JP6829564B2 - Liquid plasma generator, liquid plasma generation method, treatment liquid purification device and treatment liquid purification method - Google Patents

Description

The present invention is an in-liquid plasma generation technique for generating plasma in the liquid by applying an electric field to the liquid having bubbles, and a treatment liquid for purifying the treatment liquid in which the active species is contained in the liquid using the technology. It is about refining technology.

Many techniques have been proposed for purifying a liquid containing a chemically active active species as a treatment liquid as a means for producing a reaction product or a means for detoxifying harmful substances / bacteria. As an example thereof, for example, Patent Document 1 describes a technique for purifying a treatment liquid (= water + active species) by using a submerged plasma generation technique for generating plasma in water by an underwater discharge. In the apparatus described in Patent Document 1, water is stored in an insulating container and fine bubbles of oxygen-rich gas are introduced into the water. Then, an AC pulse is applied to a pair of electrodes arranged so as to sandwich the container from the outside to generate an in-bubble discharge, thereby exciting oxygen in the bubble. In addition, the ultraviolet rays generated at this time excite the water on the outer peripheral surface of the bubble to generate OH radicals as active species. Then, the generated OH radicals are sequentially dissolved in water. As a result of repeating this underwater discharge by an AC pulse, a large amount of OH radicals are contained in the water with a short energization. In this way, the treatment liquid (= water + OH radical) is purified by the submerged plasma.

Japanese Unexamined Patent Publication No. 2001-9463

In the above-mentioned conventional technique, since the submerged plasma is generated while the water is stored in the insulating container, it is necessary to generate the submerged plasma every time the water is replaced with the insulating container. That is, while the water was replaced in the insulating container, the generation of plasma in the liquid had to be interrupted, and there was room for improvement in terms of efficiency. In addition, since submerged plasma is generated while water is stored in an insulating container, this is one of the main factors for raising the temperature of the stored water. Therefore, it may be necessary to adjust the temperature after the purification treatment of the treatment liquid, and the active species in the water may be inactivated during the temperature adjustment.

The present invention has been made in view of the above problems, and includes a submerged plasma generation technique capable of efficiently performing submerged plasma while preventing the temperature of the liquid that has received submerged plasma from rising. It is an object of the present invention to provide a treatment liquid purification apparatus and a treatment liquid purification method capable of efficiently purifying a treatment liquid containing an active species in a liquid by using the plasma generation technique in the liquid.

The first aspect of this invention is a plasma generator in liquid, is formed of an insulating material, a pipe for flowing the liquid in the tube, is connected to one end of the pipe, the liquid supply for supplying liquid to the pipe and parts, for the liquid flowing in the liquid supply portion before the liquid is supplied to the pipe, a branch pipe for introducing the gas supplied from the gas supply source in the bubble introduction position, inserted into the branch pipe the opening and closing valve When a plurality of electrodes along the outer wall of the pipe are placed separately from one another, a power supply for generating plasma in a liquid flowing through the pipe by applying a voltage to the plurality of electrodes, the control to the liquid-off valve The introduction amount control unit is provided with an introduction amount control unit that creates a bubble-rich state and a bubble-poor state in the liquid by changing the amount of bubbles in the liquid over time, and the introduction amount control unit flows through the liquid supply unit per unit time. It is characterized by creating a bubble-rich state by controlling the on-off valve so that the gas is sent to the bubble introduction position at a flow rate larger than the flow rate of the liquid .

Further, the second aspect of the present invention is a method of generating plasma in a liquid, in which a first step of introducing a gas into a liquid at a bubble introduction position and a liquid into which the gas is introduced are formed of an insulating material. It includes a second step of circulating in the pipe and a third step of applying a voltage to a plurality of electrodes arranged apart from each other along the outer wall of the pipe to generate plasma in the liquid flowing through the pipe. in the first step, the amount of bubbles in the liquid flowing through the pipe temporally varied to leave create a state bubbles-rich and bubble-poor, with greater rate than the flow rate of the liquid flowing per unit time It is characterized by creating a bubble-rich state by sending gas to the bubble introduction position .

