JP4121226B2 - Liquid passing method and apparatus for liquid passing capacitor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention obtains a desalting solution from which the ionic components of the liquid to be treated are removed by applying a DC voltage to the pair of electrodes held therein, and then regenerates the pair of electrodes by short-circuiting or reversely connecting them. In addition, the present invention relates to a method and an apparatus for passing a liquid-type condenser that collects the removed ion component together with the liquid to be treated and removes and collects the ion component of the liquid to be treated according to the purpose.
[0002]
[Prior art]
The liquid-passing capacitor uses an electrostatic force to remove and recover (regenerate) ionic components in the liquid to be treated, and its principle is as follows. In other words, a liquid-flowing capacitor is removed by applying a DC voltage to the pair of electrodes it holds and adsorbing ionic components, charged particles, or organic substances in the liquid to be treated to the pair of electrodes. To obtain a desalted solution from which the ionic components have been removed, and then short-circuit the pair of electrodes or reversely connect a DC power source to release the ionic components adsorbed on the pair of electrodes and regenerate the pair of electrodes. However, the removal ion component is repeatedly collected as a concentrated liquid together with the liquid to be treated in the liquid.
[0003]
Such a liquid passing type capacitor is disclosed in Japanese Patent Laid-Open No. 5-258992. In this example of the known example, an inlet for introducing a liquid to be processed into a column and a liquid from which ion components have been removed are discharged. An outlet is provided, and the pair of electrodes is accommodated in the column. In both of these pairs of electrodes, a high surface area conductive surface layer is supported on a conductive support layer, and a nonconductive porous spacer is further included. Therefore, a pair of electrodes is 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, a high surface area conductive. The surface layer has a six-layer structure. The pair of electrodes are wound around a hollow porous central tube with a 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 and are connected to a DC power source. A liquid supply source to be processed is connected to the inlet of the column, and a switching valve for separating the desalted liquid from which the ionic component has been removed and the concentrated liquid from which the ionic component has been recovered is connected to the outlet.
[0004]
The liquid passing method of the above liquid passing type capacitor will be described with reference to FIG. In FIG. 5, reference numeral 50 denotes a liquid passing type capacitor. First, the switching valve 51 is opened, the switching valve 52 is closed, the switch 53 is turned on, a DC voltage is applied to the pair of electrodes 54 and 55, and the liquid to be processed is supplied from the liquid source 56 to be processed. When supplied to the capacitor 50, an ion component is adsorbed on the pair of electrodes 54 and 55, and a desalted solution from which the ion component is removed on the downstream side of the switching valve 51 is obtained. If this state continues, the water quality monitoring device 57 measures that the ionic components are gradually adsorbed and saturated by the pair of electrodes 54 and 55 and the ionic component removal performance gradually decreases. To turn off the DC voltage. Then, the switching valve 51 is closed and the switching valve 52 is opened, and in order to regenerate the ion component removal performance, the switch 58 is turned on and the pair of electrodes 54 and 55 are short-circuited or the DC power source 59 is turned on. When the reverse connection is established, the ionic components adsorbed on the pair of electrodes 54 and 55 are released, and a concentrated liquid is obtained 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 regenerated. One cycle of removal and recovery (regeneration) of ionic components in the liquid to be treated is completed. And the to-be-processed liquid is always supplied to the flow-through type capacitor | condenser 50 from the to-be-processed liquid supply source 56, The said cycle is repeated and the desalted liquid from which the ionic component was removed, and the concentrated liquid which collect | recovered the ionic component alternately Can get to.
[0005]
[Problems to be solved by the invention]
However, in the conventional liquid passing type capacitor passing method, the processing liquid (desalted liquid or concentrated liquid) may contain bubbles. In particular, bubbles are included when the applied voltage is increased to perform an operation for highly removing ionic components. Such bubbles cause various obstacles in the subsequent stage of the liquid passing type capacitor. For example, when desalinating liquid or concentrated liquid is further sent to a use point using a pump, the bubbles interfere with smooth pump passage, and may cause the pump to stop in some cases. Further, when the desalted liquid is passed through the ion exchange resin tower in order to further reduce the ion component, the bubbles cause separation of the ion exchange resin, and the ion component is not sufficiently reduced.
[0006]
Accordingly, an object of the present invention is to provide a desalting solution that can obtain a desalting solution or a concentrated solution that does not contain bubbles and that has an improved ionic component removal rate, in the passing method of the passing-through capacitor. It is an object of the present invention to provide a liquid passing method and apparatus for a liquid capacitor.
