JP2002343689A - Regeneration method of liquid passing type electric double-layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regeneration method of a fluid-passing type electric double-layer capacitor where its demineralization efficiency and be kept properly. SOLUTION: In the regeneration method of a fluid-passing type electric double-layer capacitor 2, its anode-side and cathode-side electrodes are subjected to a short-circuiting or connected in reverse, and warmed water, having water temperature not lower than 40 deg.C, is fed to it through a warmed water feed passage 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the supply of water for boilers of power plants, the production of semiconductors, the production of pure water used for fuel cell power generation, the production of water for cooling towers, the recycle use, and the collection of various wastewaters. The present invention relates to a method for regenerating a flow-through type electric double layer capacitor to be used.

[0002]

2. Description of the Related Art Conventionally, a deionizer equipped with an ion-exchange membrane or an ion-exchange resin has been used for pure water production and the like. A pure water apparatus using an ion exchange membrane or an ion exchange resin usually requires regeneration and replacement of the membrane and the resin. However, improvement in work efficiency has been desired. In recent years, as a pure water production device that can improve such inconvenience regarding replacement and regeneration,
A deionization device called a flow-through type electric double layer capacitor is provided. As this liquid-permeation type electric double layer capacitor, those described in JP-A-6-325983 can be exemplified. The flow-through type electric double layer capacitor has a configuration in which two high-surface-area conductor layers are sandwiched by a fluid passage therebetween, and a collector is arranged outside these conductor layers. By applying voltage to
The ionic substance in the supply water flowing through the liquid passage is electrically adsorbed on the conductor layer, so that treated water having a reduced ionic substance concentration can be obtained. Activated carbon is suitable as a conductor constituting the conductor layer. In a flow-through type electric double layer capacitor, before the adsorption of the ionic substance to the conductor layer reaches saturation, the anode side and the cathode side are short-circuited or connected in reverse, and cleaning water is supplied to remove the ionic substance. A regeneration process for desorbing substances and discharging them as washing wastewater is performed periodically.

[0003]

However, in the conventional reproducing method, there is a problem that the ionic substance is easily desorbed from the conductive layer and the desalting efficiency is deteriorated.
Also, if microorganisms grow in the flow-through type electric double layer capacitor, these microorganisms may be separated at the time of passing water and flow out with the treated water, which may cause microbial contamination in downstream equipment. It was desired to control breeding. Also, scale was sometimes generated in the liquid-permeation type electric double layer capacitor. In particular, when a large amount of metal ions such as Ca or silica is contained in the supply water, scale is likely to occur, and it has been desired to suppress the generation of scale. The present invention has been made in view of the above circumstances, and the following three objects can be given as its objects. (1) To provide a regenerating method capable of maintaining good desalination efficiency of a flow-through type electric double layer capacitor. (2) To provide a regeneration method capable of suppressing the growth of microorganisms in a flow-through type electric double layer capacitor. (3) To provide a regenerating method capable of preventing the generation of scale in a flow-through type electric double layer capacitor.

[0004]

According to the present invention, there is provided a method for regenerating a liquid-permeation type electric double-layer capacitor, comprising: short-circuiting or reverse-connecting an anode and a cathode of a liquid-permeation type electric double-layer capacitor; It is characterized in that hot water having a water temperature of 40 ° C. or higher is supplied to the electric double layer capacitor. In the regeneration method of the present invention, a method of supplying acidic water having a pH of 6 or less to the flow-through type electric double layer capacitor can also be adopted. In the regeneration method of the present invention, a pH 8
The above-described method of supplying alkaline water can also be adopted. In the regeneration method of the present invention, a method of supplying ultrapure water to the liquid-permeation type electric double layer capacitor can also be adopted.
In the regeneration method of the present invention, a method of supplying hydrogen-containing water to the flow-through type electric double layer capacitor can also be adopted. Further, in the present invention, in the regeneration step of the flow-through type electric double layer capacitor, two or more of the above-mentioned hot water, acidic water, alkaline water, ultrapure water, and hydrogen-containing water are supplied to the flow-through type electric double layer capacitor. A method can also be adopted.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIG. 1 shows a pure water producing apparatus which can be suitably used for carrying out the method for regenerating a flow-through type electric double layer capacitor of the present invention. The electric double layer condenser 2 for electrically adsorbing and removing ionic substances is provided with a hot water supply path 3 for supplying hot water to the electric double layer condenser 2.