A third aspect of the present invention is a treatment liquid purification apparatus for purifying a treatment liquid containing an active species, wherein the in-liquid plasma generator, a liquid supply unit connected to one end of a pipe, and the like. It is equipped with a liquid outlet connected to the other end of the pipe, the liquid supply part supplies the liquid to the pipe, and the submerged plasma generator contains the active species generated by generating plasma in the liquid. The treatment liquid is purified, and the liquid extraction unit takes out the treatment liquid from the submerged plasma generator.
A fourth aspect of the present invention is a treatment liquid purification device for purifying a treatment liquid containing an active species, which is a storage tank for storing a liquid, a submerged plasma generator, a liquid take-out unit, and a pump. The submerged plasma generator is made of an insulating material and has a pipe for circulating liquid in the pipe from the outside, and a liquid supply unit connected to one end of the pipe to supply the liquid to the pipe. A branch pipe that introduces the gas supplied from the gas supply source at the bubble introduction position to the liquid flowing in the liquid supply section before the liquid is supplied to the pipe, an on-off valve inserted in the branch pipe, and a pipe. A plurality of electrodes arranged apart from each other along the outer wall of the, a power supply that applies a voltage to the plurality of electrodes to generate plasma in the liquid flowing through the pipe, and a switch valve that controls the air bubbles in the liquid. It includes an introduction amount control unit that changes the amount over time to create a bubble-rich state and a bubble-poor state in the liquid, and processes the liquid by containing the active species generated by generating plasma. The liquid is purified, the liquid supply unit is connected to the storage tank, the liquid is supplied to the pipe, the pump is inserted in the liquid supply unit, and the liquid is continuously supplied from the storage tank to the pipe, and the liquid is supplied. The take-out part is connected to the other end of the pipe and the storage tank, and the liquid take-out part is characterized in that the treatment liquid is taken out from the submerged plasma generator and returned to the storage tank.
A fifth aspect of the present invention is a method for purifying a treatment liquid, wherein the liquid stored in the storage tank is fed to the first step and the liquid fed in the first step. The second step of introducing the gas at the bubble introduction position, the third step of circulating the liquid into which the gas was introduced into the pipe formed of the insulating material, and the third step of flowing the gas into the pipe, were arranged apart from each other along the outer wall of the pipe. The fourth step of applying a voltage to a plurality of electrodes to generate plasma in the liquid flowing in the pipe, and the fifth step of purifying the treatment liquid by containing the active species generated by generating the plasma in the liquid. The sixth step of returning the purified treatment liquid to the storage tank and the seventh step of increasing the amount of active species in the treatment liquid stored in the storage tank by repeating the first to sixth steps. In the second step, the amount of bubbles in the liquid is changed over time to create a bubble-rich state and a bubble-poor state in the liquid, which is larger than the flow rate of the liquid flowing per unit time. It is characterized by creating a bubble-rich state by sending gas to the bubble introduction position at a flow rate.
Further, a sixth aspect of the present invention is a method for purifying a treatment liquid, wherein the liquid stored in the storage tank is fed to the first step and the liquid fed in the first step. The second step of introducing the gas at the bubble introduction position, the third step of circulating the liquid into which the gas was introduced into the pipe formed of the insulating material, and the third step of flowing the gas into the pipe, were arranged apart from each other along the outer wall of the pipe. The fourth step of applying a voltage to a plurality of electrodes to generate plasma in the liquid flowing in the pipe, and the fifth step of purifying the treatment liquid by containing the active species generated by generating the plasma in the liquid. The sixth step of returning the purified treatment liquid to the storage tank and the seventh step of increasing the amount of active species in the treatment liquid stored in the storage tank by repeating the first to sixth steps. The second step is characterized in that the amount of bubbles in the liquid is changed with time to create a bubble-rich state and a bubble-poor state in the liquid.

In the invention configured as described above, the liquid flows through the pipe while changing the amount of bubbles introduced into the liquid with time to create a bubble-rich state and a bubble-poor state in the liquid. Further, a plurality of electrodes are arranged apart from each other along the outer wall of the pipe, and an electric field is formed in the pipe by applying a voltage to these electrodes. Then, plasma is predominantly generated by the circulation of the liquid in a bubble-rich state in the electric field. Further, following the generation of plasma, a liquid in a bubble-poor state flows in, and the active species generated by the generation of the plasma is involved to purify the liquid containing the active species, that is, the treatment liquid. That is, plasma can be generated while continuously supplying the liquid, plasma in the liquid can be efficiently performed, and a treatment liquid containing an active species can be efficiently purified. Further, as described above, the liquid in which the plasma is generated in the liquid, that is, the liquid in the bubble-rich state does not stay in the pipe as it is, and the liquid in the bubble-poor state flows in immediately after the plasma is generated. The temperature rise can be reliably prevented.

