KR102183195B1 - Hybrid distillation device and method - Google Patents

Abstract

The present invention relates to a hybrid desalination apparatus and method,
A thermal process unit of a method of desalination by evaporating the water intake, a reverse osmosis process unit of desalination of the sea water by a reverse osmosis method, and a forward osmosis process unit of desalination of the sea water by a forward osmosis method, and The process unit and the forward osmosis process unit are arranged in parallel so that the seawater is introduced into the reverse osmosis process unit and the forward osmosis process unit, respectively, the thermal process unit is disposed at a rear end of the forward osmosis process unit, and the forward osmosis process unit Is characterized in that it comprises a unit for desalination of the seawater by using the brine discharged from the thermal process unit and the reverse osmosis process unit as a draw solution.
According to the present invention, the cost is reduced by using the brine discharged from the thermal process as a draw solution for the FO process, and the high-temperature heat discharged from the thermal process is used in the RO process to improve efficiency and energy There is an effect of reducing the amount of use.

Description

Hybrid distillation device and method {Hybrid distillation device and method}

The present invention relates to a hybrid desalination apparatus and method, and more particularly, to reduce costs by using salt water discharged from the thermal process in the FO process, and improve efficiency by using high-temperature heat discharged from the thermal process in the RO process. It relates to a hybrid desalination apparatus and method that can be made.

About 40% of the world's population currently suffers from a shortage of drinking water due to the expansion of water shortage areas due to the regional concentration of rainfall due to an increase in population and an improvement in living standards and due to extreme weather conditions. And it is expected that the lack of drinking water will increase due to contamination of groundwater.

For this reason, various methods for desalination of seawater have been developed, and the types include evaporation using a heat source, forward osmosis and reverse osmosis using an osmosis phenomenon, and in addition to the electrodialysis method, crystallization method, ion exchange membrane method, solvent extraction method, And pressure adsorption method.

Among the evaporation methods, the multi-stage evaporation method (Multi-Stage Flash, MSF), the multi-effect method (Multi-Effect Distillation, MED), and the reverse osmosis method are typically applied to the desalination of seawater (hereinafter, MSF and MED processes are thermally applied. Defined as fair).

Recently, in order to improve the efficiency of a seawater desalination plant, a multi-stage evaporation method or a hybrid method of producing fresh water by using a mixture of a multi-effect method and a reverse osmosis method has been applied.

However, since such a conventional hybrid method is advantageous to be installed adjacent to a thermal power plant or the like to provide a heat source, there is a limit to installing a hybrid power plant alone. In addition, even in the case of the hybrid method, the thermal process and the reverse osmosis process are not operated in an integrated manner, but are operated independently, so there is a problem that the advantages of the hybrid method cannot be properly exhibited.

Accordingly, there is a need to solve the problems of the existing hybrid seawater desalination system and improve desalination efficiency by applying the forward osmosis type seawater desalination device as disclosed in Korean Patent Application Publication No. 2011-0134591 to the existing hybrid system.

Korean Patent Publication 2011-0134591 (Publication date 2011. 12. 15)

It is an object of the present invention to provide a hybrid desalination apparatus and method capable of improving efficiency by using salt water discharged from the thermal process in the FO process to reduce cost, and using high temperature heat discharged from the thermal process in the RO process. will be.

The hybrid desalination apparatus of the present invention includes a thermal process unit of a method of desalination by evaporating the water intake, a reverse osmosis process unit of desalination of the seawater by a reverse osmosis method, and a forward osmosis process of desalination of the seawater by a forward osmosis method. A unit, wherein the reverse osmosis process unit and the forward osmosis process unit are arranged in parallel so that the seawater is input to the reverse osmosis process unit and the forward osmosis process unit, respectively, and the thermal process unit is at the rear end of the forward osmosis process unit. The forward osmosis process unit is characterized in that it comprises a unit for desalination of the seawater using the thermal process unit and the brine discharged from the reverse osmosis process unit as a draw solution.

And a final treatment unit for mixing and treating TDS (Total Dissolved Solids) of treated water produced from the thermal process unit and the reverse osmosis process unit so as to become a target TDS.

The collected seawater is characterized in that it is introduced through a seawater supply line.

It further includes a salt water concentration control unit for mixing the TDS of the salt water according to the target TDS and supplying it to the forward osmosis process unit.

The reverse osmosis process unit is characterized in that it comprises a pre-treatment unit receiving the water intake and pre-treatment.

The thermal process unit is characterized in that it includes a pretreatment unit receiving and pretreating the treated water discharged from the forward osmosis process unit.

