JP2001087767A - Method and device for passing liquid in liquid passing type capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for passing liquid in a liquid passing type capacitor which keeps the separation ability of ionic component in the liquid passing type capacitor constant even in the operation over a long period and allows the electrode material to have a long life. SOLUTION: In this method for passing liquid in a liquid passing type capacitor, the ionic component of the liquid to be treated during the liquid passing is removed and desalted liquid is produced by impressing DC voltage to a pair of electrodes, thereafter, the pair of electrodes are short-circuited or DC power source is inversely connected and the ionic component which is removed is recovered as concentrated liquid together with the liquid to be treated during the liquid passing. Therein, the liquid to be treated is adjusted to <=30 deg.C or >=50 deg.C, <= pH 5 or >= pH 9, or is subjected to deaeration treatment or reduction treatment and, thereafter, is passed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a desalting solution in which ionic components of a liquid to be treated are removed by applying a DC voltage to a pair of electrodes held in the solution, and then a short circuit or reverse connection is performed. In addition to regenerating a pair of electrodes, the removed ion component is collected together with the liquid to be processed in the liquid, and the ionic component of the liquid to be processed is removed and recovered in accordance with the purpose. The present invention relates to a method of passing a liquid through a condenser that allows liquid to flow.

[0002]

2. Description of the Related Art A flow-through type condenser removes and recovers (regenerates) ionic components in a liquid to be treated by using electrostatic force, and its principle is as follows. In other words, the flow-through capacitor applies a DC voltage to a pair of electrodes held by the flow-through capacitor, and removes ionic components, charged particles, and organic substances of the liquid to be processed by adsorbing the pair of electrodes. Then, a desalted solution from which the ionic components have been removed is obtained, and then the pair of electrodes is short-circuited or a DC power supply is reversely connected to release the ionic components adsorbed on the pair of electrodes, thereby regenerating the pair of electrodes. The removal of the removed ion component together with the liquid to be treated in the liquid as a concentrated solution is repeatedly performed.

Such a flow-through type capacitor is disclosed in Japanese Patent Application Laid-Open
In one example of this known example, an inlet for introducing a liquid to be treated into a column, and an outlet for discharging a liquid from which ionic components have been removed are provided. Contains electrodes. Each of the pair of electrodes has a high-surface area conductive surface layer supported by a conductive support layer, and further includes a non-conductive porous spacer. Accordingly, the pair of electrodes is composed of a non-conductive porous spacer of one electrode, a conductive support layer, a high surface area conductive surface layer, a non-conductive porous spacer of the other electrode, a conductive support layer, and a high surface area conductive layer. It has a six-layer structure of a surface layer. This pair of electrodes is wound around a hollow porous central tube with the high surface area conductive surface layer inside, forming a cartridge. Lead wires extend from the conductive support layer of one electrode and the conductive support layer of the other electrode outside the column, and are connected to a DC power supply. A supply source of the liquid to be treated is connected to the inlet of the column, and a switching valve for separating a desalted solution from which the ionic components have been removed and a concentrated solution from which the ionic components have been recovered is connected to the outlet.

[0004] A method of passing a liquid through the above-described liquid-passing type condenser will be described with reference to FIG. In FIG. 8, reference numeral 50 denotes a liquid-flow condenser. First, the switching valve 51 is opened, and the switching valve 52 is opened.
Is closed, the switch 53 is turned on, and the pair of electrodes 5
When a DC voltage is applied to the liquid supply 4 and 55 and the liquid to be treated is supplied from the liquid supply source 56 to the liquid condenser 50, the ion component is adsorbed on the pair of electrodes 54 and 55, and the switching valve 51
On the downstream side of the deionized water from which the ionic components have been removed.
When this state continues, the water quality monitoring device 57 measures that the ion component is gradually adsorbed on the pair of electrodes 54 and 55 and becomes saturated and the ion component removal performance gradually decreases. 51 is closed and the switching valve 52 is opened, and the switch 53 is turned off to stop the application of the DC voltage. Then, in order to regenerate the ion component removal performance, the switch 58 is turned on and the pair of electrodes 54,
55 or short-circuit the DC power supply 59,
The ionic component adsorbed on the pair of electrodes 54 and 55 is released, and a concentrated solution in which the ionic components are recovered on the downstream side of the switching valve 52 while the pair of electrodes 54 and 55 are being regenerated is obtained.
One cycle of removal and recovery (regeneration) of the ionic component in the liquid to be treated is completed. Then, the liquid to be treated is constantly supplied from the liquid supply source 56 to the flow-through condenser 50, and the above cycle is repeated to alternate the desalted liquid from which the ionic components have been removed and the concentrated liquid from which the ionic components have been recovered. Can be obtained.