It is a figure which shows the structure of the processing liquid purification apparatus equipped with one Embodiment of the liquid plasma generator which concerns on this invention. It is a perspective view which shows the appearance structure of the plasma generation part. It is a vertical sectional view of the plasma generating part shown in FIG. 2A. FIG. 2 is a cross-sectional view taken along the line CC in FIG. 2B. It is a timing chart which shows the operation of the processing liquid purification apparatus 1 of FIG. It is a figure which shows the generation state of plasma. It is a vertical sectional view which shows another example of a plasma generation part.

FIG. 1 is a diagram showing a configuration of a processing liquid purification apparatus equipped with an embodiment of the submerged plasma generator according to the present invention. This treatment liquid purification apparatus 1 is an apparatus for purifying a treatment liquid in which an active species is dissolved in water stored in a storage tank 2, and an underwater plasma (the present invention) is used in a plasma generating unit 3 to generate an active species. (Equivalent to an example of "in-liquid plasma") is generated. Thus, in this embodiment, water corresponds to an example of the "liquid" of the present invention.

FIG. 2A is a perspective view showing an external configuration of the plasma generating portion, FIG. 2B is a vertical sectional view of the plasma generating portion shown in FIG. 2A, and FIG. 2C is a sectional view taken along line CC in FIG. 2B. The plasma generating unit 3 has a pipe 31 formed of an insulating material, two band-shaped electrodes 32 and 33 formed of a conductive material, and an insulating cover 34. The pipe 31 extends in the vertical direction, and the pipe 311 formed inside the pipe 31 is a path for circulating water as described later, and is a plasma generation region in which active species are generated by the generation of underwater plasma (FIG. It functions as reference numeral 35) in 2B. The band-shaped electrodes 32 and 33 are extrapolated to the pipe 31 in a state of being separated by a certain distance in the extending direction of the pipe 31 (vertical direction in FIG. 2B). Further, on the outer peripheral surface of the pipe 31, the inter-electrode region 312 sandwiched between the electrodes 32 and 33 and the electrodes 32 and 33 are closely covered with an insulating material from the outside in the radial direction of the pipe 31 (left-right direction in FIG. 2B). As described above, the insulating cover 34 is provided. As a result, the electrodes 32 and 33 are insulated from each other while maintaining a constant distance between the electrodes. These electrodes 32 and 33 are electrically connected to the AC power supply 4, and by applying a voltage including an AC component from the AC power supply 4 to the electrodes 32 and 33, the storage tank 2 to the pipe 31 are as described below. Generates plasma in the water supplied to (generation of submerged plasma).

As shown in FIG. 1, the lower end of the pipe 31 in the vertical direction is connected to the storage tank 2 via the pipe 51. A pump 6 is inserted in the pipe 51, and the water stored in the storage tank 2 (or as will be described later) is operated by operating the pump 6 in response to an operation command from the control unit 7 that controls the entire device. Water containing the active species purified in the above, that is, a treatment liquid) is supplied to the pipe 31 (FIGS. 2A, 2B, 2C) of the plasma generating section 3 via the pipe 51, and is inside the pipe 311 of the pipe 31. Flows from the lower side to the upper side. This pipe 51 is branched at the bubble introduction position IP between the pump 6 and the plasma generation unit 3, and the gas introduced from the bubble introduction unit 8, for example, argon gas, is branched from the bubble introduction unit 8 via the branch pipe 52 extending from the bubble introduction position IP. It is possible to introduce a bubble into the water flowing in the pipe 51 by sending a mixed gas with air, an oxygen gas, or the like to the bubble introduction position IP.