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It further comprises a waste heat recovery means for recovering the waste heat from the thermal process unit and supplying it to the reverse osmosis process unit.

The reverse osmosis process unit is characterized in that a plurality.

In addition, the present invention includes the step of taking seawater (S100), the steps of supplying and processing the seawater to a reverse osmosis process unit and a forward osmosis process unit arranged in parallel (S200, S300), and in the forward osmosis process unit Steps in which the produced treated water is introduced into the thermal processing unit to be desalted (S400), and the TDS of the treated water produced in the reverse osmosis processing unit and the fresh water produced in the thermal processing unit is adjusted in the final processing unit (S500) And, it provides a hybrid desalination method comprising the step (S600) of finally supplying the fresh water passed through the final treatment unit.

After the step S200, determining the TDS of the treated water produced in the reverse osmosis process (S250).

In the step S250, if the TDS of the treated water produced by the reverse osmosis process unit is less than or equal to a target value, the treated water is sent to the final treatment unit.

In the step S250, if the TDS of the treated water produced by the reverse osmosis process unit is greater than or equal to the target value, the step of performing an additional reverse osmosis process (S270) is further included.

The hybrid desalination apparatus and method according to an embodiment of the present invention uses brine discharged from the thermal process as a draw solution for the FO process to reduce cost, and transfer high-temperature heat discharged from the thermal process to the RO process. By using it, there is an effect of improving efficiency and reducing energy use.

1 is a block diagram showing a hybrid desalination apparatus according to the present invention,
2 is a flow chart illustrating a hybrid desalination method according to FIG. 1.

Hereinafter, a hybrid desalination apparatus and method according to an embodiment of the present invention will be described in detail with reference to the drawings.

In general, water can be classified according to the concentration of Total Dissolved Solids (TDS), and water with a TDS of about 10,000 to 50,000 mg/l (ppm) is seawater and that of 10,000 to 10,000 mg/l. Radix, less than 300mg/l is called fresh water. The source water for desalination is seawater, brackish water, or drift water or groundwater that is higher in salinity than general fresh water (hereinafter, it will be described based on an example of treating seawater for convenience, but seawater defined here is the brackish water or drift above It should be understood as a concept that can be substituted with water and groundwater).

First, a hybrid desalination apparatus according to the present invention will be described with reference to FIG. 1.

1 is a block diagram showing a hybrid desalination apparatus according to the present invention.

As shown in Figure 1, the hybrid desalination apparatus 10 according to the present invention is largely a thermal process unit 200, a forward osmosis (FO) process unit 300, and reverse osmosis (RO). ) It consists of a process unit 400. The reverse osmosis process unit 400 and the forward osmosis process unit 300 are arranged in parallel, but are disposed so that the brine discharged from the reverse osmosis process unit 400 is discharged to the forward osmosis process unit 300, and the forward osmosis process unit 400 ) May be implemented in a form in which the thermal processing unit 200 is disposed at the rear end.

The collected seawater is fed into the forward osmosis process unit 300 and the reverse osmosis process unit 400, respectively, and treated, and the brine of the furnace treated in the thermal process unit 200 is introduced into the forward osmosis process unit 300. , The treated water that has passed through the forward osmosis process unit 300 is introduced into the thermal process unit 200 and treated. The collected seawater is supplied to the forward osmosis process unit 300 and the reverse osmosis process unit 400 through the seawater supply line 100. The treated water desalized in each of the thermal process unit 200, the forward osmosis process unit 300, and the reverse osmosis process unit 400 is supplied to the final treatment unit 700 through the treated water discharge line 600, and has a high concentration. The brine is recovered and recycled through the brine line 500 (the understanding of the basic configuration of each unit is obvious to those skilled in the art, so a detailed description will be omitted).

The thermal process unit 200 may be a multi-stage evaporation (MSF) or multiple effect (MED) desalination facility, and is largely composed of a pretreatment unit 210, a steam generator 230, and a heat exchange unit 250.

In the pretreatment unit 210, by chemically pretreating the collected seawater, feed water from which scale, foam, and chlorine are removed is produced and supplied to the steam generator 230.

However, in this embodiment, since the reverse osmosis process unit 400 is disposed in front of the thermal process unit 200, the reverse osmosis process unit 400 includes a pretreatment unit 410, and the thermal process unit 200 includes a pretreatment unit. By omitting it, it is possible to complete the pretreatment of seawater supplied to the hybrid desalination apparatus 10'' through one pretreatment unit. That is, by removing the scale factor from the reverse osmosis process unit 400, the steam cost according to the temperature rise in the thermal process unit 200 is reduced, and the scale removal cost does not increase even when the temperature rises. ) Can be reduced and the throughput of treated water can be increased.

