KR101778022B1 - Closed type desalination system using forward osmosis and reverse osmosis - Google Patents

Closed type desalination system using forward osmosis and reverse osmosis Download PDF

Info

Publication number
KR101778022B1
KR101778022B1 KR1020160023267A KR20160023267A KR101778022B1 KR 101778022 B1 KR101778022 B1 KR 101778022B1 KR 1020160023267 A KR1020160023267 A KR 1020160023267A KR 20160023267 A KR20160023267 A KR 20160023267A KR 101778022 B1 KR101778022 B1 KR 101778022B1
Authority
KR
South Korea
Prior art keywords
osmosis module
water
seawater
reverse osmosis
module
Prior art date
Application number
KR1020160023267A
Other languages
Korean (ko)
Other versions
KR20170100864A (en
Inventor
이은수
김관엽
김윤중
남해욱
이상호
윤희철
이병준
Original Assignee
주식회사 포스코
재단법인 포항산업과학연구원
주식회사 포스코건설
철강융합신기술연구조합
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 포스코, 재단법인 포항산업과학연구원, 주식회사 포스코건설, 철강융합신기술연구조합 filed Critical 주식회사 포스코
Priority to KR1020160023267A priority Critical patent/KR101778022B1/en
Publication of KR20170100864A publication Critical patent/KR20170100864A/en
Application granted granted Critical
Publication of KR101778022B1 publication Critical patent/KR101778022B1/en

Links

Images

Classifications

    • 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
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/08—Prevention of membrane fouling or of concentration polarisation
    • 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
    • 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
    • C02F2209/40—Liquid flow rate
    • 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

Abstract

The present invention relates to a closed circulation type desalination system using positive osmosis and reverse osmosis, and more particularly to a positive osmosis module for receiving seawater inflow water and reused inflow water to dilute seawater. A circulation pump for returning the concentrated water discharged from the forward osmosis module to the reuse inflow water of the positive osmosis module to form closed circulation; A discharge valve for discharging the concentrated water discharged from the forward osmosis module to stop the inflow of the reclaimed inflow water by closed circulation and to introduce new reclaimed inflow water to operate in batch mode; A pressurized reverse osmosis module that receives the diluted seawater discharged from the forward osmosis module and discharges fresh water and seawater concentrated water; An energy recovery device for reducing the pressure applied to the seawater concentrated water to recover energy; A conductivity measuring device for measuring the conductivity of each of the seawater influent, the concentrated water discharged from the positive osmosis module, and the diluted sea water discharged from the positive osmosis module; And a flux measuring device for diluted seawater discharged from the forward osmosis module, and a desalination method using the same.

Description

CLOSED TYPE DESALINATION SYSTEM USING FORWARD OSMOSIS AND REVERSE OSMOSIS BACKGROUND OF THE INVENTION [0001]

The present invention relates to a closed circulation type desalination system using positive osmosis and reverse osmosis, and more particularly, to a closed circulation type desalination system using purified osmosis and reverse osmosis, The present invention relates to a desalination system capable of freely adjusting the recovery rate and the operation cycle of a forward osmosis process.

As the global water shortage is worsening, efforts are being made to secure new water resources instead of relying on existing surface water and groundwater. Among them, desalination of seawater is attracting attention as an alternative to solve the problem of water shortage by removing seawater from seawater existing in large quantities on the earth as an influent and then making it into fresh water. In addition, reuse of sewage that reuses used water has attracted attention as a way to secure additional water resources.

However, seawater desalination is a water treatment process that consumes a lot of energy compared to other methods of securing water resources, and thus has a disadvantage that the production cost of water is relatively high. For seawater desalination, evaporation method and reverse osmosis method are mainly used. For evaporation method, 15 ~ 20 kWh / m 3 and reverse osmosis method requires about 3.5 ~ 5.5 kWh / m 3 energy. Although the energy cost of seawater desalination has been lowered constantly due to the optimization of the process, it is difficult to expect any further energy savings because it is close to the thermodynamic limit in recent years.

On the other hand, sewage reuse requires less energy than seawater desalination and is generally known to be less than 50% of reverse osmosis seawater desalination. Micro-filtration, ultrafiltration, and reverse osmosis are used for sewage reuse. Compared with seawater desalination, the influent of sewage reuse has low osmotic pressure due to low salinity. Therefore, reverse osmosis membranes used at this time use BWRO different from SWRO used for seawater desalination and operate at relatively low operating pressure. However, in sewage reuse, the performance of the BWRO membrane is deteriorated due to membrane contamination, so that the cost of producing water gradually increases, and the membrane must be frequently cleaned or replaced.