The bubble introduction section 8 has a gas supply source 81 for supplying the introduced gas via the branch pipe 52, and an on-off valve 82 inserted in the branch pipe 52. By opening and closing the on-off valve 82 in response to an open / close command from the control unit 7, the amount of air bubbles introduced into the water supplied to the plasma generating unit 3 via the pipe 51 is changed over time. That is, when the on-off valve 82 is opened in response to the opening command from the control unit 7, the introduced gas is pressure-fed through the branch pipe 52 and the on-off valve 82 during the opening, and is sent to the water at the bubble introduction position IP. The introduction of air bubbles creates a bubble-rich state in the water. On the contrary, when the on-off valve 82 is closed in response to the closing command from the control unit 7, the supply of the introduced gas is stopped while the on-off valve 82 is closed, and water is generated through the pipe 51 in a bubble-poor state. It is supplied to 3. As described above, in the present embodiment, the control unit 7 functions as the "introduction amount control unit" of the present invention, and as will be described later with reference to FIG. 3, the control unit 7 opens and closes at regular time intervals. By repeating the opening and closing of the valve 82, water in a bubble-rich state and water in a bubble-poor state are alternately supplied to the pipe 31 of the plasma generating section 3. In addition, if a structure is adopted in which the on-off valve discharges a constant gas flow rate even if the on-off valve does not open and close in time, gas-liquid separation can be performed in the pipe to create gas-rich water and gas-poor water. You can. In this case, the above structure corresponds to an example of the "introduction amount control unit" of the present invention.

The upper end of the pipe 31 of the plasma generating unit 3 is connected to the storage tank 2 by the pipe 53, and the water subjected to the underwater plasma treatment by the plasma generating unit 3 can be taken out from the plasma generating unit 3 and returned to the storage tank 2. It is possible. In the treatment liquid purification apparatus 1, the water stored in the storage tank 2 (including water containing an active species) circulates through the pipes 51, 31, and 53, and the plasma generating unit 3 performs the circulation. By generating underwater plasma in water, the concentration of active species contained in water can be increased.

When the water containing the active species, that is, the treatment liquid is purified in this way, it is necessary to discharge the treatment liquid from the storage tank 2 to the outside at an appropriate timing. For this purpose, the pipe 54 is connected to the lower side surface of the storage tank 2. An on-off valve 55 is inserted in the pipe 54, and when the on-off valve 55 is opened in response to an opening command from the control unit 7, the treatment liquid (= water + active species) stored in the storage tank 2 is opened. Can be taken out to the outside. Further, a pipe 56 is connected to the upper side surface of the storage tank 2, and the storage tank 2 is connected to a water supply source (not shown) by the pipe 56. An on-off valve 57 is inserted in the pipe 56, and when the on-off valve 57 is opened in response to an opening command from the control unit 7, water before purification, that is, water containing no active species is introduced into the storage tank 2. Be replenished. Further, a pipe 58 is connected to the ceiling surface of the storage tank 2, and the internal space of the storage tank 2 is connected to the surrounding atmosphere of the treatment liquid purification device 1 by the pipe 58. An on-off valve 59 is inserted in the pipe 58, and when the on-off valve 59 opens in response to an opening command from the control unit 7, the internal space of the storage tank 2 communicates with the surrounding atmosphere of the processing liquid purification device 1. The inside of the storage tank 2 can be returned to the atmospheric pressure, and the on-off valve 59 functions as a so-called leak valve.

Next, a method of purifying the treatment liquid, that is, water containing the active species by the treatment liquid purification apparatus 1 configured as described above will be described with reference to FIG.

FIG. 3 is a timing chart showing the operation of the processing liquid purification apparatus 1 of FIG. In this treatment liquid purification apparatus 1, the control unit 7 controls each unit of the apparatus as follows according to a program stored in the memory in advance to purify the treatment liquid (= water + active species). In the treatment liquid purification apparatus 1, the on-off valves 55, 57, and 59 are "closed", "opened", and "opened", respectively, in order to replenish and store the untreated water in the storage tank 2. Then, when a predetermined amount of water is stored in the storage tank 2, the on-off valve 57 is closed according to the opening / closing command from the control unit 7 to stop the replenishment of water.

Then, when a processing liquid purification command is given to the control unit 7 from the outside, the pump 6 operates in response to the operation command from the control unit 7. As a result, the water in the storage tank 2 is circulated via the pipes 51, 31, and 53. Further, the control unit 7 alternately gives an opening command and a closing command to the on-off valve 82, and as shown in FIG. 3, the opening and closing of the on-off valve 82 are alternately repeated.

