JP2005279384A - Method for producing ideal drinking water from sea water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing ideal drinking water from sea water by which mineral components and desalination ratio can be selectively adjusted by performing a process of separating concentrated sea water into concentrated salt water and desalinated water according to electrodialysis. <P>SOLUTION: The method for producing drinking water is provided for producing drinking water containing a mineral component by extracting the mineral component included in sea water and adding the extracted mineral component to fresh water which is obtained by removing salt content from sea water, wherein the method for producing drinking water comprises: a filtration step of eliminating contaminants etc. from raw sea water with a filter; a first separation step of separating filtrated sea water into the fresh water and the concentrated sea water according to reverse osmosis method; a second separation step of separating the separated concentrated sea water into the concentrated salt water and desalinated water according to electrodialysis method; and a mixing step of adding a proper quantity of the separated desalinated water to the fresh water, mixing the fresh water to which the separated water is added and obtaining the drinking water which properly contains the mineral content included in sea water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing drinking water containing mineral components from seawater.

Conventionally, a method of producing drinking water from seawater includes a step of taking water from seawater, a step of filtering the taken seawater, a reverse osmosis separation step of separating the filtered seawater into fresh water and concentrated seawater by a reverse osmosis membrane, Drinking water containing mineral components retained by seawater by having a nanofiltration step for separating the separated concentrated seawater into a natural salt-containing liquid and mineral components that are rich in sodium chloride with respect to the active ingredients contained in the nanofiltration membrane Like to get. (For example, see Patent Document 1)
JP 2002-172392 (page 3)

  However, this method separates concentrated seawater into a natural salt-containing liquid and a mineral component using a nanofiltration membrane, so the mineral component and the desalination rate can be proportionally increased or decreased by adjusting the number of stages of the filtration membrane. There is a problem that the components and the desalting rate cannot be adjusted selectively.

  The present invention solves the above-mentioned problems and is ideal from seawater that can selectively adjust mineral components and desalination rate by performing a step of separating concentrated seawater into concentrated salt water and desalted water by electrodialysis. It is an object of the present invention to provide a method for producing typical drinking water.

In order to solve the above problems, the method for producing ideal drinking water from seawater according to the present invention employs the following method.
In a method for producing drinking water that produces mineral water containing mineral components by extracting and adding mineral components held in seawater to fresh water from which salt has been removed from seawater, filtration is performed by removing contaminants from raw seawater using a filter. A first separation step of separating the filtered seawater into fresh water and concentrated seawater by a reverse osmosis method, and a second separation step of separating the separated concentrated seawater into concentrated brine and demineralized water by electrodialysis. And a mixing step of obtaining drinking water appropriately containing the mineral components of seawater by adding an appropriate amount of the separated desalted water to the fresh water and mixing.

  Demineralized water separated from concentrated seawater was subjected to sieving with an inorganic molecular sieve to remove heavy metal ions contained in the demineralized water.

  The demineralized water from which heavy metal ions have been removed was filtered with a microfilter to precisely adjust the mineral content in the demineralized water.

  Treating concentrated salt water obtained by separating desalted water from concentrated seawater by an evaporation method to obtain a crystal product of the components contained in the concentrated salt water

  Effect of Claim 1 Seawater is separated into fresh water and concentrated seawater in the first separation step of the reverse osmosis method, and the separated concentrated seawater is separated into concentrated saltwater and desalted water in the second separation step of the electrodialysis method. If this is done, the salt concentration and mineral components in the desalted water can be selectively adjusted, so if the mineral components adjusted in this way are mixed with fresh water, the appropriate amount of mineral components in the seawater is taken into health. It is possible to obtain an ideal drinking water having an excellent effect and can be widely used as a raw material for drinking, beverages, foods, and the like.

  Effect of Claim 2 The desalted water from which the concentrated salt water has been separated can remove unfavorable health-related substances such as polyvalent metal ions dissolved in the desalted water when treated with an inorganic molecular node. .

  Effect of Claim 3 When demineralized water is filtered through a microfiltration membrane having ultrafine pores, the number and amount of mineral components can be appropriately adjusted.

Effect of Claim 4 If concentrated salt water is processed by the evaporation method, a mixed crystal of sodium chloride and potassium chloride contained in the concentrated salt water can be obtained, and potassium chloride can also be separated from this mixture by flotation. Furthermore, if ultra flotation or ion flotation is employed, useful dissolved substances in the concentrated seawater can also be recovered.

  Hereinafter, an embodiment of a method for producing ideal drinking water from seawater according to the present invention will be described.

The raw seawater used in this method is preferably deep ocean water taken from a depth of 200 mm or more. However, it is not limited to deep water, and all seawater containing salt and mineral components can be used. Then, the seawater is taken from the ocean and stored in the water storage tank 1 shown in FIG. 1, and is supplied to the following processes by the pump 2 so that each process is sequentially performed.