[0007]
[Means for Solving the Problems]
In such a situation, the present inventor has intensively studied, and as a result, the generation of bubbles is mainly oxygen gas and hydrogen gas generated by water electrolysis. the provided, by increasing the voltage applied to the FTC intentionally, for example, the applied voltage V ₁ (V) ~ 2.0V higher value V ₂ than the applied voltage electrolysis occurs in water electrolysis of water occurs It has been found that if the liquid passing treatment is carried out in the range of (V), the desalting solution from which the ionic component removal rate is increased and the bubbles are removed can be obtained, and the present invention has been completed.
[0008]
That is, the present invention (1) applies a DC voltage to a pair of electrodes to remove an ionic component of a liquid to be treated in the liquid flow to obtain a desalted solution, and then short-circuits the pair of electrodes or a DC power source. In a flow-through capacitor that is reversely connected and collects the removed ionic component as a concentrate together with the liquid to be treated or the recovery water, the desalted liquid or the concentrate obtained from the liquid-flow condenser is removed. It is intended to provide a flow-through method for a flow-through capacitor, which is obtained by passing through a liquid separation device to obtain a desalted liquid or a concentrated liquid from which bubbles are removed. By adopting such a configuration, it is possible to obtain a desalted liquid or concentrated liquid from which bubbles have been removed by a simple method, and as a result, when the desalted liquid or concentrated liquid is further sent to a point of use using a pump. When the desalted liquid is passed through the ion exchange resin tower to prevent the pump from stopping due to bubbles and to further reduce the ionic components, the bubbles are stable without causing separation of the ion exchange resin. It is possible to reduce the ion component.
[0009]
Further, in the present invention (2), the applied voltage of the liquid-flowing capacitor is a value V _{2 that} is 2.0 V higher than the applied voltage V ₁ (V) at which electrolysis of water occurs to the applied voltage at which electrolysis of water occurs. The present invention provides the liquid-passing method for a liquid-passing capacitor according to the invention (1), which is in the range of (V). By adopting such a configuration, it is possible to obtain a desalting solution that has the same effects as the above-described invention and that has a further improved ionic component removal rate.
[0010]
In the present invention (3), a DC voltage is applied to the pair of electrodes to remove the ionic components of the liquid to be treated, and the pair of electrodes are removed by short-circuiting or reversely connecting a DC power source. A liquid-flow condenser that collects the ionic components in the liquid to be treated or the water for recovery, and a gas-liquid separation device that gas-liquid separates the desalted liquid or concentrated liquid obtained from the liquid-flow condenser. The liquid-flow type capacitor device characterized by the above is provided. By adopting such a configuration, the inventions (1) and (2) can be implemented.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, a liquid passing method of the liquid passing type capacitor according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flowchart showing a liquid passing method of a liquid passing type capacitor according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes a flow-through condenser, and the downstream side of the flow-through condenser 1 is connected to a water quality monitoring device 8 by an outflow pipe 6, and the outflow pipe 10 of the water quality monitoring device 8 further has a switching valve 12A. The gas / liquid separator 2 is connected to the liquid outflow pipe 17. In addition, the outflow pipe 10 has a concentrate outflow pipe 21 having a switching valve 12B branched from now on. The upstream side of the liquid passing capacitor 1 is connected to the liquid supply source 5 to be processed by a connection pipe 3. The processing liquid supply source 5 includes a processing liquid tank and a liquid feed pump for quantitatively supplying the processing liquid from now on (not shown). The gas-liquid separation device 2 includes an apparatus part in contact with the liquid phase, here a treatment liquid outflow pipe 22 connected to the bottom surface part, and an apparatus part in contact with the gas phase, here an exhaust pipe 23 connected to the top plate part. .
[0012]
The first liquid-flowing capacitor 1 includes at least a pair of electrodes 30 and 31. The electrodes 30 and 31 are connected to each other via a switch 33A. The electrode 30 is connected to a cathode of a DC power supply 34 via a switch 32A. It is connected to the. The operation control of the devices shown in FIG. 1 is performed by a known control device such as a sequencer or a microcomputer. As the detailed operation control, for example, a liquid passing method of a liquid passing capacitor described later is used. Can be mentioned.
[0013]
The structure of the liquid-flowing capacitor 1 is not particularly limited, but here, electrodes 30 and 31 formed by contacting a high surface area activated carbon with a collecting electrode such as metal or graphite are accommodated in a column. A non-conductive spacer is interposed. Then, when a treatment 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 30 and 31 adsorb ions, and the ionic components are removed and desalting is performed. Then, when the pair of electrodes 30 and 31 are short-circuited, the electrically neutralized and adsorbed ions are released from the pair of electrodes 30 and 31, and the pair of electrodes 30 and 31 are regenerated. In addition, a concentrated liquid in which a concentrated ionic component is recovered can be obtained.
