KR20150139486A - The manufacturing process development of Processed deep seawater using NF/RO/ED membrane connection system - Google Patents

Abstract

The present invention relates to a mineral content control technology for removing sulfate ions and chlorine ions and remaining useful minerals such as magnesium and calcium during seawater (deep seawater or concentrated seawater) desalination, and, more specifically, to development of a process linking system for optimal water quality control during the seawater desalination, which comprises the steps of: selectively controlling the minerals by using a combined method of electrodialysis (ED), nano-filtration (NF) and reverse osmosis (RO) systems; removing specific materials by using the electrodialysis membrane (ED) and a nano-filter membrane (NF) in the seawater (deep seawater) desalination. The present invention is a process capable of simultaneously manufacturing processed deep seawater including desalinated water, concentrated water, mineral desalinated water, mineral enriched water, and brine by linking ED, NF, and RO processes, saving energy compared with a technology including the existing evaporation method, and manufacturing the processed deep seawater in a large quantity. Furthermore, the present invention is a new technology capable of removing sulfate ions and chlorine ions and manufacturing mineral enriched water, thereby manufacturing high hardness drinking water (hardness 1,200 mg/L) which meets drinking water standards.

Description

[0002] The present invention relates to a process for the production of deep sea water (NF / RO / ED membrane connection system) using an NF / RO /

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing deep sea water for producing high hardness water through seawater desalination (deep seawater raw water or concentrated water desalination). More particularly, the present invention relates to a nano- ), And electrodialysis (ED) system, the sulfate and chloride ions contained in the seawater are removed, and magnesium, calcium, etc., which are useful minerals, are concentrated to be remained and the existing desalination methods (evaporation method, reverse osmosis method RO / ED membrane separation system to overcome the problems of the deep sea water treatment.

In general, 1.0 kg of seawater contains 965 g (96.5%) of water, 18.98 g (1.9%) of chlorine ion, 10.556 g of Na ⁺ and 1.1% of sulfate ion and 2.649 g of SO ₄ ^{2 -,} 0.3%), magnesium ion is ^{1.272 g (Mg 2+, 0.1%} ), calcium ion is ^{0.400 g (Ca 2+, 0.04%} ), potassium ions ^{0.38 g (K +, 0.04%} ), bicarbonate ions It is known that 0.14 g (HCO ^{3 -} , 0.01%) of the main component ion is dissolved in 3.4% and the remaining 0.1% is present in the trace metal dissolved and 92 kinds of dissolved substances exist in seawater.

In particular, seawater (deep sea water) is deep sea water at depths of 200m or more, which is not reached by sunlight. It is located far away from the coast and is not mixed with atmospheric or surface water (river) due to difference in temperature and density of surface water. It is structurally blocked from pollution sources such as organic pollutants (organic compounds such as pathogens and fertilizer pesticides) due to its structure. It is known as a marine water resource that has maintained its clean characteristic for a long time. Deep sea water also contains various minerals such as zinc, selenium, and manganese as well as the four major minerals (magnesium, calcium, potassium, sodium), and is known as a natural minerals resource through water quality control and desalination.

Generally, deficiency and excess of minerals cause various diseases, and physical and mental development is inhibited, so it is important to maintain the mineral balance in the body. Minerals such as calcium, magnesium, and potassium are important elements that play a role in body composition, body function control, and are one of the five nutrients needed by humans. Calcium (Ca ²⁺ ) is a mineral component that functions in bone and tooth formation, muscle, nerve and heart function, and blood coagulation. In the case of deficiency, calcium, calcium, Anxiety and the like occur.

In addition, magnesium (magnesium, Mg ^{2 +)} is the energy generated, nervous system regulation, vitamin B, and perform functions such as facilitating of the E metabolism, at the time of lack of heart disease, high blood pressure, kidney stones, insomnia, arrhythmia, hypotension, loss of appetite, (K ⁺ ) performs functions such as regulation of intracellular acid base equilibrium, moisture regulation, maintenance of neurological function, preservation of cell function, vasodilation, and oxygen supply to the brain. Arrhythmia, loss of appetite, muscle spasms, constipation, fatigue, asthenia and hypoglycemia occur.

