JP2001087769A - Desalting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desalting device capable of simple and efficient desalting treatment. SOLUTION: This desalting device 20a is obtained by connecting in series a liquid passing type condenser 1 for removing an ion component in liquid to be treated under liquid passing by applying direct current voltage to a pair of electrodes and recovering the removed ion component into the liquid to be treated under liquid passing by short-circuiting a pair of the electrodes or reversibly connecting a direct current power source with a single of plural desalting means 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a desalination apparatus capable of obtaining high-purity liquid quality, and more particularly, to a simple desalination apparatus comprising a flow-through condenser and other desalination means connected in series. The present invention relates to a desalination apparatus capable of performing high-efficiency desalination.

[0002]

2. Description of the Related Art Hitherto, as a simple desalting method for converting raw water such as industrial water or city water to pure water, a method using a flow-through condenser has been proposed. The flow-through condenser is
The removal and recovery (regeneration) of ionic components in the liquid to be treated are performed using electrostatic force, and the 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.

On the other hand, conventionally, methods for producing deionized water or high-purity water include a method for obtaining deionized water using an ion exchange apparatus filled with an ion exchange resin, a method for obtaining distilled water using a distillation apparatus, A method using an electric deionized water producing device, a method using a reverse osmosis membrane device, and the like are known. The electric deionized water production apparatus generally requires regeneration with a drug in the method using an ion exchange resin, so that deionization using the ion exchange resin and electrodialysis action are combined, and regeneration with a drug is not required. This is preferable in that deionized water is obtained. In addition, a reverse osmosis membrane device is usually used by connecting a plurality of units in series, or is installed in the preceding stage of the ion exchange device, and the permeated water from which organic substances and ionic components have been removed is treated in the subsequent ion exchange device. And high water quality.

[0004]

However, in the case where the flow-through type condenser is intended for a high degree of desalination, the desalination capacity is insufficient. That is, the desalting ability of the flow-through condenser mainly depends on the applied voltage, the electrode area, the quality of the water to be treated, and the treatment flow rate. If the applied voltage is increased, it is effective in improving the quality of the treated water, but the applied voltage per unit cell is higher than the electrolysis voltage of water, that is, about 1.2.
When the voltage is increased to V or more, the current efficiency of desalination is extremely reduced, and at the same time, the life of the flow-through capacitor is shortened. Therefore,
The applied voltage cannot be increased to about 1.2 V or more. After all, under this condition, in the range considering the quality of the treated water,
Even if the ratio between the electrode area and the processing flow rate (electrode area / processing flow rate) is increased, the desalination performance is not sufficient. In addition, there is also a problem that silica, boron, and the like in the liquid to be treated cannot be sufficiently removed by the liquid-flow type capacitor.

A method for obtaining deionized water using a conventional ion exchange apparatus, a method for obtaining distilled water using a distillation apparatus,
The method of using an electric deionized water production device and the method of using a reverse osmosis membrane device are effective desalination means, but when both are used alone, the contamination of the water to be treated, especially fine particles and organic matter, Has the problem of a decrease in processing capacity due to That is, the fine particles and organic substances having electrical properties are irreversibly attached to the ion exchanger (resin), the reverse osmosis membrane, and the ion exchange membrane of the electric deionized water producing apparatus, and the ion exchange is performed. In the case of a device, the reaction rate of ion exchange is reduced, in the case of a distillation device, the number of fine particles in distilled water is increased, in the case of an electro-deionized water production device, the operating voltage is increased, and in the case of a reverse osmosis membrane device, Each appears as a decrease in flux. Further, in a multi-stage reverse osmosis membrane device in which the permeated water of the reverse osmosis membrane device is further passed through the reverse osmosis membrane device for treatment, the carbon dioxide in the water to be treated cannot be removed as it is, and the pH is changed by adding an alkali. In addition, the carbon dioxide gas is ionized and dissociated into a form that can be removed by a reverse osmosis membrane device. Therefore, although the original purpose is desalination, there is a problem that the addition of alkali such as caustic soda deteriorates the quality of treated water.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional desalination apparatuses, and to provide a desalination apparatus capable of performing a simple and highly efficient desalination treatment. is there.

