KR101778021B1 - Eco-friendly desalination system using forward osmosis and reverse osmosis - Google Patents

Eco-friendly desalination system using forward osmosis and reverse osmosis Download PDF

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KR101778021B1
KR101778021B1 KR1020160023311A KR20160023311A KR101778021B1 KR 101778021 B1 KR101778021 B1 KR 101778021B1 KR 1020160023311 A KR1020160023311 A KR 1020160023311A KR 20160023311 A KR20160023311 A KR 20160023311A KR 101778021 B1 KR101778021 B1 KR 101778021B1
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reverse osmosis
concentrated water
water
seawater
pressure
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KR20170100882A (en
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김윤중
이은수
김관엽
남해욱
이상호
윤희철
이병준
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주식회사 포스코
재단법인 포항산업과학연구원
주식회사 포스코건설
철강융합신기술연구조합
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/002—Forward osmosis or direct osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/06—Energy recovery
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/08—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/10—Accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/445—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by forward osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/05—Conductivity or salinity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/138—Water desalination using renewable energy
    • Y02A20/144—Wave energy

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environmentally friendly desalination system using positive osmosis and reverse osmosis, and more particularly to an eco-friendly desalination system using a pressurizing pump for pressurizing seawater inflow water. A first reverse osmosis module for receiving seawater inflow water pressurized by the pressurizing pump and discharging fresh water and seawater concentrated water; A second reverse osmosis module for receiving the seawater concentrated water discharged from the first reverse osmosis module and discharging fresh water and seawater concentrated water; A first energy recovery device for reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy; A pressure delayed osmosis module for supplying decompressed seawater concentrate water to the active layer side and supplying wastewater to the support layer to discharge diluted seawater concentrated water and waste water concentrated water; A second energy recovery device for delivering the pressure of the diluted seawater concentrated water discharged from the pressure delay osmosis module to the waste water concentrated water; A third reverse osmosis module that receives the wastewater concentrated water pressurized by the second energy recovery device and discharges fresh water and wastewater concentrated water; And a positive osmosis module for receiving the diluted seawater concentrated water through the second waste water concentrated water discharged from the third reverse osmosis module and the second energy recovery device to discharge the diluted seawater concentrated water and the waste water concentrated water, An eco-friendly desalination apparatus using osmosis and reverse osmosis, and an eco-friendly desalination method to which such apparatus can be applied.

Figure R1020160023311

Description

TECHNICAL FIELD [0001] The present invention relates to an eco-friendly desalination system using positive osmosis and reverse osmosis (ECO-FRIENDLY DESALINATION SYSTEM USING FORWARD OSMOSIS AND REVERSE OSMOSIS)

The present invention relates to an eco-friendly desalination system using positive osmosis and reverse osmosis, and more particularly, to a system for reducing the volume of wastewater by treating the wastewater with a positive osmosis method using the chemical potential of concentrated water of a reverse osmosis process, To reduce the salinity of the water, thereby producing water of suitable quality for discharge.

Recently, water shortages and wastewater treatment in industrial complexes have been pointed out as serious problems. Power plants, steel mills, and petrochemical complexes require a large amount of industrial water. Recently, due to the increase in climate change and water demand, existing water resources are increasingly unable to meet the demand for industrial water.

In addition, in such an industrial complex, a large amount of wastewater is inevitably generated. In the case where the amount of wastewater generated is large, the treatment cost for treating the wastewater is high, and in many cases, it is difficult to satisfy the water quality standards of the effluent water .

Conventional methods to cope with such shortage of industrial water include reusing wastewater generated in an industrial complex by advanced treatment techniques such as membrane bioreactor or reverse osmosis and desalination of previously unused water resources such as seawater and water And a method of utilizing the information by using the technology have been proposed.

However, reuse of wastewater and desalination of seawater / nautical water not only require a lot of energy costs but also cause problems such as membrane contamination and increased maintenance costs. Reverse osmosis membranes for wastewater treatment often require frequent cleaning and replacement due to frequent membrane contamination. Higher energy than 4 kWh / m 3 is required for desalination. There was a problem that was difficult to cope with. In addition, the concentrated water that necessarily occurs in the desalination process has a relatively high salinity, which may cause additional problems when discharging to a nearby sea area.

