KR101766780B1

KR101766780B1 - Spacer for enhancing power density and reverse electrodialysis electric generating device comprising the spacer

Info

Publication number: KR101766780B1
Application number: KR1020150164285A
Authority: KR
Inventors: 김한기; 김찬수; 정남조; 나종찬; 이서윤
Original assignee: 한국에너지기술연구원
Priority date: 2014-11-21
Filing date: 2015-11-23
Publication date: 2017-08-11
Also published as: KR20160061894A

Abstract

The present invention relates to a spacer used in a reverse electrodialyzone generator and a reverse electrodialyzer comprising the same, wherein the spacer has a line opening of 150 to 1200 μm and an open area of 59 to 90% And a reverse electrodialysis power generation device including
According to the present invention as described above, it is possible to improve the effective area of an electrode or a film in an RED power generation device or the like by providing a spacer having a high open area.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for improving power density and a reverse electrodialysis

The present invention relates to a spacer used in a reverse electrodialysis power generation apparatus and a reverse electrodialysis power generation apparatus including the same, and more particularly, to a method of manufacturing a spacer using a spacer for improving power density, The present invention relates to a spacer which can be minimized.

In RED (Reverse Electro-Dialysis), the spacer prevents the contact between the cation and the anion exchange membrane, increases the electrochemical potential, secures the channel for seawater and fresh water, And it plays a role of reducing concentration polarization occurring at the interface between ion exchange membrane and seawater and fresh water. However, the portion of the ion exchange membrane and the spacer is not directly contacted with the seawater and the fresh water, and therefore, the electrochemical potential is not formed. This is called a shadow effect by the spacer.

In order to minimize the shading effect by the spacer, it is preferable to use a spacer having the maximum open area, and finally, it is preferable to construct a RED cell which does not use a spacer.

In order to solve the above-mentioned problem of the spacer, a channel is directly formed in the ion exchange membrane and is called a profiled membrane. The profile membrane can minimize problems such as the shading effect caused by the use of the spacer, but the ion exchange membrane must have a certain thickness or more in order to engrave a certain type of flow path in the membrane. The performance of the ion exchange membrane suitable for the profile membrane, It is a betrayal of exchange membrane performance. So far, the output density using a profile membrane is at most 0.8 W / m ² , which is about 50% of the world's highest RED generation density reported so far.

The ion exchange membrane suitable for RED must be thinner than the ion exchange membrane used for ED (Electro-Dialysis), etc., and does not require a support and does not require a large mechanical strength. Also, in general, the inhomogeneous membrane has a relatively high electrical resistance due to structural reasons as compared to the homogeneous membrane. The properties of such ion exchange membranes are a direct cause of lowering the output density of RED in actual research results. It is reported that the RED has to have a power density of 2.0 W / m ² or more per weak ion-exchange membrane area in order to commercialize it.

Also, in the case of the profile membrane, there is a technical difficulty in matching the positions of the channels formed in seawater and fresh water in the assembling process, and the formed seawater and the fresh water channel have limitations in stably maintaining them from pressure and electrostatic osmosis. Further, the profile membrane requires an additional manufacturing process, which raises the unit price of the ion exchange membrane and makes it difficult to match the position of the flow path formed in the ion exchange membrane in the assembly process.

Korean Patent Registration No. 10-1394081

It is an object of the present invention to minimize the hydraulic losses occurring in the seawater and the fresh water channel inside the RED cell by using a spacer having a high opening area that can maximize the use area of the ion exchange membrane.

In order to achieve the above object, the present invention provides a spacer having an inter-line gap of 150 to 1200 μm and an open area of 59 to 90%.

The spacer may have a thickness of 0.1 to 0.2 mm.

The material of the spacer may be at least one material selected from the group consisting of polyester, polyethylene terephthalide, polyethylene, polypropylene and polytetrafluoroethylene, and the material of the spacer may further include a carbon-based yarn .

According to another aspect of the present invention, there is provided a plasma display panel comprising: an anode electrode and a cathode electrode arranged opposite to each other; A plurality of cation exchange membranes and a plurality of anion exchange membranes disposed alternately between the node electrode and the cathode electrode; And a spacer interposed between the cation exchange membrane and the anion exchange membrane, wherein the spacing of the spacers is 150-1200 占 퐉 and has an open area of 59-90% Providing the device is another aspect.

The spacer may have a thickness of 0.1 to 0.2 mm.