The steam generating unit 230 evaporates the feed water to make steam, and the heat exchange unit 250 heats the heat with steam to produce fresh water. Fresh water produced by the thermal process unit 200 is supplied to the final treatment unit 700, and the TDS of the produced fresh water is 10 ppm or less.

However, brine generated after producing fresh water in the thermal processing unit 200 is usually a high-concentration brine with a TDS of 61,000 to 63,000 ppm at about 46 degrees Celsius. The high-concentration brine thus generated is supplied to the forward osmosis process unit 300 through TDS control.

The forward osmosis process unit 300 includes a forward osmosis membrane module 310 for absorbing fresh water in seawater as a draw solution by contacting a high concentration draw solution and seawater with a forward osmosis membrane therebetween, and a forward osmosis membrane module ( It consists of a fresh water separation module 330 that separates the fresh water absorbed by the draw solution in 310). As the difference in osmotic pressure between the induction solution and the seawater to be treated increases, the extraction of freshwater in seawater is easier, so as described above, the high concentration generated in the thermal process unit 200 in the induction solution used in the forward osmosis membrane module 310 It is suggested how to use the brine of. When the TDS of fresh water separated in the forward osmosis process unit 300 meets the drinking water standard (TDS 100-200 ppm) or the fresh water standard, the treated water is immediately supplied to the final treatment unit 700. When the separated fresh water is slightly less than the fresh water standard or the drinking water standard, the treated water is supplied to the thermal processing unit 200 and reprocessed.

Alternatively, although not shown in the drawings, the treated water may be supplied to the thermal process unit 200 or the reverse osmosis process unit 400 regardless of the TDS of fresh water separated by the forward osmosis process unit 300.

Since the high-concentration brine generated in the thermal process unit 200 is utilized in the forward osmosis process unit 300, adverse environmental effects can be reduced, and the cost of separately providing the induction solution can be reduced.

Meanwhile, the reverse osmosis process unit 400 includes a pretreatment unit 410 for pretreating the water intake, a reverse osmosis membrane module 430 for separating fresh water using a reverse osmosis method in which high pressure is applied using a high pressure pump, and the separated fresh water. It consists of a post-processing unit 450 to process. The pretreatment of the reverse osmosis process is also performed by introducing a chemical agent to remove scale, foam, chlorine, remove contaminants by coagulation, adjust pH, etc., and this is the same as the pretreatment process of the thermal process unit 200 described above, so a detailed description Omit it. However, in the present invention, the pretreatment process of the thermal process unit 200 is basically performed in a reverse osmosis process. However, if seawater does not flow into the reverse osmosis process unit 400 and the treated water treated by the thermal process unit 200 is supplied to the reverse osmosis process unit 400 and processed, the pretreatment unit is not provided in the reverse osmosis process unit 400. It should be provided in the thermal process unit 200 without.

In this embodiment, since seawater is introduced into the reverse osmosis process unit 400 as well as the forward osmosis process unit 300, the pretreatment process is performed in the reverse osmosis process unit 400, but the reverse osmosis process unit 400 and the thermal process A pretreatment unit may be provided on both sides of the unit 200.

The post-treatment unit 450 of the reverse osmosis process unit 400 may exist separately, or may be integrated and operated with the final treatment unit 700. Alternatively, although not shown in the drawing, when the pretreatment unit is not provided in the reverse osmosis process unit 400, an auxiliary pretreatment unit is placed at the front end of the reverse osmosis process unit 400 so that elements that are not pretreated in the thermal process unit 200 Additional pre-treatment can also be performed. However, it is obvious that the auxiliary pretreatment unit can also be omitted by managing the pretreatment of seawater in the pretreatment unit of the thermal processing unit 200 to be properly performed.

If the TDS of the treated water treated in the reverse osmosis process unit 400 is 500 ppm or less, the treated water is sent to the final treatment unit 700, and if the TDS of the treated water is 500 ppm or more, it is not shown in the drawing, but an additional reverse osmosis process unit is used. Can be placed and processed. If the TDS of the treated water that is firstly treated in the reverse osmosis process unit 400 is within a target value, an additional reverse osmosis process is not required, so there is an effect of reducing cost. In this embodiment, the reverse osmosis process unit 400 produces treated water, and the high concentration brine (TDS 60,000-67,000 ppm) discharged from the reverse osmosis process unit 400 is introduced into the forward osmosis process unit 300 through the brine line 500. do. The high-concentration brine of the reverse osmosis process introduced into the forward osmosis process unit 300 is supplied to the forward osmosis process unit 300 together with the high-concentration brine discharged from the thermal process unit 200 and is used as a desalination solution for freshwater separation.

