KR20120000647A - Apparatus and method of boron removing for sea water desalination - Google Patents

Abstract

PURPOSE: Boron eliminating apparatus and method for seawater desalination are provided to eco-friendly implement operational processes based on solar energy and to product drinking water based on seawater by lowering the concentration of boron contained in the seawater. CONSTITUTION: A boron eliminating apparatus(100) includes a pre-treating part(110), a pump(120), a reverse osmosis membrane(130), a solar energy collecting board(142), an evaporating part(140), and a mixing part(150). The pre-treating part eliminates colloidal materials, organic materials, inorganic materials, microorganisms from seawater. The reverse osmosis membrane separates the pre-treated seawater into filtered water and concentrated water to be discharged. The evaporating part heat-exchanges the concentrated water with the solar energy collecting board and produces desalinated water. The mixing part mixes the desalinated water and the filtered water. Boron contained in the seawater is eliminated when the filtered water and the concentrated water are separated, and the desalinated water is produced.

Description

Apparatus and Method of Boron Removing for Sea Water Desalination

The present invention relates to an apparatus and a method for removing boron for seawater desalination, and more particularly, to separate seawater into concentrated water and filtered water by reverse osmosis membrane (RO) and evaporation using solar heat obtained by a solar heat collecting plate as the concentrated water. The present invention relates to a boron removal apparatus and method for seawater desalination that can obtain drinking water by mixing the fresh water produced by steam generation in a desalination apparatus and the filtered water separated by the reverse osmosis membrane.

About 97% of the world's water is seawater, and desalination of seawater has attracted much attention as the water shortage is intensifying.

Sea water contains many kinds of salts, so it has to be removed for use as drinking water. In addition, seawater is known to contain about 3 to 5 mg / l of boron, although there are some differences depending on the region and season. Boron has been reported to be a carcinogen that can cause disorders in the digestive and nervous systems if consumed for a long time.

The content of boron is 1.0mg / ℓ or less (2009. 9) in Korea drinking water quality standards, and the content of boron is 2.4mg / ℓ or less (2009. 11) according to the World Health Organization (WHO) standards Total Dissolved Solids (evaporation residues) are required to be less than 500 ppm to desalination seawater to drinking water. Therefore, it was necessary to develop a method for effectively removing boron from seawater during the desalination of seawater.

In addition, the energy required for the removal of boron from seawater was used electricity generated using a solar power panel, but there was a problem in that the removal rate of boron was lowered because the power generation efficiency of the solar power panel was low.

On the other hand, the filtered water produced by the conventional method of producing fresh water using reverse osmosis membrane has high salinity removal rate, so it can be used as drinking water, but some boron, which is difficult to remove with reverse osmosis membrane, needs to be removed below the recommended value. On the other hand, while freshwater obtained by evaporation is easy to remove boron, there is a problem that it is difficult to obtain a lot of production water.

The present invention has been made to solve the above problems, it is possible to remove the boron in the sea water by applying directly to the concentrated water separated by the reverse osmosis membrane without converting the solar heat collected by the solar heat collecting plate into electricity It is an object of the present invention to provide a boron removal apparatus and method for desalination.

It is also an object of the present invention to provide an apparatus and method for removing boron for seawater desalination, in which fresh water obtained by evaporation and filtered water obtained by reverse osmosis membranes can be mixed and used as drinking water.

According to a first aspect of the present invention, an apparatus for producing fresh water from which boron is removed by treating seawater, comprising: a pretreatment unit for removing colloidal material, organic material, inorganic material, microorganism, etc. from seawater supplied from the outside; A pump for pumping the seawater discharged from the pretreatment unit; A reverse osmosis membrane for discharging the pretreated seawater into filtered water and concentrated water; A solar heat collecting plate for collecting solar heat; An evaporator for producing fresh water with steam generated by exchanging the concentrated water with the solar heat collecting plate; And a mixing unit mixing the fresh water and the filtrate discharged from the reverse osmosis membrane. It includes, and provides a boron removal device for seawater desalination in which boron is removed during separation of the filtrate and the concentrated water by the reverse osmosis membrane and fresh water production by the evaporator.