[0014]
Although it is possible to arbitrarily set as a voltage applied between the pair of electrodes 30 and 31, in the present invention, especially electrolysis of applied voltage V ₁ (V) ~ aqueous electrolysis of water occurs An ion component removal rate is increased by a value V ₂ (V) that is 2.0 V higher than the applied voltage at which the above occurs, preferably in the range of (V ₁ +0.1) to (V ₁ +1.0) V. The effect of the present invention is remarkably exhibited in that the desalted liquid can be obtained, and the desalted liquid from which bubbles have been removed can be obtained by the gas-liquid separator at the subsequent stage. FIG. 2 shows an example of the relationship between the applied voltage obtained by the flow of the liquid-pass condenser and the conductivity of the desalted water or the amount of bubbles generated. According to this example, the applied voltage V ₁ ( V) is 1.5 V, and the conductivity of the desalting rate shows a minimum value at an applied voltage slightly higher than the V ₁ value. That is, if the applied voltage is increased in order to increase the removal rate of the ionic component with a liquid-flowing capacitor, a problem of bubble generation occurs.
[0015]
Therefore, the applied voltage is in the above range, and the desalted liquid containing bubbles is subjected to gas-liquid separation processing at a later stage. If the applied voltage does not cause electrolysis of water, a desalted solution from which ion components are sufficiently removed cannot be obtained, and bubbles are generated at an applied voltage exceeding (V ₁ +2.0) V value. Since the amount increases excessively, the amount of gas adsorbed on the surface of the electrode made of activated carbon increases, and the number of ion adsorption sites decreases, which is not preferable. Here, the applied voltage V ₁ (V) at which water electrolysis occurs varies depending on the composition and properties of the liquid to be treated and the state of the electrode such as lattice defects on the electrode surface of the liquid-flowing capacitor and adhesion of impurities. . Therefore, the V ₁ value is usually defined as a voltage at which bubbles can be visually observed in the desalted liquid flowing out from the liquid-flowing capacitor. In FIG. 2, the “bubble generation amount” is based on the measurement of the gas contained in the desalted water collected in the measuring cylinder in the water tank by the water displacement method.
[0016]
As another example of the structure of the liquid-permeable capacitor 1, a pair of electrodes, which are activated carbon layers mainly composed of activated carbon with a high specific surface area, are arranged with a spacer made of a non-conductive porous liquid-permeable sheet interposed therebetween, A pair of collector electrodes is arranged outside the electrode, and a flat plate shape is formed with a holding plate arranged outside the collector electrode. A DC power source is connected to the collector electrode, and a short circuit between the collector electrodes or reverse connection of the DC power source is performed. You may do it. Further, the electrode and the collector electrode may be integrated.
[0017]
In addition, the water quality monitoring device 8 is not particularly limited as long as it is a measuring device that measures liquid quality and can accurately grasp the degree of ion removal, and includes a conductivity meter and a specific resistance meter. In the embodiment, it is a conductivity meter.
[0018]
The gas-liquid separation device 2 is a device having gas-liquid separation capability, and includes a liquid inlet 171 to be processed and a liquid outlet 221 for discharging a liquid from which gas has been substantially separated and removed, and is in contact with the gas phase A tank structure having a surface. The tank is provided with a lid on the upper surface to prevent dust and the like from entering the processing liquid, and the lid is provided with an exhaust pipe 23 for guiding gas to the outside. Further, the gas-liquid separator 2 may be a device that does not have a lid and whose liquid surface is open to the atmosphere. Moreover, the thing of the structure which provided the baffle plate in the tank may be used.
[0019]
A method for passing water through the liquid-passing capacitor 1 as described above will be described. First, the switch 32A is turned on, for example, a DC voltage that causes electrolysis of water is applied to the pair of electrodes 30 and 31, the switching valve 12A is opened, the switching valve 12B is closed, and the water quality monitoring device 8 is In a state where monitoring is possible, the pump of the processing liquid supply source 5 is operated, and the processing liquid is quantitatively supplied to the liquid condenser 1. At this stage, the flow-through capacitor 1 enters an ionic component removal step, and the liquid to be treated becomes a desalting solution from which the ionic components are adsorbed by the pair of electrodes 30 and 31 of the flow-through capacitor 1. . At this time, electrolysis of water occurs, oxygen gas and hydrogen gas are generated, and water containing bubbles is discharged through the connection pipe 17 (desalted liquid outflow pipe) and sent to the gas-liquid separator 2 at the subsequent stage.
