System for producing sodium hypochlorite and hydrogen gas

Abstract

An aspect of the present invention provides a system for producing sodium hypochlorite and hydrogen gas, comprising: a desalination unit for desalinating seawater to generate a fresh water stream and a concentrated water stream; a crystallization unit for crystallizing the concentrated water stream to generate a solid raw material containing sodium chloride; an electrolysis unit for electrolyzing reactants, derived from the solid raw material and water, to generate sodium hypochlorite and by-product gas; and a gas purification unit for purifying the by-product gas to generate hydrogen gas.

Description

Manufacturing system for sodium hypochlorite and hydrogen gas

[0001] The present invention relates to a system for producing sodium hypochlorite and hydrogen gas, and more particularly, to a system capable of simultaneously producing high-purity sodium hypochlorite and hydrogen gas.

[0002] Sodium hypochlorite (NaOCl) is applied in various fields such as water supply and sewage, wastewater treatment, seawater electrolysis and ship ballast water treatment, and sterilization and disinfection of agricultural products and food materials.

[0003] Recently, on-site sodium hypochlorite production systems have been attracting attention as suitable for small-scale water purification plants due to their stability, ease of maintenance, and cost-effectiveness. These on-site sodium hypochlorite production systems can produce low-concentration sodium hypochlorite (0.4-1.0%) through the electrolysis of brine. However, these systems have difficulties in removing byproducts during the process, low salt conversion rates and power efficiency, and their low sodium hypochlorite concentration makes them difficult to apply to large-scale facilities.

[0004] Korean Patent Registration No. 10-1226640, Korean Patent Publication No. 10-2012-0002074, etc. disclose devices and / or methods capable of producing high-concentration sodium hypochlorite using a diaphragm method. However, since a means for purifying the brine (NaCl aqueous solution) supplied to the anode chamber is not provided, there is a problem that ionic impurities such as calcium and magnesium remaining in the sodium chloride contaminate the ion exchange membrane of the electrolysis tank, thereby reducing power efficiency and shortening the lifespan of the ion exchange membrane. In addition, there is a problem that it is difficult to control the material balance of the brine supplied to the anode chamber using only a conductivity sensor and a temperature sensor.

[0005] In addition, in this type of electrolysis tank with a diaphragm type, the consumption of salt (NaCl) is greater than the consumption of water during the electrochemical reaction between salt and water, and accordingly, the concentration of the saturated brine initially supplied to the anode chamber gradually decreases. To cope with this concentration decrease, the concentration can be maintained by injecting saturated brine, but as the capacity of the anode water increases, an overflow phenomenon occurs, and this overflowed anode water goes through a separate regeneration process. However, this regeneration process not only increases the equipment, cost, and scale, but also increases the human and material burden due to the use of chemicals such as hydrochloric acid (HCl), sodium hydroxide (NaOH), and residual chlorine neutralizers.

[0006] Korean Patent No. 10-2074331 discloses a device for manufacturing high-concentration sodium hypochlorite on site using seawater or artificial salt water, but when seawater is supplied as a raw material to an installed electrolysis tank to manufacture a treatment agent, a large amount of scale may be generated in the electrolysis tank and other equipment due to impurities in the seawater, it is difficult to easily control the concentration of the treatment agent, and there are problems in that the produced disinfectant decomposes quickly and the concentration cannot be maintained constant. In addition, a device and method for producing sodium hypochlorite by electrolysis using salt, which is a solid raw material, as a raw material have been proposed, but salt contains a certain amount of bromide ions (Br). - ) is included, and there is a problem that sodium hypochlorite manufactured using it inevitably contains a byproduct called bromate, which is a substance that has a negative effect on the human body. In addition, hydrogen produced as a byproduct together with sodium hypochlorite is being diluted and released into the atmosphere (30-40 kg of byproduct hydrogen is produced when 1,000 kg of effective chlorine is produced), so there is a growing need to recover and reuse it.

[0007] Meanwhile, in the case of seawater desalination facilities that produce freshwater by thermally and physically treating seawater, the concentrated seawater generated during the process is discharged directly into the sea (generally, 1 to 1.5 tons of concentrated seawater is generated for every ton of freshwater produced), and this also raises concerns about negative environmental impacts, so various ways to utilize this appropriately are being explored.

