KR101812632B1 - Multistage immersion type membrane distillation water treatment apparatus and method thereof - Google Patents

Abstract

The present invention relates to a multistage immersion type membrane distillation water treatment apparatus and a method thereof. According to the present invention, the apparatus includes: multistage (n^th) raw water tanks which store raw water, respectively; multistage MD modules which are immersed in the raw water on the respective multistage raw water tanks, and discharge a part of the raw water as steam; multistage heat exchange units which are immersed in the raw water in the respective multistage raw water tanks, and maintain the temperature of the raw water in the respective multistage raw water tanks to a preset temperature through heat exchange with the steam supplied from the MD module on the front end; a steam generator which generates high temperature steam and supplies the generated steam to the first heat exchange unit; a condenser which condenses the steam supplied from the MD module on the rearmost end through the heat exchange and supplies the condensed steam; and a raw water supply unit which supplies the raw water of low temperature to the first raw water tank through the condenser for the heat exchange in the condenser.

Description

[0001] The present invention relates to a multi-stage immersion type membrane distillation water treatment apparatus and method thereof,

The present invention relates to a membrane distillation water treatment apparatus and method, and more particularly to a membrane distillation water treatment apparatus and method in which a membrane distillation module unit and a heat exchange unit are immersed respectively in raw water of a multi-stage raw water tank, and vapors discharged from a membrane distillation module unit at a front end are used for heat exchange The present invention relates to a multi-stage impregnated membrane distillation water treatment apparatus capable of drastically reducing thermal energy required for heating raw water and a water treatment method therefor.

Membrane distillation technology is a process technology for separating water from raw water into pure steam using a porous membrane having a hydrophobic surface.

The raw water treated by the membrane distillation method comes into contact with one side of the separation membrane, but the raw water is not permeated into the pores of the separation membrane due to the surface tension generated due to the high hydrophobicity of the separation membrane surface. As a result, water can not permeate and only steam is allowed to pass through the separation membrane to produce fresh water from the steam.

The reason for the mass transfer in the membrane distillation process is due to the temperature difference formed between the raw water at a high temperature and the filtered water at a low temperature at the boundary of the separation membrane and the difference in the vapor pressure of the water formed by the temperature difference means that water And it becomes a driving force to move from the raw water to the filtrate water.

Membrane distillation can be performed by direct contact membrane distillation (DCMD), air gap membrane distillation (AGMD), sweep gas, or the like, depending on the method applied to the filtrate water to generate such a driving force, , Sweep Gas Membrane Distillation (SGMD), and Vacuum Membrane Distillation (VMD).

This membrane distillation method is a technology to treat the target water through phase change. It is a non-volatile pollutant removal rate close to 100%, operates at a lower pressure than the reverse osmosis method, and is resistant to membrane contamination. There are advantages to be able to.

Despite these advantages, however, a large amount of energy is required to heat the raw water above a certain temperature (usually 60-80 ° C) in order to generate a difference in vapor pressure, which is the driving force of the membrane distillation technique. In addition, there is a disadvantage in that energy is also consumed to condense the vapor passing through the membrane distillation module again.

Accordingly, there is a need in the art to develop a technique for improving the energy efficiency of the membrane distillation process.

Korean Patent Registration No. 10-1605535 Korean Registered Patent No. 10-1556915

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a steam generator for a steam turbine that immerses the MD module unit and the heat exchanger unit in each multi- The present invention provides a multi-stage immersion type membrane distillation water treatment apparatus and method capable of drastically reducing the heat energy required for condensation of the membrane.

In addition, the present invention allows the raw water temperature of each source to be constantly maintained through heat exchange in multi-stage heat exchangers immersed in each multi-stage source water tank, so that raw water can be converted into steam The present invention provides a multi-stage impregnated membrane distillation water treatment apparatus and method.