[0005]

However, according to the above-mentioned conventional method for passing a liquid through a condenser, the ability to remove ionic components from the liquid to be treated decreases as the cycle of passing the liquid through the condenser increases. There's a problem. As a method for recovering such electrode removing ability, there is a method of temporarily stopping supply of the liquid to be treated and providing a cleaning step of supplying a chemical such as an acid, an alkali or a bactericide. There are various problems such as installation of supply facilities and treatment of waste liquid of chemicals.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the need for chemical cleaning to recover the electrode removing ability, to keep the ionic component separation ability of the flow-through condenser constant even over a long period of operation, It is an object of the present invention to provide a method and an apparatus for passing a liquid through a condenser which can extend the life of the liquid.

[0007]

Under such circumstances, the present inventors have made intensive studies and as a result, have applied a DC voltage to at least a pair of electrodes to remove ionic components of the liquid to be treated during the passage. After that, in a flow-through method of a flow-through condenser in which a short-circuit or reverse connection is performed and the removed ionic component is recovered in the water to be processed, the liquid to be processed is set to a specific temperature range or a specific pH value. Alternatively, if the liquid is passed through degassing or reduction treatment, the effective surface area of the electrode can be maintained without reducing the effective surface area of the electrode even during long-term operation, and the ionic component separation ability of the liquid-flow condenser is constant. And it was found that the life of the electrode material could be extended, and the present invention was completed.

That is, according to the first aspect of the present invention, a direct current voltage is applied to a pair of electrodes to remove ionic components of a liquid to be processed in a flowing solution to obtain a desalted solution. A method of passing a liquid through a condenser in which a DC power supply is reversely connected and the removed ion component is recovered as a concentrated solution together with a liquid to be processed in the liquid, wherein the liquid to be processed is 30%.
It is intended to provide a method for passing a liquid through a condenser, wherein the liquid is passed at a temperature of not higher than 50 ° C. or lower than 50 ° C.

Further, according to the present invention, a desalinated solution is obtained by applying a DC voltage to a pair of electrodes to remove ionic components of the liquid to be processed during the passage, and then short-circuiting the pair of electrodes or A method of passing a liquid through a condenser in which a DC power supply is reversely connected and the removed ionic component is recovered as a concentrated solution together with the liquid to be treated in the liquid, wherein the liquid to be treated has a pH of 5 or less or a pH of 9 or less. The present invention provides a method for passing a fluid through a fluid-flow condenser, characterized in that the fluid is passed.

Further, according to the invention of claim 3, a DC voltage is applied to the pair of electrodes to remove ionic components of the liquid to be processed in the flowing liquid to obtain a desalted solution, and thereafter the pair of electrodes is short-circuited or Reversely connecting a DC power supply, a method of passing a liquid through a condenser in which the removed ionic component is recovered as a concentrated solution together with the liquid to be processed in the liquid, wherein the liquid to be processed is degassed. And a method for passing a liquid through a liquid-flow condenser.

Further, according to the present invention, a DC voltage is applied to a pair of electrodes to remove ionic components of the liquid to be processed in the flowing liquid to obtain a desalted solution, and then the pair of electrodes is short-circuited or Reversely connecting a DC power supply, a method of passing a liquid through a condenser in which the removed ionic component is recovered as a concentrated solution together with the liquid to be processed in the liquid, wherein the liquid to be processed is reduced. The present invention provides a method of passing a liquid through a liquid-passing type capacitor.