In other words, the minerals contained in seawater (deep sea water) can be a very useful mineral source for modern people whose mineral balance has been lost due to wrong eating habits, environmental pollution. However, since seawater contains a considerable amount of salt (NaCl), there is a problem that potassium, calcium, magnesium, etc., which are useful minerals in the desalination process for removing salinity, are removed together.

The seawater desalination methods include evaporation method, reverse osmosis membrane method, and electrodialysis method. The evaporation method utilizes the principle of evaporating seawater, evaporating water as a solvent, and leaving a solute. The reverse osmosis membrane (RO) uses an ionic substance dissolved in water as a membrane to exclude salt, It is a way to pass.

Electrodialysis (ED) is a method for obtaining pure fresh water by arranging alternately an anion membrane and a cation membrane, and then applying a DC voltage to an electrode located at both ends of the anion membrane and the cation membrane to remove cations and anions.

In addition, the method of extracting minerals from existing seawater is a method of extracting minerals in seawater by concentrating seawater (deep seawater) by evaporating and separating minerals such as calcium salt and magnesium salt by using difference of solubility.

However, when these desalination methods are used, it is difficult to efficiently separate calcium and magnesium from various minerals contained in seawater, and there is a disadvantage in that the recovery rate of mineral components is low and energy is large. In addition, since the mineral salts extracted by the desalination method and the mineral extraction method are combined with cations without removing the anion chlorine ion (Cl ^- ) and sulfate ion (SO ₄ ^2- ), the mineral salts are reused When producing mineral water by dissolving, the chlorine ion and the sulfate ion, which are the items of water quality standards to be consumed, are redissolved, so that it is impossible to manufacture a high hardness water having a hardness of 400 or higher.

The present invention relates to a manufacturing process of seawater (deep sea water) treated with water for producing high hardness water by solving the problems of conventional seawater desalination methods such as evaporation method and reverse osmosis (RO) method, (RO), and electrodialysis (ED) system, sulfuric acid ions and chlorine ions are removed while useful minerals such as magnesium and calcium are concentrated to maintain the high hardness water in the NF / RO / ED And to provide a deep ocean wastewater treatment process using a membrane coupling system.

Korean Patent Publication No. 10-732066 discloses a method for producing a water-soluble polymer, which comprises: obtaining concentrated water containing an ion component and fresh water from which the ion component is removed; Separating the crystals of calcium salt, sodium salt and sulfate by heating and concentrating the concentrated water; Concentrating the concentrated water to obtain a mixed salt slurry of a potassium salt and a magnesium salt; Washing the slurry with water to obtain a solution in which the magnesium salt is dissolved and potassium salt crystals; And a step of concentrating the solution in which the magnesium salt is dissolved to obtain a crystal in which a potassium salt and a magnesium salt are mixed and separating the magnesium salt solution having improved purity by filtration to obtain a high purity minerals An efficient extraction method is disclosed. Korean Patent Registration No. 10-0885175 discloses a method for producing a concentrated water and a primary permeated water by passing deep seawater through a pretreatment and then passing it through a RO (reverse osmosis membrane) to prepare a primary concentrated water and a primary permeated water, And the second concentrated water is evaporated and crystallized by using a MVR (Decompression Controlled Vapor Deposition Compression Evaporation) system, the evaporated and crystallized mineral salt is separated into a particle size separator Separating the first permeated water through a second RO (osmotic membrane) to produce a second permeated water and a third concentrated water; and separating the separated mineral salt into the second permeable water And a method for producing mineral salts and mineral salts comprising minerals separated from deep ocean water. In Korean Patent Laid-Open No. 10-2011-0068589, deep-sea water is drawn into the first magnetic treatment reactor for the water to be treated (raw water), and the ozone is injected into the first ozone generator to oxidize and oxidize the oxides After coagulation, the coagulated material is removed from the first filter. Treating the water to be treated to the second magnetic treatment reactor to apply a magnetic force to the ozone generator, injecting ozone into the second ozone generator, passing the ozone through a reaction tank filled with activated carbon, and removing the coagulated material from the second filter ≪ / RTI > is disclosed for an ocean deep seawater desalination system. Korean Patent Laid-Open Publication No. 10-2012-0108402 discloses an MF filtration step; An SWRO step of treating the MF permeated water by reverse osmosis; A BWRO step of treating the SWRO permeate with reverse osmosis; A fresh water intake step of taking BWRO permeated water as fresh water; An NF filtration step of introducing the BWRO concentrated water by the BWRO step into the SWRO step and filtering the concentrated water by the SWRO step with a nanofilter; A low-concentration mineral water intake step of taking NF permeated water with low-concentration mineral water; High-concentration mineral water intake step of taking NF-concentrated water with high-concentration mineral water; Wherein the low-concentration mineral water and the high-concentration mineral water taken in the low-concentration mineral water taking-in step and the high-concentration mineral take-in step are respectively mixed or mixed together to obtain the mineral water from the seawater. . However, such a prior art technique can be used to effectively produce mineral water from deep seawater by using a complex process of nanofiltration (NF), reverse osmosis (RO) and electrodialysis (ED) systems as in the present invention , To remove sulfuric acid ion and chlorine ion, to concentrate the useful minerals such as magnesium and calcium, to reduce the energy cost of production and to meet the drinking water quality standard of high purity, deep sea water treatment using NF / RO / ED membrane connection system The constitution regarding the water production process is not disclosed and shows a difference.

Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to eliminate chloride ion and sulfate ion in seawater (deep sea water) and to extract sodium from the useful minerals such as calcium, magnesium, potassium, While increasing the purity. The NF / RO / NF / RO / NF process for simultaneous mass production of deep ocean waters (desalted water, concentrated water, mineral desalination water, mineral concentrated water, ED separator coupling system for the deep sea water treatment.

In order to solve the above-described problems, the present invention provides a method for producing a concentrated osmosis membrane, comprising the steps of: 1) pretreating seawater and then passing it through a reverse osmosis membrane (RO) to produce concentrated water and desalted water; 2) pretreating seawater and preparing mineral-concentrated water and desalted water using NF 3; 3) putting the demineralized water of 1) into the salt concentration tank, putting the concentrated water of 2) into the hardness concentration tank and operating the ion exchange membrane (ED); 4) a step of producing a mineral water which satisfies the water quality standard for producing water by producing a mineral water-concentrated water in the salt concentration tank and the mineral water-concentrated water in the salt concentration tank of 3), and by branding it with demineralized water.

The pretreatment of the deep seawater in step 1) or 2) is performed through sand filtration, rapid filtration membrane, microfiltration (MF), immersion membrane filter (SMF) and ultra filtration (UF) In addition to the process of producing concentrated water and desalted water, it is possible to use deep sea water, electrodialysis membrane, and NF-RO membrane in addition to the process of producing concentrated water and desalted water. Is used.

(NF), reverse osmosis membrane (RO), electrodialysis (ED), and the like can be used in place of the NF membrane (NF) And the hardness of the mineral water produced by continuous use is 1,200 mg / L.

The present invention relates to a method for producing a high hardness water by simultaneously using a nanofilter (NF), a reverse osmosis membrane (RO), and an electrodialysis method (ED), wherein potassium, magnesium, Ion and sulfate ions can be produced efficiently by separating them with low-cost energy, and it is possible to produce a high-hardness water suitable for water quality standards and efficiently produce mineral raw materials of various products including useful minerals having high purity, (Deionized water, concentrated water, mineral desalted water, mineral concentrated water, and water) at the same time.

Fig. 1 shows the results of the individual process water production process and component analysis of NF, RO and ED.
Figure 2 shows the NF membrane separation performance evaluation.
3 shows a schematic diagram of an NF / RO 3-stage device.
FIG. 4 shows a process flow chart of a method of producing a high-hardness mineral-concentrated water using NF / RO / ED.
5 shows the NF / RO / ED, NF / ED coupling process and component analysis results.
Figure 6 shows the hardness / TDS ratio for each membrane separation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows the results of the individual process water production process and component analysis of NF, RO and ED. First, in the RO system process, deep sea water was separated into concentrated water and production water using a pressure condition of 50 kgf / cm ² . The NF system process separates the concentrated water and the production water by using the pressure condition of 20 kgf / cm ² , and the concentrated water produced can be operated once more (two stages) to obtain the concentrated water and the produced water.

In the ED system, raw water was added to both the salt concentrator and the hardness concentrator using Electrolyte (0.1N NaNO ₃ ) and Conductivity (10 mS / cm).

NF, RO, and ED, which are representative methods of producing high-hardness mineral-concentrated water, were tested under the same conditions as above, and the results of the component analysis are shown in FIG.