[0008] The present invention is intended to solve the problems of the prior art described above, and the purpose of the present invention is to provide a system for manufacturing sodium hypochlorite and hydrogen gas that can implement and improve productivity, environmental friendliness, and economic feasibility in a balanced manner.

[0009] One aspect of the present invention provides a system for producing sodium hypochlorite and hydrogen gas, comprising: a desalination means for desalinating seawater to produce a freshwater stream and a concentrated water stream; a crystallization means for crystallizing the concentrated water stream to produce a solid raw material including sodium chloride; an electrolysis means for electrolyzing a reactant derived from the solid raw material and water to produce sodium hypochlorite and a by-product gas; and a gas purification means for purifying the by-product gas to produce hydrogen gas.

[0010] In one embodiment, the desalination means may include a reverse osmosis device that removes impurities from the seawater to generate a permeate stream; and a concentrator that removes impurities from the permeate stream to generate the fresh water stream and the concentrated water stream.

[0011] In one embodiment, the reverse osmosis device may include a nanofiltration membrane that removes sulfate from the seawater while the seawater passes through the reverse osmosis device, thereby generating the permeate stream.

[0012] In one embodiment, the concentrator may include a first concentrator comprising at least one of a membrane crystallizer and a brine concentrator for removing solid calcium sulfate dihydrate from the permeate stream to produce a first freshwater stream and a first brine stream; a second concentrator for precipitating residual sulfate from the first concentrate stream to produce a second concentrate stream; and a third concentrator for concentrating the concentration of sodium chloride in the second concentrate stream to a saturation point to produce a second freshwater stream and the brine stream.

[0013] In one embodiment, the crystallization means may include at least one of a membrane crystallizer and a brine concentrator that crystallizes the concentrate stream to produce the solid raw material and magnesium-rich stream.

[0014] In one embodiment, the content of sodium chloride in the solid raw material may be 99 wt% or more, and the content of bromine (Br) may be 300 ppm or less.

[0015] In one embodiment, the electrolysis means may include a raw material supply device including a raw material tank in which the solid raw material is stored, a water supply device providing a water stream to the raw material tank, and a mixing device mixing the solid raw material and the water stream to produce a raw material aqueous solution; and an electrolysis device electrolyzing the raw material aqueous solution to produce sodium hypochlorite and a by-product gas.

[0016] In one embodiment, the electrolysis device is a membraneless electrolysis tank, and the membraneless electrolysis tank can produce a mixture including sodium hypochlorite and a by-product gas.

[0017] In one embodiment, the gas purification means may include a gas-liquid separation device that separates sodium hypochlorite in an aqueous solution and gaseous by-product gas from the mixture; and a hydrogen purification device that removes impurities from the by-product gas to generate hydrogen gas.

[0018] In one embodiment, the electrolysis device may include a membrane-type electrolysis tank including an anode chamber for reacting the raw material aqueous solution to obtain an anode product, a cathode chamber for reacting water and cations provided from the anode chamber to obtain a cathode product and a by-product gas, and a membrane dividing the anode chamber and the cathode chamber; and a reaction tank for reacting the anode product and the cathode product to produce sodium hypochlorite.

[0019] In one embodiment, the gas purification means may include a moisture adsorption device for removing residual moisture from the by-product gas; and a hydrogen purification device for removing impurities from the by-product gas to generate hydrogen gas.

[0020] In one embodiment, the fresh water stream may be connected to the water supply device.

[0021] A system for producing sodium hypochlorite and hydrogen gas according to one aspect of the present invention comprises: a desalination means for desalinating seawater to produce a freshwater stream and a concentrated water stream; a crystallization means for crystallizing the concentrated water stream to produce a solid raw material including sodium chloride; an electrolysis means for electrolyzing a reactant derived from the solid raw material and water to produce sodium hypochlorite and a by-product gas; and a gas purification means for purifying the by-product gas to produce hydrogen gas; thereby capable of simultaneously producing high-purity sodium hypochlorite and hydrogen gas.