According to a fifth aspect of the present invention, a DC voltage is applied to a pair of electrodes to remove ionic components of the liquid to be processed during the passage, and the pair of electrodes is short-circuited or a DC power supply is reversely connected. Having a flow-through condenser for recovering the removed ionic components together with the liquid to be processed in the flow-through, and a deaeration means positioned upstream of the flow-through type condenser to deaerate the liquid to be processed. A feature of the present invention is to provide a liquid flowing device for a liquid flowing condenser.

According to a sixth aspect of the present invention, a DC voltage is applied to a pair of electrodes to remove ionic components of the liquid to be processed during the passage, and the pair of electrodes is short-circuited or a DC power supply is reversely connected. Having a flow-through condenser that collects the removed ionic components together with the liquid to be processed in the flow-through liquid, and a reduction unit that is located upstream of the flow-through type condenser and reduces the liquid to be processed. The present invention provides a liquid-flowing device for a liquid-flowing condenser.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a description will be given of a method for passing a liquid through a liquid-flow condenser according to an embodiment of the present invention with reference to FIG. FIG. 1 is a flow chart showing a method for passing a liquid through a liquid-passing type capacitor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a liquid-flow condenser. The upstream side of the liquid-flow condenser 1 is connected to a pretreatment device 4 by a supply pipe 2, and further connected to a liquid supply source 5 by a connection pipe 3. On the other hand, the downstream side thereof is connected to a water quality monitoring device 8 by a connection pipe 6, and further, an outflow pipe 7 of the water quality monitoring apparatus 8 has a desalted liquid outflow pipe 9 having a switching valve 11 and a concentrated liquid outflow pipe having a switching valve 12. There are 10 branches. The liquid-to-be-treated supply source 5 includes a liquid-to-be-treated tank and a liquid feed pump for supplying the liquid to be treated quantitatively from the tank (not shown).

The liquid-flow condenser 1 has at least a pair of electrodes 30 and 31 built therein.
, And the electrode 31 is connected to the anode of the DC power supply 34. The pair of electrodes 30 and 31 of the flow-through capacitor 1 are connected to each other via a switch 35. The operation control of the devices shown in FIG. 1 is performed by known control devices such as a sequencer and a microcomputer.
For example, there is a method for passing a liquid through a later-described liquid-passing condenser.

The structure of the flow-through type capacitor 1 is not particularly limited, but here, electrodes 30 and 31 in which a high-surface-area activated carbon is in contact with a collecting electrode of metal, graphite or the like are accommodated in a column. A non-conductive spacer is interposed between 31. Then, this liquid-flow condenser 1
When a DC power source 34 is connected to the pair of electrodes 30 and 31 and a liquid containing ions is passed through the column in a state where a DC voltage, for example, 1 to 2 V is applied, the pair of electrodes 3
0 and 31 adsorb the ions, the ionic components are removed, and a desalted solution can be obtained.
Is short-circuited, the ions that have been electrically neutralized and adsorbed are separated from the pair of electrodes 30 and 31, and the pair of electrodes 30, 3
1 can be regenerated and a concentrated liquid in which a concentrated ionic component is recovered can be obtained. The voltage applied between the pair of electrodes 30 and 31 can be set arbitrarily.

As another structural example of the liquid-passing type capacitor 1, a pair of electrodes, which are activated carbon layers mainly composed of activated carbon having a high specific surface area, are arranged with a spacer made of a non-conductive porous liquid-permeable sheet interposed therebetween. Then, a pair of collector electrodes are arranged outside the electrodes, and a flat plate shape is further arranged with a pressing plate outside the collector electrodes, a DC power supply is connected to the collector electrodes, and a short circuit between the collector electrodes or a DC power supply is further provided. A reverse connection may be performed. Further, the electrode and the collecting electrode may be integrated.