Recently, a method to combine reverse osmosis with reverse osmosis has been devised as a method to overcome the problems of reverse osmosis process used in sewage reuse and seawater desalination. Unlike reverse osmosis, pure osmosis is a process driven by a difference in osmotic pressure, which has the advantage of low energy consumption by itself. However, since the reverse osmosis membrane has a relatively low ion removal rate and recovery rate than that of the reverse osmosis membrane, a method for complementing the reverse osmosis membrane is required. In the conventional method, advanced nanomaterials for improving the performance of the positive osmosis membrane have been studied. However, since it takes much time to commercialize them, a new process for solving the drawbacks is required in the conventional osmosis membrane.

Therefore, when a water treatment technique capable of solving such problems is provided, it is expected to be widely applicable in related fields.

Accordingly, one aspect of the present invention is to provide a combined water treatment apparatus capable of reducing energy and suppressing membrane contamination by combining a closed circulation type forward osmosis process and a reverse osmosis process.

Another aspect of the present invention is an efficient water treatment process in which the purified osmosis process is performed in a batch circulation manner and the water produced by the osmosis treatment is sequentially treated by low pressure reverse osmosis and high pressure reverse osmosis .

According to one aspect of the present invention, there is provided an osmosis module comprising: a forward osmosis module for receiving seawater inflow water and reuse inflow water to dilute seawater; A circulation pump for returning the concentrated water discharged from the forward osmosis module to the reuse inflow water of the positive osmosis module to form closed circulation; A discharge valve for discharging the concentrated water discharged from the forward osmosis module to stop the inflow of the reclaimed inflow water by closed circulation and to introduce new reclaimed inflow water to operate in batch mode; A pressurized reverse osmosis module that receives the diluted seawater discharged from the forward osmosis module and discharges fresh water and seawater concentrated water; An energy recovery device for reducing the pressure applied to the seawater concentrated water to recover energy; A conductivity measuring device for measuring the conductivity of each of the seawater influent, the concentrated water discharged from the positive osmosis module, and the diluted sea water discharged from the positive osmosis module; And a flux measuring device for the diluted seawater discharged from the positive osmosis module. The closed circulation type desalination device using positive osmosis and reverse osmosis is provided.

According to another aspect of the present invention, there is provided a method comprising: supplying seawater influent and re-inflow water to a positive osmosis module to obtain concentrated water and diluted seawater; Supplying the concentrated water discharged from the forward osmosis module to the reuse inflow water of the forward osmosis module by using a circulation pump and circulating the concentrated water through the circulation pump; A step of stopping the inflow of the reuse inflow water by the closed circulation and opening the discharge valve to introduce the new reuse inflow water, and discharging the concentrated water discharged from the forward osmosis module; Supplying diluted seawater discharged from the forward osmosis module to a pressurized reverse osmosis module to discharge fresh water and seawater concentrated water; And recovering the energy by reducing the pressure applied to the seawater concentrated water, wherein the discharge valve is opened when the at least two of the following formulas (1) to (3) are satisfied: positive osmosis and reverse osmosis There is provided a closed circulating desalination method using:

J / Ji < 0.8 (1)

Cr / Cs > 0.05 (2)

CF > 0.4 ... (3)

(Where J is the flux value at time t of the positive osmosis membrane in the forward osmosis module, Ji is the initial flux value of the positive osmosis membrane in the forward osmosis module,

In the equation (2), Cs is the conductivity value of the seawater influent, Cr is the conductivity value of the concentrated water discharged from the forward osmosis module,

In the formula (3), CF is an enrichment factor, the enrichment factor CF is represented by the following formula (4)

Figure 112016019117369-pat00001
... (4)

Where A is the area of the quasi-osmosis membrane and V is the area of the total volume in the positive osmotic loop, ie, the sum of the piping volume and the volume of the space within the membrane module.

The closed circulation type desalination system using the positive osmosis and reverse osmosis according to the present invention can operate the closed osmosis process in a closed circulation type and a batch mode to suppress the biofilm contamination that may occur due to the long term stay of the reuse inflow water. In addition, the recovery rate and the operation period of the positive osmosis process can be freely adjusted, so that it is possible to flexibly cope with the change in the osmosis flux according to the state change of each of the membrane and the influent water. Further, And so on, so that the membrane contamination can be suppressed continuously. On the other hand, the energy consumption can be reduced by first treating the diluted seawater with low-pressure reverse osmosis and then treating with high-pressure reverse osmosis.

Figure 1 schematically illustrates the construction of an exemplary desalination system of the present invention.
Figure 2 schematically illustrates the flow of an exemplary desalination system 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, a desalination system capable of restraining biofilm contamination that may occur due to long-term retention of reuse inflow water by operating the forward osmosis process in a closed circulation system and a batch system, and freely adjusting the recovery rate and operation cycle of the osmosis process / RTI &gt;

More specifically, the closed circulation type desalination apparatus using positive osmosis and reverse osmosis according to the present invention comprises a forward osmosis module for receiving seawater inflow water and reuse inflow water to dilute seawater; A circulation pump for returning the concentrated water discharged from the forward osmosis module to the reuse inflow water of the positive osmosis module to form closed circulation; A discharge valve for discharging the concentrated water discharged from the forward osmosis module to stop the inflow of the reclaimed inflow water by closed circulation and to introduce new reclaimed inflow water to operate in batch mode; A pressurized reverse osmosis module that receives the diluted seawater discharged from the forward osmosis module and discharges fresh water and seawater concentrated water; An energy recovery device for reducing the pressure applied to the seawater concentrated water to recover energy; A conductivity measuring device for measuring the conductivity of each of the seawater influent, the concentrated water discharged from the positive osmosis module, and the diluted sea water discharged from the positive osmosis module; And a flux measuring device for the diluted seawater discharged from the positive osmosis module.