The power supply may further include an electrolysis unit for producing sodium hypochlorite (NaOCl) used for sterilization of raw water and cleaning of the pretreatment unit by applying power to the concentrated water.

The mixing unit may mix the fresh water produced by the evaporator and the filtered water separated by the reverse osmosis membrane in a ratio of 1: 3 to 5.

It may further include an energy recovery unit for recovering the pressure and flow rate of the concentrated water discharged from the reverse osmosis membrane to reduce the operation amount of the pump.

According to a second aspect of the present invention, there is provided a method of producing fresh water from which boron is removed by treating seawater, the method comprising: removing colloidal material, organic material, inorganic material, microorganism, and the like from seawater; Pumping the sea water; Separating and discharging the pressurized seawater into filtered water and concentrated water; Collecting solar heat; Generating fresh water by generating steam from the concentrated water using the solar heat; Mixing the filtered water with the fresh water produced by evaporation of the concentrated water; It provides a boron removal method for seawater desalination comprising.

Electrolyzing the concentrated water may further comprise the step of producing sodium hypochlorite.

Recovering the pressure and flow rate of the concentrated water may further comprise the step of reusing the pressure of the sea water.

According to a third aspect of the present invention, there is provided a boron removal method for seawater desalination in which seawater is evaporated and recovered by solar heat collected by a solar heat collecting plate to produce fresh water from which boron is removed.

The present invention as described above has the effect of producing drinking water using seawater by making the concentration of boron contained in seawater to be below a certain level.

In addition, by using solar heat to desalination of sea water has the effect of producing fresh water environmentally friendly.

In addition, by mixing the filtered water produced by the reverse osmosis membrane and fresh water produced by evaporation in a certain ratio has the effect of producing fresh water stably.

1 is a view showing the configuration of the boron removal device for seawater desalination according to an embodiment of the present invention.
2 is a flowchart illustrating a boron removal method for seawater desalination according to an embodiment of the present invention.
3 is a flowchart illustrating an energy recovery step and an electrolysis step according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of the boron removal device for seawater desalination according to an embodiment of the present invention. 2 is a flowchart illustrating a boron removal method for seawater desalination according to an embodiment of the present invention, and FIG. 3 is a flowchart illustrating an energy recovery step and an electrolysis step according to an embodiment of the present invention.

1, the boron removal apparatus 100 according to an embodiment of the present invention may include a pretreatment unit 110, a pump 120, a reverse osmosis membrane 130, an energy recovery unit 132, and an electrolysis unit 134. , An evaporator 140 and a mixer 150.

In addition, the evaporator 140 includes a solar heat collecting plate 142 to supply heat required for evaporation.

The configuration of the boron removing apparatus 100 according to an embodiment of the present invention shown in FIG. 1 will be described with reference to FIGS. 2 and 3.

The pretreatment unit 110 removes and discharges foreign substances such as colloidal substances, organic substances, inorganic substances, and microorganisms from the seawater collected through an external seawater intake apparatus (not shown) (S110). Here, the pretreatment unit 110 may use a standard pretreatment method or a membrane center pretreatment method. The standard pretreatment method is a method using sand filtration, multilayer filtration, cartridge filter, etc., and the membrane-centered pretreatment method is a method using a microfiltration membrane (MF), an ultrafiltration membrane (UF), or the like.

In the present embodiment, the pretreatment unit 110 is composed of a fibrous filter 112 and the ultrafiltration membrane filter 114. The fibrous filter 112 and the ultrafiltration membrane filter 114 are continuously arranged so that the seawater passes in turn. At this time, the arrangement of the filter may be reversely arranged by the user's needs, and in addition to the user's needs, various types of filters may be used in the pretreatment unit 110, and a plurality of filters of the same type may be connected and used. have.

The pump 120 applies pressure to the seawater so that the seawater pretreated in the pretreatment 110 can be easily moved to a component described later (S120).

The reverse osmosis membrane 130 receives the seawater being pumped through the pump 120, and separates the filtered and concentrated water (S130). Here, the concentrated water is supplied to the mixing unit 150 through the energy recovery unit 132, the electrolysis unit 134, and the evaporator 140, which will be described later, and the filtered water is supplied to the mixing unit described later.

