, membrane distillation, and the like.
The electrodialysis method is a membrane separation technology which utilizes an ion exchange membrane to separate anions and cations in the brine under the action of an electric field, so that the concentration of salt in a fresh water chamber is reduced to obtain fresh water. The electrodialysis device utilizes the directional migration of ions under the action of an electric field and achieves the aim of desalting through a permselective ion exchange membrane. The electrodialysis brackish water desalination technology is mature, has the main advantages of simple process, high desalination rate, low water production cost, convenient operation, no environmental pollution and the like, and has the defects of strict requirement on water quality, pretreatment on raw water and the like.
Reverse osmosis is a process of applying a higher pressure to one side of a concentrated solution than natural osmosis to reverse the direction of natural osmosis and to press ions in the solution to the other side of a semipermeable membrane, which is contrary to the normal osmosis process in the nature and is called reverse osmosis. The reverse osmosis desalination method can remove more than 90% of soluble salts, more than 99% of colloidal microorganisms, organic matters and the like from water. Compared with other water treatment methods, the method has the advantages of no phase change, normal-temperature operation, simple equipment, high benefit, small occupied area, convenient operation, low energy consumption, wide application range, high automation degree, good water outlet quality and the like.
The conventional reverse osmosis process comprises the process flows of raw water → a pretreatment system → a high-pressure water pump → a reverse osmosis membrane module → purified water. The pretreatment system can adopt rough filtration, active carbon adsorption, fine filtration and the like according to the water quality condition of raw water and the requirement of outlet water, the fine filtration is indispensable and is set up for protecting a reverse osmosis membrane and prolonging the service life of the reverse osmosis membrane, and in addition, the composite membrane is very sensitive to free chlorine in water, so the pretreatment system is usually equipped with the active carbon adsorption.
The reverse osmosis system adopts reverse osmosis composite membrane, and its tolerance to chlorine is only 1000mg/(L x h), and the filter effluent water generally contains residual chlorine 0.1-1.0mg/L, so that it has need of adding sodium hydrogen sulfite (3mg/L for reducing residual chlorine in water to make free chlorine content less than 0.1mg/L, so that it can meet the water-feeding requirements of reverse osmosis device2+、SO4 2-、Mg2+、Ba2+、Sr2+The plasma content is high, and insoluble components are easily formed to be deposited on the surface of the reverse osmosis membrane in the reverse osmosis desalination process, so that the performance of the device is reduced. Therefore, the scale inhibitor sodium hexametaphosphate is adopted as the scale inhibition and dispersion agent Flocon260(27mg/L), and hydrochloric acid (30 percent hydrochloric acid) is added when necessary, so that the scale formation of various insoluble salts such as calcium carbonate, calcium sulfate, barium and the like in the film can be effectively prevented, and the deposition of iron-aluminum oxide and other pollutants is prevented.
When bitter water is desalinated by the existing reverse osmosis method, a scale inhibitor is directly mixed with pretreated raw water and filtered by a reverse osmosis membrane. Although the mode inhibits the membrane scaling, a large amount of scale inhibitor is wasted, and the mode only has an inhibiting effect, can not clear the scaled adhesive substances on the membrane, and has higher frequency of replacing the reverse osmosis membrane. Therefore, a method and a device for inhibiting membrane scaling in the desalination treatment of brackish water are provided.