[0022] In particular, the above-described system for manufacturing sodium hypochlorite and hydrogen gas utilizes concentrated seawater, which was previously discharged or discarded as a by-product during seawater desalination, as one of the raw materials used in manufacturing sodium hypochlorite, and at the same time converts hydrogen gas, which was released into the atmosphere as a by-product during sodium hypochlorite manufacturing, into a reusable form, thereby enabling balanced implementation and improvement of productivity, environmental friendliness, and economic feasibility.

[0023] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0024] Figure 1 shows a system for manufacturing sodium hypochlorite and hydrogen gas according to one embodiment of the present invention.

[0025] Figure 2 shows a system for manufacturing sodium hypochlorite and hydrogen gas according to another embodiment of the present invention.

[0026] Figure 3 shows a manufacturing system for sodium hypochlorite and hydrogen gas according to another embodiment of the present invention.

[0027] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0028] Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with other elements intervening. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that the other components may be included, unless otherwise specifically stated.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0030] FIG. 1 illustrates a system for producing sodium hypochlorite and hydrogen gas according to one embodiment of the present invention. Referring to FIG. 1, the system for producing sodium hypochlorite and hydrogen gas according to one embodiment of the present invention may include a desalination means (100) for desalinating seawater to produce a fresh water stream (FWS) and a concentrated water stream (CWS); a crystallization means (200) for crystallizing the concentrated water stream (CWS) to produce a solid raw material including sodium chloride; an electrolysis means (300) for electrolyzing a reactant derived from the solid raw material and water to produce sodium hypochlorite and a by-product gas; and a gas purification means (400) for purifying the by-product gas to produce hydrogen gas.

[0031] The above-described desalination means (100) can desalinate seawater to produce a freshwater stream (FWS) and a concentrated water stream (CWS). The desalination means (100) may include a reverse osmosis device (110) that removes impurities from the seawater to produce a permeate stream (PS); and a concentration device that removes impurities from the permeate stream (PS) to produce the freshwater stream (FWS) and the concentrated water stream (CWS).

[0032] The reverse osmosis device (110) may include a nanofiltration membrane that removes sulfate from the seawater while the seawater passes through the reverse osmosis device (110) to generate the permeate stream (PS). The nanofiltration membrane may be selective for filtering sulfate but may have low selectivity for filtering cations. The nanofiltration membrane may reduce the concentration of sulfate in the permeate stream (PS) to below the stoichiometric concentration of calcium. The impurity (i1) removed in the reverse osmosis device (110) may be sulfate, which may be discharged from the reverse osmosis device (110) for separate treatment and / or environmentally acceptable disposal.

[0033] If necessary, an additional reverse osmosis unit (not shown) can be used to further concentrate the cations (sodium, calcium, magnesium, etc.) in the permeate stream (PS) and transport them to the concentrator, where any resulting byproducts can also be discharged for separate treatment and / or environmentally acceptable disposal.

[0034] The concentrator can remove impurities from the permeate stream (PS) to generate the fresh water stream (FWS) and the concentrated water stream (CWS). The concentrator can include a first concentrator (121) including at least one of a membrane crystallizer and an evaporative concentrator that removes solid calcium sulfate dihydrate as an impurity (i2) from the permeate stream (PS) to generate a first fresh water stream (FWS1) and a first concentrated water stream (CWS1); a second concentrator (122) that precipitates residual sulfate from the first concentrated water stream (CWS1) to generate a second concentrated water stream (CWS2); and a third concentrator (123) that concentrates the concentration of sodium chloride in the second concentrated water stream (CWS2) to a saturation point to generate the second fresh water stream (FWS2) and the concentrated water stream (CWS).

[0035] The first concentrator (121) may include at least one of a membrane crystallizer and an evaporative concentrator that removes solid calcium sulfate dihydrate as an impurity (i2) from the permeate stream (PS) to generate the first fresh water stream (FWS1) and the first concentrated water stream (CWS1).

[0036] The first freshwater stream (FWS1) above contains trace amounts of salt or substantially does not contain it, so it can be discharged to the outside of the first concentration device (121) or used to manufacture a raw material aqueous solution that is fed into the electrolysis device (320) by connecting it to the water supply device (311) of the electrolysis means (300).