  Since the seawater stored in the tank 2 contains contaminants such as turbidity and suspended matter, the filtration process using the former filter 3 and the latter filter 4 shown in FIG. The filter 4 in the subsequent stage uses a filter capable of performing microfiltration using a known nanomembrane or the like so that contaminants can be removed to the micron level.

  The raw seawater excluding the contaminants contains salt and mineral components in the fresh water. Therefore, the first separation device 5 of the reverse osmosis method shown in FIG. This separation device 5 separates raw seawater into fresh water and concentrated seawater using a known osmosis membrane that hardly allows other than water molecules, and the fresh water is fed to a fresh water tank 6. The raw material that is sent to obtain the ideal drinking water, the concentrated seawater is sent to the concentrated seawater tank 7 and separated into concentrated salt water and desalted water in the next step, and the mineral components in the desalted water are added to the fresh water. Concentrated saline is used for salt production and others.

  Concentrated seawater from which fresh water has been separated by the reverse osmosis separation device 5 removes salt and obtains demineralized water having mineral components, so that the second separation device 8 of electrodialysis shown in FIG. Is subjected to a separation step in which concentrated seawater is separated into concentrated salt water and demineralized water by performing electrodialysis using as a polar solution, and the separated concentrated salt water is sent to the concentrated salt water tank 9, and the demineralized water is demineralized water tank. Send to 10.

As shown in FIG. 2, the second separation device 8 transmits only cations and does not transmit anions, and conversely, transmits only anions and transmits cations. The anion exchange membranes 13 that are not allowed to be placed are alternately disposed in the polar sodium sulfate water solution, and the cation exchange membrane 11 is connected to the + electrode 14 and the anion exchange membrane 13 is connected to the − electrode 15. When a direct current is applied to the electrodes 14 and 15, electrodialysis is performed, and the dissociated Na ⁺ moves toward the negative electrode 14, passes through the cation exchange membrane 12, and reaches the phosphorus chamber. Permeation is blocked by the anion exchange membrane 13. On the other hand, the dissociated Cl ⁻ moves toward the positive electrode 14, passes through the anion exchange membrane 13, reaches the phosphorus chamber, and is blocked by the next cation exchange membrane 12. Therefore, every other room has a room in which Na ⁺ and Cl ⁻ are accumulated, and as a result, NaCl concentration is performed.

The ion exchange membrane of the separator 8 is characterized by selectively separating and concentrating divalent ions and monovalent ions (Na ⁺ , K ⁺ , Li ⁺ , Cl ^−, etc.) among the ions dissolved in the demineralized water. Most of the monovalent charged ions are sodium chloride, and the component (NaCl) is efficiently and selectively removed for desalting. It is also possible to make the desalting rate at that time as high as about 98%. However, important mineral components having a bivalent charge or higher such as Mg ⁺⁺ (magnesium) and Ca ⁺⁺ (calcium) are concentrated on the desalted water side, and these become the main mineral components of drinking water.

Further, the desalination rate can be controlled at will, and in that case, the automatic sensor index value can be set by voltage and current. According to the research data, it was confirmed that the best condition that does not cause electrolysis of salt water can be obtained by setting the voltage value to 1.5 V and the current value to within 0.6 A. The percentage when the desalination rate is focused on the NaCl concentration can be as low as 0.5% or 0.1% or less from the content of 3.5% of the raw water. As described above, the content of the desalted water and the mineral component can be freely adjusted within a certain range. This is an advantage of the electrodialysis method and a feature of the electrochemical method.

When fresh water and desalted water containing mineral components are obtained from the raw seawater as described above, a predetermined amount of fresh water in the fresh water tank 6 is sent to the drinking water preparation tank 15 shown in FIG. This is a mixing process that adds and mixes demineralized water in an amount that provides a mineral concentration. Fresh water obtained from seawater by mixing is an ideal drinking water and mineral containing an appropriate amount of mineral components held by seawater. It will be water.

However, demineralized water obtained from seawater as described above contains dissolved polyvalent metal ions and the like, and some of these components are unfavorable for health. Therefore, in order to remove such heavy metal ions having a high molecular weight, the desalted water sent from the desalted water tank 10 is filtered by the filter 16 shown in FIG. This filter 16 has a structure that forms a packed bed of particles having a molecular decoration function, such as known natural zeolite, which is an inorganic substance. When demineralized water is passed through the packed bed, heavy metal ions having a high molecular weight are removed and healthy. The above problem is eliminated, and this filtration is totally expected to have a physical effect, and the effect should be adjusted by adjusting the size of the molecular sieve as necessary. This is a very characteristic technique of this process.