[0006] The flow-through type electric double layer capacitor 2 is shown in FIG.
As shown in (a) and (b), activated carbon layers 6 and 6, which are conductor layers mainly composed of activated carbon having a high specific surface area, are arranged with a separator 5 made of an electrically insulating porous liquid-permeable sheet interposed therebetween. ,
Collector electrodes 7, 7 are arranged outside these activated carbon layers 6, 6,
Further, the plate-shaped one is formed by arranging press plates 9, 9 via gaskets 8, 8 outside these collector electrodes 7, 7.

[0007] The separator 5 serves as a liquid passage for supplying water, and is made of an organic or inorganic material such as filter paper, porous polymer membrane, woven fabric, nonwoven fabric, etc., through which liquid can easily pass and which has electrical insulation. The thickness of the sheet is about 0.01 to 0.5 mm, particularly 0.02 to 0.3 mm.
mm is preferable.

The activated carbon layer 6 is formed by a layer mainly composed of activated carbon having a high specific surface area. The high specific surface area activated carbon has a BET specific surface area of 1000 m ² / g or more, preferably 1500 m ² / g or more, more preferably 200 m ² / g or more.
0 to 2500 m ² / g activated carbon. If the BET specific surface area is too small, the removal rate of the ionic substance when passing through a liquid (raw water) containing the ionic substance decreases.
If the BET specific surface area is too large, the removal rate of the ionic substance tends to decrease rather.
It is not necessary to increase the T specific surface area more than necessary.

The activated carbon constituting the activated carbon layer 6 may be in any form, such as powder or granules, or fibrous.
In the case of a powdery or granular material, it is used after being formed into a flat plate or a sheet. In the case of a fibrous material, it is used after being processed into a woven or nonwoven fabric. When powdered and granular activated carbon is formed into a flat plate or sheet, it is significantly more advantageous in terms of cost than when fibrous activated carbon is processed into a woven or nonwoven fabric.

For forming the granular activated carbon into a flat plate or a sheet, for example, the granular activated carbon is mixed with a binder component (polytetrafluoroethylene, phenol resin, carbon black, etc.) and / or a dispersion medium (solvent, etc.). This can be carried out by forming into a plate shape and, if necessary, subjecting it to a heat treatment. When the activated carbon layers 6 and 6 are formed into a flat plate or a sheet, the perforations may be formed as necessary. The thickness of the activated carbon layer 6 is preferably about 0.1 to 3 mm, particularly about 0.5 to 2 mm, but is not necessarily limited to this range.

The collector 7 is made of a good electrical conductor such as a copper plate, an aluminum plate, a carbon plate, or foil-like graphite, and is formed and arranged in close contact with the activated carbon layer 6. The thickness of the collector 7 is not particularly limited, but is preferably about 0.1 to 0.5 mm. Note that each of the collector electrodes 7 is provided with a terminal (lead) 7a to facilitate application of a voltage.

As the holding plate 9, a flat plate made of a material such as resin which is electrically insulating and hardly deformed is used. One of these holding plates 9 is provided with a liquid inlet 10 through which supply water is introduced, and the other is formed with a liquid outlet 11 through which treated water is led out. In addition, both holding plates 9, 9
Are formed with a number of fixing bolt holes 12. Bolts 13 are inserted into these bolt holes 12, 12 and fastened by nuts 14. With such a configuration, the flow-through type electric double layer capacitors 2 and 3 have a flat plate-like structure in which each member is pressed by the holding plates 9 and 9. Gaskets 8, 8 provided between the collecting electrodes 7, 7 and the holding plates 9, 9 are frames for holding the gap between the collecting electrodes 7, 7 and the holding plates 9, 9 in a liquid-tight manner. Shape. Instead of providing the gaskets 8, 8, a member having a sealing function may be provided on the holding plates 9, 9.

The hot water supply path 3 is connected to the supply water inlet side 2a of the liquid-flow type electric double layer condenser 2, and uses the hot water supplied from a supply source (not shown) as cleaning water as the liquid flow-type electric double layer condenser. It can be led to the capacitor 2. Reference numeral 4 denotes a discharge path connected to the treated water outlet side 2b of the liquid-flow type electric double layer condenser 2 so that the washing drainage can be discharged from the liquid-flow type electric double layer condenser 2.