Therefore, by using the chemical potential of the concentrated water of the reverse osmosis process, the wastewater generated in the industrial complex can be treated by the positive osmosis method to reduce the volume, and the salt concentration of the reverse osmosis concentrated water can be lowered, When desalination technology is developed, it is expected to be widely applied in related fields.

Accordingly, one aspect of the present invention is to provide an environmentally friendly desalination apparatus by reverse osmosis-positive osmosis fusion.

Another aspect of the present invention is to provide an eco-friendly desalination method by reverse osmosis-positive osmosis fusion.

According to one aspect of the present invention, a pressurizing pump for pressurizing seawater inflow water; A first reverse osmosis module for receiving seawater inflow water pressurized by the pressurizing pump and discharging fresh water and seawater concentrated water; A second reverse osmosis module for receiving the seawater concentrated water discharged from the first reverse osmosis module and discharging fresh water and seawater concentrated water; A first energy recovery device for reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy; A pressure delayed osmosis module for supplying decompressed seawater concentrate water to the active layer side and supplying wastewater to the support layer to discharge diluted seawater concentrated water and waste water concentrated water; A second energy recovery device for delivering the pressure of the diluted seawater concentrated water discharged from the pressure delay osmosis module to the waste water concentrated water; A third reverse osmosis module that receives the wastewater concentrated water pressurized by the second energy recovery device and discharges fresh water and wastewater concentrated water; And a positive osmosis module for receiving the diluted seawater concentrated water through the second waste water concentrated water discharged from the third reverse osmosis module and the second energy recovery device to discharge the diluted seawater concentrated water and the waste water concentrated water, An environmentally friendly desalination apparatus using osmosis and reverse osmosis is provided.

According to another aspect of the present invention, there is provided a method for recovering freshwater, comprising: a first reverse osmosis step of pressurizing seawater inflow water to supply it to a first reverse osmosis module to obtain fresh water and seawater concentrated water; A second reverse osmosis step of supplying the seawater concentrated water obtained in the first reverse osmosis step to the second reverse osmosis module to obtain fresh water and seawater concentrated water; A first energy recovery step of reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy; A pressure delayed osmosis step of supplying decompressed seawater concentrated water to the active layer side of the pressure delay osmosis module and supplying wastewater to the support layer of the pressure delay osmosis module to obtain diluted seawater concentrated water and wastewater concentrated water; A second energy recovery step of delivering the pressure of the diluted seawater concentrated water obtained in the pressure delayed osmosis step to the waste water concentrated water; A third reverse osmosis step of supplying wastewater concentrated water pressurized by the second energy recovery step to the third reverse osmosis module to obtain fresh water and wastewater concentrated water; And supplying the diluted seawater concentrated water obtained in the second energy recovery step to the normal osmosis module to obtain further diluted seawater concentrated water and waste water concentrated water A method of eco-desalination using reverse osmosis is provided.

According to the eco-friendly desalination system using the positive osmosis and reverse osmosis according to the present invention, the wastewater generated in the industrial complex is subjected to the positive osmosis treatment using the chemical potential possessed by the reverse osmosis process of seawater desalination, And it is possible to control the salinity concentration of the reverse osmosis concentrated water generated from seawater desalination so as to be suitable for discharge and to solve the problem of membrane contamination which may occur in the industrial wastewater treatment by the positive osmosis treatment, By using reverse osmosis concentrated water having an osmotic pressure as an inducing solution, it is possible to improve more economical efficiency by improving more positive osmosis flux. Further, the industrial wastewater can be additionally obtained by reverse osmosis treatment after the positive osmosis treatment and high-quality industrial water.

FIG. 1 schematically illustrates an exemplary environmentally friendly desalination system using positive osmosis and reverse osmosis of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

According to the present invention, there is provided an eco-friendly desalination system for producing wastewater of a water quality suitable for discharge by reducing the volume of the waste water by using the chemical potential of the concentrated water of the reverse osmosis process and by reducing the volume of the reverse osmosis- / RTI >