Here, while the on-off valve 82 is in the open state, the introduced gas is sent from the gas supply source 81 to the bubble introduction position IP via the branch pipe 52. As a result, bubbles are introduced into the water flowing in the pipe 51 toward the plasma generating unit 3. In the present embodiment, the introduced gas is sent to the bubble introduction position IP at a flow rate larger than the flow rate of the water flowing through the pipe 51 per unit time. Therefore, as shown in FIG. 3, the amount of bubbles at the bubble introduction position IP is relatively large, and the bubbles are rich in water. Therefore, bubbles having a relatively large size are present in water.

On the other hand, while the on-off valve 82 is in the closed state, the introduction of bubbles is stopped at the bubble introduction position IP, and as shown in FIG. 3, the amount of bubbles at the bubble introduction position IP is relatively small, and bubbles are generated in water. It is in a poor state. As described above, in the present embodiment, the opening / closing operation of the on-off valve 82 changes the amount of bubbles introduced into the water over time to create a bubble-rich state and a bubble-poor state in the water (bubble introduction). motion). Then, the water whose bubble amount is adjusted in this way is supplied to the pipe 31 of the plasma generation unit 3 via the pipe 51. Therefore, as shown in FIG. 3, the water flowing vertically above the pipe 31 is also temporally switched between a bubble-rich state and a bubble-poor state. The amount of time lag between the middle graph and the lower graph in FIG. 3 corresponds to the distance from the bubble introduction position IP to the plasma generating unit 3.

Further, the control unit 7 controls the AC power supply 4 in synchronization with the bubble introduction operation, and applies a voltage from the AC power supply 4 to the electrodes 32 and 33. This is because when a voltage is applied to the electrodes 32 and 33 when the water in a bubble-rich state is located in the plasma generation region 35 surrounded by the electrodes 32 and 33 in the pipeline 311 of the pipe 31, for example, in FIG. While plasma is generated as shown in column (a) of (a), even if a voltage is applied to the electrodes 32 and 33 when water in a bubble-poor state is located in the plasma generation region 35, (b) in the figure. This is because plasma is not generated as shown in the column. In FIG. 4, the insulating cover 34 is removed in order to confirm the plasma generation state, and the members held by the alligator clip are the electrodes 32 and 33, and in the column (a), around the electrodes 32 and 33. The white area is the plasma generation area.

While the operation of the pump 6 and the opening / closing of the on-off valve 82 are continued in this way, plasma is generated when water in a bubble-rich state is flowing through the plasma generation region 35, and active species are generated. Subsequently, water in a bubble-poor state dissolves the active species in the plasma generation region 35, the treatment liquid (= water + active species) is purified, and is returned to the storage tank 2 via the pipe 53. By repeating such a series of operations (hereinafter referred to as "treatment liquid purification operation"), the amount of active species in the treatment liquid stored in the storage tank 2 increases with the passage of time. Then, after the treatment liquid purification operation is continued for a predetermined time, the treatment liquid purification operation is stopped by stopping the pump 6 and continuing to close the on-off valve 82.

Then, when a processing liquid discharge command is given to the control unit 7, the control unit 7 gives an opening command to the on-off valve 55 to open the on-off valve 55. As a result, the purified treatment liquid (= water + active species) is discharged from the storage tank 2. When purification of the treatment liquid is required and a purification command is given to the control unit 7 from the outside, purification of the treatment liquid is repeated in the same manner as described above.

As described above, in the present embodiment, water is continuously supplied to the plasma generation unit 3 by the pump 6 and bubbles are intermittently introduced at the bubble introduction position IP, so that the piping 31 of the plasma generation unit 3 is introduced. It creates a bubble-rich state and a bubble-poor state in the water supplied to the plasma. Then, since the voltage is applied to the electrodes 32 and 33 while the water in a bubble-rich state is flowing through the plasma generation region 35, plasma can be reliably generated to generate an active species. Moreover, immediately after the production of the active species, water in a bubble-poor state flows through the plasma generation region 35 to purify the treatment liquid in which the active species is dissolved and sent to the storage tank 2. Therefore, the processing liquid can be continuously purified while the pump 6 is operated while opening and closing the on-off valve 82.

Further, in the above embodiment, since the underwater plasma treatment is performed while flowing water in the pipe 31, it is possible to reliably prevent the temperature rise of the treatment liquid (= water + active species).