Next, a method for producing pure water using the pure water producing apparatus 1 will be described. Using the water supply pump P1, supply water such as city water is introduced into the flow-through type electric double layer capacitor 2 through the introduction path 15, and current supply to the collector electrode 7 is started. Of ionic substances.

FIG. 3 (a) shows an example in which the ionic substance contained in the feed water is sodium chloride and the high surface area conductive layer is an activated carbon layer 6.
This will be described with reference to FIG. As shown in FIG. 3A, at the time of voltage application, sodium ions in the supply water are electrically adsorbed on the activated carbon layer 6 in contact with the collector electrode 7 on the cathode side,
Chlorine ions are electrically adsorbed on the activated carbon layer 6 in contact with the collector electrode 7 on the anode side, and treated water having a low salt concentration is obtained. The treated water is discharged out of the system through the treated water path 16. (Hereinafter, in the flow-through type electric double layer capacitor 2, the step of adsorbing and removing the ionic substance on the activated carbon layer 6 is referred to as a desalination step.)

Next, a first embodiment of a method for regenerating a flow-through type electric double-layer capacitor of the present invention will be described by taking as an example a case where the flow-through type electric double-layer capacitor 2 of the pure water producing apparatus 1 is regenerated. I do. In the flow-through type electric double layer capacitor 2, when water is continuously passed for a long time, the adsorption of ions to the activated carbon layers 6, 6 approaches saturation, and the concentration of sodium chloride in the treated water increases. Therefore, before the ions reach the adsorption saturation, the ions are desorbed from the activated carbon layer 6 and discharged as described below.

That is, as shown in FIG. 3 (b), in the flow-through type electric double layer capacitor 2, the hot water supplied from the hot water supply path 3 is used as cleaning water as the supply water inlet side 2a.
To the flow-through type electric double layer capacitor 2 and short-circuit or reverse-connect the collector electrodes 7 on the anode side and the cathode side. As hot water, water obtained by heating city water or pure water using a heater or the like can be used, and the temperature is 40 ° C. or higher (preferably 50 ° C. or higher, more preferably 60 ° C. or higher). If the temperature is lower than the above range, the effect of increasing the ion desorption efficiency is undesirably reduced. As a result, the ions adsorbed on the activated carbon layers 6, 6 are desorbed, the desorbed ions are washed away with warm water, and are discharged from the treated water outlet 2b through the discharge path 4 as cleaning wastewater. (Hereinafter, a step of desorbing the ionic substance by short-circuiting or reverse connection between the anode side and the cathode side is referred to as a regenerating step.) After the regenerating step is completed, the power supply to the collecting electrode 7 is restarted again. Desalination is performed.

In the regenerating method of the present embodiment, in the step of regenerating the flow-through type electric double layer capacitor 2, hot water from the hot water supply path 3 is used as washing water. In general, the solubility of salts in water increases as the temperature of the water increases,
In the regeneration step, elution of the ionic substance adsorbed on the activated carbon layer 6 can be promoted. For this reason, the desorption efficiency of the ionic substance can be increased, and the activated carbon layer 6 can be sufficiently cleaned. Therefore, the ionic substance removal rate in the desalting step following this regeneration step can be kept high. Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed.

Further, since hot water is used, even when salts such as Ca salts are deposited in the flow-through type electric double layer capacitor 2, elution of the salts (deposits) can be promoted.
For this reason, the occurrence of scale can be suppressed. In addition, since hot water is used, the growth of microorganisms in the flow-through type electric double layer capacitor 2 can be suppressed. Even if the microorganisms grow, the adhesion of the microorganisms is weakened, and the microorganisms are separated and discharged. Can be. For this reason, microbial contamination can be prevented from occurring in the downstream device.

In the present invention, in the regeneration step, acidic water can be used as washing water. Hereinafter, a second embodiment of the reproducing method of the present invention will be described with reference to FIG. In the following description, reference numeral 3 indicates an acidic water supply path for supplying acidic water to the flow-through type electric double layer condenser 2. When producing pure water using the above-described pure water production apparatus, if the supply water contains a large amount of cationic substances (especially Ca ions), the cationic substances may form negative ions in the supply water or the cleaning water. It may form a salt (such as calcium carbonate) by ionic bonding with an ionic substance (such as carbonate ion). In this case, in the desalting step, salts such as calcium carbonate are likely to deposit in the liquid-flow type electric double layer capacitor 2 (for example, the activated carbon layer 6).