An eco-friendly desalination apparatus using positive osmosis and reverse osmosis according to the present invention comprises a pressurizing pump for pressurizing seawater inflow water; A first reverse osmosis module for receiving seawater inflow water pressurized by the pressurizing pump and discharging fresh water and seawater concentrated water; A second reverse osmosis module for receiving the seawater concentrated water discharged from the first reverse osmosis module and discharging fresh water and seawater concentrated water; A first energy recovery device for reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy; The pressure-reduced seawater concentrated water is supplied to the active layer side, the wastewater is supplied to the support layer side, and the diluted seawater concentrated water and the wastewater concentrated water are discharged; A second energy recovery device for delivering the pressure of the diluted seawater concentrated water discharged from the pressure delay osmosis module to the waste water concentrated water; A third reverse osmosis module that receives the wastewater concentrated water pressurized by the second energy recovery device and discharges fresh water and wastewater concentrated water; And a positive osmosis module for receiving the diluted seawater concentrated water that has been passed through the third reverse osmosis module and the second energy recovery device to discharge additional diluted seawater concentrated water and waste water concentrated water .

FIG. 1 schematically illustrates an environmentally friendly desalination system using positive osmosis and reverse osmosis according to the present invention. Referring to FIG. 1, a seawater inflow water 11 is pressurized by a pressurizing pump 31, The fresh water 15 is processed through the second reverse osmosis module 21 and the second reverse osmosis module 22 and the produced fresh water 15 can be supplied to the final treated water transfer facility.

At this time, the concentrated water obtained from the second reverse osmosis module passes part of the energy to the pressure pump 31 through the first energy recovery device 42, and then is supplied to the pressure delay osmosis module 23. The wastewater 12 is supplied to the support layer of the pressure delay osmosis module 23 and a portion of the wastewater is moved toward the seawater concentrate water by the pressure delay osmosis membrane module 23 due to the osmotic pressure difference to dilute the seawater.

At this time, the diluted seawater concentrated water in the pressure delay osmosis module 23 passes through the second energy recovery device 41 to supply the pressure to the wastewater concentrated water, and then to the osmosis membrane module 24. Therefore, the wastewater concentrated water coming from the pressure delay osmosis module 23 has a high pressure, and this pressure can be used to drive the reverse osmosis module 25.

As a result, the reverse osmosis module 25 for wastewater treatment can be operated by the chemical potential (osmotic pressure) of seawater concentrated water without additional pump or energy supply to produce treated water (fresh water). The treated water (fresh water, 15) thus produced can be supplied to the industrial water via the final treated water transfer facility.

On the other hand, the diluted seawater concentrated water after the pressure is delivered is further diluted in the positive osmosis membrane module 24, where the concentrated water of the reverse osmosis membrane module 25 is used as the supply water for the osmosis, . Finally, the diluted seawater concentrated water 13 may be sent to the concentrated water discharge facility, and the concentrated wastewater may be transferred to the waste water concentrated water 14 discharge facility and finally treated at the wastewater treatment plant.

The reverse osmosis pressure pump 31 of the present invention is preferably a high pressure pump, and the high pressure means a pressure of 25 atm or higher and 85 atm or lower, which is generally used in the seawater desalination process.

*

In the present invention, the pressure-delayed osmosis module 23 moves pollutants in the wastewater supplied from the wastewater inflow water 12 to the surface of the membrane to form a reversible cake layer on the membrane surface, And can serve to mitigate film contamination in the module 25.

On the other hand, the forward osmosis module 24 reduces the volume of the wastewater by reducing the osmotic pressure difference between the diluted seawater concentrated water and the wastewater concentrated water supplied thereto, and at the same time, decreasing the salt concentration of the seawater concentrated water, Drain water can be obtained.

Furthermore, the eco-friendly desalination apparatus of the present invention may further include an apparatus for measuring the conductivity of seawater inflow water on the upstream side of the first reverse osmosis module. The conductivity measuring apparatus can measure the salt concentration of the seawater influent water to adjust the recovery rate in the second reverse osmosis step, and the recovery rate (Re 2 ) in the second reverse osmosis step can be calculated from the following equation (1) .

*

Figure 112016019141850-pat00001
... (1)

In the above formula (1), the values of a1 to d1 and the definition of CD are as follows:

a1: 8.01 10 -11

b1: -50.64580519

c1: 112.4839503

d1: 2.558 10 -6

CD: Conductivity of seawater (μS / cm)

Meanwhile, T is the inlet water temperature, P 1 is the first reverse osmosis operating pressure of the process (bar), P 2, max is the second reverse maximum working pressure (bar), P NDP of the booster pump of the projection step is a reverse osmosis process Pure operating pressure (bar), Re 1 represents the first reverse osmosis recovery rate, and Re 2 represents the second reverse osmosis recovery rate.