The pretreatment device 4 is for adjusting the liquid to be treated supplied to the flow-through condenser 1 to a specific property, and is used to adjust the temperature of the liquid to be treated to 30 ° C. or less or 50 ° C. or more. Exchanger, pH of the liquid to be treated is pH 5 or less or pH 9
There are a pH adjusting means for adjusting as described above, a deaerator for degassing the liquid to be treated, and a reducing device (reducing means) for reducing the liquid to be treated. These pretreatment devices may be installed alone or in combination of two or more. Here, the liquid to be treated is not particularly limited, and may be, for example, city water, industrial water, river water or permeated water obtained by subjecting these to reverse osmosis membrane treatment, or ultrapure water for electronic parts such as semiconductor wafers and liquid crystal displays. And the condensate of the circulating system of the steam turbine of the power plant, and the like. If these are included in, for example, the above temperature range, the pretreatment device 4 can be omitted. . The liquid to be treated of the present invention may be subjected to a pretreatment of raw water such as a coagulation sedimentation treatment and a filtration treatment which are performed in the case of so-called pure water production or the like, which is different from the above pretreatment.

The heat exchanger for adjusting the temperature of the liquid to be treated to 30 ° C. or less, preferably 0 to 20 ° C. includes a cooler and a heater. The temperature of the liquid to be treated is 50 ° C. or more, preferably 60 ° C. A heater is used as a heat exchanger for adjusting the temperature to a boiling point or lower. In addition, when the liquid to be treated is heated, bubbles are likely to be generated, and gas is accumulated on the surface of the activated carbon electrode or in the fine pores, which is not preferable in that the effective electrode surface is reduced. It is preferable to perform the deaeration treatment before or after the heat treatment. By setting the liquid to be treated in the above temperature range, it is possible to prevent the generation of microorganisms in the flow-through condenser, and to suppress a decrease in the effective electrode surface area due to the microorganisms or the metabolites of the microorganisms covering the carbon electrode surface. it can. Conventionally, in a liquid treatment apparatus, as a method of preventing the generation of microorganisms, there is a method of continuously or intermittently injecting an oxidizing agent. However, the use of an oxidizing agent oxidizes an activated carbon electrode and lowers ionic component removal performance. .

The pH adjusting means for adjusting the pH of the liquid to be treated to pH 5 or less, preferably pH 1 to pH 3 is provided with an acidic solution storage tank and an acidic solution supply pump, and the pH is adjusted between the acidic solution supply point and the flow-through condenser. A device with a meter can be used (not shown). Examples of the acidic liquid include a sulfuric acid solution and a hydrochloric acid solution. PH adjusting means for adjusting the pH of the liquid to be treated to pH 9 or higher, preferably pH 10 to pH 13, includes:
Equipped with an alkaline liquid storage tank and an alkaline liquid supply pump,
A device in which a pH meter is arranged between the alkaline liquid supply point and the flow-through condenser can be used (not shown). Examples of the alkaline liquid include caustic soda and trimethylammonium hydroxide. By setting the liquid to be treated in the above pH range, it is possible to prevent the generation of microorganisms in the flow-through condenser, and to suppress the decrease in the effective electrode surface area due to the surface of the carbon electrode being covered with microorganisms or metabolites of microorganisms. it can.

The liquid to be treated preferably has a lower TOC concentration in that the effect of microorganisms can be reduced. The liquid to be treated has a TOC concentration of 1000 ppb or less, preferably 100 ppb or less. In order to reduce the TOC concentration of the liquid to be treated, a known method generally used may be applied.

As a deaerator for degassing the liquid to be treated, any gas components such as nitrogen, oxygen, ammonia, methane and volatile organic hydrocarbons dissolved in the liquid to be treated can be removed in advance. For example, a vacuum deaerator, a membrane deaerator, a heating deaerator and the like can be used. With these deaerators, the liquid to be treated is adjusted to, for example, a dissolved oxygen gas concentration of 1.0 mg / L or less, preferably 0.1 mg / L or less. In addition, the deaerator can also use a method of supplying the liquid into the depressurized tank. Further, a method may be used in which the generation of bubbles is promoted by applying ultrasonic vibration to the liquid to be treated, and the generated bubbles are removed immediately before the liquid condenser. By degassing the liquid to be treated, for example, it is possible to prevent gas from accumulating on the surface of the activated carbon electrode or in the fine pores, and to suppress a decrease in the effective electrode surface area due to the accumulation of the gas.