The multi-stage impregnated membrane distillation water treatment apparatus according to an embodiment of the present invention includes: a multi-stage (n) water tank for storing raw water therein; A multi-stage MD module unit immersed in the raw water for each of the multi-stage raw water tanks to discharge part of the raw water by steam; A multi-stage heat exchanger for immersing the raw water in each of the multi-stage raw water tanks and maintaining the temperature of the raw water in each of the multi-stage raw water tanks at a predetermined temperature through heat exchange with steam discharged from the MD module at the front end; A steam generator for generating steam at a high temperature and supplying the steam to the heat exchanger at the first stage; A condenser for condensing and discharging the steam supplied from the MD module at the last stage through heat exchange; And a raw water supply unit for supplying low-temperature raw water for heat exchange in the condenser to the raw water tank of the first stage through the condenser, wherein steam, which is heat-exchanged and discharged in the heat exchanger of the first stage, Is recovered.

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In the present invention, the apparatus further includes a filtration water tank for receiving and storing the vapor heat-exchanged and discharged from the second-stage to the n-th (n > = 3) heat-

At this time, the filtering water tank receives and stores the steam discharged from the condensing unit.

In the present invention, the steam generating unit supplies steam at a temperature higher than the temperature of the raw water in the raw water tank of the first stage to the heat exchanging unit of the first stage.

In the present invention, the MD module unit may include a vacuum type membrane distillation separation membrane, and further includes a vacuum pump for generating a vacuum pressure in an area where steam inside the MD unit unit is generated.

In the present invention, the multi-stage immersion type membrane distillation water treatment apparatus may further include: a temperature detector for detecting the temperature of raw water stored in the raw water tank of the first stage; And a steam temperature controller for controlling the temperature of the steam generated in the steam generator using the temperature of the raw water detected by the temperature detector.

In the present invention, the multi-stage source water tanks are connected to each other so that raw water from the first stage to the n < th > stage (integer of n 3) flows through the raw water tanks of the respective stages, And is discharged to the outside in time.

In the present invention, the raw water supply unit supplies raw water to each of the source water tanks of the second stage to the n-th stage (n is an integer of 3).

In the present invention, each of the multi-tier source water tanks further includes a multi-stage aeration unit which is installed in each of the multi-tiered source water tanks and aeration continuously or continuously in a predetermined period.

In addition, the multi-stage immersion type membrane distillation water treatment method according to the embodiment of the present invention includes a multi-stage MD module unit which is immersed in raw water in each multi-stage raw water tank and discharges a part of raw water by steam, And a multi-stage heat exchanging unit for maintaining the temperature of the raw water at a predetermined temperature for each of the multi-stage raw water tanks through heat exchange with steam. The method for membrane distillation water treatment in a membrane distillation water treatment apparatus, A first step of supplying raw water to a water tank; A second step of supplying high-temperature steam from the steam generating unit to the heat exchanging unit in the first stage; And the steam is converted into a part of the raw water in the MD module part of the first stage inside the raw water tank of the first stage where heat exchange is performed in the heat exchanging part of the first stage, To a heat exchange unit; A fourth step of sequentially repeating the third step until the n-th stage (n is an integer of 3) to the raw water tank; And a fifth step of condensing and discharging steam discharged from the n-th stage MD module unit through heat exchange in a condensing unit, and the steam discharged from the heat exchanging unit in the first stage is discharged to the steam generating unit do.

In the present invention, in the first step, heat is exchanged with steam using raw water supplied from the raw water supply unit in the condenser to condense the steam.

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In the present invention, the steam that is heat-exchanged and discharged from each of the second to n-th heat exchangers is supplied to the filtering water tank.

In the present invention, the steam generator supplies steam at a temperature higher than the temperature of the raw water of the raw water tank of the first stage to the heat exchanger of the first stage.

In the present invention, the multi-stage raw water tanks are connected to each other so that raw water flows from the first stage to the nth stage through the raw water tank of each stage, and the raw water is discharged to the outside at a predetermined time in the nth stage raw water tank.

In the present invention, the raw water supply unit supplies raw water to each of the second to n-th raw water tanks.

In the present invention, the second step and the third step include aeration continuously or at a predetermined period in the atmospheric portion immersed in the raw water for each of the multi-stage raw water tanks.

In the present invention, after the first step, the temperature detecting unit detects the temperature of raw water of the raw water tank of the first stage; And controlling the temperature of the steam generated in the steam generator in the steam temperature controller using the detected temperature of the raw water.