The reverse osmosis membrane 130 is divided into sea water or brackish water, and the reverse osmosis membrane is filled and used in a vessel (not shown).

Here, the insertion pressure refers to the pressure caused by the phenomenon that the solvent moves from the lower concentration of the solute to the higher concentration when two liquids having different concentrations are blocked by the semipermeable membrane. In addition, reverse osmosis means a phenomenon in which a pure solvent is released from the solution through the semipermeable membrane when a pressure higher than the osmotic pressure is applied.

Filtrated water is fresh water in which salinity such as boron is reduced to a certain degree. Although the amount of salt is reduced, some of the boron remains, so it is necessary to remove boron to a level below the recommended level for use as drinking water.

When the concentrated water is discharged from the reverse osmosis membrane 130, since the concentrated water maintains a predetermined pressure state and a flow rate supply state, it is preferable to recover the pressure and flow rate of the concentrated water to reduce energy consumed throughout the apparatus.

The energy recovery unit 132 allows a predetermined flow rate of the concentrated water discharged from the reverse osmosis membrane 130 to be introduced into the inside, and the concentrated water introduced when the seawater discharged by the pump 120 flows into the reverse osmosis membrane 130. The energy of the concentrated water is recovered by applying a pressure and a flow rate (S132). The energy recovery unit 132 is installed on a pipe connecting the pump 120 and the reverse osmosis membrane 130. The configuration of the energy recovery unit 132 may use a pressure exchanger method or a turbo charger method according to a user's selection.

The amount of operation of the pump 120 is reduced by the pressure of the brine and the flow rate recovery, so that the energy used by the entire apparatus is reduced by about 30%.

The electrolysis unit 134 electrolyzes a part of the concentrated water discharged from the reverse osmosis membrane 130 to produce sodium hypochlorite (NaOCl) (S134). The electrolysis unit 134 consists of a container having a predetermined size and an electrode installed inside the container, and applies power to the concentrated water introduced into the container using the electrode.

This is explained in more detail.

A portion of the concentrated water passing through the energy recovery unit 132 is introduced into the electrolysis unit 134. The electrolysis unit 134 applies a power source having a predetermined current and voltage to the concentrated water by using an electrode to produce sodium hypochlorite.

The production of sodium hypochlorite can be expressed by the following formula.

In this embodiment, sodium hypochlorite produced in the electrolysis unit 134 is used for chemical cleaning of the ultrafiltration membrane filter 114 constituting the raw water sterilization and pretreatment unit 110. The ultrafiltration membrane filter 114 can keep the filtration performance constant by chemical cleaning.

A portion of the concentrated water that has passed through the energy recovery unit 132 is introduced into the evaporator 140, and a portion of the concentrated water is discharged into the seawater.

The evaporator 140 may evaporate the concentrated water through heat exchange (S140), and recover the same to produce fresh water. The evaporator 140 is formed of a container having a predetermined space therein. In addition, the evaporator 140 is connected to the solar heat collecting plate 142 so that the discharge and inflow of the heat source for heat exchange with the concentrated water. The evaporator 140 exchanges the introduced concentrated water with the heat medium of the solar heat collecting plate 142.

The solar heat collecting plate 142 supplies heat using the collected solar heat directly, and heats the supplied heat with the concentrated water so that the concentrated water is heated. The concentrated water introduced into the solar heat collecting plate 142 is evaporated in the evaporator 140, and the vapor of the concentrated water is liquefied by touching the inner upper surface of the evaporator 140. Liquefied steam is collected and discharged into fresh water. In order to facilitate the collection of steam, it is preferable that a separate collection mechanism is installed inside the evaporator 140.

Since the solar heat collecting plate 142 for evaporating the concentrated water operates only when the altitude of the sun is higher than a predetermined angle, the daily operating time of the solar heat collecting plate 142 in the mid-latitude region such as Korea is approximately 4-5 hours. The operating time of the solar heat collecting plate 142 may be increased by going to a low latitude region such as the tropics.

In addition to the operation time of the solar heat collecting plate 142, the concentrated water is used as industrial water, and when it is necessary to generate steam at a time other than the solar heat collecting plate 142, a separate burner may be used.