In the present embodiment, in the regeneration step, the acidic water from the acidic water supply path 3 is supplied to the flow-through type electric double layer capacitor 2 as washing water, and the collector electrodes 7 on the anode side and the cathode side, 7 is short-circuited or short-circuited. As the acidic water, water whose pH has been lowered by adding an acid (such as hydrochloric acid or sulfuric acid) to city water or pure water can be used. The pH of the acidic water is 6 or less (preferably 5
Hereinafter, it is more preferably 4 or less, and still more preferably 3 or less. If the pH is more neutral than 6, the efficiency of desorbing ionic substances and deposits decreases, which is not preferable. The acidic water has a water temperature of 40 ° C. or higher (preferably 5 ° C.).
By setting the temperature to 0 ° C. or higher, more preferably 60 ° C. or higher, the desorption efficiency of ionic substances and deposits can be further increased. By this regeneration step, the activated carbon layer 6,
The ionic substance adsorbed on 6 is desorbed, the desorbed ionic substance is washed away with acidic water, and discharged from the discharge path 4 as washing wastewater. Thereafter, it is preferable that water (pure water or the like) having a low ionic substance concentration be supplied to the liquid-type electric double layer capacitor 2 for further washing.

In the regeneration method of the present embodiment, in the step of regenerating the flow-through type electric double layer capacitor 2, the acidic water from the acidic water supply path 3 is used as washing water, so that the ionic substance adsorbed on the activated carbon layer 6 is used. Can be efficiently desorbed from the activated carbon layer 6 and the activated carbon layer 6 can be sufficiently cleaned. In addition, since many salts such as Ca salts have higher solubility in the acidic region than in the neutral region, even when such salts are deposited in the flow-through type electric double layer capacitor 2,
This salt (deposit) can be easily eluted.
For this reason, even when the concentration of the cationic substance (Ca or the like) in the feed water is high, scale generation is prevented, and
The flow-through type electric double layer capacitor 2 can be sufficiently cleaned. Therefore, the ionic substance removal rate in the desalting step can be kept high. Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed. Also, since acidic water is used in the regeneration step,
The growth of microorganisms in the flow-through type electric double layer capacitor 2 can be suppressed, and even if the microorganisms grow, the adhesive force of the microorganisms can be weakened, and the microorganisms can be exfoliated and discharged. For this reason, microbial contamination can be prevented from occurring in the downstream device.

In the present invention, alkaline water can be used as the cleaning water. Hereinafter, a third embodiment of the reproducing method of the present invention will be described with reference to FIG. In the following description, reference numeral 3 indicates an alkaline water supply path for supplying alkaline water to the flow-through type electric double layer capacitor 2. When producing pure water using the pure water production apparatus, if the supply water contains a large amount of silica that is a poorly water-soluble substance,
In a state where a part thereof is not ionized, it is easy to deposit in the liquid-flow type electric double layer capacitor 2 (the activated carbon layer 6 and the like).

In the present embodiment, in the regeneration step, the alkaline water from the alkaline water supply path 3 is supplied to the flow-through type electric double layer capacitor 2 as washing water, and the collector electrode 7 on the anode side and the cathode side, 7 is short-circuited or short-circuited. As the alkaline water, water whose pH has been increased by adding a basic compound (such as sodium hydroxide) to city water or pure water can be used. The pH of the alkaline water is 8 or more (preferably 9 or more, more preferably 10 or more, more preferably 11 or more). If the pH is more neutral than 8, the efficiency of desorbing ionic substances and deposits (such as silica) is undesirably reduced. By setting the temperature of the alkaline water to 40 ° C. or higher (preferably 50 ° C. or higher, more preferably 60 ° C. or higher), the desorption efficiency of ionic substances and deposits such as silica can be further increased. As a result, the ionic substances and deposits (silica and the like) adsorbed on the activated carbon layers 6 and 6 are desorbed, the desorbed substances are washed away with alkaline water, and discharged from the discharge path 4 as cleaning wastewater. Thereafter, it is preferable that water having a low ionic substance concentration be supplied to the liquid-type electric double layer condenser 2 for further washing, and then discharged from the discharge path 4 as washing wastewater.