[0007]

Under such circumstances, the present inventor has conducted intensive studies and as a result, has connected a liquid-flow condenser and one or more other desalination means in series to form a desalination apparatus. It has been found that if the liquid to be treated is passed through this, a simple and highly efficient desalination treatment is possible, and the present invention has been completed.

That is, in the present invention (1), a DC voltage is applied to a pair of electrodes to remove an ionic component of a liquid to be processed during the passage, and the pair of electrodes is short-circuited or a DC power supply is reversely connected. And a desalination apparatus characterized in that a flow-through condenser for recovering the removed ionic components into the liquid to be processed and a single or a plurality of desalination means are connected in series. Things.

The present invention (2) is characterized in that the desalting means comprises:
The present invention provides the desalination apparatus according to the above (1), wherein the desalination apparatus is arranged on the downstream side of the liquid-flow condenser.

[0010] In the present invention (3), the desalting means preferably comprises:
The present invention provides the desalination apparatus according to the above (1) or (2), which is an ion exchange apparatus, a reverse osmosis membrane apparatus, a distillation apparatus, or an electric deionized water production apparatus.

Further, the present invention (4) provides a reverse osmosis membrane device,
A dc voltage is applied to the pair of electrodes to remove ionic components of the liquid to be treated during the passage of the liquid, and the pair of electrodes is short-circuited or the DC power supply is reversely connected to remove the ionic components from the liquid to be treated during the passage of the liquid. It is another object of the present invention to provide a desalination apparatus characterized in that a flow-through condenser to be recovered in a processing liquid is connected in this order.

Further, the present invention (5) is characterized in that a single-stage or a plurality of stages of reverse osmosis membrane devices are further provided downstream of the liquid-flow condenser, wherein the desalination is carried out. An apparatus is provided.

In the present invention (6), the desalination apparatus according to (4), further comprising a single-stage or a plurality of stages of ion-exchange columns disposed downstream of the liquid-flow condenser. Is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The desalination apparatus of the present invention comprises a flow-through condenser and one or more desalination means connected in series. The flow-through capacitor is not particularly limited, but contains a pair of electrodes in which a high surface area activated carbon is in contact with a collecting electrode such as a metal or graphite in a column, and a non-conductive spacer is interposed between the pair of electrodes. It was made. When a direct current power supply is connected to the pair of electrodes and a liquid to be treated containing ions is passed through the column in a state where a direct current voltage, for example, 1 to 2 V is applied, the pair of electrodes is connected to the pair of electrodes. Adsorbs ions, the ionic components are removed, and a desalted solution can be obtained.After that, when the pair of electrodes is short-circuited, the ions that have been electrically neutralized and adsorbed are separated from the pair of electrodes, In addition to regenerating a pair of electrodes, a concentrated solution in which a concentrated ionic component is recovered can be obtained. The voltage applied between the pair of electrodes 30, 31 can be set arbitrarily.

Such a flow-through type capacitor is disclosed in
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 to form a cartridge. Lead wires extend from the conductive support layer of one electrode and the conductive support layer of the other electrode to the outside of the column, are connected to a DC power supply, a liquid supply source is connected to an inlet of the column, and an outlet is provided. Is connected to 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.

Further, as another structural example of the liquid-passing type capacitor, a pair of electrodes, which are activated carbon layers mainly composed of activated carbon having a high specific surface area, are sandwiched between spacers made of a non-conductive porous liquid-permeable sheet. It arranges, a pair of collector electrodes is arranged outside the electrodes, and furthermore, it has a flat plate shape in which a holding plate is arranged 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. The reverse connection may be performed. Further, the electrode and the collecting electrode may be integrated.