1, the seawater inflow water 11 introduced into the forward osmosis membrane module is supplied to the reuse inflow water 12, Since it has a higher osmotic pressure, it can be used as an induction solution for the positive osmosis process, so that high-quality treated water filtered by dissolved ions, organic substances and particulate matter in the reusing influent 12 can be passed through the positive osmosis membrane module 21 . In the present invention, the seawater inflow water 11 passes through the osmosis membrane module 21 once, while the reused concentrated water 12 passes through the osmosis membrane module 21 for a certain period of time, And in this case, the discharge valve 52 continuously operates the circulating water pump 32 at a constant speed without being opened. As a result, the seawater influent 11 in the forward osmosis process is treated continuously, and the reusing influent 12 can be treated batchwise.

On the other hand, it is preferable that the discharge valve is opened when at least two of the following formulas (I) to (III) are satisfied.

J / Ji < Jc &gt; (I)

Cr / Cs > Rc ... (II)

CF > Fc ... (III)

In the formula (I), J is the flux value at time t of the osmosis membrane in the forward osmosis module, Ji is the initial flux value of the osmosis membrane in the forward osmosis module, and Cs in the formula (II) Con is the conductivity value, and Cr is the conductivity value of the concentrated water discharged from the positive osmosis module.

On the other hand, in the formula (III), CF is an enrichment factor, the enrichment factor CF is as shown in the following formula (4)

Figure 112016019117369-pat00002
... (4)

In this case, A is the area of the quasi-osmosis membrane, and V is the total volume in the positive osmosis circulation loop, that is, the sum of the piping volume and the volume of the space in the membrane module.

The thresholds Jc, Rc, and Fc used in the respective conditions can be selected and applied according to the characteristics of the reused water and the osmosis membrane to be processed among the values having the following ranges. Jc is a threshold value for flux, Rc is a threshold value for the relative concentration of the osmosis concentrated water, and Fc is a threshold value for the osmosis concentrating factor.

Threshold Jc Rc Fc range 0.5 to 0.8 0.05 to 0.3 0.4 to 0.9

If the above condition is not satisfied, the average flux of the positive osmosis becomes too low to require a larger number of membrane modules, excessive membrane contamination, Nano filtration or low-pressure reverse osmosis process can not be operated properly.

Therefore, in the case of the forward osmosis process, if two or more of them can not be satisfied, it is preferable to terminate the cycle of the batch operation in the long-term operation.

Therefore, preferably, the discharge valve is opened when at least two of the following formulas (1) to (3) are satisfied.

J / Ji < 0.8 (1)

Cr / Cs > 0.05 (2)

CF > 0.4 ... (3)

In the equation (1), J is the flux value at time t of the positive osmosis membrane in the forward osmosis module, Ji is the initial flux value of the positive osmosis membrane in the forward osmosis module, and Cs in the formula (2) And Cr is the conductivity value of the concentrated water discharged from the positive osmosis module.

On the other hand, in the formula (3), CF is an enrichment factor, the enrichment factor CF is represented by the following formula (4)

Figure 112016019117369-pat00003
... (4)

In this case, A is the area of the quasi-osmosis membrane, and V is the total volume in the positive osmosis circulation loop, that is, the sum of the piping volume and the volume of the space in the membrane module.

(1) to (3) ', wherein J, Ji, Cr, Cs and CF are as defined in the above formulas (1) to 3).

J / Ji < 0.5 (1) &quot;

Cr / Cs > 0.3 (2) &quot;

CF > 0.9 ... (3) &quot;

That is, it is determined based on the total ion concentration (conductivity) of the flux, seawater and reused water of the osmosis membrane as a method for determining the period of the batch operation in the forward osmosis process. Each of the apparatuses 71, 72 and 73 monitors the conductivity of the seawater inflow water 11, the reuse inflow water 12 and the purified osmosis treatment water 15 to obtain a conductivity value. In addition, a flux measuring device of a positive osmosis membrane is provided to acquire a flux value and an initial flux value.

Meanwhile, the desalination apparatus of the present invention may further include a reuse inflow pump for supplying reuse inflow water to the normal osmosis module.

In addition, the apparatus may further include a positive osmosis treatment water storage tank for storing the diluted seawater discharged from the positive osmosis module, wherein the apparatus for measuring the conductivity of the diluted seawater discharged from the positive osmosis module comprises: As shown in FIG.