The influent water temperature (T, 占 폚) is not particularly limited, but is preferably 0 to 100 占 폚, more preferably 0 to less than 100 占 폚, and more preferably 0 to 50 占 폚.

The operating pressure (P 1 , bar) of the first reverse osmosis process is preferably 20 to 80 bar, more preferably 30 to 70 bar. When the operating pressure of the first reverse osmosis process is less than 20 bar, the osmotic pressure of the seawater is lower than the osmotic pressure of the seawater, so that water is difficult to be discharged from the rear end. If the operating pressure is more than 80 bar, have.

The maximum operating pressure (P 2, max , bar) of the booster pump in the second reverse osmosis process is preferably 10 to 40 bar, more preferably 20 to 30 bar. At this time, when the maximum operating pressure of the booster pump of the second reverse osmosis process is less than 10 bar, water is difficult to be discharged from the downstream end, and when it exceeds 40 bar, the pressure is excessively applied, .

The pure working pressure (P NDP ) of the reverse osmosis process is preferably 2 to 15 bar, more preferably 5 to 10 bar. At this time, when the pure operation pressure of the reverse osmosis process is less than 2 bar, water is difficult to be discharged at the downstream end, and when it exceeds 15 bar, the operation flux excessively increases and fouling can be accelerated.

On the other hand, the first reverse osmosis recovery rate (Re 1 ) is preferably from 20% to 50%, that is, from 0.2 to 0.5, and when the recovery rate is less than 20%, the process economy is deteriorated. The consumption of energy required for the process is further increased, which is undesirable for the process economy.

For example, if the electrical conductivity is 50,000 μS / cm, the recovery rate of the first reverse osmosis process is 40% (ie 0.4), the operating pressure of the first reverse osmosis process is 60 bar, the influent water temperature is 25 ° C., Assuming that the operating pressure is 5 bar and the maximum operating pressure of the second reverse osmosis booster pump is 20 bar, the recovery rate of the second reverse osmosis process may be determined to be 47.6% (ie, 0.476) or less in the above equation.

That is, the conductivity measuring device 51 thus added determines the recovery rate of the second reverse osmosis membrane module 22 in the range as described above in consideration of the maximum operating pressure of the booster pump 32 in accordance with the salt concentration of the incoming seawater. It is desirable to be able to automatically adjust the temperature to within a predetermined range.

Preferably, the first energy recovery device reduces the pressure of 50 to 70%, preferably 50 to 60% of the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module. This is because in order to obtain the maximum energy production in the pressure delay osmosis, it is necessary to operate at a pressure equivalent to 50% of the osmotic pressure of the incoming seawater concentrated water. For example, if the concentrated water pressure in the first reverse osmosis process is 60 bar and the osmotic pressure is 54 bar, the first energy recovery device collects the pressure of 33 bar (about 55%) and delivers it to the first high- Condensate with a pressure of 28 bar must be sent through pressure delayed osmosis. Accordingly, when the pressure of the seawater concentrate is reduced by 50 to 70%, a pressure corresponding to 50% of the osmotic pressure can be obtained. This pressure is transmitted through the pressure delay osmosis to generate additional energy.

The turbocharger-type energy recovery device 42 is preferably a turbocharger-type energy recovery device, and the turbocharger-type energy recovery device 42 may be a concentrator It is possible to recover only about 50% of the pressure of the water and to supply the seawater concentrated water whose pressure is reduced to about 1/2 to the pressure delayed osmosis module 23.

Meanwhile, it is preferable that the second energy recovery device collects about 100% of the diluted seawater concentrate pressure discharged from the pressure delay osmosis module and delivers it to the wastewater concentrated water. Preferably, the second energy recovery device recovers at least 90% of the diluted seawater concentrate pressure discharged from the pressure delay osmosis module, more preferably 100%.

The second energy recovery device that can be used at this time is preferably a positive energy recovery device. The volumetric energy recovery device 41 recovers 90 to 100% of the pressure of the diluted seawater produced from the pressure-delayed osmosis membrane module 23 and transfers it to the wastewater concentrated water coming from the pressure delay osmosis module, The reverse osmosis membrane module 25 can be operated without an additional high-pressure pump.