In the present invention, the desalting means is not particularly limited, but includes, for example, a distillation apparatus, an ion exchange apparatus, a reverse osmosis membrane apparatus, and an electric deionized water producing apparatus. As a distillation apparatus, for example, raw water consisting of pure water or the like is heated in an evaporator equipped with a heating device to obtain steam, and the steam is condensed in a condenser to form distilled water, which is cooled. An apparatus is provided in which the distilled water is sent to a cooler to reduce the temperature to a use temperature, and the distilled water is stored in a storage bottle or a storage tank set in a water sampling port through a distilled water supply pipe connected to a cooler.

Examples of the ion exchange device include, for example, a strongly acidic cation exchanger (strongly acidic cation exchange resin)
"Exchange resin" and "exchange resin" including "exchange resin"), a cation exchange resin such as a weakly acidic cation exchange resin or a strongly basic anion exchange resin, an anion exchange resin such as a weakly basic anion exchange resin, or What combined these etc. is mentioned. These may be either single beds or mixed beds. In addition, a boron selective resin or a cartridge polisher containing a polyhydric alcohol capable of selectively removing boron as a functional group (non-regeneration type ion exchange resin device)
Etc. can also be used. As the boron selective resin, for example, Amberlite IRA743T can be used.

As an electric deionized water producing apparatus, for example, a gap formed by a cation exchange membrane and an anion exchange membrane is basically filled with an ion exchanger to form a deionization chamber. While passing the water to be treated, a direct current is applied through the both ion exchange membranes to produce deionized water while electrically removing ions from the concentrated water flowing outside the both ion exchange membranes. Things. For this reason, ions are concentrated in the concentrated water.

In the present invention, as a mode in which a liquid-flow condenser and a single or a plurality of desalination means are connected in series, a single or a plurality of desalination means are provided in the first stage, and a liquid-flow condenser is provided in the second stage. Installation type, a liquid-flow condenser in the first stage,
There are three modes, one in which a single or a plurality of desalination means are provided in the subsequent stage, and the other in which a single or a plurality of desalination means is provided in the front and rear stages of the flow-through condenser. When the flow-through condenser is connected to the subsequent desalting means, the desalinate outflow pipe of the flow-through condenser and the liquid supply pipe of the desalination apparatus are connected. The following are listed as specific examples of the connection form. The flow direction of the liquid to be treated is from left to right. (1) Flow-through condenser + ion exchanger (2) Flow-through condenser + distillation apparatus (3) Flow-through condenser + electric deionized water production equipment (4) Flow-through condenser + reverse osmosis membrane device (5 ) Reverse osmosis membrane device + liquid-flow condenser (6) Reverse osmosis membrane device + liquid-flow condenser + reverse osmosis membrane device (7) Liquid-flow condenser + reverse osmosis membrane device + non-regeneration ion exchange device (8) Liquid condenser + reverse osmosis membrane device + electric deionized water production equipment (9) Flow-through condenser + reverse osmosis membrane device + distillator (10) Flow-through condenser + reverse osmosis membrane device + liquid-flow condenser + reverse Osmotic membrane device

As the ion exchange apparatus in the above (1), for example, a mixed resin of an anion exchange resin and a cation exchange resin is filled to form an ion exchange tower, and when the mixed resin reaches a flow-through point, a new resin is formed. A non-regeneration type ion exchange device to be exchanged, and an in-situ regeneration type ion exchange device which similarly regenerates with an acid or alkali at the stage when the mixed resin reaches the cross-flow point are exemplified.