Reduction device (reduction means) for reducing the liquid to be treated
Examples thereof include a reducing agent injection means, a hydrogen gas dissolving means, a filtration device using activated carbon or activated carbon fiber, and the like, and these may be used alone or in combination of two or more. Examples of the reducing agent include sodium sulfite and sodium bisulfite. The injection amount of the reducing agent may be an amount sufficient to reduce and neutralize the oxidizing agent in the liquid to be treated. When the liquid to be treated is city water, examples of the oxidizing agent in the city water include sodium hypochlorite,
Chloramine and the like can be mentioned, and examples of the oxidizing agent contained in the washing wastewater of electronic parts include ozone, hydrogen peroxide and the like. In addition, the dissolution of hydrogen gas by the hydrogen gas dissolving means may generate bubbles in the flow-through condenser, and is preferably controlled to be equal to or lower than the saturation solubility of hydrogen gas. In this case, a separate treatment liquid supply pipe may be provided, and the dissolved amount may be controlled by a method of adding hydrogen gas to a part of the treatment liquid and mixing the hydrogen gas with the non-dissolved treatment liquid. Since the oxidizing agent in the liquid to be treated is reduced and neutralized by reducing the liquid to be treated by the reducing device (reducing means),
Oxidation on the surface of the activated carbon electrode of the flow-through capacitor is suppressed, and a decrease in the effective electrode surface area can be suppressed.

The water quality monitoring device 8 is not particularly limited as long as it is a device for measuring liquid quality and is an index measuring device capable of accurately grasping the degree of ion removal, and examples thereof include a conductivity meter and a resistivity meter. In this embodiment, the conductivity meter is used. It should be noted that the water quality monitoring device may perform measurement by partially bypassing the treated water.

Next, a description will be given of a method of passing a liquid through the liquid-flow condenser according to the present invention. First, the switch 32 is turned on to apply a DC voltage to the pair of electrodes 30 and 31, and the switching valve 11 is opened.
The switching valve 12 is closed, the water quality monitoring device 8 is placed in a monitoring enabled state, the pump of the liquid to be treated 5 and the pretreatment device 4 are operated, and the pretreated liquid to be treated is passed through the condenser 1. Quantitatively. At this stage, the liquid-flow condenser 1 enters an ionic component removing step, and the liquid to be treated is adsorbed on the pair of electrodes 30 and 31 of the liquid-flow condenser 1 to become a desalted liquid from which the ionic components have been removed. The water is discharged through the desalting liquid discharge pipe 9.

When this state is continued, the ion adsorbing capacity of the pair of electrodes soon approaches a saturated state, the ion removing ability decreases, and the conductivity of the desalted solution gradually increases. When the conductivity measured by the water quality monitoring device 8 becomes an uncollectable value of the desalted liquid, the switching valve 11 is closed, the switching valve 12 is opened, the switch 32 is immediately turned off, and the application of the DC voltage is stopped. Further, the switch 35 is turned on to short-circuit the pair of electrodes 30 and 31, the adsorbed ion component is separated from the pair of electrodes 30 and 31, and moved to the liquid side to regenerate the pair of electrodes 30 and 31. Enter the process.

The above-described removal step and recovery step are defined as one cycle, and by repeating this cycle, the desalted solution from which the ionic components have been removed from the liquid to be treated and the high ion concentration in which the removed ionic components have been recovered can be obtained. In addition to obtaining a concentrated solution, the saturation and regeneration of the pair of electrodes 30 and 31 of the flow-through condenser 1 are repeated.

In the present invention, the pretreatment is basically desirably a continuous treatment. However, even in the case of intermittent treatment, the ion-removing ability of the flow-through condenser whose performance has deteriorated by removing bubbles on the surface is remarkably recovered. You can also.

In the present invention, examples of the desalted solution include softened water, demineralized water, pure water, and solution desalted solution. These desalted liquids are used for boiler water, drinking water, washing water and the like. The concentrated liquid can be used for recovering valuable resources.

In the present invention, a plurality of liquid-passing condensers may be provided. For example, two liquid-passing condensers are arranged in parallel, and one of the liquid-passing condensers is used as an ion component removing step, and the other liquid-passing condenser is used as an ion-permeable condenser. The present invention can also be applied to a liquid passing method in which a component recovery step is performed alternately and repeatedly.