Further, in the above embodiment, since the on-off valve 82 is opened and the introduced gas is sent to the bubble introduction position IP at a flow rate larger than the flow rate of the water flowing through the pipe 51 per unit time, it exists in the plasma generation region 35. The bubble size becomes large, the probability that the electric field generated in the plasma generation region 35 by applying the voltage to the electrodes 32 and 33 reaches the bubbles increases, and the plasma lighting is predominant. Further, in the plasma generation region 35, the closer to the inner wall surface of the pipe 31, the stronger the electric field, and the larger the bubble size, the more easily the bubbles come into contact with the inner wall surface of the pipe 31 to generate plasma, and the processing liquid is purified. Can be done efficiently.

Further, the arrangement posture of the pipe 31 and the water supply direction in the plasma generating unit 3 are arbitrary, but as shown in FIG. 2B, the pipe 31 is erected in the vertical direction and water in which bubbles are introduced. The following effects can also be obtained by configuring the pipe 31 so as to flow vertically from the lower side to the upper side. That is, due to the action of the flow of water and the gravity of water (water in a bubble-poor state) existing on the downstream side of the bubble (upper side in FIG. 2B) in the flow direction of the water, the bubble becomes flat in the lateral direction. A part of it approaches the inner wall surface of the pipe 31. As a result, plasma is more likely to be generated, and the treatment liquid can be purified more efficiently.

Further, in order to secure the insulating property between the electrodes 32 and 33, for example, it is possible to simply insert a band-shaped insulator, but it is possible to provide the insulating cover 34 by providing an insulating material between the electrodes 32 and 33. Since the electrodes 32 and 33 are filled and the entire electrodes 32 and 33 are sealed with an insulating material, the plasma is likely to be generated.

As described above, in this embodiment, water is taken as an example of the "liquid" of the present invention, and the "submerged plasma generator" of the present invention is provided by the plasma generating unit 3, the AC power supply 4, the control unit 7, and the bubble introducing unit 8. Consists of. Further, the pipes 51 and 53 correspond to an example of the "liquid supply unit" and the "liquid extraction unit" of the present invention, respectively. Further, the insulating cover 34 corresponds to an example of the "insulated portion" of the present invention. Further, the AC power supply 4 corresponds to an example of the "power supply" of the present invention.

By the way, in order to generate plasma more efficiently in the plasma generation region 35, it is desirable to consider the materials of the pipe 31 and the insulating cover 34. This is because when a relatively high voltage containing an AC component is applied to the electrodes 32 and 33 to generate plasma, the current mainly flows through the four routes R1 to R4 (see FIG. 2B). Then, plasma can be efficiently generated by flowing a current through the route R1 passing through the pipe 311 of the pipe 31. For that purpose, it is desirable to select the insulator so that the dielectric constant ε31 of the insulator constituting the pipe 31 is larger than the dielectric constant ε34 of the insulator constituting the insulating cover 34. The combination of insulators is arbitrary as long as these conditions are satisfied. For example, the pipe 31 is provided with titanium dioxide (relative permittivity εr31 = 100), Rochelle salt (relative permittivity εr31 = 100 to 2000), barium titanate (relative permittivity εr31 = 100). While it is formed of relative permittivity εr31 = 1200), the insulating cover 34 is made of acrylic resin (relative permittivity εr34 = 2.7 to 4.5), glass (relative permittivity εr34 = 3.7-10), quartz (relative permittivity εr34 = 3.7-10), etc. It may be formed of a relative permittivity εr34 = 3.5 to 4), alumina (relative permittivity εr34 = 8.5), or the like.

Further, in order to generate plasma more efficiently in the plasma generation region 35, the diameter of the bubbles is close to the inner diameter of the pipe 31, and the distance between the electrodes 32 and 33 (the region between the electrodes in the longitudinal direction of the pipe 31). It is desirable to approximate it with a length of 312). In addition, the distance between electrodes is as follows,
Distance between electrodes ≥ Thickness of pipe 31 x (εr34 / εr31)
It is desirable to satisfy. In addition, the wall thickness of the insulating cover 34 has the following relationship.
(Thickness of insulation cover 34) ≧ (Thickness of pipe 31) × (εr34 / εr31)
It is desirable to satisfy.