[0020]
If this state is continued, the ion adsorption ability of the pair of electrodes eventually approaches a saturated state, the ion removal ability decreases, and the conductivity of the desalting solution gradually increases. When the electrical conductivity measured by the water quality monitoring device 8 becomes a desalted liquid collection impossible value, the switching valve 12A is closed and the switching valve 12B is opened, and the application of the DC voltage to the liquid passing type capacitor is immediately stopped. When the switch 32A is turned off and the switch 33A is turned on in this state, the ion component adsorbed on the pair of electrodes 30 and 31 is desorbed, and an ion recovery process for regenerating the pair of electrodes 30 and 31 is entered. Further, in the concentration step, the ionic components are recovered by passing recovery water such as pure water or industrial water together with or separately from the flowing water, and the system is passed out of the system through the concentrate outflow pipe 21. It is discharged or sent to the next process.
[0021]
The removal step and the recovery step are defined as one cycle, and by repeating this cycle, a desalted solution from which the ionic component has been removed from the liquid to be treated and a concentrated solution having a high ion concentration from which the removed ionic component has been recovered. In addition, the saturation and regeneration of the pair of electrodes 30 and 31 of the liquid-flowing capacitor 1 are repeated. In this case, it is not possible to obtain a desalted liquid from the flow-through capacitor during the ion component recovery step. For this reason, if you want to obtain a desalted solution even during the ionic component recovery process, install multiple flow-through capacitors and implement the ionic component recovery process for each flow-through capacitor so that the required minimum amount is secured. Control the time.
[0022]
The desalted liquid containing bubbles discharged from the removal step (desalting step) is supplied to the gas-liquid separator 2, the gas-liquid is separated, the gas is exhausted from the exhaust pipe 23, and the bubbles disappear. The liquid is sent to the next process such as an ion exchange resin tower through the treatment liquid outflow pipe 22. According to the present embodiment, it is possible to obtain a desalting solution from which ionic components are highly removed and bubbles are removed.
[0023]
Next, a liquid passing method of the liquid passing type capacitor according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a flowchart showing a liquid passing method of the liquid passing capacitor according to the second embodiment of the present invention. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, description thereof is omitted, and only different points will be described. That is, the point different from FIG. 1 in FIG. 3 is that the gas-liquid separation device 2 a is connected to the concentrate outflow pipe 21. That is, when the pair of electrodes 30 and 31 are reversely connected in the ion component recovery step, the liquid-type capacitor 1 is applied with a voltage higher than an applied voltage at which electrolysis of water occurs on the pair of electrodes 30 and 31. In some cases, the concentrate may contain bubbles. In the present embodiment, since the above configuration is adopted, it is possible to obtain a desalted solution and a concentrated solution in which bubbles disappear, respectively, which is suitable not only for the desalted solution but also for the purpose of collecting the concentrated solution. is there.
[0024]
In the present invention, as the installation position of the gas-liquid separation device 2, in addition to the positions shown in the above embodiment, in the middle of the connection pipe 6 and in the middle of the connection pipe 10 in FIG.
[0025]
【Example】
EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.
Example 1
An experimental operation was performed by passing city water through a liquid condenser with the flow shown in FIG. As a result, the conductivity of the demineralized water was measured to obtain the ionic component removal rate, and the presence or absence of bubbles in the demineralized water was confirmed.
・ Water to be treated; city water (conductivity 330μS / cm)
・ Specification and operation condition equipment of liquid-type capacitor; (Capacitor; manufactured by Kansai Thermal Chemical Co., Ltd.)
Total activated carbon amount of activated carbon electrode: 253 g
Activated carbon electrode surface area: 1500 m ² / g
Applied voltage: DC 2.0V
The operation was performed by repeating a desalting step of removing an ionic component for 45 minutes by applying a DC voltage of 2.0 V, and then a concentrating step of desorbing the adsorbed ions by short-circuiting the electrodes for 15 minutes. The concentrated water discharged in the concentration process was discharged out of the system. During the test, the average treated water flow rate in the desalting step was 0.3 L / min.
・ Gas-liquid separator: Stainless steel tank with lid as shown in Fig. 4 (inner diameter 80mm, height 200mm)
In FIG. 4, the gas-liquid separator 2 b includes a container main body 210 and a lid 211, and a desalted liquid outflow pipe 17 (processed liquid inflow pipe) is connected to a portion in contact with the liquid phase at a lower side of the container main body. The liquid inlet 171 b to be treated is provided, and the processing liquid inflow pipe 221 b to which the treated water outflow pipe 22 is connected is provided at a portion in contact with the liquid phase at the upper part on the other side, and the gas discharge pipe 23 b is connected to the lid 211. Has been.