In the regeneration method of this embodiment, in the step of regenerating the flow-through type electric double layer capacitor 2, the alkaline water from the alkaline water supply path 3 is used as washing water, so that the ionic substance adsorbed on the activated carbon layer 6 is used. This promotes the elution of deposits and deposits, efficiently removes the ionic substances and deposits from the activated carbon layer 6, and sufficiently cleans the activated carbon layer 6. Therefore, the ionic substance removal rate in the desalting step can be kept high. Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed.

In particular, when the supply water contains a large amount of silica, which is a poorly water-soluble substance, and a part of the silica is deposited in the flow-through type electric double layer capacitor 2, the following expression (1) is obtained. The silica can be ionized by the alkaline water to make it easily eluted. SiO ₂ + OH ⁻ → HSiO ₃ ⁻ (1) Therefore, the generation of scale can be suppressed, and the inside of the liquid-flow type electric double layer capacitor 2 can be sufficiently cleaned. Further, since alkaline water is used in the regeneration step, the growth of microorganisms in the flow-through type electric double layer capacitor 2 can be suppressed. Even if the microorganisms grow, the adhesion of the microorganisms is weakened and the microorganisms are separated. Can be discharged. For this reason, microbial contamination can be prevented from occurring in the downstream device.

In the present invention, ultrapure water can be used as the cleaning water. Hereinafter, a fourth embodiment of the reproducing method of the present invention will be described with reference to FIG. In the following description, reference numeral 3 indicates an ultrapure water supply path for supplying ultrapure water to the flow-through type electric double layer capacitor 2.

In the present embodiment, in the regeneration step, ultrapure water from the ultrapure water supply path 3 is supplied to the flow-through type electric double layer capacitor 2 as washing water, and the collector electrode between the anode side and the cathode side is used. 7, 7 is short-circuited (short-circuited) or reverse-connected. It is preferable to use the following as ultrapure water.・ Electric resistivity: 18 MΩ · cm or more ・ Fine particles (the number of fine particles having a diameter of 0.1 μm or more in 1 ml);
5 or less ・ Microorganisms (the number of microorganisms in 1 L); 10 or less ・ Organic substances (TOC): 10 μg / l or less As ultrapure water, reverse osmosis membrane separation device, ion exchange device,
Those manufactured using an ultraviolet oxidation device, a flow-through type electric double layer condenser, a microfiltration membrane separator, an ultrafiltration membrane separator, or the like can be used.

In the regeneration method of the present embodiment, in the step of regenerating the liquid-flow type electric double layer capacitor 2, ultrapure water from the ultrapure water supply path 3 is used as cleaning water. Since ultrapure water has a very low concentration of dissolved substances and solids, it promotes elution of ionic substances and deposits (salts and the like) adsorbed on the activated carbon layer 6 in the regeneration step, The efficiency of desorption of substances and deposits can be increased. Further, since ultrapure water having a low concentration of dissolved substances and the like can be used, ionic substances and the like can be prevented from being re-adsorbed to the activated carbon layer 6 during the regeneration step, and the activated carbon layer 6 can be sufficiently cleaned. Therefore, the ionic substance removal rate in the desalting step can be kept high. Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed.

In the present invention, hydrogen-containing water containing hydrogen gas can be used as the cleaning water. FIG. 4 shows a pure water production apparatus that can suitably carry out the fourth embodiment of the regeneration method of the present invention. The pure water production apparatus 21 shown here comprises a raw water supply path 22 and a hydrogen supply path. Gas supply path 2
3, a hydrogen gas dissolving membrane device 24 for dissolving hydrogen gas from the supply route 23 in raw water from the supply route 22 to obtain hydrogen-containing water, A hydrogen-containing water supply path 25 for supplying to the electric double-layer capacitor 2.