Disclosure of Invention
The invention aims to provide a method and a device for inhibiting membrane scaling in the process of desalinating brackish water, so as to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for inhibiting membrane scaling in a brackish water desalination process, comprising the steps of:
s1, preprocessing the bitter saline water: removing colloid and suspension impurities in the brackish water by coagulation and filtration, and reducing turbidity; selecting FeCl3As a coagulant, addingThe amount is 1.0-2.5 mg/L; after being mixed by a mixer, the mixture is filtered by a mechanical filter, so that the pollution index of the effluent water quality is less than 5 and the turbidity is less than 1;
s2, adding medicine to eliminate residual chlorine: pumping 1.5-3.0mg/L sodium bisulfite through a metering pump, so that residual chlorine in the brackish water reacts with the sodium bisulfite to form neutral salt; controlling the pH value of the brackish water to be between 7.0 and 7.5, and controlling free chlorine to be less than 0.1 mg/L;
s3, security filtering: a group of security filters with the filtering precision of 10 mu m are arranged in front of a high-pressure pump of the brackish water desalination device and are used for protecting the safe operation of the high-pressure pump and a membrane element;
s4, adding a security filter and a pipeline: two groups of security filter cores with the precision of 10 microns and 5 microns are additionally arranged on the inner side of the membrane component, the security filter core with the precision of 5 microns is sleeved on the outer side of the security filter core with the precision of 10 microns, and a spirally distributed pipeline is arranged between the two security filter cores; the surface of the pipeline is provided with micropores with the diameter of 0.1-0.2 mm;
s5, pumping scale inhibitor: one end of a pipeline in the S4 extends out of a shell of the reverse osmosis membrane component and is communicated with a pulse pump, a water inlet of the pulse pump is communicated with two water pipes through a reversing valve, one ends of the two water pipes are respectively communicated with a liquid storage tank of a scale inhibitor and a liquid storage tank of hydrochloric acid, the scale inhibitor is pumped in a pulse mode through the pulse pump during desalination treatment, a vibration water film is formed between two groups of security filter elements, and ions which are easy to scale in concentrated liquid are prevented from passing through the security filter elements to form scale and being in contact with the reverse osmosis membrane; plays a role in inhibiting the membrane fouling;
s6, pumping hydrochloric acid: adjusting a reversing valve to reverse every 30-45 minutes according to the concentration of the concentrated solution in the process of desalting the brackish water, pumping a hydrochloric acid solution into the pipeline for 3-5 minutes, respectively treating the condensed water scale through the hydrochloric acid solution, and inhibiting the membrane from scaling.
Preferably, the scale inhibitor in S5 is sodium hexametaphosphate with the concentration of 27mg/L, and the hydrochloric acid solution in S6 is dilute hydrochloric acid with the content of 30%.
Preferably, the minimum pulse pressure output of the pulse pump is 1.05 times the reverse osmosis pressure and the maximum pulse pressure output of the pulse pump is 1.15 times the reverse osmosis pressure.
Preferably, the pulse pump can be replaced by a pressure stabilizing pump, and the output pressure of the pressure stabilizing pump is 1.10 times of the reverse osmosis pressure.
The invention also provides a device for inhibiting membrane scaling in the brackish water desalination treatment, which comprises:
the two inlets of the electromagnetic directional valve are respectively communicated with a scale inhibitor storage tank and a hydrochloric acid storage tank through an anti-corrosion water pipe, and the outlet of the electromagnetic directional valve is communicated with a pulse pump;
the reverse osmosis membrane filter comprises a shell, wherein a reverse osmosis membrane assembly, an outer security filter element and an inner security filter element are arranged in the shell, the reverse osmosis membrane assembly is arranged on the outer side of the outer security filter element, a support rod with two ends fixedly connected to the shell is arranged between the outer security filter element and the inner security filter element, a spiral pipeline is fixedly connected to the support rod, and micropores are formed in the surface of the spiral pipeline;
the outlet of the pulse pump is connected with a communicating pipe, and one end of the communicating pipe penetrates through the shell and is communicated with one end of the spiral pipeline.
Preferably, the device also comprises a pretreatment tank, one side of the pretreatment tank is communicated with a security filter, the outlet of the security filter is communicated with a high-pressure pump, and one end of the high-pressure pump is communicated with the reverse osmosis membrane filter through a raw water inlet pipe.
Preferably, the inside center of reverse osmosis membrane filter still installs a support section of thick bamboo, the hole of permeating water has been seted up on the surface of a support section of thick bamboo.
Preferably, one end of the reverse osmosis membrane filter is connected with a concentrated solution discharge pipe, and one side of the reverse osmosis membrane filter is communicated with a purified water discharge pipe.
Preferably, the diameter of the micro-holes is set to 0.1 to 0.2 mm.