The spacer may be made of one or more materials selected from the group consisting of polyester, polyethylene terephthalide, polyethylene, polypropylene, and polytetrafluoroethylene. The material of the spacer may be a carbon- .

The cation exchange membrane and the anion exchange membrane are homogeneous membranes having an electrical resistance of 3 Ω / cm ² or less and a thickness of 2 mm or less.

According to the present invention, there is provided a spacer for improving the effective area of an electrode or a film in an RED power generation apparatus or the like and improving the output density of the RED power generation apparatus by setting the material of the spacer, the gap between the wires, It is effective.

Further, the spacer according to an embodiment of the present invention has an effect of minimizing the hydraulic loss occurring in the seawater and the fresh water channel inside the RED cell.

Figure 1 shows a micrograph of a conventional spacer and profile membrane.
2A shows a photograph of a conventional spacer.
2B is a photograph of a spacer according to an embodiment of the present invention.
FIG. 3 shows a configuration diagram of a reverse electrodialysis and estroation apparatus according to another embodiment of the present invention.
4 is an enlarged view of a spacer according to an aspect of the present invention.
FIG. 5 is a graph showing changes in an open area according to a change in line spacing of spacers according to an embodiment of the present invention.
FIGS. 6 and 7 are graphs comparing output densities of openings of the same material of a spacer according to an embodiment of the present invention. FIG.
8 is a graph illustrating changes in RED output according to the type of the spacer according to an embodiment of the present invention.
FIG. 9 is a graph showing a change in electrical resistance value of seawater and a fresh water channel according to a thickness change of a spacer according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

FIG. 3 shows a configuration of a reverse electrodialyzed generator including a spacer according to an embodiment of the present invention.

4 is an enlarged view of a spacer according to an aspect of the present invention.

3 and 4, a spacer 100 having an improved open area according to an embodiment of the present invention has an opening area w of 150 to 1200 μm and an open area a ₀ of 59 to 90% Respectively. Among the characteristics of the spacer, the size of the mesh (space) possessed by the spacer can be expressed through the interval (opening, w) between the lines. The spacing between the lines (opening, w) is a major factor in determining the porosity of the mesh, and is a factor that determines the cut-off size and the precision of printing when used for filtering and printing applications, (w) can be expressed as Equation (1) below.

Equation 1: spacing between lines (opening, w) = (25,400 / scale number per area) - (diameter)

The open area is determined by the mesh count, the thread diameter, and the gap between the lines (opening, w). The open area (a ₀ ) is calculated as a function of the distance (w) between the line diameter (d) and the ship's ship, and can be calculated by the following equation (2).

(Open area, a ₀ ) = {line spacing w / line spacing w + line diameter d ² } 100

The spacers 100 may have a thickness h of 0.1 to 0.2 mm. When it is less than 0.1 mm, it is not easy to secure the flow path of seawater and fresh water, and when it exceeds 0.2 mm, the electrical resistance is increased and the efficiency of the ion exchange membrane is decreased.

The material of the spacer 100 may be at least one selected from the group consisting of polyester, polyethylene terephthalide, polyethylene, polypropylene, and polytetrafluoroethylene.

The spacer 100 may further include a carbon-based yarn. Preferably, the carbon-based raw material is a poly (ethylene terephthalate) glycol (CAS No. 25038-59-9) (CAS No .: 13463-67-7), Carbon black (CAS No .: 1333-86-4), Surfactant, and preferably poly (C ₁₀ H ₈ O ₄ ) _n ), TiO _2, and carbon black are used as a carbon-based yarn to improve electrical conductivity.

In the case of a conventional spacer having a thickness of 0.1 mm, the opening has a value between 100 and 200, and an open area of 45 to 57% in a spacer of 1 layer type is obtained. That is, when 1 m ² of ion exchange membrane is used in RED, the area of ion exchange membrane that can actually be used is about 0.5 m ² . Also, when the thickness is 0.2 mm, the opening has a value between 200 and 300, and the opening area has 42 to 51%. In both cases, they do not have an open area of up to 60%.