Next, a desalination apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flowchart of the desalination apparatus of the present embodiment. In FIG. 1, a desalination apparatus 20a is composed of a first-stage liquid-flow condenser 1 and a second-stage desalination means 2. The downstream side of the flow-through condenser 1 is connected to a water quality monitoring device 5 by a discharge pipe 8, and the discharge pipe 9 of the water quality monitoring device 5 is a desalted liquid discharge pipe 1 having a switching valve 13.
1 and a concentrated liquid discharge pipe 10 having a switching valve 12, and the desalted liquid discharge pipe 11 is connected to the desalting means 2.
The upstream side of the flow-through condenser 1 is connected to a liquid supply pump 3 for quantitatively supplying the water to be treated through a supply pipe 7 via a safety filter 4 having an absolute pore diameter of 10 μm in the middle.

The flow-through capacitor 1 includes at least a pair of electrodes 30 and 31, and the electrode 30 is connected to a cathode of a DC power supply 34 via a switch 32. The pair of electrodes 30 and 31 are connected to each other via a switch 35. The operation control of the devices shown in FIG. 1 is performed by a known control device such as a sequencer or a microcomputer. The detailed operation control includes, for example, a method of passing a liquid through a condenser described later. No.

In FIG. 1, the water quality monitoring device 5 is for measuring liquid quality, and is not particularly limited as long as it is an index measuring device capable of accurately grasping the degree of ion removal. In this embodiment, the conductivity meter is used.

A desalination method using the desalination apparatus of the first embodiment will be described. In FIG. 1, when the liquid feed pump 3 is driven, the liquid to be treated, such as city water, industrial water, recovered water, river water, or sugar solution, is supplied to the flow-through condenser 1 by the supply pipe 7 through the safety filter 4. Is done. In the flow-through condenser 1, the switch 32 is turned on, a DC voltage is applied to the pair of electrodes 30, 31, the switching valve 13 is opened, the switching valve 12 is closed, and the water quality monitoring device 5 is set in the monitoring state. At this stage, the liquid-flow condenser 1 enters a desalting step (ion component removal step), and the liquid to be treated is adsorbed on the pair of electrodes 30 and 31 of the liquid-flow condenser 1 to remove the ion components. It becomes a liquid and is sent to the desalting means 2 by the desalting liquid discharge pipe 11.

When this state continues, a pair of electrodes 30,
The ionic component is gradually adsorbed to 31 and approaches a saturated state,
The ionic component removal performance decreases, and the conductivity of the desalted solution gradually increases. When the electric conductivity measured by the water quality monitoring device 5 becomes a non-desalted liquid sampling impossible value, the switching valve 13 is closed and the switching valve 12 is opened, the switch 32 is immediately turned off, and the flow through the condenser 1 is stopped. The application of the DC voltage is stopped, and the switch 35 is turned on to short-circuit the pair of electrodes 30 and 31,
Alternatively, the DC power supply 34 is reversely connected, the adsorbed ion component is separated from the pair of electrodes 30 and 31, and moved to the liquid to be treated, thereby regenerating the pair of electrodes 30 and 31. That is, the flow-through condenser 1 enters a concentration step (ion component recovery step), and the concentrated liquid in which the ionic components are concentrated is discharged out of the system by the concentrated liquid discharge pipe 10.

The desalting step (removing step) and the concentrating step (recovering step) are defined as one cycle, and the cycle is repeatedly performed to remove the ionic components from the liquid to be treated and to remove the ionic component. In addition to obtaining a concentrated solution having a high ion concentration from which the ionic components have been recovered, the saturation and regeneration of the pair of electrodes 30 and 31 of the flow-through condenser 1 are repeated.

Next, in the desalting means 2, a trace amount of ionic components contained in the desalted solution desalted by the flow-through condenser is further removed, and a highly desalted solution is obtained from the outlet pipe 14. be able to. Further, when the desalting means 2 is a device for discharging a concentrated liquid such as a reverse osmosis membrane device or an electric deionized water producing device, the concentrated liquid discharged from the desalting means 2 is returned to the return pipe 15 (FIG. 1). , Two-dot chain line), the liquid recovery rate can be improved by returning to the liquid to be treated.