In the hybrid desalination apparatus according to an embodiment of the present invention having the above configuration, since the high-concentration salt water discharged from the thermal processing unit 200 is about 46 degrees Celsius, the production efficiency of the forward osmosis processing unit 300 can be improved. I can. That is, as the temperature increases, the temperature response and permeability of the membrane are improved, so that the heat of the thermal processing unit 200 improves the freshwater productivity of the forward osmosis processing unit 300. In addition, a waste heat recovery means (refer to the heat transfer arrow in Fig. 1) for recovering waste heat from the thermal process unit 200 and supplying it to the reverse osmosis process unit 400 is additionally provided to reverse the heat of the thermal process unit 200. It can also be used for the two-process unit 400.

When the temperature of the feed water increases, the viscosity decreases, and when the viscosity decreases, the membrane permeability improves. Therefore, when the temperature of the feed water supplied to the reverse osmosis process unit 400 increases, the efficiency of the high-pressure pump improves and energy It is possible to obtain an effect of improving economic efficiency due to reduction and an effect of increasing the output of treated water. That is, in the past, in the hybrid process system of the thermal process and the reverse osmosis process, an additional heat exchanger was required to increase the temperature of the reverse osmosis process, but in the present invention, since the heat of the thermal process unit 200 is transferred, there is no need for an additional heat exchanger. One effect can be achieved.

Fresh water supplied to the final treatment unit 700 through such a process is supplied with TDS adjusted according to the intended use.

Fresh water supplied to the final treatment unit 700 is fresh water treated by the thermal processing unit 200 (TDS is 10 ppm or less) and fresh water (TDS is 500 ppm or less) that has passed through the reverse osmosis processing unit 400, and is added here. Fresh water (TDS of 500 ppm or less) passed through the forward osmosis process unit 300 may be supplied. The final treatment unit 700 mixes fresh water produced in each unit according to the use of the fence, and supplies the TDS by adjusting it to suit the purpose. That is, the final treatment unit 700 mixes so that the TDS of the final fresh water is in the range of 100 to 200 ppm when the treated water is supplied as drinking water, and the TDS of the final fresh water is mixed and supplied so that the TDS of the final fresh water is 300 ppm or less when it is supplied as living water. do. As described above, by mixing fresh water through the thermal process and fresh water through the reverse osmosis process, the mineral remineralization process required for the thermal process can be omitted, thereby improving economic efficiency as the process is optimized.

In the hybrid desalination apparatus of the present invention described above, the TDS of the brine to be recovered and reused is preferably maintained at a level of about 60,000 to 70,000 ppm. To this end, a brine treatment means for controlling the concentration of brine introduced into the forward osmosis process unit 300 may be additionally provided. The brine treatment means is a brine tank in which brine recovered from the thermal processing unit 200 and the reverse osmosis processing unit 400 are stored, respectively, a concentration control unit that checks the TDS of the stored brine and mixes the brine to obtain an appropriate TDS, and mixes It can be composed of a tank or the like.

The hybrid desalination method according to the hybrid desalination apparatus of the present invention having the above-described configuration will be described as follows (since each process step has already been described, the desalination method will be described focusing on the circulation process of seawater, saltwater, and treated water. To).

2 is a flow chart illustrating a hybrid desalination method according to FIG. 1.

As shown in FIG. 5, the seawater taken first is supplied to the reverse osmosis process unit 400 (S100), and the reverse osmosis process unit 400 produces treated water through pretreatment (S150) and desalination treatment ( S200). The TDS of the produced treated water is determined (S250), and if the TDS is 500 ppm or less, it is supplied to the final treatment unit 700 (S500), and if the TDS of the treated water is 500 ppm or more, an additional reverse osmosis process unit 400 is configured. Can be processed (S270).

In the description of the above-described embodiment, since the TDS of 300 mg/l or less was defined as fresh water, the treated water treated in the reverse osmosis process unit 400 corresponds to a somewhat higher concentration than fresh water. However, since the final treatment unit 700 can produce fresh water suitable for the purpose by mixing it with fresh water of low TDS, if the TDS of the treated water produced in the reverse osmosis process unit 400 is 500 ppm or less, it is sent to the final treatment unit 700. will be.