According to the present invention, the MD module units are immersed in a raw water tank and are connected in a multi-stage in series, and the latent heat energy of the steam generated at each stage is used for heating the raw water in the next stage. By using the raw water flowing into the water tank for heating, the thermal efficiency can be greatly improved as compared with the existing apparatus.

In addition, according to the present invention, since the raw water of the raw water tank is maintained at a constant temperature, steam of high temperature can be produced, and the energy consumption can be drastically reduced because the latent heat energy is recycled.

Further, according to the present invention, since the membrane distillation water treatment apparatus of the present invention is driven only by electric energy, the structure of the apparatus is simple and maintenance is easy.

In addition, the present invention can reduce the occurrence of film contamination of the MD module portion through aeration continuously or by a predetermined period by immersing the aeration device in the multi-stage raw water tank.

1 is a configuration diagram of a multi-stage immersion type membrane distillation water treatment apparatus according to an embodiment of the present invention.
2 is a flowchart illustrating a multi-stage immersion type membrane distillation water treatment method according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the difference that the embodiments of the present invention are not conclusive.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, May be "connected," "coupled, " or" connected. &Quot;

1 is a configuration diagram of a multi-stage immersion type membrane distillation water treatment apparatus according to an embodiment of the present invention.

1, a multi-stage immersion type membrane distillation and water treatment apparatus 100 according to the present invention includes a multi-stage raw water tank 101, a multi-stage membrane distillation module 102, a multi-stage heat exchanger 103, (104), a condenser (105), and a raw water supply unit (106).

In the raw water tank 101, n (integer numbers n > = 3) are arranged in a serial manner and are configured in multi-stages, and each stores raw water therein. The raw water can be supplied to the raw water tanks 101 of each stage in various ways. For example, raw water may be supplied to the source water tank 101 at each stage in the raw water supply unit 106 described later, or raw water may be supplied only to the source water tank 101a at the first stage at the forefront of the raw water supply unit 106, The first to n-th stage raw water tanks 101b to 101n are connected to each other and are connected to each other through the raw water tanks 101a of the first stage and the raw water tanks 101b to 101n- It is possible to supply the raw water to the water tank 101n. And the raw water is discharged to the outside at a predetermined time at the n-th stage raw water tank 101n at the last stage. This is to allow the raw water to flow out from the first stage to the nth stage while generating steam in the raw water, and when the concentration of the raw water is increased, the raw water is externally introduced.

Membrane Distillation (MD) module section 102 also has a multi-stage structure. Specifically, each stage of the MD module unit 102 is installed so as to be immersed in the raw water of the source water tank 101 at each stage. Each of the MD module units 102 of these stages discharges a part of the supplied raw water by steam and supplies it to the heat exchanging unit 103 at the next stage. That is, the steam discharged from the MD module 102a of the first stage, which is the foremost stage, is supplied to the second stage heat exchanger 103b, which is the next stage, and the steam discharged from the MD module 102b of the second stage, And is supplied to the third stage heat exchanger 103c as the next stage. The steam discharged from the MD module unit 102i of the i-th stage is supplied to the heat exchanger 103i + 1 of the (i + 1) th stage which is the next stage by repeating this process. The vapor discharged from the n-th stage MD module section 102n at the last stage is supplied to the condensing section 105 to be described later and condensed. Since the MD module 102n at the rearmost end (n-th stage) has no heat exchanger for discharging the steam at the rear end of the MD module 102n, the steam is discharged to the condenser 105, Condensate. The condensed steam becomes filtered water and supplied to the filtration water tank 107.

The MD module part 102 is divided into a raw water area and a steam area based on an internal membrane, and when the raw water in the raw water area contacts one surface of the membrane, due to the high hydrophobicity of the membrane surface, Is not permeated into the pores of the separator, but only the steam passes through the separator to collect the vapor into the vapor region. These vapors then become fresh water. In this way, in the MD module unit 102, due to the difference in temperature formed between the raw water at a high temperature and the steam at a low temperature, the water in the liquid state is converted into the vapor state, It is moving.