Preferably, the filtering accuracy of the cartridge filter is set to 10 μm or 5 μm.
Compared with the prior art, the invention has the beneficial effects that:
the invention directly arranges two groups of security filtering filter cores on the inner side of the reverse osmosis membrane component, and a spiral pipeline is arranged between the two groups of security filtering filter cores, when in use, the scale inhibitor is injected into the spiral pipeline and directly reaches the surface of the reverse osmosis membrane component to form a scale inhibitor layer structure, thereby improving the inhibition effect of membrane scaling; and hydrochloric acid can be injected within a specified time by using the reversing electromagnetic valve, so that the scale on the scaled surface can be removed, the scale formation of the membrane can be further inhibited, and the service time of the reverse osmosis membrane is prolonged. When the scale inhibitor is designed, the pulse pump is also used as a delivery pump of the scale inhibitor, the pulse force can be used for disturbing the stable flow velocity formed by reverse osmosis pressure to form a disturbed flow velocity layer, scaling is not easy to form, and the effect of inhibiting membrane scaling is improved.
Drawings
FIG. 1 is a flow chart of a method for inhibiting membrane fouling in a brackish water desalination process according to the present invention;
FIG. 2 is a schematic structural diagram of a device for inhibiting membrane scaling in the desalination treatment of brackish water according to the present invention;
FIG. 3 is a schematic view showing the internal structure of a reverse osmosis membrane filter according to the present invention;
fig. 4 is a structural schematic diagram of the spiral pipeline of the present invention.
In the figure: 1. a pretreatment tank; 2. a cartridge filter; 3. a high pressure pump; 4. a reverse osmosis membrane filter; 5. a scale inhibitor storage tank; 6. a hydrochloric acid storage tank; 7. an anti-corrosion water pipe; 8. an electromagnetic directional valve; 9. a pulse pump; 10. a communicating pipe; 11. a raw water inlet pipe; 12. a concentrated solution discharge pipe; 13. a purified water discharge pipe; 401. a housing; 402. a reverse osmosis membrane module; 403. an outer security filter element; 404. an inner security filtering element; 405. a support cylinder; 406. water permeable holes; 407. a support bar; 408. a spiral pipeline; 409. and (4) micro-pores.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Referring to fig. 1, the present invention provides a technical solution:
a method for inhibiting membrane scaling in a brackish water desalination process, comprising the steps of:
s1, preprocessing the bitter saline water: removing colloid and suspension impurities in the brackish water by coagulation and filtration, and reducing turbidity; selecting FeCl3As a coagulant, the adding amount is 1.0-2.5 mg/L; after being mixed by a mixer, the mixture is filtered by a mechanical filter, so that the pollution index of the effluent water quality is less than 5 and the turbidity is less than 1;
s2, adding medicine to eliminate residual chlorine: pumping 1.5-3.0mg/L sodium bisulfite through a metering pump, so that residual chlorine in the brackish water reacts with the sodium bisulfite to form neutral salt; controlling the pH value of the brackish water to be between 7.0 and 7.5, and controlling free chlorine to be less than 0.1 mg/L;
s3, security filtering: a group of security filters with the filtering precision of 10 mu m are arranged in front of a high-pressure pump of the brackish water desalination device and are used for protecting the safe operation of the high-pressure pump and a membrane element;
s4, adding a security filter and a pipeline: two groups of security filter cores with the precision of 10 microns and 5 microns are additionally arranged on the inner side of the membrane component, the security filter core with the precision of 5 microns is sleeved on the outer side of the security filter core with the precision of 10 microns, and a spirally distributed pipeline is arranged between the two security filter cores; the surface of the pipeline is provided with micropores with the diameter of 0.1-0.2 mm;
s5, pumping scale inhibitor: one end of a pipeline in the S4 extends out of a shell of the reverse osmosis membrane component and is communicated with a pulse pump, a water inlet of the pulse pump is communicated with two water pipes through a reversing valve, one ends of the two water pipes are respectively communicated with a liquid storage tank of a scale inhibitor and a liquid storage tank of hydrochloric acid, the scale inhibitor is pumped in a pulse mode through the pulse pump during desalination treatment, a vibration water film is formed between two groups of security filter elements, and ions which are easy to scale in concentrated liquid are prevented from passing through the security filter elements to form scale and being in contact with the reverse osmosis membrane; plays a role in inhibiting the membrane fouling;
s6, pumping hydrochloric acid: adjusting a reversing valve to reverse every 30-45 minutes according to the concentration of the concentrated solution in the process of desalting the brackish water, pumping a hydrochloric acid solution into the pipeline for 3-5 minutes, respectively treating the condensed water scale through the hydrochloric acid solution, and inhibiting the membrane from scaling.