[0037] The first concentrated water stream (CWS1) is obtained by removing solid calcium sulfate dihydrate and the first fresh water stream (FWS1) from the permeate stream (PS), and the concentration of cations (sodium, magnesium, etc.) other than calcium in the first concentrated water stream (CWS1) may be more concentrated than that in the permeate stream (PS).

[0038] The second concentrator (122) may generate a second concentrator stream (CWS2) by precipitating residual sulfate (i3) from the first concentrator stream (CWS1). The first concentrator stream (CWS1) is derived from the permeate stream (PS) generated in the reverse osmosis device (110), and a trace amount of sulfate may still remain in the first concentrator stream (CWS1). In response to this, the second concentrator (122) may precipitate insoluble salts by adding soluble salts of alkaline earth metals to the first concentrator stream (CWS1). The insoluble salts may be removed from the second concentrator (122), and the second concentrator stream (CWS2) generated thereby may be transferred to the third concentrator (123). For example, the soluble salt may be barium chloride and / or barium hydroxide, and the insoluble salt may be barium sulfate, but is not limited thereto.

[0039] The third concentrator (123) may be configured to concentrate the concentration of sodium chloride in the second concentrated water stream (CWS2) to a saturation point to generate a second fresh water stream (FWS2) and the concentrated water stream (CWS).

[0040] The second freshwater stream (FWS2) above contains trace amounts of salt or substantially does not contain it, so it can be discharged to the outside of the third concentration device (123) or used to manufacture a raw material aqueous solution that is fed into the electrolysis device (320) by connecting it to the water supply device (311) of the electrolysis means (300).

[0041] The above-mentioned concentrated water stream (CWS) is produced by concentrating the concentration of sodium chloride in the second concentrated water stream (CWS2) to a saturation point, and the concentration here can also be achieved by a device such as a membrane crystallizer, an evaporative concentrator, or a heat treatment device. Generally, the saturation concentration of sodium chloride is about 360,000 ppm, so in order for the concentration of sodium chloride in the second concentrated water stream (CWS2) to reach this point, the second concentrated water stream (CWS2) can be concentrated so that the content of total dissolved solids (TDS) is 200,000 ppm or more, preferably, 250,000 ppm or more.

[0042] The crystallization means (200) may include at least one of a membrane crystallizer and an evaporative concentrator that crystallizes the concentrate water stream (CWS) to produce the solid raw material and a magnesium-rich stream (MRS). The solid raw material is obtained by crystallizing the concentrate water stream (CWS) from which magnesium has been substantially removed, and the solid raw material may be highly purified sodium chloride. The magnesium-rich stream (MRS) may be transported to a process for producing a useful material derived from magnesium, or may be discharged to the crystallization means (200) for separate treatment and / or environmentally acceptable disposal.

[0043] Among the solid raw materials, the content of sodium chloride may be 99 wt% or more, preferably 99.5 wt% or more, and the content of bromine (Br) may be 300 ppm or less, preferably 250 ppm or less, and more preferably 230 ppm or less. In addition, the concentrations of calcium (Ca) and magnesium (Mg) among the solid raw materials may each be 5,000 ppm or less, preferably 3,000 ppm or less, and more preferably 2,000 ppm or less, and the insoluble matter among the solid raw materials may be 0.5 wt% or less, preferably 0.2 wt% or less. By maximizing the content of sodium chloride among the above solid raw materials and minimizing the content of other impurities such as bromine, calcium, and magnesium to increase the purity of the above solid raw materials, it is possible to appropriately solve the problems of a large amount of scale occurring in equipment including the electrolysis means (300) due to impurities, the problem of difficulty in easily controlling the concentration and purity of sodium hypochlorite, the problem of accelerated decomposition of manufactured sodium hypochlorite, and the problem of excessive production of bromate, a hazardous substance among sodium hypochlorite.

[0044] The electrolysis means (300) may include a raw material supply device including a raw material tank (312) in which the solid raw material is stored, a water supply device (311) that provides a water stream to the raw material tank (312), and a mixing device (313) that mixes the solid raw material and the water stream to produce a raw material aqueous solution; and an electrolysis device (320) that electrolyzes the raw material aqueous solution to produce sodium hypochlorite and a by-product gas.