The heat exchanging unit 103 is also configured to be multi-stage, and is installed so as to be immersed in the raw water of the source water tank 101 at each stage. Each of the heat exchanging units 103 receives steam discharged from the MD module unit 102 at the front end. At this time, raw water in the source water tank 101 at each stage is converted into high temperature through heat exchange with such steam. Whereby the raw water in the source water tank 101 at each stage is maintained at a predetermined temperature. As described above, in the embodiment of the present invention, since the steam discharged from the front-end MD module unit 102 is supplied to the heat exchanging unit 103 at the subsequent stage, the heat exchanging unit 103 at the subsequent stage is required to supply the heat energy required for heat- So that the energy consumption can be reduced. In this way, the process of supplying the steam discharged from the shear stage to the rear stage is continuously performed in succession from the frontmost stage (first stage) to the rear stage (stage n).

The steam generating unit 104 generates high temperature steam and supplies it to the heat exchanging unit 103a at the first stage (the foremost stage). This is because, since the first stage heat exchanging unit 103 is not provided with the MD module of the front stage, the steam generating unit 104 can supply the high temperature steam to the heat exchanging unit 103a at the foremost stage . Such high-temperature steam is used for heat exchange with the raw water in the first-stage heat exchanger 103a. That is, the raw water needs to be maintained at a high temperature to convert the raw water to steam in the MD module. Since the raw water supplied from the raw water supply unit 106 is relatively low in temperature, in order to convert the raw water into high temperature, Heat exchange should take place. In order to perform such heat exchange, the steam generating unit 104 supplies high temperature steam to the heat exchanging unit 103a. At this time, it is preferable that the steam generating unit 104 supplies steam having a temperature higher than the temperature of raw water in the raw water tank 101a of the first stage to the heat exchanging unit 103a of the first stage. This is because the temperature of the steam must be higher than the temperature of the raw water in order to raise the temperature of the raw water through heat exchange between the steam and the raw water. The steam discharged from the heat exchanger 103a in the first stage is discharged to the steam generator 104 again. Therefore, the high-temperature steam supplied from the steam generating unit 104 to the heat-exchanging unit 103a at the first stage is discharged as relatively low-temperature steam after heat exchange with the raw water, And the steam generating unit 104 heats the steam again to supply the steam to the first heat exchanging unit 103a at a predetermined temperature.

The condenser 105 condenses the steam supplied from the MD module 102n at the n-th stage, which is the last stage, through heat exchange and discharges it to the filtration water tank 107. For this heat exchange, the condensing section 105 receives the low-temperature raw water from the raw water supply section 106. The steam supplied from the MD module 102n at the n-th stage is heat-exchanged with the raw water supplied from the raw water supply part 106 in the condensing part 105 and condensed and then discharged to the filtration water tank 107 .

The raw water supply unit 106 supplies raw water of low temperature to the raw water tank 101a of the first stage which is the foremost stage through the condensing unit 105. [ That is, when the low-temperature raw water is supplied to the first-stage raw water tank 101a, the raw water is supplied through the condenser 105 as described above, thereby condensing the steam in the condenser 105. [ In this manner, the raw water supply unit 106 supplies raw water to the raw water tank 101a at the first stage, but may supply raw water to each of the raw water tanks 101a to 101n at each stage as described above in other embodiments. At this time, the raw water supply unit 106 can supply the raw water to the raw water tank 101 using a pump (not shown).

As described above, in the embodiment of the present invention, the multi-stage MD module section 102 and the multi-stage heat exchange section 103 are immersed in the raw water in the multi-stage raw water tank 101 to repeatedly move and circulate raw water and steam So that the filtered water is continuously generated. Particularly, in this case, instead of generating fresh water directly from the steam discharged from the MD module unit 102 at each stage, the steam discharged from the MD module unit 102 at each stage is subjected to heat exchange in the heat exchanging unit 103 at the downstream stage And in the case of the heat exchanger of the foremost stage, the steam is supplied from the steam generator 104 to the heat exchanger 103 so that a separate heat source for supplying heat energy required for heat exchange in each stage heat exchanger 103 It is possible to provide a merit that the apparatus is not necessary and the use amount of heat energy can be remarkably reduced.