In the first embodiment, the first-stage flow-through condenser is a device for roughly removing ionic components in the liquid to be treated, and the second-stage desalting means removes remaining ionic components, organic substances, fine particles and the like. It is preferable to use a finishing device in that desalting can be performed efficiently. In this case, the liquid quality of the desalted liquid flowing out of the desalting step of the flow-through condenser has a conductivity of 100 μS / cmμ or less, preferably 10 to 50 μM.
S / cm, and the water quality of the desalted liquid flowing out of the desalting means is 1.0 to 18.25 M when the desalting means is an ion exchange device.
Ω · cm, preferably 10 to 18.25 MΩ · cm,
When the desalting means is a distillation apparatus, it is 0.2 to 2.0 μS / cm, preferably 0.2 to 1.0 μS / cm, and when the desalting means is a reverse osmosis membrane apparatus, it is 1.0 to 10 μS / cm. cm, preferably 1.
0 to 5.0 μS / cm, and when the desalting means is an electric deionized water production device, the pressure is 1.0 to 18.25 MΩ · cm, preferably 10 to 18.25 MΩ · cm.

Next, a desalination method using the desalination apparatus of the second embodiment will be described with reference to FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted, and different points will be mainly described. The desalination apparatus 20b of FIG. 2 is different from the desalination apparatus 20a of FIG. 1 in that the subsequent desalination means is a reverse osmosis membrane apparatus 2b, and the non-permeate of the reverse osmosis membrane apparatus 2b is returned to the liquid to be treated. The reverse osmosis membrane device 2a is provided at the point where the pipe 15 is provided,
And a return pipe 16 for returning the concentrated liquid of the flow-through condenser 1 to the liquid to be treated through the concentrated liquid outlet pipe 10.

Thus, the liquid to be treated is supplied to the reverse osmosis membrane device 2a.
The main components of the permeated liquid are molecular anions such as carbonic acid and bicarbonate, monovalent cations such as sodium, and silica. From the permeate having such a liquid quality, bicarbonate ions and sodium ions are removed by the flow-through condenser 1. As a result, as shown in the following formula: H ₂ CO ₃ ⇔H ⁺ + HCO ₃ ²⁻ , the bicarbonate ionization of the remaining molecular carbonic acid proceeds, and the bicarbonate ion is removed by the liquid-flow condenser 1. As the carbonic acid-derived substance in the liquid to be treated is removed by the flow-through condenser 1, the liquid to be treated changes from acidic to neutral, and the proportion of bicarbonate ions increases. Next, the residual bicarbonate ion is removed from the desalted liquid obtained from the flow-through condenser 1 by the reverse osmosis membrane device 2b, and becomes a permeate having a high liquid quality.
In addition, since the concentrated liquid obtained from the flow-through condenser 1 and the non-permeated liquid of the reverse osmosis membrane device 2b are returned to the liquid to be treated, the liquid collection efficiency can be improved.

Further, since the hardness component is also removed from the treated water of the flow-through condenser, the alkali region in which the pH can be adjusted without precipitating the hardness component is expanded. Therefore, if necessary, if an alkali is added to the flow-through condenser-treated water and the water is passed through the subsequent desalination means, particularly a reverse osmosis membrane device, ionization of carbonic acid, silica or boron proceeds,
The quality of the permeated water of the reverse osmosis membrane device can be further improved.

In the above embodiment, the number of the flow-through condensers is one, but a plurality of the flow-through condensers are arranged in parallel to increase the ion concentration of the desalted solution or the ion concentration. May be obtained continuously.