The opening (w), the open area (a ₀ ), the diameter (d), etc. between the lines in the spacer 100 according to an embodiment of the present invention are different from each other depending on the material. In the case of having a thickness (L) of 0.1 mm, a mesh using a raw material containing carbon black or the like has an opening (w) of 150 or more and an open area of 59% In the case of a mesh fabricated using the above method, the opening (w) between lines may be 300 or more and the open area (a ₀ ) may be 72% or more. Also, when the thickness L is 0.1 to 0.2 mm, the maximum line opening (w) is 1100 or more and the open area (a ₀ ) is 84.9%. In addition, it is possible to make the gap (opening, w) between the maximum lines to be not less than 1100 and the open area (a ₀ ) to be not less than 85% without limiting the thickness L in the production and selection of the spacer. On the other hand, as the distance between lines (opening, w) increases, the open area (a ₀ ) increases, but as the threshold, the open area (a ₀ ) can not exceed 90%.

The spacer is disposed between the cation and the anion exchange membranes to secure a channel through which seawater and fresh water can flow, and to prevent contact between the ion exchange membranes to secure space for increasing the electrochemical potential. In addition, the spacers form turbulence in the flow of seawater and fresh water, thereby reducing concentration polarization occurring at the interface between the ion exchange membrane and seawater and fresh water. The thickness of the spacer is the same as the flow path of seawater or fresh water in the cell in the reverse electrodeposition generator (RED), and the interval between the cation exchange membrane and the anion exchange membrane is determined. As the interval between the ion exchange membranes is shortened, The resistance is also reduced. Therefore, it is preferable to consider the compressibility of the gasket and the thickness of the spacer, and optimize the interval between the ion exchange membranes in consideration of the pressure loss due to the flow of the influent in the RED stack.

The RED cell includes an anion exchange membrane, a spacer and a cation exchange membrane, and the hydraulic energy loss in the RED cell is mainly caused by a pressure drop inside the cell.

In addition to the RED power generation devices, the spacers can also be used for electrodialysis (ED), diffusion dialysis, electrodialysis reversal (EDR), electric deionization (EDI), capacitive deionization (CDI) the effective area of the electrode or membrane can be increased by up to 30% compared with the conventional one in the desalination process such as reverse osmosis (RO), forward osmosis (FO), and electrochemical water treatment technique using electrode and ion exchange membrane such as electrode capacitive deionization have.

The electrical resistance R in the RED cell can be expressed by the following Equation 3, and the electrical resistance R is dependent on the thickness of the spacer (the thickness of the flow path) when Equation 3 is taken into consideration. More particularly, on the thickness of the fresh water area.

Equation 3:

(h: thickness (m) of the spacer (flow path),?: porosity of the spacer,?: electric conductivity of the oil (S / m)

The net power efficiency (P _net ) in the RED can be calculated from Equation 4, which excludes the pressure loss inside the stack at the total generated energy (P _gross )

Equation 4:

(OCV: electric potential of RED cell when current is 0, Ri: internal resistance of RED cell, Δp: pressure loss, q: flow rate, L:

The reverse electrodeposition generator device 10 according to another embodiment of the present invention includes an anode electrode 210 and a cathode electrode 230 facing each other; A plurality of cation exchange membranes 310 and a plurality of anion exchange membranes 330 alternately disposed between the node electrode 210 and the cathode electrode 230; And a spacer 100 interposed between the cation exchange membrane 310 and the anion exchange membrane 330. The spacer 100 may have a mesh size and a diameter ratio η of 5 or more and an open area of 70% .

The spacer 100 may have a thickness h of 0.05 to 0.2 mm. More preferably, the spacer 130 forming the fresh water channel has a thickness h ₁ of 0.05 to 0.1 mm and the spacer 110 forming the sea water channel may have a thickness h ₂ of 0.15 to 0.2 mm.

The cation exchange membrane 310 and the anion exchange membrane 330 are homogeneous membranes having an electrical resistance of 3 Ω / cm ² or less and a thickness of 2 mm or less. The heterogeneous membrane has a resistance value of more than 2 times as compared with the homogeneous membrane with an electrical resistance value of 8 Ω / cm ² , which reduces the power density of the electrodialysis power plant.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

Example 1.

Conventional single spacers, twisted spacers, profiled spacers, spacers according to one embodiment of the present invention and their output values were measured and shown in Table 1.