That is, the forward osmotic treatment water 15 treated by the forward osmosis is first transferred to the forward osmotic treatment water storage tank 61 and then supplied to the low pressure reverse osmosis membrane module 22 by the low pressure reverse osmosis pump 33 have. Further, the water removed by the low-pressure reverse osmosis can be additionally treated by the high-pressure reverse osmosis membrane module 23 at the rear stage. At this time, the concentrated water of the high-pressure reverse osmosis membrane module passes through the energy recovery device 41, Pressure reverse osmosis pump 34 and then discharged.

The energy recovery device that can be used in the present invention may be, but is not limited to, a pressure regulator (PX) or a turbocharger (TC).

Meanwhile, in the present invention, the pressurized reverse osmosis module is preferably a low pressure reverse osmosis membrane module, and the low pressure is a low pressure of 10 bar to 40 bar.

When the low-pressure reverse osmosis module can sufficiently produce the necessary fresh water, it is possible to provide only a single reverse osmosis module, but it may be equipped with an additional reverse osmosis module if necessary. In this case, the added reverse osmosis module is preferably a high-pressure reverse osmosis module. Here, the high pressure is a high pressure of 40 to 90 bar.

Meanwhile, in some cases, the nanofiltration membrane module may be used in place of the low pressure reverse osmosis membrane module 22 in some cases. The low-pressure reverse osmosis membrane module 22 may be composed of two or more stages.

That is, in this case, in the present invention, the reverse osmosis module includes a primary pressurization reverse osmosis module for receiving diluted seawater discharged from the forward osmosis module and discharging fresh water and primary seawater concentrated water; And a secondary pressurized reverse osmosis module that receives at least a portion of the primary seawater-concentrated water and discharges fresh water and secondary seawater-concentrated water, wherein the energy recovery device is configured to pressurize the secondary seawater- To regenerate the energy, and to regulate the amount of the primary seawater concentrated water supplied to the secondary pressurized reverse osmosis module.

At this time, the amount of the influent transferred from the low-pressure reverse osmosis to the high-pressure reverse osmosis can be regulated by the regulating valve 51 so that it can be flexibly operated according to the inflow water condition and the water usage amount. On the other hand, the purified osmosis and low pressure reverse osmosis membrane module treated water 16 treated by the low pressure reverse osmosis membrane module 22 and the high pressure reverse osmosis membrane module 23 and the purified osmosis, The module treatment water 17 is mixed and then sent to the place of use.

When the value obtained by multiplying the primary seawater concentrated water flow rate of the primary pressurized reverse osmosis module by the recovery rate of the secondary pressurized reverse osmosis module exceeds the maximum producible flow rate of the secondary pressurized reverse osmosis module And the value obtained by multiplying the primary seawater concentrated water flow rate of the first pressurized reverse osmosis module by the recovery rate of the second pressurized reverse osmosis module is the maximum production amount of the second pressurized reverse osmosis module When the flow rate is equal to or less than the flow rate, it is preferable to supply the first concentrated seawater concentrated water to the second pressurized reverse osmosis module.

A first pressurizing means for applying pressure to the primary pressurized reverse osmosis module, and a second pressurizing means for applying pressure to the secondary pressurized reverse osmosis module, wherein the pressure of the second pressurizing means is higher than that of the first pressurizing means More preferably, the pressure of the first pressurizing means is a low pressure of 10 bar to 40 bar, and the pressure of the second pressurizing means is a high pressure of more than 40 bar to 90 bar.

The reuse inflow water that can be used in the present invention is at least one selected from the group consisting of sewage, river water, and wastewater treatment water, but is not limited thereto.

Furthermore, according to another aspect of the present invention, there is provided a desalination method to which the desalination apparatus as described above can be applied.

The closed circulation type desalination method using positive osmosis and reverse osmosis according to the present invention comprises the steps of: supplying seawater influent and reused inflow water to a positive osmosis module to obtain concentrated water and diluted seawater; Supplying the concentrated water discharged from the forward osmosis module to the reuse inflow water of the forward osmosis module by using a circulation pump and circulating the concentrated water through the circulation pump; A step of stopping the inflow of the reuse inflow water by the closed circulation and opening the discharge valve to introduce the new reuse inflow water, and discharging the concentrated water discharged from the forward osmosis module; Supplying diluted seawater discharged from the forward osmosis module to a pressurized reverse osmosis module to discharge fresh water and seawater concentrated water; And recovering the energy by reducing the pressure applied to the seawater concentrated water, wherein the discharge valve may be opened when at least two of the following formulas (1) to (3) are satisfied.

J / Ji < 0.8 (1)

Cr / Cs > 0.05 (2)

CF > 0.4 ... (3)

In the equation (1), J is the flux value at time t of the positive osmosis membrane in the forward osmosis module, Ji is the initial flux value of the positive osmosis membrane in the forward osmosis module, and Cs in the formula (2) And Cr is the conductivity value of the concentrated water discharged from the positive osmosis module.