The solar heat collecting plate 142 used in the present embodiment may use a flat plate type, a vacuum tube type, a ruminant type heat collector, and a configuration in which the installation angle is changed according to the circumference of the sun. Since the configuration of the angle change of the solar vacuum tube collector and the solar collector plate is a well-known technique, a detailed description thereof will be omitted.

Since solar heat is used for steam generation, the evaporation unit 140 may produce fresh water in an environmentally friendly manner. The fresh water produced is 99.9% boron removed from the concentrated water, the TDS is less than 10ppm.

Fresh water produced in the evaporator 140 has a high salinity removal rate, so that drinking water can be used as drinking water. To this end, fresh water produced by the evaporator 140 is supplied to the mixing unit 150.

The mixing unit 150 mixes the filtered water discharged from the reverse osmosis membrane 130 and the fresh water produced by the evaporation unit 140 at a predetermined ratio, so as to achieve boron removal below a required value (S150). That is, the fresh water produced by the evaporator 140 is mixed with the filtered water discharged from the reverse osmosis membrane 130 so that the boron concentration of the mixed water is 0.5 ppm or less suitable for drinking.

In the present embodiment, it is preferable to mix fresh water and filtrate in a ratio of 1: 3 to 5, but the mixing ratio may be varied so that the boron concentration of the mixed water is 0.5 ppm or less.

The mixed water of fresh water and filtered water may be discharged from the mixing unit 150 and immediately supplied to the user, and may be stored in a separate storage tank and used when necessary.

The present invention configured as described above can stably produce fresh water from which boron has been removed by allowing the concentration of boron to desalination seawater to be below a certain level.

In addition, by using solar heat in desalination has the effect of producing fresh water environmentally friendly.

In addition, it is possible to stably produce fresh water by mixing the filtered water produced by the reverse osmosis membrane and fresh water produced by evaporation at a predetermined ratio.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

100: boron removal device
110: preprocessing unit
120: pump
130: reverse osmosis membrane
140: evaporation unit
150: mixing part

Claims (8)

In the device for treating seawater to produce fresh water without boron,
A pretreatment unit for removing colloidal substances, organic substances, inorganic substances, microorganisms, etc. from seawater supplied from the outside;
A pump for pumping the seawater discharged from the pretreatment unit;
A reverse osmosis membrane for discharging the pretreated seawater into filtered water and concentrated water;
A solar heat collecting plate for collecting solar heat;
An evaporator for producing fresh water with steam generated by exchanging the concentrated water with the solar heat collecting plate; And
Mixing unit for mixing the fresh water and the filtered water discharged from the reverse osmosis membrane;
Including,
Separation of the filtered water and the concentrated water by the reverse osmosis membrane and boron is removed during fresh water production by the evaporator.
Boron removal device for seawater desalination. The method of claim 1,
It further comprises an electrolysis unit for producing sodium hypochlorite (NaOCl) used for the sterilization of raw water and washing the pretreatment unit by applying power to the concentrated water.
Boron removal device for seawater desalination. The method of claim 1,
The mixing unit mixes the fresh water produced by the evaporator and the filtered water separated by the reverse osmosis membrane in a ratio of 1: 3 to 5.
Boron removal device for seawater desalination. The method of claim 1,
Further comprising an energy recovery unit for recovering the pressure and flow rate of the concentrated water discharged from the reverse osmosis membrane to reduce the operation amount of the pump
Boron removal device for seawater desalination. In the method of treating seawater to produce fresh water without boron,
Removing colloidal substances, organic substances, inorganic substances, microorganisms, etc. from seawater;
Pumping the sea water;
Separating and discharging the pressurized seawater into filtered water and concentrated water;
Collecting solar heat;
Generating fresh water by generating steam from the concentrated water using the solar heat; And
Mixing the filtered water with the fresh water produced by evaporation of the concentrated water;
Containing
How to remove boron for seawater desalination. The method of claim 5,
Electrolytically decomposing the concentrated water to produce sodium hypochlorite
How to remove boron for seawater desalination. The method of claim 5,
And recovering the pressure and flow rate of the concentrated water and reusing the pressure of the seawater.
How to remove boron for seawater desalination. Evaporation and recovery of seawater by solar heat collected by a solar collector plate to produce fresh water without boron
How to remove boron for seawater desalination.

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