The collected seawater is supplied to the reverse osmosis process unit 400 and is also supplied to the forward osmosis process unit 300. The seawater is treated by the forward osmosis process unit 300 (S300), and the treated water produced by the forward osmosis process unit 300 is input to the thermal process unit 200 and processed (S400). In the forward osmosis process unit 300, fresh water of less than 10 ppm TDS is directly sent to the final treatment unit 700 (see FIG. 1), and treated water having a higher TDS is input to the thermal process unit 200.

Meanwhile, the high concentration brine generated in the thermal process unit 200 and the reverse osmosis process unit 400 is introduced into the forward osmosis process unit 300 and used as a draw solution (S300). The treated water treated in the reverse osmosis process unit 400 and the fresh water produced in the thermal process unit 200 are fed into the final treatment unit 700, and the TDS is adjusted according to the purpose (S500), and then supplied as the final treated water. It becomes (S600).

When the high-concentration brine discharged from the thermal processing unit 200 and the reverse osmosis processing unit 400 is injected into the forward osmosis processing unit 300, the brine discharged from the two processes is mixed so as to maintain an appropriate TDS to obtain TDS. Can be adjusted.

One embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The scope of the present invention is limited only by the matters described in the claims, and those of ordinary skill in the technical field of the present invention can improve and change the technical idea of the present invention in various forms. Therefore, as long as these improvements and changes are apparent to those of ordinary skill, they will fall within the scope of the present invention.

10: hybrid desalination device 100: seawater supply line
200: Thermal process unit 300: Forward osmosis process unit
400, 410: reverse osmosis process unit 500: high concentration brine line
600: treated water discharge line 700: final treatment unit

Claims (13)

A thermal process unit of a method of desalination by evaporating the water intake;
A reverse osmosis process unit for desalination of the seawater by a reverse osmosis method,
It includes a forward osmosis process unit for desalination of the seawater in a forward osmosis method,
The reverse osmosis process unit and the forward osmosis process unit are arranged in parallel so that the seawater is introduced into the reverse osmosis process unit and the forward osmosis process unit, respectively, and the thermal process unit is disposed at a rear end of the forward osmosis process unit,
The forward osmosis process unit includes a unit for desalting the seawater by using brine discharged from the thermal process unit and the reverse osmosis process unit as a draw solution,
Hybrid desalination apparatus further comprising a waste heat recovery means for recovering the waste heat from the thermal process unit and supplying it to the reverse osmosis process unit.
The method of claim 1,
Hybrid desalination apparatus further comprising a final treatment unit for mixing and treating TDS (Total Dissolved Solids) of treated water produced from the thermal process unit and the reverse osmosis process unit to become a target TDS.
The method of claim 1,
Hybrid desalination apparatus, characterized in that the water intake is introduced through a seawater supply line.
The method of claim 1,
Hybrid desalination apparatus further comprising a salt water concentration control unit for mixing the TDS of the salt water according to the target TDS and supplying it to the forward osmosis process unit.
The method of claim 1,
The reverse osmosis process unit is a hybrid desalination apparatus, characterized in that it comprises a pre-treatment unit receiving the water intake and pre-treatment.
The method of claim 1,
The thermal process unit comprises a pre-treatment unit receiving and pre-treating the treated water discharged from the forward osmosis process unit.
delete delete The method of claim 2,
Hybrid desalination apparatus, characterized in that the plurality of reverse osmosis process units.
Intake of seawater (S100) and,
Steps (S200, S300) in which the seawater is supplied to and processed, respectively, to a reverse osmosis process unit and a forward osmosis process unit arranged in parallel,
Step (S400) of desalination by introducing the treated water produced in the forward osmosis process unit into a thermal process unit,
Adjusting the TDS of the treated water produced in the reverse osmosis process unit and the fresh water produced in the thermal process unit in a final treatment unit (S500),
The step (S600) of finally supplying the fresh water passed through the final treatment unit,
A hybrid desalination method comprising the step of recovering waste heat from the thermal process unit and supplying it to the reverse osmosis process unit.
The method of claim 10,
Hybrid desalination method further comprising the step (S250) of determining the TDS of the treated water produced in the reverse osmosis process after the step S200.
The method of claim 11,
When the TDS of the treated water produced in the reverse osmosis process unit in the step S250 is less than or equal to a target value, the treated water is sent to the final treatment unit.
The method of claim 12,
In the step S250, when the TDS of the treated water produced in the reverse osmosis process unit exceeds the target value, the hybrid desalination method further comprises a step of performing an additional reverse osmosis process (S270).

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