On the other hand, in the formula (3), CF is an enrichment factor, the enrichment factor CF is represented by the following formula (4)

Figure 112016019117369-pat00004
... (4)

In this case, A is the area of the quasi-osmosis membrane, and V is the total volume in the positive osmosis circulation loop, that is, the sum of the piping volume and the volume of the space in the membrane module.

As described above in connection with Table 1 above, Jc is a threshold value for flux, Rc is a threshold value for the relative concentration of the osmosis concentrated water, and Fc is a threshold value for the osmosis concentrating factor.

Fig. 2 exemplarily shows, as a flowchart, a method of controlling the closed circulating positive osmosis process based on the conductivity of influent water and treated water. The flow chart of FIG. 2 shows the beginning and end of one cycle in the batch operation of the normal osmosis process.

More specifically, when the operation of the forward osmosis process is started, the conductivity Cs of the seawater influent water; Conductivity (Cr) of the circulating water, that is, the concentrated water discharged from the positive osmosis module; And the initial flux Ji of the forward osmosis module are respectively measured and the flux J of the forward osmosis treatment water is also measured and a value J / Ji divided by the initial flux Ji thereof is obtained.

When two or more of the above three conditions are satisfied, the discharge valve 52 is opened to discharge the concentrated reused inflow water 12 from the normal osmosis membrane module 21 and the closed circulating desalination device, (12) and the operation is repeated.

2, the influent seawater conductivity Cs is measured first and the concentration coefficient is measured last. However, these values can be measured in any other order, and further, the flux J of the forward osmosis treated water shown in FIG. (J / Ji) obtained by dividing the initial flux (Ji) by the initial flux (Ji) is performed at the time of the initial determination. Judgment is made based on the value J from the second cycle onwards, 3) may be determined in any order, and when two or more of them are satisfied, the discharge valve is opened.

Meanwhile, the step of supplying the pressurized reverse osmosis module to discharge the fresh water and the concentrated sea water includes supplying the diluted seawater discharged from the forward osmosis module to the first pressurized reverse osmosis module to discharge the fresh water and the first seawater concentrated water ; And supplying a portion of the primary seawater concentrated water to a secondary pressurized reverse osmosis module to discharge fresh water and secondary seawater concentrated water, wherein the energy recovery step is a step of reducing the pressure applied to the secondary seawater- Wherein the value obtained by multiplying the primary seawater concentrate flow rate of the primary pressurized reverse osmosis module by the recovery rate of the secondary pressurized reverse osmosis module exceeds the maximum producible flow rate of the secondary pressurized reverse osmosis module And the value obtained by multiplying the flow rate of the primary seawater concentrated water of the first pressurized reverse osmosis module by the recovery rate of the second pressurized reverse osmosis module is larger than that of the second pressurized reverse osmosis module When the flow rate is equal to or less than the maximum production flow rate, it is preferable to supply the primary seawater concentrated water to the secondary pressurized reverse osmosis module.

That is, in the present invention, the pressurized reverse osmosis module is preferably a low pressure reverse osmosis membrane module, and the low pressure is a low pressure of 10 bar to 40 bar.

When the low-pressure reverse osmosis module can sufficiently produce the necessary fresh water, it is possible to operate with only a single reverse osmosis module, but it can be operated with an additional reverse osmosis module if necessary. In this case, the added reverse osmosis module is preferably a high-pressure reverse osmosis module. At this time, the high pressure is more than 40 bar Lt; / RTI &gt; to 90 bar.

At this time, the amount of the influent transferred from the low-pressure reverse osmosis to the high-pressure reverse osmosis can be regulated by the regulating valve 51 so that it can be flexibly operated according to the inflow water condition and the water usage amount. On the other hand, the purified osmosis and low-pressure reverse osmosis membrane module treated water (16) treated by the low-pressure reverse osmosis membrane module (22) and the high-pressure reverse osmosis membrane module (23) The membrane module treatment water 17 is mixed and then sent to the place of use.

(1) to (3) ', wherein J, Ji, Cr, Cs and CF are as defined in the above formulas (1) to 3).

J / Ji < 0.5 (1) &quot;

Cr / Cs > 0.3 (2) &quot;

CF > 0.9 ... (3) &quot;

The process of supplying the reuse inflow water to the osmosis module may be performed using a reuse inflow pump, and the step of recovering the energy may be performed by a pressure exchanger (PX) or a turbocharger (TC) But is not limited thereto.

Meanwhile, the pressure of supplying the diluted seawater discharged from the forward osmosis module to the primary pressurized reverse osmosis module and discharging the fresh water and the primary seawater concentrated water may be such that at least a part of the primary seawater- It is preferable that the pressure of the first pressurized reverse osmosis module is lower than the pressure of the step of supplying the fresh water and the second seawater concentrated water to the reverse osmosis module and the pressure of the first pressurized reverse osmosis module is a low pressure of 10 to 40 bar, The pressure of the two modules is higher than 40 bar to 90 bar.