[0031]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but this is merely an example and does not limit the present invention. Example 1 The liquid to be treated had a conductivity of 330 μS / cm, a pH of 5.9, and a temperature of 23.
Using industrial water having a temperature of 0.8 ° C. and TOC of 0.8 ppm, a flow-through type condenser manufactured by Kansai Thermal Chemical Co., Ltd. was used, and one condenser was arranged and connected as shown in FIG. The pretreatment device is a membrane deaerator (equipped with a Liqui-cel 2.5 inch type (Celgard) as a deaerator), performs vacuum deaeration at an absolute pressure of 100 torr, and has a dissolved oxygen concentration of 0.1 mg / L. Was passed through a liquid condenser. The voltage applied to the liquid-passing type capacitor was DC 1.2 V. The water to be treated is continuously supplied to the flow-through condenser at a rate of 250 ml / min, and the removal step and the recovery step as described above are repeated.
(Cycles). At this time, the quality of the effluent of the liquid-flow condenser was monitored with a conductivity meter. The result is shown in FIG.
Shown in

Here, the ion-removing ability of the flow-through condenser is determined by the amount of demineralized water from which ionic components have been removed to a predetermined concentration in the removing step, if the flow rate of the water to be treated is constant. Therefore, the time during which the 10% concentration of the water to be treated is maintained (hereinafter, referred to as “time to reach a 10% concentration value”) is used as an index of the ion removal ability of the liquid condenser. This will be described with reference to FIG. FIG. 2 shows a typical example of the relationship of the conductivity of the effluent with the passage of time. In the figure, at the beginning of the removal step, the conductivity of the water to be treated is reduced to 330 μS / cm to 20 μS / cm, and the ionic components are removed to obtain demineralized water. After that, when the ion component is accumulated in the electrode and approaches the saturated state, the quality of the effluent water decreases, and after 26 minutes, exceeds 33 μS / cm, which is 1/10 of the conductivity of the water to be treated. Thereafter, the electrode is short-circuited and the electrode regeneration step, that is, the recovery step is performed, whereby a concentrated solution of the ionic component accumulated in the flow-through condenser is obtained, and the conductivity of the liquid to be treated is increased. In FIG. 2, the time to reach the 10% density value is 26 minutes.
Therefore, if the time required to reach the 10% concentration value is shorter than the time required to reach the 10% concentration value in the initial operation, it can be understood that the ionic component removing ability of the flow-through condenser is reduced.

In the first embodiment, as is apparent from FIG. 3, the membrane deaeration was performed as a pretreatment for the water to be treated.
Even after the cycle, the ability to remove ion components at the beginning of operation was maintained.

Comparative Example 1 The procedure was performed in the same manner as in Example 1 except that the operation of the pretreatment device was stopped. The results are shown in FIG. From FIG. 3, it can be seen that the ionic component removing ability of the flow-through condenser decreased from about the 20th cycle operation, and to about 40% of the initial ability in the 50 cycle operation.

Example 2 After the 50-cycle operation of Comparative Example 1, the operation of the pretreatment device was started, and the operation was continued in the same manner as in Example 1. The results are shown in FIG. From FIG. 3, the flow-through condenser with reduced ion component removal ability gradually recovered its removal ability due to the supply of degassed water. This is probably because the gas accumulated in the fine pores of the electrode was dissolved in the degassed water and removed, and the effective surface area of the electrode was restored.

Examples 3 to 8, Comparative Examples 2 and 3 The pretreatment device was a membrane deaerator and a heat exchanger, and the temperature of the water to be treated was changed from 23 ° C. to 10 ° C. (Example 3) and 20 ° C. (Example 4). ),
30 ° C. (Example 5), 35 ° C. (Comparative Example 2), 40 ° C. (Comparative Example 3), 50 ° C. (Example 6), 60 ° C. (Example 7) or 70 ° C. (Example 8). 100 cycle operations
The procedure was performed in the same manner as in Example 1 except that the cycle operation was performed. FIG. 4 shows the results. At any of the above temperatures, the initial removal ability was maintained in the initial stage such as the 10-cycle operation. From FIG. 4, in the operation for a long time, the flow temperature of the water to be treated exceeds 30 ° C.
It can be seen that those having a temperature lower than 0 ° C. have reduced removal ability.