In the present invention, as described above, the steam that is heat-exchanged and discharged in the heat exchanging unit 103a of the first stage is returned to the steam generating unit 104, but the remaining heat exchanging units 102b to 102n ) Is supplied to the filtration water tank (107). The filtration water tank 107 is supplied with steam and stored therein. Also, the filtration water tank 107 also receives and stores the steam discharged from the n-th stage MD module unit 102n at the rearmost end. The vapor discharged from the MD module 102n at the n-th stage is supplied to the filtration water tank 107 via the condenser 105. In the condenser 105, And is condensed and supplied to the filtration water tank 107.

The multi-stage immersion type membrane distillation water treatment apparatus 100 according to the present invention includes a temperature detection unit 109 for detecting the temperature of the raw water stored in the raw water tank 101a at the first stage, And a steam temperature controller 110 for controlling the steam generator 104 using the steam temperature controller 110. In addition, the multi-stage immersion type membrane distillation water treatment apparatus 100 may further include a vacuum pump 111 or an aeration portion 108 selectively.

The temperature detection unit 109 detects the temperature of the raw water stored in the raw water tank 101a of the first stage in real time and transfers the detected temperature to the steam temperature control unit 110. [ Then, the steam temperature control unit 110 controls the operation of the steam generator 104 so that the temperature of the raw water tank 101a of the first stage becomes a predetermined temperature according to the detected temperature. For example, when the temperature of the source water tank 101a of the first stage is lower than a predetermined reference temperature, the steam generator 104 is controlled to generate steam at a higher temperature in the steam generator 104, And controls the steam generating unit 104 to generate steam at a lower temperature when the temperature is higher than the predetermined temperature. This is for keeping the temperature of the raw water stored in the raw water tank 101a of the first stage at a predetermined temperature constant.

The vacuum pump 111 generates a vacuum pressure in a region where steam is generated in the MD module unit 102. The MD module unit 102 according to the present invention may include various types of membrane distillation membranes. For example, in the embodiment of the present invention, it is preferable to include a vacuum type membrane distillation separation membrane. However, the present invention is not limited thereto, and other types of membrane distillation separation membranes known in the art can be applied as long as raw water can be discharged by steam. For example, a vacuum pump 111 is used to generate a vacuum pressure in the vapor region of the MD module unit 102 at each stage in order to implement a Vacuum Membrane Distillation (VMD) module. In this embodiment, after the raw water is supplied to the source water tank 101 at each stage, the steam generating area of the MD module unit 102 at each stage maintains the vacuum pressure lower than the vapor pressure by the vacuum pump 111. [ At this time, the amount and temperature of the steam generated in the MD module unit 102 at each stage can be predicted through the following equations (1) to (4) to control the steam pressure at each stage. First, the water permeation flux Jw, which is the production flow rate (m 3) per unit time (1 hr) per unit area (1 m 2) in the MD module unit 102 and the temperature T m ) Can be obtained.

Tm is the temperature of the raw water on the surface of the membrane module of the MD module part = temperature of the steam, Cm is the temperature of the membrane module on the surface of the membrane module of the MD module part, Jw is the water permeation flux, AB is the water permeability coefficient in the MD module part, Pv is the vapor pressure, And P0 is the vacuum pressure.

K is the mass transfer coefficient, ln is the natural logarithm, and Cb is the salt concentration of the raw water.

Where Hv is the latent heat of evaporation of water, hw is the heat transfer coefficient, and Tb is the temperature of the raw water.

Here, the vapor pressure of the raw water can be calculated through Equation (4). By adjusting the vacuum pressure P0, it is possible to control the production amount and the temperature of the steam.

The aeration unit 108 is provided so as to be immersed in the raw water in each of the source water tanks 101 at each stage and is allowed to continuously or aeration according to a predetermined cycle. Through this aeration, contaminants and the like attached to the membrane module of the MD module unit 102 are removed. For example, the aeration section 108 generates air bubbles in the raw water to remove contaminants attached to the membrane module by air bubbles.

2 is a flowchart illustrating a multi-stage immersion type membrane distillation water treatment method according to an embodiment of the present invention.

Referring to FIG. 2, in the multi-stage immersion type membrane distillation water treatment method according to the present invention, raw water is stored for each of the multi-stage raw water tanks 101a to 101n, The MD module units 102a to 102n and the multi-stage heat exchanging units 103a to 103n are respectively immersed in the multi-stage immersion type membrane distillation water treatment apparatus.