When it is desired to precisely adjust the number and amount of mineral components in the demineralized water after removing the polyvalent metal ions and the like as described above, the demineralized water discharged from the filter 16 is 1 is passed through a microfilter 17 shown in FIG. This microfilter 17 uses a publicly known non-woven fabric as a filtration membrane, makes the pores (pores) between fibers ultra fine by increasing or decreasing the number of laminated layers, and increasing the strength by bonding or the like. By performing filtration using a filtration membrane that meets the purpose, the number and amount of mineral components can be precisely adjusted.

When the number and amount of mineral components in the desalted water are precisely adjusted, the predetermined amount of fresh water in the fresh water tank 6 and the number and amount of mineral components in the drinking water preparation tank 15 shown in FIG. Send the amount of mineral water adjusted to the required mineral concentration and mix. The prepared drinking water is sterilized by indirect heating at 80 ° C. or higher by the heat sterilizer 18 shown in FIG. 1 and ultraviolet sterilized by the ultraviolet sterilizer 19 and sent to the storage tank 20. Substances and bacteria unfavorable to health are also removed, and drinking water with a higher degree of ideality is stored in which the mineral components are precisely prepared in an appropriate number and amount as shown in the component table of Table 1.

The drinking water produced as described above was most suitable as drinking water for cooking, cooking, production of beverages, foods, etc., and the content of mineral components was as shown in Table 1.

  Moreover, the concentrated salt water produced in the production of the drinking water is used as a raw material for producing salt. In order to produce sodium chloride with this concentrated salt water, a multiple (triple to quadruple) effect evaporator is used as the evaporator 21 shown in FIG. 1, and crystal salt such as sodium chloride is obtained by boiling the concentrated salt water. In consideration of energy thermal efficiency at the time of evaporation, a pressure reduction method is adopted in which the pressure is reduced to 760 mmHg or less and the boiling point is about 50 ° C. In this way, the crystallized sodium chloride can be dehydrated into a product salt by a centrifuge, and if an appropriate amount of demineralized water containing mineral components is added to the concentrated brine and the evaporation method is carried out, It is possible to produce a salt containing a mineral component lacking in the salt. Furthermore, when the concentrated salt water is boiled, the crystallization of both sodium chloride and potassium chloride components progresses. The separation of both crystals adopts the flotation method. To do.

  As conditions for the above flotation separation, crystal particle size distribution, pulp concentration, PH, and the like are decisive factors. As a surfactant for flotation separation of potassium chloride under these conditions, a cationic collector dodecyl ammonium acetate (amine-based) is used, and when sodium chloride is levitated, alkylbenzene sulfonic acid, olein It is characterized by using an anionic collection material such as acid and sodium oleate, and it has been proved that adding a trace amount (several ppm) of lead chloride as an activator is more effective.

Moreover, the carrier flotation technique can be applied by using fine particles such as TiO2 <Zro2 <CaCo3 <Ba2 <TiO as carriers exhibiting the adsorption characteristics of dissolved ionic components.

  Furthermore, a variety of technical means such as ultra-floating by forming metal complex compounds with active agents such as keratin protein or ion flotation by forming metal soap scum with amine-based interfacial agents. Useful to recover useful dissolved substances efficiently.

The method of the present invention contributes to the market provision of ideal water suitable for drinking, cooking, beverages, food production, etc. by dissolving the mineral content held by simply treating seawater.

It is a flowchart of the method of manufacturing ideal water from the seawater concerning the present invention. It is a block diagram of the separator by the electrodialysis method used for the said method.

Explanation of symbols

1 Raw material seawater tank 3, 4 Filter 5 Reverse osmosis method separation device 7 Concentrated seawater tank 8 Electrodialysis membrane method separation device 16 Drinking water preparation tank

Claims (4)

In the method for producing drinking water for producing drinking water containing mineral components by extracting and adding mineral components held by seawater to fresh water obtained by removing salt from seawater,
A filtration step of removing contaminants from raw seawater with a filter;
A first separation step of separating filtered seawater into fresh water and concentrated seawater by a reverse osmosis method;
A second separation step of separating the separated concentrated seawater into concentrated salt water and demineralized water by electrodialysis;
A suitable amount of separated desalted water is added to the above-mentioned fresh water and mixed to produce ideal drinking water from seawater, characterized by having a mixing step of obtaining drinking water appropriately containing mineral components possessed by seawater Method. The ideal drinking water from the seawater according to claim 1, wherein the desalted water obtained by separating the concentrated saltwater from the concentrated seawater is subjected to a sieving treatment with an inorganic molecular sieve to remove heavy metal ions contained in the desalted water. How to manufacture. The ideal beverage from seawater according to claim 2, wherein the demineralized water from which heavy metal ions have been removed by sieving is subjected to a filtration process with a microfilter to precisely adjust the amount of mineral components in the demineralized water. A method of producing water. The concentrated salt water obtained by separating the desalted water from the concentrated sea water is treated by evaporation to obtain a crystal product or the like of the component contained in the concentrated salt water, thereby producing ideal drinking water from the sea water according to claim 1. Method.

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