Further, in the above embodiment, the outer peripheral surface of the insulating cover 34 is finished as a cylindrical surface. For example, as shown in FIG. 5, the outer peripheral surface region 341 corresponding to the inter-electrode region 312 of the outer peripheral surface is made an uneven surface. You may finish it. In this case, the shortest distance along the surface of the outer peripheral surface region 341, the so-called creepage distance, becomes long, making it difficult for the plasma to light up on the atmospheric side, and the plasma can be generated more efficiently in the plasma generation region 35. ..

Further, in the above embodiment, water is stored in the storage tank 2 and water is supplied from the storage tank 2, but water is supplied from the water supply source (not shown) to the plasma generation unit 3 via the pipe 51. It may be configured to do so. Further, in the above embodiment, water is used as the "liquid" of the present invention, but other liquids may be used. Further, although the introduced gas such as a mixed gas of argon gas and air or an oxygen gas is supplied to introduce the bubbles, other gas may be supplied to introduce the bubbles.

Further, in the above embodiment, voltage is applied to the two electrodes 32 and 33 to generate plasma, but the number of electrodes is not limited to this, and three or more electrodes may be provided. .. Further, the AC voltage applied to the electrodes 32 and 33 may include a pulse component. Further, in the above embodiment, the voltage application and the application stop are switched according to the bubble rich state and the bubble poor state, but the voltage may be constantly applied.

The present invention can be applied to an in-liquid plasma generation technique and a general treatment solution purification technique for purifying a treatment solution containing an active species using the technique.

1 ... Processing liquid purification device 3 ... Plasma generator 4 ... AC power supply 7 ... Control unit (introduction amount control unit)
8 ... Bubble introduction part 31 ... Piping 32, 33 ... Electrode 34 ... Insulation cover (insulation part)
52 ... Branch piping 81 ... Gas supply source 82 ... On-off valve 312 ... Electrode-to-electrode area 341 ... Outer peripheral surface area IP ... Bubble introduction position

Claims (12)