The raw water supply unit 106 supplies raw water of low temperature to the raw water tank 101a of the first stage (S101). The high-temperature steam is supplied from the steam generator 104 to the first heat exchanger 103a (S103). In the heat exchanging portion 103a, the high-temperature steam supplied and the low-temperature raw water are heat-exchanged with each other (S105). By this heat exchange, the temperature of the raw water in the raw water tank 101a of the first stage is maintained at a preset high temperature. After the heat exchange in the heat exchanging part 103a of the first stage, the steam is recovered to the steam generating part 104 again.

Subsequently, the MD module 102a of the first stage converts part of the high-temperature raw water into steam (S107) and supplies the steam to the second-stage heat exchanger 103b (S109). The heat exchanging unit 103b of the second stage performs heat exchange between the supplied steam and the raw water in the raw water tank 101b of the second stage (S111). By this heat exchange, the raw water is converted into high temperature.

Steps S107, S109, and S111 are continuously performed up to the n-th stage (S113). That is, the high-temperature steam is supplied from the front-end MD module unit 102 to the downstream heat exchanger 103, and the heat exchanger 103 at the downstream stage performs heat exchange between the supplied steam and the raw water. It continues to the n-th stage of the unit.

If the heat exchange is performed in the n-th stage heat exchanger 103n at the rearmost end (S115), the MD module unit 102n at the n-th stage does not have a rear end and is discharged The steam is supplied to the condensing section 105 in step S117 and the condensation section 105 condenses the steam through the heat exchange using the low temperature raw water supplied from the raw water supply section 106 in step S119, (S121). That is, since there is no downstream end in the n-th stage of the MD module 102n, the steam discharged from the n-th MD module 102n is supplied to the condenser 105, The steam is condensed through the heat exchange between the low-temperature raw water supplied from the steam generator 106 and the steam, and the condensed filtrate is supplied to the filtration water tank 107.

In addition, although not shown in the drawing, when foreign substances accumulate in the raw water circulated while steam is generated while the raw water is circulated in the multi-stage MD module unit 102, or when the concentration of the raw water becomes high, It can be discharged to the outside. In particular, when the raw water tanks 101 at each stage are connected to each other and raw water flows from the first stage to the n-th stage, the raw water is discharged to the outside at a predetermined time by the n-th stage raw water tank 101n.

In the aeration unit 108, the raw water is immersed in the raw water for each stage of the respective stages and aerated continuously or in accordance with a predetermined period to remove contaminants and the like attached to the membrane modules of the respective MD modules 102 Remove it.

As described above, in the multistage immersion type membrane distillation water treatment apparatus and method according to the present invention, the vapor discharged from the MD module section at the front end is supplied to the heat exchanging section at the downstream end, and the vapor at the upstream end is used for heat exchange at the downstream end. A part of the steam discharged from the MD module part is compressed at the vapor pressure shaft part and converted into high temperature steam so as to be supplied to the heat exchanging part at the foremost stage and used for the heat exchange at the most upstream part, The amount of use can be drastically reduced, and a separate heat energy source for heat exchange with raw water is not required. Therefore, the implementation cost of the apparatus is low, and the system is simple and easy to maintain.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. Furthermore, the terms "comprises", "comprising", or "having" described above mean that a component can be implanted unless otherwise specifically stated, But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

101, 101a to 101n: source water tanks 102, 102a to 102n: membrane distillation (MD)
103, 103a to 103n: heat exchanger 104: steam generator
105: condensing part 106: raw water supply part
107: Filtration water tank 108, 108a-108n:
109: Temperature detection unit 110: Steam temperature control unit
111: Vacuum pump

Claims (19)