In the present embodiment, in the regeneration step, hydrogen-containing water obtained by dissolving hydrogen gas in raw water in the hydrogen gas dissolving membrane device 24 is supplied to the flow-through type electric double layer condenser 2 as washing water. The collector electrodes 7 on the anode side and the cathode side are short-circuited or short-circuited.
City water, pure water, ultrapure water and the like can be used as the raw water. Among them, it is particularly preferable to use ultrapure water. The dissolved hydrogen gas concentration in the hydrogen-containing water is desirably 0.7 mg / L or more (preferably 1.2 mg / L or more, more preferably 1.4 mg / L or more). If the dissolved hydrogen gas concentration is less than the above range, the efficiency of desorption of deposits such as fine particles is reduced, which is not preferable.

In this regeneration step, the efficiency of deposit desorption can be increased by subjecting the liquid-flow type electric double layer capacitor 2 to ultrasonic treatment using an ultrasonic treatment device (not shown). In this ultrasonic treatment, the output is set to 1
0 W / L-set to the internal volume of the apparatus or more, and the frequency of the ultrasonic wave is 4 to
Preferably, it is 10 kHz.

In the regeneration method of the present embodiment, in the step of regenerating the flow-through type electric double-layer capacitor 2, the hydrogen-containing water from the hydrogen-containing water supply path 25 is used as washing water, so that the flow-through type electric double-layer capacitor is used. 2 can be in a state where it can be easily detached from the activated carbon layer 6. For this reason, in the regeneration step, the efficiency of desorbing the deposit can be increased. Therefore, the ionic substance removal rate in the desalting step can be kept high. Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed.

The hydrogen-containing water can also be produced by a method in which hydrogen gas is dissolved in raw water by gas-liquid contact using bubbling, line mixing or the like. Hydrogen-containing water can also be produced by electrolysis of pure water or ultrapure water.

In the present invention, the one shown in FIG. 5 can be used as the liquid-passing type electric double layer capacitor. The flow-through type electric double layer capacitor shown here has an end plate 23.
1, 232, insulating layers 235, 236, single-sided terminal electrodes 233, 234, and double-sided intermediate electrodes 237 to 243. One-sided terminal electrodes 233, 234, double-sided intermediate electrode 23
Nos. 7 to 243 are formed by bonding a conductor (activated carbon or the like) sheet to one or both surfaces of a collector electrode made of a titanium sheet with a binder such as a conductive epoxy. When using the liquid-flow type electric double layer capacitor, these electrodes are alternately used as a cathode and an anode in the arrangement direction, and the water to be treated flows into the first treatment chamber 250 through the holes 261 and 262 (arrows). A), ionic substances are applied to the electrodes 233 and 237
To the electrode 2 and then withdraw water from the processing chamber 250
37, the liquid is introduced into the processing chamber adjacent below through the holes 263 (arrow B). Thereafter, as shown by arrows C to G, the processing water is continuously passed through the processing chambers, and the processing water is supplied to the holes 264, 265, 266.
(Arrow H).

[0036]

The effects of the present invention will be clarified below with reference to specific examples. (Examples 1 to 5) Pure water was produced using the pure water producing apparatus 1 shown in FIG. The equipment specifications and processing conditions were as follows. Flow-through electric double layer capacitor 2: electrode area: 13000
cm ² × 250 sheets (the anode side and the cathode side are 12
1.3 V (current value: 5 to 12 A) Frequency of regeneration step (collector electrode 7 on anode side and collector electrode 7 on cathode side)
Once / 90 minutes (each time the anode and cathode were inverted)

In the present embodiment, pure water was produced using city water as supply water. In the regeneration step, pure water (warm water) heated in advance to the temperature shown in Table 1 is supplied to the supply path 3
Type electric double layer condenser 2 as washing water through
The hot water was used to remove and discharge the ionic substance.

The results of measuring the conductivity of the effluent from the liquid-flow type electric double-layer capacitor 2 and the inflow water (supply water) into the liquid-flow type electric double-layer capacitor 2 one month after the start of water flow. Are shown in Table 1. Table 1 also shows the ionic substance removal rates calculated from the conductivity. The conductivity was measured immediately before the regeneration step.

(Comparative Example 1) Pure water was produced in the same manner as in Examples 1 to 5, except that pure water at normal temperature was used as washing water. The test results are also shown in Table 1.

(Examples 6 to 9) In the regeneration step, acidic water was used as washing water. As the acidic water, a water whose pH was adjusted by adding hydrochloric acid to pure water was used. The device specifications and the processing conditions were determined according to the first embodiment. The test results are also shown in Table 1.