Conventional Spacer And Spacer Characteristics and Output value (D. Vermas Etc., 2014) Normal Spacer Twisted Spacer Profiled Spacer This Patent This Patent Membrane Ralex® AMH / CMH-PES Tokuyama AMV / CMV Type 1 Layer 2 Layer No spacer 1 Layer 1 Layer Material PA PA - PET PET
+
Carbon black Open Area (%) 46 83 83 84.9 59.2 Porosity (%) 72 88 83 - - Power density (W / m ² ) ~ 0.4
(Net) ~ 0.6
(Net) ~ 0.8
(Net) 1.4
(Gross) 1.84
(Gross)

Referring to Table 1, when the material of the spacer is employed as a material of polyethylene terephthalide (1.4 W / m ² ) and polyethylene terephthalate + carbon black (1.84 W / m ² ), conventional spacers are employed, It can be confirmed that the output density is improved.

Example 2.

The output values of the reverse electrodeposition generator according to the change of the mesh size and the diameter ratio of the wire diameter, the thickness, and the open area of the spacer according to an embodiment of the present invention were measured and are summarized in Table 2, Respectively.

Spacer thickness, Material, line Spacing (opening), Spacer Change in RED Output with Open Area Change Name Material Mesh Count Thread Opening Open Area (%) Power Density (W / m ² ) Nominal Thickness 0.1 mm TYPE 1 (Black 130) Polyester + Carbon Black 130 45 150.4 59.2 1.84 TYPE 2 (Black 180) Polyester + Carbon Black 180 45 96.1 46.4 1.66 TYPE 3 (White 90) Polyester 90 45 237.2 70.7 1.75 TYPE 4 (White 70) Polyester 70 55 307.9 72.0 1.81 Sefar 03-160 / 53 Nylon 114 61 160 53.0 - Sefar 03-125 / 45 Nylon 135 62 125 45.0 - Sefar 03-190 / 57 Nylon 102 62 190 57.0 - Nominal Thickness 0.2 mm TYPE 5 (White 25) Polyester 20 100 1170.0 84.9 1.4 PE 80 PE 58 - 285 40.3 1.0 Sefar 03-300 / 51 Nylon 61 122 300 51.0 1.1 Sefar 03-225 / 42 Nylon 74 122 225 42.0 -

Referring to Table 2, when the thickness of the spacer is 0.1 mm (Type 1 to 4), the output density is higher than that when the thickness is 0.2 mm (Type 5) and the same thickness and the same material It can be seen that the higher the open area, the higher the output density.

Example 3.

FIG. 9 shows changes in the electrical resistance values of the seawater and the fresh water channel according to the thickness of the spacer according to an embodiment of the present invention at a spacer porosity of 80%, a seawater of 50 mS / cm and a fresh water of 200 uS / cm . 9, when the thickness of the fresh water channel was fixed to 0.1, 0.2 and 0.3 mm, the electric resistance value inside the RED cell was constant even when the thickness of the sea water channel was changed, but the thickness of the sea water channel was 0.1 and 0.2 mm As the thickness of the fresh water channel was increased, the electric resistance value inside the RED cell was increased. It can be seen that the electric resistance value inside the RED cell is closely related to the thickness of the fresh water channel, and that the smaller the thickness of the fresh water channel is, the smaller the electric resistance value inside the RED cell is.

Having described specific portions of the present invention in detail, those skilled in the art will appreciate that these specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

10: Reverse electrodialysis and estrus apparatus 100: Spacer
210: anode electrode 230: cathode electrode
300: ion exchange membrane 310: cation exchange membrane
330: Cation exchange membrane

Claims

The line-to-line spacing is 150 to 1200 μm, the open area is 59 to 90%
At least one material selected from the group consisting of polyester, polyethylene terephthalide, polyethylene, polypropylene and polytetrafluoroethylene,
Wherein the material comprises a carbon based yarn.

The method according to claim 1,
Wherein the spacer has a thickness of 0.1 to 0.2 mm.

delete

An anode electrode and a cathode electrode provided opposite to each other;
A plurality of cation exchange membranes and a plurality of anion exchange membranes disposed alternately between the node electrode and the cathode electrode; And
And a spacer interposed between the cation exchange membrane and the anion exchange membrane,
Wherein the spacers have a line spacing of 150-1200 占 퐉 and an open area of 59-90% and are selected from the group consisting of polyesters, polyethylene terephthalate, polyethylene, polypropylene, and polytetrafluoroethylene Wherein the at least one material is a carbon-based yarn.

6. The method of claim 5,
Wherein the spacer has a thickness of 0.1 to 0.2 mm.

delete

6. The method of claim 5,
Wherein the cation exchange membrane and the anion exchange membrane are homogeneous membranes having an electrical resistance of 3 Ω / cm ² or less and a thickness of 2 mm or less.