1, the second energy recovery device 41 is a volumetric energy recovery device in which the water supplied to the upper left side flows to the lower left side, the water flowing to the upper right side flows to the lower right side, Are not mixed with each other, only the pressure is transmitted. Therefore, the diluted seawater concentrate coming to the upper right is lowered to the atmospheric pressure when it is discharged to the lower right, and the wastewater concentrated water coming into the upper left has atmospheric pressure at the inflow, but when discharged to the lower left, I have.

According to the present invention, the wastewater is discharged from the industrial wastewater discharged from at least one process selected from the group consisting of a power generation process, a steel manufacturing process, a petrochemical process, a leather production process, a paper manufacturing process, a fiber chemical process, But the present invention is not particularly limited thereto, and it is possible to remove the solid matter from various wastewater discharged from various industrial fields.

As described above, according to the present invention, the wastewater generated in the industrial complex is treated by the positive osmosis method using the chemical potential of the concentrated water of the reverse osmosis process, thereby reducing the volume and reducing the salt concentration of the reverse osmosis concentrated water. You can acquire water.

According to another aspect of the present invention, there is provided an environmentally friendly desalination method using the forward osmosis and reverse osmosis to which the desalination apparatus as described above can be applied. The eco-friendly desalination method using positive osmosis and reverse osmosis according to the present invention comprises: a first reverse osmosis step of pressurizing seawater inflow water and supplying it to a first reverse osmosis module to obtain fresh water and sea water concentrated water; A second reverse osmosis step of supplying the seawater concentrated water obtained in the first reverse osmosis step to the second reverse osmosis module to obtain fresh water and seawater concentrated water; A first energy recovery step of reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy; A pressure delayed osmosis step of supplying decompressed seawater concentrated water to the active layer side of the pressure delay osmosis module and supplying wastewater to the support layer of the pressure delay osmosis module to obtain diluted seawater concentrated water and wastewater concentrated water; A second energy recovery step of delivering the pressure of the diluted seawater concentrated water obtained in the pressure delayed osmosis step to the waste water concentrated water; A third reverse osmosis step of supplying wastewater concentrated water pressurized by the second energy recovery step to the third reverse osmosis module to obtain fresh water and wastewater concentrated water; And supplying the diluted seawater concentrated water obtained in the second energy recovery step to the normal osmosis module to obtain further diluted seawater concentrated water and waste water concentrated water .

Further, the desalination step of the present invention may further include the step of adjusting the recovery rate in the second reverse osmosis step by measuring the salt concentration of the seawater influent water, and the recovery rate of the second reverse osmosis step is expressed by the equation ).

That is, the salinity concentration can be measured by the conductivity measuring device 51, and the type of the conductivity measuring device is not particularly limited. At this time, the conductivity measuring device can automatically adjust the recovery rate of the second reverse osmosis membrane module 22 within the above-mentioned range in consideration of the maximum operating pressure of the booster pump 32 according to the salt concentration of the incoming seawater Is preferably used.

The first energy recovery step may reduce the pressure of 30 to 50% of the pressure applied to the seawater concentrated water obtained from the second reverse osmosis step. This is because in order to obtain the maximum energy production in the pressure delay osmosis, it is necessary to operate at a pressure equivalent to 50% of the osmotic pressure of the incoming seawater concentrated water. That is, when the pressure of the seawater concentrated water is reduced by 50 to 70%, a pressure corresponding to 50% of the osmotic pressure can be obtained, and this pressure is transmitted through the pressure delay osmosis to generate additional energy.

The turbocharger-type energy recovery device 42 is preferably a turbocharger-type energy recovery device, and the turbocharger-type energy recovery device 42 may be a concentrator It is possible to recover only about 50% of the pressure of the water and to supply the seawater concentrated water whose pressure is reduced to about 1/2 to the pressure delayed osmosis module 23.

Meanwhile, in the second energy recovery step, about 100% of the diluted seawater concentrate pressure discharged from the pressure delay osmosis module is collected and transferred to the wastewater concentrated water. Preferably, the second energy recovery step recovers at least 90% of the diluted seawater concentrate pressure discharged from the pressure delay osmosis module, more preferably 100% of the pressure.

The second energy recovery device that can be used at this time is preferably a positive energy recovery device. The volumetric energy recovery device 41 recovers 100% of the pressure of the diluted seawater produced from the pressure-delayed osmosis membrane module 23 and transfers it to the wastewater concentrated water coming from the pressure delay osmosis module, The membrane module 25 can be operated without an additional high-pressure pump.