Examples 9 to 15 and Comparative Examples 4 to 6 The pretreatment device was a heat exchanger (heater), a membrane deaerator, and a pH.
The temperature of the water to be treated is set at 30 ° C. and the pH of the water to be treated is adjusted to pH 5.9.
2 (Example 9), pH 3 (Example 10), pH 4 (Example 11), pH 5 (Example 12), pH 6 (Comparative Example 4), pH 7 (Comparative Example 5), pH 8 (Comparative Example 6), pH
9 (Example 13), pH 10 (Example 14) or pH 1
1 (Example 15), except that the 50-cycle operation was changed to the 100-cycle operation. FIG. 5 shows the results.

Examples 16 to 22 and Comparative Examples 7 to 9 Example 9 was repeated except that the temperature of the water to be treated was changed from 30 ° C. to 35 ° C.
To 15 and Comparative Examples 4 to 6. FIG. 6 shows the results.

Examples 23 to 29 and Comparative Examples 10 to 12 Example 9 was repeated except that the temperature of the water to be treated was changed from 30 ° C. to 40 ° C.
To 15 and Comparative Examples 4 to 6. The results were the same as in FIG.

From FIGS. 5 and 6, even in the flow-through temperature range of 30 ° C. to 40 ° C. in which a decrease in the ionic component removing ability was observed, if the pH value of the water to be treated was maintained at 4 or less or 9 or more, It can be seen that a decrease in the ability to remove components can be prevented.

Example 30, Comparative Example 13 Instead of industrial water as the liquid to be treated, the conductivity was 330 μS /
The first water-passing treatment was performed in the same manner as in Example 1, except that city water having a pH of 6.0, a temperature of 20 ° C, and a 50-cycle operation were changed to a 1500-cycle operation. Next, the city water was continuously supplied to a commercial activated carbon treatment device (PCF-500A).
(Manufactured by Organo Co., Ltd.), an activated carbon treatment (pretreatment) for filtration was performed, and a second water passing treatment was performed with 500 cycles of the treatment. Next, instead of the activated carbon treatment, a reduction treatment (pretreatment) of injecting 3 ppm of sodium bisulfite was performed, and a third water passing treatment was performed with 500 cycles of the reduction treatment. Next, return to city water
A fourth water passing treatment was performed in the same manner as the water passing treatment. FIG. 7 shows the results.

From FIG. 7, it was observed that the removal performance was gradually reduced, though very slightly, in the first and fourth water passage treatments. This is because an oxidizing substance such as sodium hypochlorite in city water attacked the electrode and reduced the electrode surface area. In the second and third water passing treatments, the tendency to decrease the electrode removing ability stopped, and in the subsequent fourth water passing treatment, the tendency to decrease again was exhibited. In the second water passing treatment and the third water passing treatment, the tendency of the electrode removing ability to decrease has stopped.
This is because the oxidizing agent in city water was neutralized by the reduction treatment with activated carbon or sodium bisulfite, and the oxidation of the electrode was suppressed.

[0043]

According to the present invention, the liquid passing temperature of the liquid to be treated is set to 30 ° C. or less or 50 ° C. or more, or the pH of the liquid to be treated is adjusted.
Since the value is adjusted to pH 5 or lower or pH 9 or higher, it is possible to prevent the generation of microorganisms in the electrode, and to suppress an effective decrease in the electrode surface area due to the microorganisms or metabolites of the microorganisms covering the carbon electrode surface. In addition, since the liquid to be treated is supplied after being degassed, gas is prevented from accumulating on the surface of the activated carbon electrode or in the fine pores, and a reduction in the effective electrode surface area due to the accumulation of the gas can be suppressed. In addition, since the liquid to be treated is supplied after being reduced, oxidation of the surface of the activated carbon electrode is suppressed,
The reduction in effective electrode surface area due to the oxide film can be suppressed. This solves the problem that the ability to remove ionic components from the liquid to be treated is reduced as the processing cycle is repeated. Further, if the pre-processing is performed by combining a plurality of the pre-processing means for the liquid to be processed, the above-mentioned effect becomes more remarkable.