A plurality of raw water tanks each storing raw water therein;
A multi-stage MD module unit immersed in the raw water for each of the multi-stage raw water tanks and discharging part of the raw water as steam;
A multi-stage heat exchange unit for maintaining the temperature of the raw water in each of the multi-stage source water tanks through respective heat exchanges with the steam discharged from the front-end MD module unit,
A steam generator for generating high temperature steam and supplying the high temperature steam to the first stage heat exchanger;
A condenser for condensing and discharging the steam supplied from the MD module at the last stage through heat exchange; And
And a raw water supply unit for supplying raw water of low temperature to the raw water tank of the first stage through the condensing unit for heat exchange in the condensing unit,
Wherein the steam exchanged in the heat exchanging unit of the first stage is discharged to the steam generating unit. delete The method according to claim 1,
Further comprising a filtration water tank for receiving and storing the vapor heat-exchanged and discharged respectively in the second to n-th stages (n > = 3) heat exchange units. The method of claim 3,
Wherein the filtering water tank receives and stores the steam discharged from the condensing unit. The method according to claim 1,
Wherein the steam generator supplies the steam at a temperature higher than the temperature of the raw water inside the raw water tank of the first stage to the heat exchanger of the first stage. The method according to claim 1,
Wherein the MD module unit includes a vacuum type membrane distillation separation membrane and further comprises a vacuum pump for generating a vacuum pressure in an area where steam is generated for each of the MD modules. The method according to claim 1,
A temperature detector for detecting the temperature of raw water stored in the source water tank of the first stage; And
A steam temperature controller for controlling the temperature of the steam generated in the steam generator using the temperature of the raw water detected by the temperature detector; Further comprising the steps of: The method according to claim 1,
The multi-stage source water tanks are connected to each other so that raw water flows from the first stage to the n-th stage (an integer of n? 3) through the source water tanks of each stage, and in the source tank of the nth stage, A multi-stage immersion membrane distillation water treatment apparatus. The method according to claim 1,
Wherein the raw water supply unit supplies the raw water to the source water tanks of the second stage to the n-th stage (integer of n? 3), respectively. 10. The method according to any one of claims 1 to 9,
Wherein the multi-stage immersion water treatment apparatus further comprises a multi-stage immersion water treatment unit which is installed in each of the multi-stage raw water tanks and which augments continuously or continuously in a predetermined period. The temperature of the raw water is preset for each multi-stage raw water tank through heat exchange between the multi-stage MD module unit which is immersed in the raw water in each of the multi-stage raw water tanks and discharges part of the raw water by steam and steam supplied from the MD module unit of the previous stage In a membrane distillation water treatment apparatus comprising a multi-stage heat exchanging unit for maintaining a temperature of the multi-
A first step of supplying raw water from the raw water supply unit to the raw water tank of the first stage;
A second step of supplying high-temperature steam from the steam generating unit to the heat exchanging unit in the first stage;
And the steam is converted into a part of the raw water in the MD module part of the first stage inside the raw water tank of the first stage where heat exchange is performed in the heat exchanging part of the first stage, To a heat exchange unit;
A fourth step of sequentially repeating the third step until the n-th stage (n is an integer of 3) to the raw water tank; And
A fifth step of condensing the vapor discharged from the n-th stage MD module part through heat exchange in a condensing part and discharging the vapor; Lt; / RTI >
Wherein the vapor exchanged in the heat exchanging unit of the first stage is discharged to the steam generating unit. 12. The method according to claim 11,
And the steam is condensed by performing heat exchange with the steam using the raw water supplied from the raw water supply unit in the condensing unit. delete 13. The method of claim 12,
Wherein the steam exchanged in the second to n-th heat exchanging units is supplied to the filtering water tank. 12. The method of claim 11,
Wherein the steam generating unit supplies steam having a temperature higher than the temperature of the raw water of the raw water tank of the first stage to the heat exchanging unit of the first stage. 12. The method of claim 11,
Wherein the multi-stage raw water tanks are connected to each other so that raw water flows from the first stage to the n-th stage through the raw water tank of each stage, and in the raw water tank of the n-th stage, Water treatment method. 12. The method of claim 11,
Wherein the raw water supply unit supplies raw water to each of the second to n-th raw water tanks. 12. The method of claim 11, wherein the second and third steps comprise:
And continuously aerating the raw water in the raw water for each of the multi-stage raw water tanks in accordance with a predetermined cycle. 12. The method of claim 11, wherein after the first step,
Detecting the temperature of the raw water of the raw water tank of the first stage in the temperature detection unit; And
Controlling the temperature of the steam generated in the steam generating unit in the steam temperature control unit using the temperature of the raw water; Further comprising the steps of:

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