According to the present invention, the wastewater is discharged from the industrial wastewater discharged from at least one process selected from the group consisting of a power generation process, a steel manufacturing process, a petrochemical process, a leather production process, a paper manufacturing process, a fiber chemical process, But the present invention is not particularly limited thereto, and it is possible to remove the solid matter from various wastewater discharged from various industrial fields.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

The desalination system of the present invention as shown in FIG. 1 was operated in a steel plant where 2000 m 3 / day of water was used and 2000 m 3 / day of wastewater was generated, and the results were as follows.

- Seawater intake: 25,000 m 3 / day, TDS = 30,000 mg / L

- Water production by seawater desalination by two-stage reverse osmosis: 1500 m 3 / day

- Reverse osmosis concentrated water generation rate: 1000 m 3 / day, TDS = 75,000 mg / L

- Wastewater flow rate supplied to pressure delay osmosis: 1000 m 3 / day

- Pressure generation due to pressure delay osmosis: 23 bar

- diluted seawater concentrate concentration by pressure delay osmosis: 50,000 mg / L

- Wastewater treated by pressure delayed osmosis: 500 m 3 / day

- wastewater further treated by additional reverse osmosis: 1050 m 3 / day

- Wastewater finally enriched by positive osmosis: 180 m 3 / day

- Final dilution of seawater by cleansing: 1770 m 3 / day, TDS = 42,300 mg / L

Based on the above results, it was confirmed that when the water reducing system of the present invention is applied, the amount of wastewater generated is reduced by 91%, and the salt concentration of seawater is reduced to 56%, which is suitable for discharge.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

11: Seawater influent
12: Reuse (wastewater) Influent
13: Seawater concentrate
14: Concentrated wastewater
15: Fresh water (treated water)
21: First reverse osmosis module
22: Second reverse osmosis module
23: Pressure Delay Osmosis Module
24: Forward Osmosis Module
25: Third reverse osmosis membrane module
31: Reverse osmosis pressure pump
32: Booster pump
41: Second (volumetric) energy recovery device
42: 1st (turbocharger type) energy recovery device
51: Conductivity measuring device

Claims (15)