The scale inhibitor in the S5 is set to be sodium hexametaphosphate with the concentration of 27mg/L, and the hydrochloric acid solution in the S6 is dilute hydrochloric acid with the content of 30%. The minimum pulse pressure output of the pulse pump is 1.05 times of the reverse osmosis pressure, and the maximum pulse pressure output of the pulse pump is 1.15 times of the reverse osmosis pressure.
Referring to fig. 2-4, the present invention provides a device for inhibiting membrane scaling in desalination of brackish water, comprising:
the scale inhibitor storage tank 5 and the hydrochloric acid storage tank 6 are respectively communicated with two inlets of the electromagnetic directional valve 8 through an anti-corrosion water pipe 7, and an outlet of the electromagnetic directional valve 8 is communicated with a pulse pump 9;
a reverse osmosis membrane filter 4, wherein the reverse osmosis membrane filter 4 comprises a casing 401, a reverse osmosis membrane assembly 402, an outer security filter element 403 and an inner security filter element 404 are installed inside the casing 401, the reverse osmosis membrane assembly 402 is arranged outside the outer security filter element 403, a support rod 407 with two ends fixedly connected to the casing 401 is further arranged between the outer security filter element 403 and the inner security filter element 404, a spiral pipeline 408 is fixedly connected to the support rod 407, and a micropore 409 is arranged on the surface of the spiral pipeline 408;
an outlet of the pulse pump 9 is connected with a communicating pipe 10, and one end of the communicating pipe 10 penetrates through the shell 401 and is communicated with one end of a spiral pipeline 408.
The device is characterized by further comprising a pretreatment tank 1, wherein one side of the pretreatment tank 1 is communicated with a cartridge filter 2, an outlet of the cartridge filter 2 is communicated with a high-pressure pump 3, and one end of the high-pressure pump 3 is communicated with a reverse osmosis membrane filter 4 through a raw water inlet pipe 11. The inside center of reverse osmosis membrane filter 4 still installs a support section of thick bamboo 405, the hole 406 of permeating water has been seted up on the surface of a support section of thick bamboo 405. One end of the reverse osmosis membrane filter 4 is connected with a concentrated solution discharge pipe 12, and one side of the reverse osmosis membrane filter 4 is communicated with a purified water discharge pipe 13. The diameter of the micropores 409 is set to be 0.1-0.2 mm. The filtration accuracy of the cartridge filter 2 was set to 10 μm.
Example 2
Unlike embodiment 1, the pulse pump 9 in embodiment 1 is replaced with a pressure stabilizing pump having an output pressure 1.10 times the reverse osmosis pressure. While the filtration accuracy of the canister filter 2 is set to 5 μm. The design of the pulse pump 9 is changed, the constant pressure pump is used for continuous output to form a stable water film which is vertical to the pressure direction of osmotic pressure, and when the concentration of the concentrated solution is high, the mode can be adopted.
Example 3
Different from the embodiment 1, the scale inhibitor and the hydrochloric acid are not required to be injected separately, the hydrochloric acid is directly added into the scale inhibitor, and after mixing, the mixture is pumped into the spiral pipeline 408 by using a pulse pump.