[0034]

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 A liquid to be treated (raw water) was prepared by treating city water with activated carbon, degassing with a degassing membrane (100 torr), and adjusting the temperature to 20 ° C., and having a desalination flow as shown in FIG. Using a desalting apparatus, desalting was performed under the following desalting conditions. Table 1 shows the quality of the obtained treated water together with the raw water. In the present embodiment, when the processing flow rate of the liquid-flow condenser is insufficient, first, the liquid-flow condenser is operated to store the demineralized water of the liquid-flow condenser in a clean tank (not shown), and then the subsequent step is performed. It was used for processing. (Desalination conditions) ・ Specifications and operating conditions of the flow-through condenser Capacitor: Total activated carbon of activated carbon electrode manufactured by Kansai Thermochemical Co .; 252 g Applied voltage: DC 1.2 V Treatment liquid flow rate; 300 ml / min Operating method; The conductivity of the waste water was monitored by a meter, and the operation was performed so as to obtain 90% of desalinated water from the desalination step.・ Specifications and operating conditions of desalting means Device: Ion exchange device “Non-regenerative cartridge polisher G5” (manufactured by Organo) Type of ion exchanger: 5L of mixed bed resin MB2 Filling ratio; = 1
2

Example 2 Example 1 was repeated except that a reverse osmosis membrane device having the following specifications and processing conditions was used as the desalting means instead of the ion exchange device.
Desalting was performed in the same manner as described above. Table 1 shows the quality of the obtained treated water. - reverse osmosis unit; "experimental machine" (manufactured by Organo Corporation) membrane; (manufactured by Nitto Denko Corporation) ES-20 operating pressure; 8 kgf / cm ²

Example 3 A desalting treatment was carried out in the same manner as in Example 1 except that an electric deionized water producing apparatus having the following specifications and processing conditions was used instead of the ion exchange apparatus as the desalting means. Table 1 shows the quality of the obtained treated water. -Electric deionized water producing apparatus; "prototype" (manufactured by Organo) The structure of the prototype and the ion-exchange resin to be filled in the desalting chamber were in accordance with Example A described in Japanese Patent Publication No. 2865389. Rating: 100L / hour Operating voltage: 50V

Example 4 A desalting treatment was carried out in the same manner as in Example 1 except that a distillation apparatus having the following specifications and processing conditions was used instead of the ion exchange device as the desalting means. Table 1 shows the quality of the obtained treated water.・ Distiller; “Auto Still Distiller” (manufactured by Yamato Scientific Co., Ltd.) Rating: 1.8 L / hour

Example 5 Using a desalination apparatus having a desalination treatment flow as shown in FIG. 2, treatment was performed under the following desalination treatment conditions. Table 1 shows the quality of the obtained treated water. Liquid to be treated: the same as in Example 1. -Flow-through condenser; the equipment and processing conditions are the same as in Example 1. Reverse osmosis membrane device: Both the former stage and the latter stage have the same apparatus and processing conditions as in Example 1.

Example 6 A desalting treatment was performed in the same manner as in Example 5, except that the reverse osmosis membrane device 2b at the subsequent stage was omitted. That is, in FIG. 2, the liquid flowing out of the desalted liquid discharge pipe 11 was obtained as treated water. Table 1 shows the quality of the obtained treated water.

Example 7 The treatment liquid of Example 2 was further desalted by the ion exchange apparatus used in Example 1. That is, in FIG. 1, the permeated water of the reverse osmosis membrane device flowing out of the desalted liquid discharge pipe 14 was further subjected to ion exchange treatment. Table 1 shows the quality of the obtained treated water.

COMPARATIVE EXAMPLE 1 Except for omitting the subsequent desalting means (ion exchange device),
The treatment was performed in the same manner as in Example 1. That is, the liquid to be treated is treated with the liquid type condenser alone to obtain treated water. Table 1 shows the quality of the obtained treated water.

Comparative Example 2 A treatment was performed in the same manner as in Example 1 except that a liquid-flow condenser was used in place of the subsequent desalting means (ion exchange device). That is, the liquid to be treated is treated by a desalination device in which two flow-through condensers are connected in series to obtain treated water. Incidentally, for the sake of the experiment, the treatment was actually performed twice with the same liquid-passing condenser. Table 1 shows the quality of the obtained treated water.
Shown in

Comparative Example 3 A voltage of 1.2 V applied to the flow-through capacitor was changed to 0 V (no current).
The procedure was performed in the same manner as in Example 5, except that That is, the liquid to be treated is treated with the reverse osmosis membrane device alone to obtain treated water. Table 1 shows the quality of the obtained treated water.