[0045] The above raw material supply device may include a raw material tank (312) in which the solid raw material, for example, salt, is stored, a water supply device (311) that provides a water stream to the raw material tank (312), and a mixing device (313) that mixes the solid raw material and the water stream to produce a raw material aqueous solution.

[0046] The above raw material tank (312) can store the solid raw material, for example, salt, produced in the crystallization means (200), and the mixing device (313) can mix the solid raw material with the water stream provided from the water supply device (311), including tap water, purified water (pure water or higher), and / or the fresh water stream (FWS), to produce a raw material aqueous solution having a preset concentration, preferably brine, more preferably, saturated brine (saturated sodium chloride aqueous solution), and provide the mixture to the electrolysis device (320).

[0047] The water stream provided from the water supply device (311) may be comprised of tap water, purified water, and / or the fresh water stream (FWS). The tap water, purified water, and / or the fresh water stream (FWS) may be stored in a water tank provided at the front end of the water supply device (311) and may be provided to the raw material tank (312) by the water supply device (311).

[0048] The above water supply device (311) may not include any expensive auxiliary device such as a filter, for example, any means for filtering and purifying water, and directly provides stored tap water, purified water, and / or the fresh water stream (FWS) to the raw material tank (312), thereby simplifying and miniaturizing the entire system, thereby improving maintainability, economy, efficiency, etc.

[0049] The above mixing device (313) can produce the raw material solution by mixing the water stream consisting of pre-stored tap water, purified water, and / or the fresh water stream (FWS) and the solid raw material stored in the raw material tank (312) at a preset ratio.

[0050] The above raw material aqueous solution includes an electrolyte and water that are raw materials of sodium hypochlorite, wherein the solid raw material is highly purified sodium chloride, and the water is the fresh water stream (FWS) treated in the desalination means (100) or treated in another manner, and substantially does not contain impurities, so that unnecessary scales, etc. generated in the electrolysis means (300) due to such impurities can be effectively prevented, and the concentration of the sodium hypochlorite aqueous solution obtained through the electrolysis device (320) can be easily and precisely controlled by adjusting the amount of the raw material aqueous solution or the applied current.

[0051] The above mixing device (313) may include a raw material aqueous solution treatment device (not shown). The raw material aqueous solution treatment device can prevent contamination of the electrolysis device (320) in advance by removing residual impurities such as calcium and magnesium contained in the raw material aqueous solution produced by the mixing device (313), for example, saturated salt water, thereby increasing the efficiency of the electrolysis reaction and contributing to increasing the durability and lifespan of the electrolysis device (320).

[0052] In addition, the raw material aqueous solution treatment device may include a heating unit equipped with a heater in a water tank of a preset standard, a pH control unit, and a softening unit (not shown) equipped with a chelating resin capable of adsorbing and removing impurities in the raw material aqueous solution that has passed through the heating unit. The heating unit may appropriately maintain the temperature, pH, etc. of an unrefined raw material aqueous solution, for example, saturated brine, to improve the adsorption efficiency of the softening unit. For example, the appropriate temperature and pH of the saturated brine may be 50 to 80°C and 9 or higher, respectively, but are not limited thereto.

[0053] The above electrolysis device (320) can generate sodium hypochlorite and byproduct gas by electrolyzing the raw material aqueous solution. The process of generating sodium hypochlorite by electrolysis of the raw material aqueous solution, which is brine, preferably saturated brine (saturated sodium chloride aqueous solution), is as follows.

[0054] When a saturated sodium chloride aqueous solution is introduced into the electrolysis device (320), chloride ions (Cl), which are anions of sodium chloride, are formed at the anode. - ) undergoes an oxidation reaction in which chlorine gas (Cl2) is converted into water (H2O), and at the cathode, water (H2O) is converted into hydrogen gas (H2) and hydroxide ions (OH - ) A reduction reaction occurs.

[0055] Chlorine gas and hydroxide ions generated at the anode and cathode, respectively, undergo a chemical reaction in a reaction vessel (324) (or reaction section) provided inside and / or outside the electrolysis device (320) to produce hypochlorite ions (OCl). - ) or hypochlorous acid (HOCl). At this time, hypochlorous acid ions and hypochlorous acid maintain a chemical equilibrium state depending on the pH. When sodium chloride (NaCl) is used, hypochlorous acid ions (OCl - ) is a sodium ion (Na + ) combines with sodium hypochlorite (NaOCl) to form sodium hypochlorite.