(Examples 10 to 13) In the regeneration step,
Alkaline water was used as washing water. As the alkaline water, a water whose pH was adjusted by adding sodium hydroxide to pure water was used. The device specifications and the processing conditions were determined according to the first embodiment. The test results are also shown in Table 1.

(Comparative Example 2) Pure water was produced in the same manner as in Examples 6 to 13, except that pure water having a pH in a neutral region was used as washing water. The test results are also shown in Table 1.

(Example 14) In the regeneration step, ultrapure water was used as washing water. The following was used as ultrapure water.・ Electric resistivity; 18.1 MΩ · cm ・ Fine particles (the number of fine particles having a diameter of 0.1 μm or more in 1 ml);
1 or less-Microorganisms (the number of microorganisms in 1 L); less than 1-Organic matter (TOC); 3 µg / l The device specifications and processing conditions were determined according to Example 1. The test results are also shown in Table 1.

Comparative Example 3 Pure water was produced in the same manner as in Example 14 except that pure water was used as cleaning water. The test results are also shown in Table 1. The following was used as the pure water. -Electric resistivity; 10.5 MΩ-cm-Fine particles (the number of fine particles having a diameter of 0.2 µm or more in 1 ml);
Approximately 200 microorganisms (the number of microorganisms in 1 L); approximately 200 organisms (TOC); 55 μg / l

(Examples 15 to 18) Pure water was produced using the pure water producing apparatus 21 shown in FIG. The hydrogen-containing water produced in the hydrogen gas dissolving membrane device 24 was used as cleaning water in the regeneration step. The device specifications and the processing conditions were determined according to the first embodiment. The test results are also shown in Table 1.

Comparative Example 4 Pure water was produced in the same manner as in Example 15 except that pure water (dissolved hydrogen concentration: less than 0.1 mg / L) was used as the cleaning water instead of the hydrogen-containing water.
The test results are also shown in Table 1.

[0047]

[Table 1]

From the comparison between Examples 1 to 5 and Comparative Example 1, it can be seen that the desalting efficiency could be improved by using warm water as the washing water. From a comparison between Examples 6 to 13 and Comparative Example 2, it can be seen that the desalting efficiency was able to be increased even when acidic water or alkaline water was used.
The comparison between Example 14 and Comparative Example 3 shows that the use of ultrapure water could increase the desalting efficiency. From a comparison between Examples 15 to 18 and Comparative Example 4, it can be seen that the desalination efficiency could be increased by using the hydrogen-containing water.

[0049]

According to the method for regenerating a liquid-permeation type electric double layer capacitor of the present invention, a water temperature of 40% is applied to a liquid-permeation type electric double layer capacitor.
Supplying hot water at a temperature of ℃ or more promotes the elution of ionic substances and deposits (salts, etc.), increases the desorption efficiency of ionic substances and deposits, and sufficiently cleans the flow-through type electric double layer capacitor. be able to. Therefore, the removal rate of ionic substances and deposits in the desalting step can be kept high.
Further, since the frequency of the regeneration step can be reduced, the processing cost can be suppressed. In addition, the growth of microorganisms in the flow-through type electric double layer capacitor can be suppressed by the hot water, and the occurrence of microbial contamination in the downstream device can be prevented.

According to the present invention, ionic substances and deposits are efficiently desorbed by using acidic water having a pH of 6 or less during regeneration of the liquid-flow type electric double-layer capacitor, and the liquid-flow type electric double-layer capacitor is sufficiently regenerated. Can be cleaned. In particular, salts such as Ca salts are often more soluble in the acidic region than in the neutral region, so even when such salts are deposited in the flow-through type electric double layer capacitor,
This deposit can be easily eluted. For this reason, even when the concentration of the cationic substance (Ca or the like) in the feed water is high, it is possible to prevent the generation of scale and to sufficiently clean the flow-through type electric double layer capacitor. Therefore, the ionic substance removal rate in the desalting step can be kept high. In addition, it is possible to suppress the growth of microorganisms in the flow-through type electric double layer capacitor, and to prevent the occurrence of microbial contamination in downstream devices.