[0044]

[Table 1]

In Table 1, “CP” is a liquid-flow condenser, and “IE”
R ”ion exchange device,“ RO ”reverse osmosis membrane device,“ EDI ”
Each shows an electric deionized water production apparatus.

From Table 1, it can be seen that the desalination apparatus in which the liquid-flow condenser and the other desalting means are connected in series is different from the single apparatus of the liquid-flow condenser alone or the other apparatus of the other desalination means. High water quality can be obtained. In particular, a high-purity water quality was obtained in the desalination apparatus (Example 7) using a flow-through condenser, a reverse osmosis membrane device, and a non-regenerative cartridge polisher. In addition, the desalination apparatus (Examples 1 to 4), which is a liquid-flow condenser to a desalination means, exhibits excellent desalination performance. The treatment liquid adsorbs fine particles and organic components having electrical properties and then applies a short circuit or a reverse potential to perform reversible desorption and discharge impurities out of the system. Therefore, these impurities are not carried into the subsequent desalination means. On the other hand, in the desalting means other than the conventional flow-through type condenser, irreversible adsorption of fine particles and organic substances occurs on the ion exchanger and the ion exchange membrane, which lowers the desalting performance.

Example 8 In Example 1, the operating conditions of the flow-through condenser were variously changed, and the effects other than the effect of improving the water quality on the subsequent ion exchanger were observed. The operation of the flow-through condenser is such that the treated water quality (desalinated water quality) of the flow-through condenser is 15
The applied voltage was adjusted so as to be 0, 100, 50 and 25 μS / cm. The effects other than the water quality improvement effect on the ion exchange device were evaluated by the reaction rate of the ion exchange resin.
The reaction rate of the ion exchange resin is disclosed in JP-A-10-267838.
And the like. Table 2 shows the results.

Example 9 In Example 2, the operating conditions of the flow-through condenser were changed variously, and the effects other than the effect of improving the water quality on the subsequent reverse osmosis membrane device were observed. The operation of the flow-through condenser is such that the treated water quality (desalinated water quality) of the flow-through condenser is 15
The applied voltage was adjusted so as to be 0, 100, 50 and 25 μS / cm. The effect other than the water quality improvement effect on the reverse osmosis membrane device is the flux (permeate flow rate) of the reverse osmosis membrane device.
Was evaluated in terms of decrease. That is, the same flat membrane as the membrane used in Example 2 was set in a small flat membrane test apparatus (C70-F type, manufactured by Nitto Denko Corporation), the operating pressure was set to 8 kgf / cm ² , and the treatment of each flow-through condenser was performed. Water was passed through, and the integrated amount of permeated water from the start of water passing until the flux became 90% of the initial value was measured. Table 2 shows the results.

Example 10 In Example 3, the operating conditions of the flow-through condenser were changed variously, and the effects other than the effect of improving the water quality on the subsequent electric deionized water producing apparatus were observed. The operation of the flow-through condenser was performed by adjusting the applied voltage so that the treated water quality (desalinated water quality) of the flow-through condenser was 150, 100, 50, and 25 μS / cm. The effects other than the effect of improving the water quality on the electric deionized water producing apparatus were evaluated by the time-dependent increase rate of the electric resistance of the stack of the electric deionized water producing apparatus at a current value of 1 A. Table 2 shows the results.

Example 11 In Example 4, the operating conditions of the flow-through condenser were changed variously, and the effects other than the effect of improving the water quality on the subsequent distillation unit were observed. In the operation of the flow-through condenser, the treated water quality (desalted water quality) of the flow-through condenser is 150, 10
The applied voltage was adjusted so as to be 0, 50, and 25 μS / cm. The effects other than the effect of improving the water quality on the still were evaluated by the number of fine particles of 2 μm or more in the distilled water. The fine particles were measured with an electronic fine particle measuring device “ROYCO4100 + 246B” (manufactured by HIAC). Table 2 shows the results.