[0056] Fig. 2 illustrates a system for producing sodium hypochlorite and hydrogen gas according to another embodiment of the present invention. Referring to Fig. 2, the electrolysis device is a membrane-less electrolysis tank (320'), and the membrane-less electrolysis tank (320') can produce a mixture containing sodium hypochlorite and a by-product gas.

[0057] In the above membrane-less electrolysis tank (320'), the above-described oxidation and reduction reactions occur at the anode and cathode, respectively, and a reaction between chlorine gas and hydroxide ions occurs in the bulk phase inside the membrane-less electrolysis tank (320'), thereby generating a mixture including sodium hypochlorite and by-product gas.

[0058] Here, the gas purification means (400) may include a gas-liquid separation device (410) that separates sodium hypochlorite in an aqueous solution and gaseous by-product gas from the mixture; and a hydrogen purification device (420) that removes impurities from the by-product gas to generate hydrogen gas.

[0059] The above-mentioned gas-liquid separator (410) may be a cyclone-type separator. This can separate the gaseous by-product gas from the liquid-phase mixture by generating a vortex due to rotation.

[0060] The above hydrogen purification device (420) can remove impurities (i4) from the by-product gas, such as moisture, water vapor, oxygen gas, and fume, to produce high-purity hydrogen gas. Processes or methods for removing such impurities may include, but are not limited to, physical, chemical, biological, or combinations of two or more thereof.

[0061] The hydrogen gas generated in the hydrogen purification device (420) may be used as a raw material for operating a fuel cell through a predetermined processing device (not shown), if necessary, or may be converted into water by contacting it with a hydrogen oxidation catalyst and then circulated to the water supply device (311), or may be appropriately diluted and discharged to the outside. The processing device may include, but is not limited to, a leak detector, a discharge barrier, a catalytic reactor and / or neutralizer for neutralizing leaked hydrogen gas, a device for preventing diffusion through absorption and / or adsorption, etc.

[0062] Fig. 3 illustrates a system for producing sodium hypochlorite and hydrogen gas according to another embodiment of the present invention. Referring to Fig. 3, the electrolysis device may include a membrane-type electrolysis tank including an anode chamber (321) for reacting the raw material aqueous solution to obtain an anode product, a cathode chamber (322) for reacting water and cations provided from the anode chamber (321) to obtain a cathode product and a by-product gas, and a membrane (323) for dividing the anode chamber (321) and the cathode chamber (322); and a reaction tank (324) for reacting the anode product and the cathode product to produce sodium hypochlorite.

[0063] The above diaphragm type electrolysis tank comprises an anode chamber (321) for obtaining an anode product by reacting the raw material aqueous solution, water and cations provided from the anode chamber (321), preferably metal ions, more preferably sodium ions (Na + ) to obtain a cathode product and a by-product gas by reacting the cathode chamber (322), and a partition (323) that partitions the anode chamber (321) and the cathode chamber (322).

[0064] The anode chamber (321) may include an anode and may contain anode products including anode water and gaseous substances generated by an electrolytic reaction at the anode. In addition, the cathode chamber (322) may include a cathode and may contain the cathode products and by-product gases generated by an electrolytic reaction at the cathode.

[0065] When the above raw material solution is salt water, preferably saturated salt water, and a preset voltage is applied to the diaphragm-type electrolysis tank, the following substances can be produced in the anode chamber (321) and the cathode chamber (322).

[0066] In the above anode chamber (321), saturated salt water having a preset concentration is electrolyzed to produce sodium ions (Na + ), chlorine gas (Cl2) and chloride ion (Cl -) can be generated, and in the cathode chamber (322), water is electrolyzed to produce hydrogen gas (H2) and hydroxide ions (OH - ) can be generated. The sodium ions generated in the anode chamber (321) can chemically and / or physically permeate the membrane (323) and move to the cathode chamber (322), and react with the hydroxide ions generated in the cathode chamber (322) to generate sodium hydroxide. As used herein, the term "chemical permeation" means that an ionic substance having a predetermined charge permeates the membrane through a chemical means such as an ion exchange reaction, and "physical permeation" means that a substance permeates the membrane by overcoming the physical and structural elements of the membrane, such as the size of the pores provided in the membrane and the thickness of the membrane. The sodium hydroxide generated in the cathode chamber (322) can be used as a reactant for generating sodium hypochlorite, and, if necessary, can also be used as a buffer for adjusting the pH of the generated sodium hypochlorite aqueous solution to increase storage stability.