In summary, the following steps: the invention changes the traditional mode of directly mixing the scale inhibitor with the raw water, and when in use, the scale inhibitor is injected into the spiral pipeline and directly reaches the surface of the reverse osmosis membrane component to form a scale inhibitor layer structure, thereby improving the inhibition effect of membrane scaling; and hydrochloric acid can be injected within a specified time by using the reversing electromagnetic valve, so that the scale on the scaled surface can be removed, the scale formation of the membrane can be further inhibited, and the service time of the reverse osmosis membrane is prolonged. When the scale inhibitor is designed, the pulse pump is also used as a delivery pump of the scale inhibitor, the pulse force can be used for disturbing the stable flow velocity formed by reverse osmosis pressure to form a disturbed flow velocity layer, scaling is not easy to form, and the effect of inhibiting membrane scaling is improved.
The parts not involved in the present invention are the same as or can be implemented by the prior art. Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. A method for inhibiting membrane scaling in the desalination treatment of brackish water is characterized in that: the method comprises the following steps:
s1, preprocessing the bitter saline water: removing colloid and suspension impurities in the brackish water by coagulation and filtration, and reducing turbidity; selecting FeCl3As a coagulant, the adding amount is 1.0-2.5 mg/L; after being mixed by a mixer, the mixture is filtered by a mechanical filter, so that the pollution index of the effluent water quality is less than 5 and the turbidity is less than 1;
s2, adding medicine to eliminate residual chlorine: pumping 1.5-3.0mg/L sodium bisulfite through a metering pump, so that residual chlorine in the brackish water reacts with the sodium bisulfite to form neutral salt; controlling the pH value of the brackish water to be between 7.0 and 7.5, and controlling free chlorine to be less than 0.1 mg/L;
s3, security filtering: a group of security filters with the filtering precision of 10 mu m are arranged in front of a high-pressure pump of the brackish water desalination device and are used for protecting the safe operation of the high-pressure pump and a membrane element;
s4, adding a security filter and a pipeline: two groups of security filter cores with the precision of 10 microns and 5 microns are additionally arranged on the inner side of the membrane component, the security filter core with the precision of 5 microns is sleeved on the outer side of the security filter core with the precision of 10 microns, and a spirally distributed pipeline is arranged between the two security filter cores; the surface of the pipeline is provided with micropores with the diameter of 0.1-0.2 mm;
s5, pumping scale inhibitor: one end of a pipeline in the S4 extends out of a shell of the reverse osmosis membrane component and is communicated with a pulse pump, a water inlet of the pulse pump is communicated with two water pipes through a reversing valve, one ends of the two water pipes are respectively communicated with a liquid storage tank of a scale inhibitor and a liquid storage tank of hydrochloric acid, the scale inhibitor is pumped in a pulse mode through the pulse pump during desalination treatment, a vibration water film is formed between two groups of security filter elements, and ions which are easy to scale in concentrated liquid are prevented from passing through the security filter elements to form scale and being in contact with the reverse osmosis membrane; plays a role in inhibiting the membrane fouling;
s6, pumping hydrochloric acid: adjusting a reversing valve to reverse every 30-45 minutes according to the concentration of the concentrated solution in the process of desalting the brackish water, pumping a hydrochloric acid solution into the pipeline for 3-5 minutes, respectively treating the condensed water scale through the hydrochloric acid solution, and inhibiting the membrane from scaling.
2. The method for inhibiting membrane fouling in a desalination process of brackish water according to claim 1, wherein: the scale inhibitor in the S5 is set to be sodium hexametaphosphate with the concentration of 27mg/L, and the hydrochloric acid solution in the S6 is dilute hydrochloric acid with the content of 30%.
3. The method for inhibiting membrane fouling in a desalination process of brackish water according to claim 1, wherein: the minimum pulse pressure output of the pulse pump is 1.05 times of the reverse osmosis pressure, and the maximum pulse pressure output of the pulse pump is 1.15 times of the reverse osmosis pressure.
4. The method for inhibiting membrane fouling in a desalination process of brackish water according to claim 1, wherein: the pulse pump can also be replaced by a pressure stabilizing pump, and the output pressure of the pressure stabilizing pump is 1.10 times of the reverse osmosis pressure.