In the present invention, the efficiency of desorption of ionic substances and deposits is increased by using alkaline water having a pH of 8 or more when regenerating the flow-through type electric double-layer capacitor. And the removal rate of ionic substances and deposits in the desalting step can be kept high. In particular, even if the supply water contains a large amount of silica, which is a poorly water-soluble substance, and a part of the silica easily deposits in the flow-through type electric double layer capacitor, the silica is ionized by the alkaline water to make it easily eluted. In addition, the scale can be suppressed and the inside of the liquid-permeation type electric double layer capacitor can be sufficiently cleaned. In addition, it is possible to suppress the growth of microorganisms in the flow-through type electric double layer capacitor, and to prevent the occurrence of microbial contamination in downstream devices.

In the present invention, the use of ultrapure water in the regeneration of the flow-through type electric double layer capacitor promotes the elution of ionic substances and deposits, and enhances the desorption efficiency of ionic substances and deposits. Can be. For this reason, the flow-through type electric double layer capacitor can be sufficiently cleaned, and the ionic substance removal rate in the desalting step can be kept high. Further, it is possible to prevent ionic substances and the like from being re-adsorbed in the flow-through type electric double layer capacitor during the regeneration step, and to sufficiently clean the flow-through type electric double layer capacitor.

In the present invention, the use of hydrogen-containing water at the time of regeneration of the flow-through type electric double layer capacitor promotes the desorption of the deposits by the hydrogen in the hydrogen-containing water, thereby improving the desorption efficiency of the deposits. it can. For this reason, the flow-through type electric double layer capacitor can be sufficiently cleaned, and the ionic substance removal rate in the desalting step can be kept high.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a pure water production apparatus capable of suitably implementing an embodiment of a flow-through type electric double layer capacitor regeneration method of the present invention.

FIGS. 2A and 2B are diagrams showing a schematic configuration of a flow-through type electric double layer capacitor, wherein FIG. 2A is an exploded perspective view and FIG. 2B is a side sectional view.

FIG. 3 is a diagram for explaining a processing principle of a liquid-permeation type electric double layer capacitor.

FIG. 4 is a schematic configuration diagram of a pure water production apparatus capable of suitably implementing another embodiment of the regeneration method of the present invention.

FIG. 5 is a schematic configuration diagram showing another example of the flow-through type electric double layer capacitor.

[Explanation of symbols]

1, 21: pure water production apparatus, 2: liquid-flow type electric double layer condenser, 3, 25: supply path (hot water supply path, acidic water supply path, alkaline water supply path, ultrapure water supply Route, hydrogen-containing water supply route)

Continuation of the front page (72) Inventor Kuroshihiro Matsushita Kurita Kogyo Co., Ltd., 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo

Claims (5)

[Claims] 1. A method for regenerating a flow-through type electric double-layer capacitor for desalinating feed water, comprising short-circuiting or reverse-connecting the anode and cathode electrodes of the flow-through type electric double-layer capacitor. A method for regenerating a liquid-flow type electric double layer capacitor, comprising supplying hot water having a water temperature of 40 ° C. or higher to the liquid type electric double layer capacitor. 2. A method for regenerating a flow-through type electric double-layer capacitor for desalinating feed water, comprising short-circuiting or reverse-connecting the anode and cathode electrodes of the flow-through type electric double-layer capacitor. A method for regenerating a liquid-flow type electric double layer capacitor, comprising supplying acidic water having a pH of 6 or less to the liquid type electric double layer capacitor. 3. A method for regenerating a flow-through type electric double-layer capacitor for desalinating feed water, comprising short-circuiting or reverse-connecting the anode and cathode electrodes of the flow-through type electric double-layer capacitor. A method for regenerating a liquid-flow type electric double layer capacitor, comprising supplying alkaline water having a pH of 8 or more to the liquid type electric double layer capacitor. 4. A method for regenerating a flow-through type electric double layer capacitor for desalinating feed water, comprising short-circuiting or reverse-connecting the anode and cathode electrodes of the flow-through type electric double layer capacitor. A method for regenerating a flow-through type electric double layer capacitor, comprising supplying ultrapure water to the liquid type electric double layer capacitor. 5. A method for regenerating a flow-through type electric double-layer capacitor for desalinating feed water, comprising short-circuiting or reverse-connecting the anode and cathode electrodes of the flow-through type electric double-layer capacitor. A method for regenerating a flow-through type electric double layer capacitor, comprising supplying hydrogen-containing water to the liquid type electric double layer capacitor.