A pressurizing pump for pressurizing seawater inflow water;
A first reverse osmosis module for receiving seawater inflow water pressurized by the pressurizing pump and discharging fresh water and seawater concentrated water;
A second reverse osmosis module for receiving the seawater concentrated water discharged from the first reverse osmosis module and discharging fresh water and seawater concentrated water;
A first energy recovery device for reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy;
A pressure delayed osmosis module for supplying decompressed seawater concentrate water to the active layer side and supplying wastewater to the support layer to discharge diluted seawater concentrated water and waste water concentrated water;
A second energy recovery device for delivering the pressure of the diluted seawater concentrated water discharged from the pressure delay osmosis module to the waste water concentrated water;
A third reverse osmosis module that receives the wastewater concentrated water pressurized by the second energy recovery device and discharges fresh water and wastewater concentrated water;
A forward osmosis module for receiving diluted wastewater concentrated water discharged from the third reverse osmosis module and diluted wastewater concentrated water passed through a second energy recovery unit to discharge further diluted seawater concentrated water and wastewater concentrated water; And
And a device for measuring the conductivity of seawater inflow water in front of the first reverse osmosis module,
The device for measuring the conductivity is an eco-friendly desalination apparatus using positive osmosis and reverse osmosis, which measures the salinity of a seawater influent water by electric conductivity and regulates the recovery rate of the second reverse osmosis module by using the following equation (1)
Figure 112017077705648-pat00004
... (1)
In the formula (1), CD is the conductivity (μS / cm) of seawater, a1 is 8.01 × 10 -11 , b1 is -50.64580519, c1 is 112.4839503 and d1 is 2.558 × 10 -6 ,
The T (℃) the inlet water temperature, the P 1 (bar) is the first operating pressure of the reverse osmosis step, the P 2, max (bar) is the maximum operating pressure of the booster pump of the second reverse osmosis step, the P NDP (bar) is the pure working pressure P NDP (bar) of the reverse osmosis process, and Re 1 is the first reverse osmosis recovery rate.
delete The eco-friendly desalination apparatus according to claim 1, wherein the first energy recovery device reduces the pressure of 50% to 70% of the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module.
The eco-friendly desalination apparatus according to claim 1, wherein the first energy recovery apparatus is a turbocharger (TC) energy recovery apparatus.
The eco-friendly desalination apparatus according to claim 1, wherein the second energy recovery device recovers 100% of the diluted seawater concentrate water pressure discharged from the pressure delay osmosis module and transfers it to the wastewater concentrated water.
The eco-friendly desalination apparatus according to claim 1, wherein the second energy recovery apparatus is a volumetric energy recovery apparatus.
The method of claim 1, wherein the wastewater is discharged from an industrial wastewater discharged from at least one process selected from the group consisting of a power generation process, a steel manufacturing process, a petrochemical process, a leather production process, a paper manufacturing process, Which is a wastewater from which ozone is removed.
A first reverse osmosis step of pressurizing the seawater inflow water and supplying it to the first reverse osmosis module to obtain fresh water and seawater concentrated water;
A second reverse osmosis step of supplying the seawater concentrated water obtained in the first reverse osmosis step to the second reverse osmosis module to obtain fresh water and seawater concentrated water;
A first energy recovery step of reducing the pressure applied to the seawater concentrated water discharged from the second reverse osmosis module to recover energy;
A pressure delayed osmosis step of supplying decompressed seawater concentrated water to the active layer side of the pressure delay osmosis module and supplying wastewater to the support layer of the pressure delay osmosis module to obtain diluted seawater concentrated water and wastewater concentrated water;
A second energy recovery step of delivering the pressure of the diluted seawater concentrated water obtained in the pressure delayed osmosis step to the waste water concentrated water;
A third reverse osmosis step of supplying wastewater concentrated water pressurized by the second energy recovery step to the third reverse osmosis module to obtain fresh water and wastewater concentrated water;
Supplying wastewater concentrated water obtained in the third reverse osmosis step and diluted seawater concentrated water obtained in the second energy recovery step to a normal osmosis module to obtain further diluted seawater concentrated water and wastewater concentrated water; And
Measuring the salinity concentration of the seawater influent using electrical conductivity and adjusting the recovery rate in the second reverse osmosis step using the following equation (1): eco-desalination method using positive osmosis and reverse osmosis:
Figure 112017077705648-pat00005
... (1)
In the formula (1), CD is the conductivity (μS / cm) of seawater, a1 is 8.01 × 10 -11 , b1 is -50.64580519, c1 is 112.4839503 and d1 is 2.558 × 10 -6 ,
The T (℃) the inlet water temperature, the P 1 (bar) is the first operating pressure of the reverse osmosis step, the P 2, max (bar) is the maximum operating pressure of the booster pump of the second reverse osmosis step, the P NDP (bar) is the pure working pressure P NDP (bar) of the reverse osmosis process, and Re 1 is the first reverse osmosis recovery rate.
delete 9. The method of claim 8,
The inflow water temperature T (占 폚) is more than 0 占 폚 and less than 100 占 폚,
The operating pressure P 1 (bar) of the first reverse osmosis process is 20 to 80 bar,
The maximum operating pressure P 2, max (bar) of the booster pump in the second reverse osmosis process is 10 to 80 bar,
The pure working pressure P NDP (bar) of the reverse osmosis process is 2 to 15 bar,
Wherein the first reverse osmosis recovery rate Re 1 is 0.2 to 0.5.
The eco-friendly desalination method according to claim 8, wherein the first energy recovery step reduces 50% of the pressure applied to the seawater concentrated water obtained from the second reverse osmosis step.
The eco-friendly desalination method of claim 8, wherein the first energy recovery step is performed by a turbocharger (TC) energy recovery device.
The eco-friendly desalination method of claim 8, wherein the second energy recovery step recovers 100% of the diluted seawater concentrate water pressure discharged from the pressure delay osmosis step and transfers it to the wastewater concentrated water.
The method of claim 8, wherein the second energy recovery step is performed by a volumetric energy recovery device.
The method of claim 8, wherein the wastewater is a solid from industrial wastewater discharged from at least one process selected from the group consisting of a power generation process, a steel manufacturing process, a petrochemical process, a leather production process, a paper manufacturing process, Which is a wastewater from which the water is removed.
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