The recycling inflow water may be at least one selected from the group consisting of sewage, river water, and wastewater treatment water, but is not limited thereto.

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

1 (a) and 1 (b) show a case in which the closed circulation type desalination system using the forward osmosis and the reverse osmosis of the present invention as shown in Fig. 1 The energy consumption of the case where the osmosis membrane module 21 and the auxiliary facilities 31, 32, 52, 71, and 72 are excluded (comparative example) are compared and the results are shown in Table 2 below.

Classification Item value Seawater influent Influent flow 160 m 3 / day TDS 30,000 mg / L Recovery rate 40% Reuse influent Influent flow 100 m 3 / day TDS 300 mg / L Recovery rate 80% Positive osmosis Transmittance 4 Lm 2- hr / bar Structural factor 250 mm Low-pressure reverse osmosis Transmittance 3 Lm 2- hr / bar Ion removal rate 99% High pressure reverse osmosis Transmittance 1 Lm 2- hr / bar Ion removal rate 99.7% Energy recovery system (ERD) efficiency 100% (assuming ideal case) Pump-motor efficiency 80% (typical)

The energy consumption (ERD applied, 50 bar) was 1.73 kWh / m 3 when only high-pressure reverse osmosis was applied as in the comparative example. However, according to the closed circulating desalination system using the osmosis and reverse osmosis of the embodiment of the present invention It was confirmed that the following results were obtained.

- Fixed osmosis flux: 29 L / m 2 -hr

- Low-pressure reverse osmosis energy usage (27 bar): 0.938 kWh / m 3

- High pressure reverse osmosis energy usage (ERD applied, 50 bar): 1.73 kWh / m 3

- Total energy usage: 1.29 kWh / m 3

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 influent
13: Seawater concentrate
14: reused concentrated water
15: Forward osmosis treatment water
16: Fixed osmosis and low pressure reverse osmosis membrane module treated water
17: Fixed osmosis, low pressure reverse osmosis membrane module and high pressure reverse osmosis membrane module treated water
21: The positive osmosis membrane module
22: Low pressure reverse osmosis membrane module
23: High pressure reverse osmosis membrane module
31: Reusable water inlet pump
32: Circulating water pump
33: Low pressure reverse osmosis pump
34: High pressure reverse osmosis pump
41: Energy recovery device
51: Regulating valve
52: discharge valve
61: The osmosis treatment water storage tank
71: Seawater conductivity measuring device
72: Reused water conductivity measuring device
73: Process water conductivity measuring device
pw: product water
sw: seawater
iw: reused water (industrial wastewater, industrial wastewater)
sc: seawater concentrate
ic: reused concentrated water (industrial wastewater concentrate)

Claims (18)