Comparative Examples 4 to 7 In each of Examples 7 to 10, each of the subsequent stage ion exchange device, reverse osmosis membrane device, electric deionized water producing device, and distiller when the flow-through condenser was de-energized. The effect other than the water quality improvement effect on water was observed with the same evaluation items. Table 2 shows the results.

[0052]

[Table 2] Footnote 1) No flow through condenser

From Table 2, it can be seen that as the quality of the treated water (desalinated water) of the first-stage flow-through condenser improves, the adverse effect on the subsequent various types of desalination means decreases, but the quality of the treated water of the first-stage flow-through condenser decreases. Is less than about 50 μS / cm, the effect is saturated. Therefore, the operation of the flow-through condenser should preferably be such that the quality of the treated water of the flow-through condenser is 50 to 100 μS / cm.

[0054]

According to the present invention, a simple and highly efficient desalination treatment can be performed. In particular, a high-purity water quality could be obtained in a desalination device using a flow-through condenser, a reverse osmosis membrane device, and a non-regenerative cartridge polisher. Also, in the desalination device that uses a liquid-flow condenser → desalination means, a direct-current voltage is applied to the electrodes in the preceding liquid-flow condenser to adsorb fine particles and organic components with electrical properties in the liquid to be treated. Then, a short circuit or a reverse potential is applied to perform reversible desorption, so that impurities are discharged out of the system. Therefore, since these impurities are not brought into the subsequent desalting means, a highly purified desalted liquid can be obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing method of a desalination apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing method of a desalination apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow-through condenser 2 Desalting means 3 Liquid sending pump 4 Safety filter 5 Water quality monitoring device 7 Supply piping 8, 9 Connection piping 10 Desalting liquid discharging piping 11 Concentrated liquid discharging piping 12, 13 Switching valve 14 Outflow piping 15, 16 Return pipe 30, 31 Electrode 32, 35 Switch 34 DC power supply

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01G 9/155 H01G 9/00 301Z F term (reference) 4D006 GA03 KA01 KA72 KB01 KB14 PA01 PB02 PC02 4D025 AA04 AB02 BA09 BA10 BA14 BA15 BB04 DA06 4D034 BA03 CA12 4D061 DA01 DB18 DC19 EA02 EA09 EB02 EB05 EB29 EB31 EB37 EB39 FA02 FA08 FA09 FA13 GA21 GC16

Claims (6)

[Claims] A dc voltage is applied to a pair of electrodes to remove ionic components of a liquid to be treated in a liquid flowing therethrough, and the pair of electrodes is short-circuited or a DC power supply is reversely connected to remove the removed ionic components. A flow-through condenser that recovers the liquid to be treated during the flow,
A desalination apparatus comprising a single or a plurality of desalination means connected in series. 2. The desalination apparatus according to claim 1, wherein the desalination unit is disposed downstream of the liquid-flow condenser. 3. The desalination apparatus according to claim 1, wherein the desalination means is an ion exchange device, a reverse osmosis membrane device, a distillation device, or an electric deionized water production device. 4. A reverse osmosis membrane device, a DC voltage is applied to a pair of electrodes to remove an ionic component of a liquid to be processed in the flowing liquid, and the pair of electrodes is short-circuited or a DC power supply is reversely connected. A desalination apparatus characterized in that a flow-through condenser for collecting the removed ionic components into the liquid to be treated is connected in this order. 5. The desalination apparatus according to claim 4, wherein a single-stage or multiple-stage reverse osmosis membrane device is further provided downstream of the liquid-flow condenser. 6. The desalination apparatus according to claim 4, wherein a single-stage or a plurality of stages of ion-exchange devices are further disposed downstream of the liquid-flow condenser.