5. An apparatus for inhibiting membrane fouling in a desalination process of brackish water, comprising:
the scale inhibitor storage tank (5) and the hydrochloric acid storage tank (6) are respectively communicated with two inlets of the electromagnetic directional valve (8) through an anti-corrosion water pipe (7), and an outlet of the electromagnetic directional valve (8) is communicated with a pulse pump (9);
the reverse osmosis membrane filter (4) comprises a shell (401), a reverse osmosis membrane assembly (402), an outer security filter element (403) and an inner security filter element (404) are installed inside the shell (401), the reverse osmosis membrane assembly (402) is arranged on the outer side of the outer security filter element (403), a support rod (407) with two ends fixedly connected to the shell (401) is further arranged between the outer security filter element (403) and the inner security filter element (404), a spiral pipeline (408) is fixedly connected to the support rod (407), and micropores (409) are formed in the surface of the spiral pipeline (408);
an outlet of the pulse pump (9) is connected with a communicating pipe (10), and one end of the communicating pipe (10) penetrates through the shell (401) and is communicated with one end of the spiral pipeline (408).
6. The apparatus for inhibiting membrane fouling in desalination of brackish water according to claim 5, wherein: the device is characterized by further comprising a pretreatment tank (1), wherein one side of the pretreatment tank (1) is communicated with a security filter (2), an outlet of the security filter (2) is communicated with a high-pressure pump (3), and one end of the high-pressure pump (3) is communicated with a reverse osmosis membrane filter (4) through a raw water inlet pipe (11).
7. The apparatus for inhibiting membrane fouling in desalination of brackish water according to claim 5, wherein: the inside center of reverse osmosis membrane filter (4) still installs and supports a section of thick bamboo (405), the hole of permeating water (406) has been seted up on the surface of a support section of thick bamboo (405).
8. The apparatus for inhibiting membrane fouling in desalination of brackish water according to claim 5, wherein: one end of the reverse osmosis membrane filter (4) is connected with a concentrated solution discharge pipe (12), and one side of the reverse osmosis membrane filter (4) is communicated with a purified water discharge pipe (13).
9. The apparatus for inhibiting membrane fouling in desalination of brackish water according to claim 5, wherein: the diameter of the micropores (409) is set to be 0.1-0.2 mm.
10. The apparatus for inhibiting membrane fouling in desalination of brackish water according to claim 5, wherein: the filtration precision of the cartridge filter (2) is set to be 10 μm or 5 μm.
CN202010823173.9A 2020-08-17 2020-08-17 Method and device for inhibiting membrane scaling in brackish water desalination treatment Withdrawn CN111943398A (en)

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CN113069930A (en) * 2021-05-06 2021-07-06 宁波朝鑫环保有限公司 Bitter water purifier roll type permeable membrane descaling system
US11502323B1 (en) 2022-05-09 2022-11-15 Rahul S Nana Reverse electrodialysis cell and methods of use thereof
US11502322B1 (en) 2022-05-09 2022-11-15 Rahul S Nana Reverse electrodialysis cell with heat pump
US11855324B1 (en) 2022-11-15 2023-12-26 Rahul S. Nana Reverse electrodialysis or pressure-retarded osmosis cell with heat pump

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113069930A (en) * 2021-05-06 2021-07-06 宁波朝鑫环保有限公司 Bitter water purifier roll type permeable membrane descaling system
US11502323B1 (en) 2022-05-09 2022-11-15 Rahul S Nana Reverse electrodialysis cell and methods of use thereof
US11502322B1 (en) 2022-05-09 2022-11-15 Rahul S Nana Reverse electrodialysis cell with heat pump
US11563229B1 (en) 2022-05-09 2023-01-24 Rahul S Nana Reverse electrodialysis cell with heat pump
US11611099B1 (en) 2022-05-09 2023-03-21 Rahul S Nana Reverse electrodialysis cell and methods of use thereof
US11699803B1 (en) 2022-05-09 2023-07-11 Rahul S Nana Reverse electrodialysis cell with heat pump
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