A forward osmosis module that receives seawater influent and re-use influent to dilute seawater;
A circulation pump for returning the concentrated water discharged from the forward osmosis module to the reuse inflow water of the positive osmosis module to form closed circulation;
A discharge valve for discharging the concentrated water discharged from the forward osmosis module to stop the inflow of the reclaimed inflow water by closed circulation and to introduce new reclaimed inflow water to operate in batch mode;
A pressurized reverse osmosis module that receives the diluted seawater discharged from the forward osmosis module and discharges fresh water and seawater concentrated water;
An energy recovery device for reducing the pressure applied to the seawater concentrated water to recover energy;
A conductivity measuring device for measuring the conductivity of each of the seawater influent, the concentrated water discharged from the positive osmosis module, and the diluted sea water discharged from the positive osmosis module; And
Flux measuring device for diluted seawater discharged from the forward osmosis module
/ RTI &gt;
The reverse osmosis module includes a primary pressurization reverse osmosis module for receiving diluted seawater discharged from the forward osmosis module and discharging fresh water and primary seawater concentrated water; And a secondary pressurization reverse osmosis module that receives at least a portion of the primary seawater concentrated water and discharges fresh water and secondary seawater concentrated water,
Wherein the energy recovery device reduces the pressure applied to the secondary seawater concentrated water to recover energy,
And a control valve for controlling the flow rate of the primary seawater concentrated water supplied to the secondary pressurized reverse osmosis module,
If the value obtained by multiplying the primary seawater concentrated water flow rate of the first pressurized reverse osmosis module by the recovery rate of the second pressurized reverse osmosis module exceeds the maximum production flow rate of the second pressurized reverse osmosis module, The concentrated water is discharged,
When the value of the primary seawater concentrated water flow rate of the primary pressurized reverse osmosis module multiplied by the recovery rate of the secondary pressurized reverse osmosis module is equal to or less than the maximum producible flow rate of the secondary pressurized reverse osmosis module, A closed circulating desalination system using pure osmosis and reverse osmosis, which supplies the whole amount to a secondary pressurized reverse osmosis module.
delete The closed circulating desalination apparatus according to claim 1, wherein the discharge valve is opened when at least two of the following expressions (1) to (3) are satisfied.
J / Ji < 0.8 (1)
Cr / Cs > 0.05 (2)
CF > 0.4 ... (3)
(Where J is the flux value at time t of the positive osmosis membrane in the forward osmosis module, Ji is the initial flux value of the positive osmosis membrane in the forward osmosis module,
In the equation (2), Cs is the conductivity value of the seawater influent, Cr is the conductivity value of the concentrated water discharged from the forward osmosis module,
In the formula (3), CF is an enrichment factor, the enrichment factor CF is represented by the following formula (4)
Figure 112016019117369-pat00005
... (4)
Where A is the area of the quasi-osmosis membrane and V is the area of the total volume in the positive osmotic loop, ie, the sum of the piping volume and the volume of the space within the membrane module.
4. The closed circulating desalination apparatus according to claim 3, wherein the equations (1) to (3) are respectively the following formulas (1) to (3) '.
J / Ji &lt; 0.5 (1) &quot;
Cr / Cs &gt; 0.3 (2) &quot;
CF &gt; 0.9 ... (3) &quot;
3. The closed circulating desalination apparatus of claim 1, further comprising a recycle inflow pump for feeding the reuse inflow water to the positive osmosis module.
The apparatus of claim 1, further comprising a positive osmotic treatment water reservoir for storing diluted seawater discharged from the positive osmosis module, wherein the device for measuring conductivity of the diluted seawater discharged from the positive osmosis module comprises: A closed circulation type desalination apparatus using a forward osmosis and a reverse osmosis provided in a storage tank.
The closed circulation type desalination apparatus according to claim 1, wherein the energy recovery apparatus is a PX (Pressure Exchanger) or a Turbocharger (TC).
2. The apparatus of claim 1, further comprising: first pressure means for applying pressure to the primary pressure reverse osmosis module; and second pressure means for applying pressure to the secondary pressure reverse osmosis module, Is larger than the pressure of the first pressurizing means, using a forward osmosis and a reverse osmosis.
9. The method of claim 8, wherein the pressure of the first pressurizing means is a low pressure of 10 bar to 40 bar and the pressure of the second pressurizing means is a high pressure of greater than 40 bar to 90 bar, Desalination device.
The closed circulating desalination apparatus according to claim 1, wherein the recycling inflow water is at least one selected from the group consisting of sewage, river water, and sewage treatment water.
Supplying the seawater inflow water and the reuse inflow water to the positive osmosis module to obtain concentrated water and diluted seawater;
Supplying the concentrated water discharged from the forward osmosis module to the reuse inflow water of the forward osmosis module by using a circulation pump and circulating the concentrated water through the circulation pump;
A step of stopping the inflow of the reuse inflow water by the closed circulation and opening the discharge valve to introduce the new reuse inflow water, and discharging the concentrated water discharged from the forward osmosis module;
Supplying diluted seawater discharged from the forward osmosis module to a pressurized reverse osmosis module to discharge fresh water and seawater concentrated water; And
And recovering the energy by reducing the pressure applied to the seawater concentrated water,
Wherein the discharge valve is opened when at least two of the following formulas (1) to (3) are satisfied: a closed-loop desalination method using positive osmosis and reverse osmosis.
J / Ji < 0.8 (1)
Cr / Cs > 0.05 (2)
CF > 0.4 ... (3)
(Where J is the flux value at time t of the positive osmosis membrane in the forward osmosis module, Ji is the initial flux value of the positive osmosis membrane in the forward osmosis module,
In the equation (2), Cs is the conductivity value of the seawater influent, Cr is the conductivity value of the concentrated water discharged from the forward osmosis module,
In the formula (3), CF is an enrichment factor, the enrichment factor CF is represented by the following formula (4)
Figure 112016019117369-pat00006
... (4)
Where A is the area of the quasi-osmosis membrane and V is the area of the total volume in the positive osmotic loop, ie, the sum of the piping volume and the volume of the space within the membrane module.
The method as claimed in claim 11, wherein the step of supplying the pressurized reverse osmosis module to discharge the fresh water and the concentrated sea water includes supplying diluted seawater discharged from the forward osmosis module to the first pressurized reverse osmosis module, Discharging the concentrated water; And supplying a part of the primary seawater concentrated water to a secondary pressurized reverse osmosis module to discharge fresh water and secondary seawater concentrated water,
Wherein the energy recovery step reduces the pressure applied to the secondary seawater concentrated water to recover energy,
If the flow rate of the primary seawater concentrated water of the primary pressurized reverse osmosis module multiplied by the recovery rate of the secondary pressurized reverse osmosis module exceeds the maximum producible flow rate of the secondary pressurized reverse osmosis module, The first primary seawater concentrated water is discharged,
When the flow rate of the primary seawater concentrated water of the primary pressurized reverse osmosis module multiplied by the recovery rate of the secondary pressurized reverse osmosis module is equal to or less than the maximum production flow rate of the secondary pressurized reverse osmosis module, And a second pressurized reverse osmosis module is supplied with the water amount,
Closed circulation type desalination method using positive osmosis and reverse osmosis.
The closed circulating desalination method according to claim 11, wherein the equations (1) to (3) are the following formulas (1) to (3), respectively.
J / Ji &lt; 0.5 (1) &quot;
Cr / Cs &gt; 0.3 (2) &quot;
CF > 0.9 ... (3) &quot;
12. The method of claim 11, wherein the step of supplying the reuse inflow water to the osmosis module is performed using a reuse inflow pump.
12. The method of claim 11, wherein the step of recovering energy is performed by a pressure exhauster (PX) or a turbo charger (TC).
13. The method of claim 12, wherein the pressure of supplying the diluted seawater discharged from the forward osmosis module to the primary pressurized reverse osmosis module and discharging the fresh water and the primary seawater- To the second pressurized reverse osmosis module at a pressure lower than the pressure of the step of discharging the fresh water and the second seawater concentrated water, using a closed osmosis and reverse osmosis.
17. The method of claim 16, wherein the pressure of the primary pressurized reverse osmosis module is a low pressure of 10 bar to 40 bar and the pressure of the secondary pressurized reverse osmosis module is high pressure of more than 40 bar to 90 bar, Closed circulation desalination method.
The method of claim 12, wherein the reuse inflow water is at least one selected from the group consisting of sewage, river water, and wastewater treatment water.
KR1020160023267A 2016-02-26 2016-02-26 Closed type desalination system using forward osmosis and reverse osmosis KR101778022B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020160023267A KR101778022B1 (en) 2016-02-26 2016-02-26 Closed type desalination system using forward osmosis and reverse osmosis