The operation method is such that the desalted water flowing into the container body 210 is filled with the liquid level at the upper surface of the processing liquid inlet 221b and a gas phase portion is formed on the liquid level, and the processing liquid is maintained so as to maintain the state. Remove air bubbles by discharging.
[0026]
As a result, the conductivity of the water from which the ionic components were removed was about 30 μS / cm, the average ionic component removal rate was about 91%, and the demineralized water did not contain bubbles.
[0027]
Comparative Example 1
The same method as in Example 1 was performed except that the gas-liquid separator 2b was not used. As a result, the average ionic component removal rate was about 91%, which was the same as in Example 1. However, the demineralized water contained bubbles.
[0028]
Comparative Example 2
The method was the same as that of Comparative Example 1 except that the applied voltage was set to 2.0V. That is, the applied voltage is set to a value at which electrolysis of water does not occur, and no gas-liquid separator is used. As a result, the demineralized water did not contain bubbles, but the conductivity of the water from which the ionic component was removed was about 50 μS / cm, and the average ionic component removal rate was reduced to about 85%.
[0029]
【The invention's effect】
According to the present invention (1), it is possible to obtain a desalted liquid or concentrated liquid from which bubbles have been removed by a simple method. As a result, the desalted liquid or concentrated liquid is further sent to a use point using a pump. In this case, it is possible to avoid stopping the pump due to bubbles, reducing the ionic component further, and passing the desalted liquid to the ion exchange resin tower without causing bubbles to separate the ion exchange resin. This makes it possible to reduce the ionic component stably.
[0030]
According to the present invention (2), in addition to the same effects as the above-described invention, a desalting solution with a further enhanced ionic component removal rate can be obtained. Moreover, according to this invention (3), the said invention (1) and (2) can be implemented.
[Brief description of the drawings]
FIG. 1 is a flow chart showing a liquid passing method of a liquid passing type capacitor according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of a relationship between an applied voltage and the conductivity of desalted water or the amount of bubbles generated in a liquid-flow capacitor.
FIG. 3 is a flowchart showing a water passing method of a liquid passing type capacitor according to a second embodiment of the present invention.
FIG. 4 is a schematic view of a gas-liquid separator used in Examples.
FIG. 5 is a flow chart showing a conventional liquid passing method for a liquid passing type capacitor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 50 Liquid-flow type capacitor | condenser 2, 2a, 2b Gas-liquid separation apparatus 3 Supply piping 5, 56 Processed liquid supply source 6, 10, Connection piping 8, 57 Water quality monitoring apparatus 12A, 12B Switching valve 17 Desalination liquid outflow piping 21 Concentrate outflow piping 22 Processing liquid outflow piping 23, 23a, 23b Exhaust pipes 30, 31, 54, 55 Electrodes 32A, 33A, 53, 58 Switch 34, 59 DC power supplies 171, 171a, 171b Treatment liquid inlets 210, 210a Container body 211 Lids 221, 221a, 221b Treatment liquid outlet

Claims (3)

A desalted solution was obtained by applying a DC voltage to the pair of electrodes to remove the ionic component of the liquid to be treated while passing through the solution, and then the paired electrodes were short-circuited or reversely connected to a DC power source to remove the solution. In a flow-through type condenser that collects an ionic component as a concentrated liquid together with the liquid to be treated or the water for collection in the liquid, the desalted liquid or the concentrated liquid obtained from the liquid-type condenser is passed through a gas-liquid separator, A liquid passing method for a liquid passing type capacitor, wherein a desalted liquid or a concentrated liquid from which bubbles are removed is obtained. The applied voltage of the liquid-flowing capacitor is in the range of an applied voltage V ₁ (V) at which electrolysis of water occurs to a value V ₂ (V) that is 2.0 V higher than an applied voltage at which electrolysis of water occurs. The liquid passing method of the liquid passing type capacitor according to claim 1. A DC voltage is applied to the pair of electrodes to remove the ionic component of the liquid to be treated, and the paired electrodes are short-circuited or a DC power supply is reversely connected to pass the removed ionic component in the liquid. A flow-through capacitor device comprising: a flow-through capacitor that is recovered in a treatment liquid or recovery water; and a gas-liquid separation device that gas-liquid separates a desalted liquid or a concentrate obtained from the flow-through capacitor. .

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