[0067] The above membrane (323) may be a cation exchange membrane. The cation exchange membrane may be a soft cation exchange membrane made of a polymer film. The cation exchange membrane may allow cations, for example, sodium ions, generated in the anode chamber (321) to permeate and move to the cathode chamber (322) through an ion exchange reaction with a functional group provided in the cation exchange membrane. In addition, the cation exchange membrane may, if necessary, include an additional layer and / or functional group that can prevent hydroxide ions generated in the cathode chamber (322) from permeating and moving to the anode chamber (321).

[0068] The above reaction tank (324) can produce sodium hypochlorite by reacting the anode product, for example, chlorine gas, produced in the anode chamber (321) of the diaphragm-type electrolysis tank, with the cathode product, for example, sodium hydroxide, produced in the cathode chamber (322). The reaction tank (324) may be an independent device or facility connected to the diaphragm-type electrolysis tank of the preceding stage through a pipe or the like, or, although not shown, may be provided integrally with the diaphragm-type electrolysis tank of the preceding stage without separate pipe.

[0069] In the latter case, a part of the interior of the diaphragm-type electrolysis tank may be provided as a space where the anode product and the cathode product are collected, thereby producing sodium hypochlorite by reacting them. In addition, when the reaction tank (324) and the diaphragm-type electrolysis tank are provided as an integral unit, a device or facility for circulating at least a part of the anode product and / or the cathode product, which is essentially provided in a conventional diaphragm-type electrolysis tank, to the anode chamber (321) and / or the cathode chamber (322), respectively, can be appropriately omitted, thereby simplifying and miniaturizing the system as a whole, thereby improving maintainability, economy, efficiency, etc.

[0070] The concentration of the sodium hypochlorite aqueous solution obtained from the above reaction tank (324) may be 0.01 to 50 wt%, preferably 0.1 to 30 wt%, and more preferably 0.2 to 15 wt%.

[0071] When the electrolysis device is the diaphragm-type electrolysis tank, the gas purification means (400) may include a moisture absorption device (410) connected to the cathode chamber (322) to remove residual moisture (i4') from the by-product gas generated in the cathode chamber (322); and a hydrogen purification device (420) to remove impurities (i4), such as water vapor, oxygen gas, fume, etc., from the by-product gas from which residual moisture has been removed, to generate high-purity hydrogen gas. Processes or methods for removing such impurities may include, but are not limited to, physical, chemical, biological, and combinations of two or more thereof.

[0072] The hydrogen gas generated in the hydrogen purification device (420) may be used as a raw material for operating a fuel cell through a predetermined processing device (not shown), if necessary, or may be converted into water by contacting it with a hydrogen oxidation catalyst and then circulated to the water supply device (311), or may be appropriately diluted and discharged to the outside. The processing device may include, but is not limited to, a leak detector, a discharge barrier, a catalytic reactor and / or neutralizer for neutralizing leaked hydrogen gas, a device for preventing diffusion through absorption and / or adsorption, etc.

[0073] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0074] The scope of the present invention is indicated by the claims set forth below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0075] <Explanation of symbols>

[0076] 100: Desalination device 110: Reverse osmosis device

[0077] 121: First concentrator 122: Second concentrator

[0078] 123: Third concentration device 200: Crystallization means

[0079] 300: Electrolysis means 311: Water supply device

[0080] 312: Raw material tank 313: Mixing device

[0081] 320: Electrolysis device 320': Diaphragm-less electrolysis tank

[0082] 321: Anode chamber 322: Cathode chamber

[0083] 323: Diaphragm 324: Reaction tank

[0084] 400: Gas purification means 410: Gas-liquid separation device / moisture absorption device

[0085] 420: Hydrogen purification unit PS: Permeate stream

[0086] FWS, FWS1, FWS2: Freshwater streams CWS, CWS1, CWS2: Concentrated water streams

[0087] MRS: Magnesium-rich streams i1, i2, i3, i4: Impurities

[0088] i4': residual moisture

Claims

1. A desalination means for generating a freshwater stream and a concentrated water stream by desalinating seawater; A crystallization means for crystallizing the above concentrated water stream to produce a solid raw material containing sodium chloride; An electrolysis means for generating sodium hypochlorite and by-product gas by electrolyzing the solid raw material and the reactant derived from water; and A gas purification means for purifying the above by-product gas to produce hydrogen gas; Manufacturing system for sodium hypochlorite and hydrogen gas.