The total dissolved solids (TDS) and hardness / Cl ^- enriched water, which represent the total amount of solids dissolved in water, are increased in order of raw water <RO <NF 1 stage <NF 2 stage <ED, Ions are most removed.

As a result of the NF membrane separation performance evaluation of FIG. 2, TDS, hardness, and Cl ^- value of the concentrated water were increased when the NF system process was operated twice, that is, when the NF system process was operated twice, The amount of minerals contained in water 1 L is increased.

3 shows a schematic diagram of an NF / RO 3-stage device. Water depends on the content of sulfate ion (SO ₄ ^2- ), salt removal, and balance of potassium, calcium and magnesium contents.

By installing the NF process in the existing RO process, highly concentrated water with a drastically reduced sulfur content can be used for mineral extraction. However, since the concentration of the concentrated water is low and the content and the purity of the chloride ion and the sulfate ion are disadvantageous, the present invention further includes a step of removing the salt component through the ED process to remove harmful factors to produce a concentrated mineral- It is possible to eliminate the inconvenience of crystallizing calcium and magnesium in the course of crystallization by removing chlorine ions and sulfate ions and then dissolving them again.

FIG. 4 shows a process flow chart of a method of producing a high-hardness mineral-concentrated water using NF / RO / ED. The conventional RO process is simple but the concentration of concentrated water is low and there are problems such as the inclusion of chlorine ions (Cl ^- ) and sulfate ions (SO ₄ ^2- ), and the electrodialysis process (ED) Although the concentration of water can be increased compared to the reverse osmosis membrane process, there is a problem of purity such as mineral separation.

In the present invention, a nanofilter membrane (NF) - reverse osmosis membrane (RO) - electrodialysis membrane (ED) process is combined to solve the problems of the RO and ED processes and to increase the production yield.

The overall process flow is to filter the seawater by pretreatment (sand filtration, rapid filtration membrane, MF, immersion membrane filter (SMF), ultrafilter (UF) (Na, Ca, Mg, Ca, K, Na, K, Na, K, Na, K, Na) (Sodium, potassium, calcium, magnesium, and the like) in the concentrated water.

The seawater (deep sea water) after the pretreatment is produced concentrated water having high purity production volume and salt content of 7% or more through the primary RO membrane process and chlorine ion and a sulfate ion (SO ₄ ^2-) is removed, the production number and the mineral content is gaining be enriched enriched, 3 drive the deep sea water (raw water), or RO (reverse osmosis membrane), the number of production ED (electric dialysis membrane) salt concentration tank of the apparatus , And NF tertiary concentrated water through the three NF membranes (nanofiltration membrane) is placed in the hardness concentration tank of the electrodialysis membrane (ED) apparatus.

When the movable charged into an electric dialysis membrane (ED) electric conductivity of 20mS / cm, 10mS / cm, 5mS / cm to the devices, or salt concentration tank, the functions are generated and hardness concentration tank has a chlorine ion (Cl ^-) Mineral also hardness of the like to remove Concentrated water is produced, which can be branded with demineralized water to produce mineral water with a mineral content (magnesium and calcium) of high hardness (1,200 mg / L) that meets water quality standards.

The function obtained by the above method was able to be processed so as to satisfy Article 2 (3) of the " Salt Industry Promotion Act " as a treatment water containing concentrated sodium chloride. In the Salt Industry Promotion Act, "salt (brine)" refers to a solid containing sodium chloride in an amount of 50% or more and a specific gravity of 5 or more at a temperature of 15 degrees Celsius (baume) Lt; / RTI &gt;

5 shows the NF / RO / ED, NF / ED coupling process and component analysis results. Based on the results shown in FIG. 1, an additional coupling process was planned and a composite system was constructed by linking the nanofiltration membrane (NF), reverse osmosis membrane (RO), and electrodialysis membrane (ED). The conditions of the ED used in the process were set to 0.5 N NaNO ₃ , 20 mS / cm, and other conditions were the same as in FIG.

The hardness values of RO and NF / ED were higher than those of NF / ED after the desalting process, respectively. This indicates that the amount of minerals contained in the concentrated water is increased by RO.