A pipe made of an insulating material that allows liquid to flow through the pipe,
A liquid supply unit connected to one end of the pipe and supplying the liquid to the pipe,
For the liquid flowing through the liquid supply portion before the liquid to the pipe is supplied, a branch pipe for introducing the gas bubbles introduced into the position of the gas supplied from the gas supply source,
An on-off valve inserted in the branch pipe and
A plurality of electrodes arranged apart from each other along the outer wall of the pipe,
A power supply that applies a voltage to the plurality of electrodes to generate plasma in the liquid flowing through the pipe, and
It is provided with an introduction amount control unit that controls the on- off valve to change the amount of the bubbles in the liquid with time to create a bubble-rich state and a bubble-poor state in the liquid.
The introduction amount control unit controls the on-off valve so as to send the gas to the bubble introduction position at a flow rate larger than the flow rate of the liquid flowing through the liquid supply unit per unit time to obtain a bubble-rich state. An in-liquid plasma generator characterized by producing . The submerged plasma generator according to claim 1.
The introduction amount control unit is a submerged plasma generator that alternately repeats the bubble-rich state and the bubble-poor state. The submerged plasma generator according to claim 1 or 2.
A submerged plasma generator further comprising an insulating portion that insulates the plurality of electrodes from each other. The submerged plasma generator according to claim 3.
The insulating portion is a liquid that is an insulating cover that covers the inter-electrode region sandwiched between the plurality of electrodes and the plurality of electrodes on the outer peripheral surface of the pipe from the outside in the radial direction of the pipe with an insulating material. Medium plasma generator. The submerged plasma generator according to claim 4.
A submerged plasma generator having an uneven shape in the outer peripheral surface region of the outer peripheral surface of the insulating cover corresponding to the inter-electrode region. The submerged plasma generator according to any one of claims 3 to 5.
A submerged plasma generator in which the dielectric constant of the pipe is larger than the dielectric constant of the insulating portion. The first step of introducing gas into the liquid at the bubble introduction position ,
The second step of circulating the liquid into which the gas is introduced in a pipe formed of an insulating material, and
A third step of applying a voltage to a plurality of electrodes arranged apart from each other along the outer wall of the pipe to generate plasma in the liquid flowing through the pipe is provided.
In the first step, the amount of bubbles in the liquid flowing through the pipe temporally varied to leave create a state bubbles-rich and bubble-poor, than the flow rate of the liquid flowing per unit time A method for generating plasma in a liquid, which comprises sending the gas to the bubble introduction position at a large flow rate to create a bubble-rich state . A treatment liquid purification device that purifies a treatment liquid containing an active species.
The submerged plasma generator according to any one of claims 1 to 6.
A liquid supply unit connected to one end of the pipe and
A liquid outlet connected to the other end of the pipe.
The liquid supply unit supplies the liquid to the pipe and
The submerged plasma generator purifies the treatment liquid by containing the active species generated by generating the plasma in the liquid.
The liquid take-out unit is a treatment liquid purification apparatus characterized in that the treatment liquid is taken out from the submerged plasma generator. The treatment liquid purification apparatus according to claim 8.
A storage tank for storing the liquid and
With a pump,
The liquid supply unit is connected to the storage tank and
The pump is inserted into the liquid supply unit, and the liquid is continuously supplied from the storage tank toward the pipe.
The liquid take-out unit is connected to the other end of the pipe and the storage tank, and the liquid take-out unit is a treatment liquid purification device that takes out the treatment liquid from the submerged plasma generator and returns it to the storage tank. A treatment liquid purification device that purifies a treatment liquid containing an active species.
A water tank that stores liquids and
Submerged plasma generator and
Liquid outlet and
With a pump,
The submerged plasma generator
A pipe made of an insulating material that allows liquid to flow from the outside into the pipe,
A liquid supply unit connected to one end of the pipe and supplying the liquid to the pipe,
A branch pipe that introduces the gas supplied from the gas supply source at the bubble introduction position to the liquid that flows in the liquid supply unit before the liquid is supplied to the pipe.
An on-off valve inserted in the branch pipe and
A plurality of electrodes arranged apart from each other along the outer wall of the pipe,
A power supply that applies a voltage to the plurality of electrodes to generate plasma in the liquid flowing through the pipe, and
An introduction amount control unit that controls the on-off valve to change the amount of the bubbles in the liquid with time to create a bubble-rich state and a bubble-poor state in the liquid.
The treatment liquid is purified by containing the active species produced by generating the plasma in the liquid.
The liquid supply unit is connected to the storage tank and supplies the liquid to the pipe.
The pump is inserted into the liquid supply unit, and the liquid is continuously supplied from the storage tank toward the pipe.
The liquid extraction unit is connected to the other end of the pipe and the storage tank, and the liquid extraction unit takes out the treatment liquid from the submerged plasma generator and returns the treatment liquid to the storage tank. apparatus. The first process of feeding the liquid stored in the water tank and
The second step of introducing gas at the bubble introduction position with respect to the liquid sent in the first step, and
The third step of circulating the liquid into which the gas has been introduced into a pipe formed of an insulating material, and
A fourth step of applying a voltage to a plurality of electrodes arranged apart from each other along the outer wall of the pipe to generate plasma in the liquid flowing in the pipe.
The fifth step of purifying the treatment liquid by containing the active species generated by generating the plasma in the liquid.
The sixth step of returning the purified treatment liquid to the storage tank, and
A seventh step of increasing the amount of active species in the treatment liquid stored in the storage tank by repeating the first to sixth steps is provided.
In the second step, the amount of the bubbles in the liquid is changed with time to create a bubble-rich state and a bubble-poor state in the liquid, which is larger than the flow rate of the liquid flowing per unit time. A treatment liquid purification method characterized in that a bubble-rich state is created by sending the gas to the bubble introduction position at a flow rate. The first process of feeding the liquid stored in the water tank and
The second step of introducing gas at the bubble introduction position with respect to the liquid sent in the first step, and
The third step of circulating the liquid into which the gas has been introduced into a pipe formed of an insulating material, and
A fourth step of applying a voltage to a plurality of electrodes arranged apart from each other along the outer wall of the pipe to generate plasma in the liquid flowing in the pipe.
The fifth step of purifying the treatment liquid by containing the active species generated by generating the plasma in the liquid.
The sixth step of returning the purified treatment liquid to the storage tank, and
A seventh step of increasing the amount of active species in the treatment liquid stored in the storage tank by repeating the first to sixth steps is provided.
The second step is a treatment liquid purification method, which comprises changing the amount of the bubbles in the liquid with time to create a bubble-rich state and a bubble-poor state in the liquid.