[Brief description of the drawings]

FIG. 1 is a flow chart showing a method for passing a liquid through a liquid-flow condenser according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the conductivity of the effluent and the time in the method for passing a fluid through a fluid-flow condenser according to an embodiment of the present invention.

FIG. 3 is a view showing the influence of the liquid passing cycle of the liquid flowing type capacitors of Examples 1 and 2 and Comparative Example 1.

FIG. 4 is a diagram showing the influence of the flowing temperature of the flowing capacitors of Examples 3 to 8 and Comparative Examples 2 and 3.

FIG. 5 is a graph showing the influence of the flow pH of the flow-through capacitors of Examples 9 to 15 and Comparative Examples 4 to 6.

FIG. 6 is a graph showing the influence of the flow pH of the flow-through capacitors of Examples 16 to 22 and Comparative Examples 7 to 9.

FIG. 7 is a view showing the influence of the liquid passing cycle of the liquid flowing type capacitors of Example 30 and Comparative Example 13.

FIG. 8 is a flowchart showing a method of passing a liquid through a conventional liquid-passing type condenser.

[Explanation of symbols]

 1, 50 Flow-through condenser 2, 3 Supply pipe 4 Pretreatment device 6, 7, 9, 10 Connection pipe 5, 56 Liquid supply source 8, 57 Water quality monitoring device 30, 31, 54, 55 Electrode 32, 35 , 53, 58 Switch 34, 59 DC power supply 11, 12, 51, 52 Switching valve

Claims (6)

[Claims] 1. A direct current voltage is applied to a pair of electrodes to remove a ionic component of a liquid to be treated in a flowing solution to obtain a desalted solution. Thereafter, the pair of electrodes is short-circuited or a direct current power supply is reversely connected. ,
A method of passing a removed liquid component through a flow-through condenser for recovering a concentrated liquid together with a liquid to be processed in the liquid, wherein the liquid to be processed is passed at a temperature of 30 ° C. or lower or 50 ° C. or higher. A method for passing a liquid through a liquid condenser. 2. A desalting solution is obtained by applying a DC voltage to a pair of electrodes to remove ionic components of the liquid to be processed in the liquid flow, and then short-circuiting the pair of electrodes or reversely connecting a DC power supply. ,
A method of passing a removed liquid component through a flow-through condenser for recovering a concentrated liquid together with a liquid to be processed in the liquid, wherein the liquid to be processed is passed at a pH of 5 or less or a pH of 9 or more. Characteristic method of passing liquid through a condenser. 3. A desalinated solution is obtained by applying a DC voltage to a pair of electrodes to remove ionic components of a liquid to be processed in the liquid flow, and thereafter short-circuiting the pair of electrodes or reversely connecting a DC power supply. ,
A method of passing a liquid through a condenser in which the removed ionic component is collected as a concentrated solution together with a liquid to be processed in the liquid, wherein the liquid to be processed is a degassed liquid. How to pass liquid through condenser. 4. A desalting solution is obtained by applying a DC voltage to a pair of electrodes to remove ionic components of the liquid to be processed in the liquid flow, and then short-circuiting the pair of electrodes or reversely connecting a DC power supply. ,
A method of passing a liquid through a condenser in which the removed ionic component is recovered as a concentrated solution together with a liquid to be processed in the liquid, wherein the liquid to be processed is one subjected to a reduction treatment. The flow method of the flow-through condenser. 5. A dc voltage is applied to a pair of electrodes to remove ionic components of the liquid to be processed in the flowing liquid, and the pair of electrodes is short-circuited or a direct current power supply is reversely connected to remove the removed ionic components. A flow-through condenser comprising: a flow-through condenser that collects together with the liquid to be processed in the flow-through; and a deaeration means positioned upstream of the liquid-flow condenser to deaerate the liquid to be processed. Liquid passing device. 6. Applying a DC voltage to a pair of electrodes to remove ionic components of the liquid to be treated in the flowing liquid, short-circuiting the pair of electrodes or reversely connecting a DC power supply to remove the removed ionic components. A flow-through condenser comprising: a flow-through condenser for collecting together with the liquid-to-be-processed in the flow-through liquid; and a reduction means positioned upstream of the liquid-flow-through condenser to reduce the liquid to be processed. Liquid device.