Also, the hardness concentration of chlorine ion (Cl ^- ) is lower in RO / NF / ED process than that of NF / ED, the amount of Cl ^- contained in concentrated water is decreased by RO process, And can produce mineral concentrated water with high concentration of mineral.

In the case of the concentrated water, the raw water <NF / ED <RO / NF / ED unique and, RO / NF / ED of Cl ^{- -} Hardness / Cl a value of NF / ED Cl ^- therefore less than the value RO / NF including the RO process / ED process to produce high-hardness mineral-concentrated water.

Figure 6 shows the hardness / TDS ratio for each membrane separation. NF / ED Hardness Concentration Tank (Mineral Concentrated Water) <RO / NF / ED Hardness / TDS Value <RO Produced Water <RO Concentrated Water < ED Hardness Concentration Tank (Mineral Condensate Water) in order. This shows that RO / NF / ED process can reduce the harmful chlorine ion and can produce highly concentrated mineral water with a large amount of oil. have.

Using the combined system of NF, RO, and ED, sulfate ions and chlorine ions are removed through seawater desalination process, while beneficial minerals such as magnesium and calcium are concentrated, It is possible to produce high hardness water according to the standard, and it is possible to efficiently produce mineral raw materials of various products including useful minerals such as calcium and magnesium in seawater.

By using the deep ocean water treatment process using the NF / RO / ED membrane connection system for the optimal water quality adjustment during seawater desalination, energy is saved compared with the technology including the existing evaporation method, and a large amount of deep sea water treatment (Hardness of 1,200 mg / L) which can meet the drinking water quality standard because it is possible to produce concentrated mineral water which is rich in magnesium and calcium which are useful minerals while removing sulfate ion and chlorine ion. It is industrially applicable.

Claims (9)

1) pretreatment of seawater (deep sea water) and then passing it through a reverse osmosis membrane (RO) to produce concentrated water and desalted water;
2) pretreatment of seawater (deep sea water), preparing mineral-concentrated water and desalted water by using NF membrane;
3) putting the desalted water in the step 1) into a salt concentration tank, putting the concentrated water in the 2) into the hardness concentration tank and operating the ED;
4) a step of producing a mineral water that satisfies the water quality standard for producing water by producing a concentrated water in the salt concentration tank and the mineral concentrated water in the salt concentration tank in the step 3), and by branding it with demineralized water, the NF / RO / ED separation membrane Deep sea water treatment method using coupled system
The method according to claim 1, wherein the pretreatment of the deep sea water in step 1) or 2) is performed by one or more methods selected from among sand filtration, rapid filtration membrane, microfiltration membrane (MF), immersion membrane filter (SMF) A method for manufacturing deep-sea water treatment using an NF / RO / ED membrane coupling system
[3] The method of claim 2, wherein the step 1) comprises the step of preparing concentrated water and desalted water by using an electrodialysis membrane or an NF-RO membrane as the deep seawater raw water. Processed water production method
[6] The method of claim 3, wherein the desalting water in step 3) is put in a salt concentrating tank by replacing deep sea water or reverse osmosis desalted water with production water using an electrodialytic membrane and an NF-RO membrane. A method of manufacturing deep sea water treated by using NF / RO / ED membrane coupling system
The method according to claim 3, wherein the nanofiltration membrane (NF) in step 2) uses two or three groups.
The method according to any one of claims 1 to 5, wherein the hardness of the prepared mineral water is 1,200 mg / L.
The method according to any one of claims 1 to 5, wherein the electric conductivity applied to the ED (electrodialysis membrane) apparatus is 5 to 20 mS / cm.
The pretreated seawater (deep sea water) was treated with high purity deionized water and concentrated water having a salt content of 7% or more through a reverse osmosis membrane (RO) process as a primary treatment;
Obtaining a mineral-enriched water in which the production water and the mineral content are concentrated by removing the chlorine ion and the sulfate ion (SO ₄ ^2- ) through the nanofiltration membrane (NF) by the secondary treatment;
And a step of producing mineral water having a high hardness and mineral concentrate in which chlorine ion (Cl &lt; &quot;&gt;) or the like is removed through an electrodialytic membrane (ED) Of Deep Sea Water Treatment Using NF / RO / ED Membrane Connection System
A method for producing a deep-sea water treatment using an NF / RO / ED membrane coupling system according to any one of claims 1 to 8,

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