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020160023267A KR101778022B1 (en) 2016-02-26 2016-02-26 Closed type desalination system using forward osmosis and reverse osmosis

Publications (2)

Publication Number Publication Date
KR20170100864A KR20170100864A (en) 2017-09-05
KR101778022B1 true KR101778022B1 (en) 2017-09-26

Family

ID=59924632

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020160023267A KR101778022B1 (en) 2016-02-26 2016-02-26 Closed type desalination system using forward osmosis and reverse osmosis

Country Status (1)

Country Link
KR (1) KR101778022B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109553202A (en) * 2017-09-26 2019-04-02 北京天诚同创电气有限公司 The control method of reverse osmosis seawater desalting method, system and system
JP7102706B2 (en) * 2017-10-30 2022-07-20 東洋紡株式会社 Seawater desalination method and seawater desalination system

Also Published As

Publication number Publication date
KR20170100864A (en) 2017-09-05

Similar Documents

Publication Publication Date Title
CN105142762B (en) The improvement of osmotic drive membranous system comprising multistage purification
US10406482B2 (en) Osmotic separation systems and methods
WO2018150980A1 (en) Reverse osmosis treatment device and reverse osmosis treatment method
CN104276711A (en) Reverse osmosis membrane treatment process for recycling industrial sewage and realizing zero release
AU2014367973B2 (en) Scale detection device and method for concentrating device, and water reclamation processing system
CN113413767B (en) Old membrane repairing method
KR101778022B1 (en) Closed type desalination system using forward osmosis and reverse osmosis
KR101387136B1 (en) Method of desalination and desalination apparatus
Altaee et al. Dual stage PRO power generation from brackish water brine and wastewater effluent feeds
Tao et al. Energy reduction and optimisation in membrane bioreactor systems
KR101402345B1 (en) System making fresh water from sea water using reverse osmosis
KR101898225B1 (en) Concentrated water reduction system
JP2000093751A (en) Reverse osmosis separation device and reverse osmosis separation method
KR101806144B1 (en) Desalination system using controlled forward osmosis and reverse osmosis
KR101402346B1 (en) Method for seawater desalinating with reverse osmosis
KR101778021B1 (en) Eco-friendly desalination system using forward osmosis and reverse osmosis
CN112456687A (en) Landfill leachate concentrated solution reduction method and system
JPWO2014007262A1 (en) Fresh water production apparatus and fresh water production method
KR20170069614A (en) Saltwater desalination system
CN101928078A (en) Method for treating wastewater with low-concentration ammonium perfluorooctanoate through all-film method
JP6269486B2 (en) Demineralized water production method
JP2000051663A (en) Apparatus and method for separation of reverse osmosis membrane
CN207375858U (en) A kind of nickeliferous heavy metal containing wastewater treatment of low concentration with high salt and reclamation set
CN214270480U (en) Landfill leachate concentrate minimizing system
CN202829636U (en) Device for processing reverse osmosis concentrated brine by using decompressing membrane distillation

Legal Events

Date Code Title Description
E701 Decision to grant or registration of patent right
GRNT Written decision to grant