2. In paragraph 1, The above desalination means, A reverse osmosis device that removes impurities from the seawater to produce a permeate stream; and A concentrator for removing impurities from the permeate stream to produce the fresh water stream and the concentrated water stream; Manufacturing system for sodium hypochlorite and hydrogen gas.

3. In paragraph 2, The above reverse osmosis device, A nanofiltration membrane comprising: a membrane for removing sulfate from the seawater while the seawater passes through the reverse osmosis device to generate the permeate stream; Manufacturing system for sodium hypochlorite and hydrogen gas.

4. In paragraph 2, The above concentration device is, A first concentrator comprising at least one of a membrane crystallizer and a brine concentrator for removing solid calcium sulfate dihydrate from the permeate stream to produce a first fresh water stream and a first concentrated water stream; A second concentrator for precipitating residual sulfate from the first concentrated water stream to produce a second concentrated water stream; and A third concentrator comprising: a second fresh water stream and the concentrated water stream; comprising: a third concentrator for concentrating the concentration of sodium chloride in the second concentrated water stream to a saturation point to generate a second fresh water stream and the concentrated water stream; Manufacturing system for sodium hypochlorite and hydrogen gas.

5. In paragraph 1, The above crystallization means is, At least one of a membrane crystallizer and a brine concentrator for crystallizing the concentrated water stream to produce the solid raw material and magnesium-rich stream, Manufacturing system for sodium hypochlorite and hydrogen gas.

6. In paragraph 1, Among the above solid raw materials, the content of sodium chloride is 99 wt% or more, and the content of bromine (Br) is 300 ppm or less. Manufacturing system for sodium hypochlorite and hydrogen gas.

7. In paragraph 1, The above electrolysis means, A raw material supply device including a raw material tank in which the solid raw material is stored, a water supply device providing a water stream to the raw material tank, and a mixing device mixing the solid raw material and the water stream to produce a raw material aqueous solution; and An electrolysis device comprising: an electrolysis device that electrolyzes the above raw material solution to produce sodium hypochlorite and by-product gas; Manufacturing system for sodium hypochlorite and hydrogen gas.

8. In paragraph 7, The above electrolysis device is a membraneless electrolysis tank, The above membrane-less electrolysis tank produces a mixture containing sodium hypochlorite and by-product gas. Manufacturing system for sodium hypochlorite and hydrogen gas.

9. In paragraph 8, The above gas purification means, A gas-liquid separation device for separating sodium hypochlorite in an aqueous solution and gaseous by-product gas from the above mixture; and A hydrogen purification device that removes impurities from by-product gas to produce hydrogen gas; Manufacturing system for sodium hypochlorite and hydrogen gas.

10. In paragraph 7, The above electrolysis device, A membrane-type electrolysis tank including an anode chamber for obtaining an anode product by reacting the above raw material aqueous solution, a cathode chamber for obtaining a cathode product and a by-product gas by reacting water and cations provided from the anode chamber, and a membrane dividing the anode chamber and the cathode chamber; and A reaction tank comprising: a reaction tank for reacting the positive electrode product and the negative electrode product to produce sodium hypochlorite; Manufacturing system for sodium hypochlorite and hydrogen gas.

11. In paragraph 10, The above gas purification means, A moisture absorption device that removes residual moisture from by-product gas; and A hydrogen purification device that removes impurities from by-product gas to produce hydrogen gas; Manufacturing system for sodium hypochlorite and hydrogen gas.

12. In paragraph 7, The above fresh water stream is connected to the above water supply device, Manufacturing system for sodium hypochlorite and hydrogen gas.

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