JP4334757B2 - Two-component mixing method using diffusion injection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-component mixing method using a diffusion injection method for mixing two components having different concentrations of components of interest.
[0002]
[Prior art]
Conventionally, for example, there has been a demand for using functional water obtained by adding a small amount of ammonia or sulfuric acid to pure water or the like as a cleaning liquid used in a manufacturing process of semiconductors, liquid crystals, and the like. As a method for producing a mixed solution containing a small amount of ammonia or the like, that is, functional water by adding a small amount of ammonia water or sulfuric acid solution to pure water or the like, usually pure water or a low concentration ammonia water or the like is prepared. It is conceivable to obtain a functional water by adding a small amount of aqueous ammonia or the like and mixing them.
[0003]
[Problems to be solved by the invention]
Usually, desired functional water can be obtained by the method of mixing the two liquids described above. However, for example, when the mixing ratio of pure water or the like to ammonia water or the like is increased to 1/1000 or less to obtain a mixed liquid in which a small amount of ammonia is injected, particularly when the total liquid volume is small, There is a problem that it is difficult to obtain a mixed solution by mixing a small amount of ammonia and a large amount of pure water.
[0004]
Also, when trying to obtain a liquid mixture by mixing two liquids normally, a control valve and a metering injection pump will be used, but if the mixing ratio is large and the overall flow rate is small, the device will have a small diameter. However, there is a problem that it is difficult to control the mixing of the two liquids because a control valve, a metering injection pump, or the like cannot be used for such a pipe.
[0005]
An object of the present invention is to solve the above-mentioned problems and to provide a two-component mixing method using a diffusion injection method that is effective particularly when the mixing ratio of two components is large and the total amount of the solution is small. is there.
[0006]
[Means for Solving the Problems]
In the two-component mixing method using the diffusion injection method of the present invention, a first solution and a second solution having a concentration of a component of interest higher than that of the first solution are brought into contact with each other through a porous medium, and the first solution is obtained by diffusion. In injecting the second solution into the first solution, a first chamber for storing the first solution is formed in one of the porous media, and a second solution for storing the second solution in the other of the porous media. When the second solution is transferred into the second chamber by pressure and then depressurized, the pressure injection amount of the second solution into the first solution and the second solution are set in the second chamber . The ratio of the second solution to the diffusion injection amount of the second solution into the first solution when the pressure is removed after being transferred to the first chamber by pressure is set to 1:10 or more, so that the second solution is brought into the first solution. It is characterized by injecting.
[0007]
In the present invention, the injection control from the second solution to the first solution is performed by diffusion through the porous medium, so that even when the mixing ratio is large and the entire flow rate is small, the mixed solution is continuously used. Obtainable. For example, when the flow rate of the first solution is as small as 5000 L / h, if the mixing ratio is to be 1/1000 or less, the injection amount of the first solution is as small as 0.083 L / min, and the pipe diameter is 1 mm. Since the following is required, commercially available control valves, metering pumps, etc. cannot be used. The present invention is particularly effective when the two liquids are mixed under such conditions.
[0008]
As a preferred specific example of the present invention, if the first solution does not contain the target component, the concentration difference of the target component can be increased between the gas-dissolved water and the second solution, and the target component via the porous medium can be increased. Can be more effectively diffused. As an example, pure water or ultrapure water is used as the first solution, and ammonia water, ozone water, sulfuric acid water, hydrogen water, or carbonated water is used as the second solution containing the component of interest.
[0009]
As another specific example of the present invention, the average pore diameter of the porous medium is set to a fractional molecular weight of 3000 or more and 0.2 μm or less, more preferably a fractional molecular weight of 10,000 or more and 0.1 μm or less. Here, when the average pore diameter of the porous medium is less than the fractional molecular weight of 3000, more preferably less than 10,000, the diffusion area of the porous medium is too large to obtain an effective transfer amount with a low diffusion rate of the component of interest. There is a case. Further, when the average pore diameter of the porous medium exceeds 0.2 μm, and more preferably exceeds 0.1 μm, the pressure transfer of the target component toward the first solution occurs when the second solution containing the target component is replenished. The amount increases, the deviation from the control value increases, and the control accuracy may decrease.
[0010]
In the present invention , when the second solution is injected into the first solution by diffusion, a first chamber for storing the first solution is formed in one of the porous media, and the second chamber is formed in the other of the porous media. A second chamber for storing the second solution is formed, the second solution is transferred into the second chamber by pressure, and then depressurized, whereby the second solution is injected into the first solution.
[0011]
At that time, the pressure injection amount of the second solution into the first solution when the second solution is transferred into the second chamber with pressure, and the pressure of the second solution into the second chamber. The ratio of the second solution to the diffusion injection amount into the first solution when the pressure is released after the transfer is set to 1:10 or more. When the ratio of the press-fitting amount to the diffusion injection amount is less than 1:10, the controllability by pressure injection determines the overall controllability rather than the controllability by diffusion injection, and the meaning of the diffusion injection method using a porous medium is significant. This is because it may be lost. Further, at that time, the porous medium has a bottomed cylindrical shape with one end closed, a first chamber is formed outside the bottomed cylindrical porous medium, and the bottomed cylindrical porous medium A second chamber is formed inside. Alternatively, the porous medium has a cylindrical shape, the first chamber is formed outside the cylindrical porous medium, the second chamber is formed inside the cylindrical porous medium, and the cylindrical shape is The porous medium is closed at one end. In either case, the present invention can be more suitably implemented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing an example of an apparatus for carrying out a two-liquid mixing method using the diffusion injection method of the present invention. In the example shown in FIG. 1, a bottomed cylindrical ceramic membrane filter 3 is provided in a container 1 via a seal 2. The container 1 is provided with an inlet 4 and an outlet 5 of pure water that do not contain, for example, a very small amount of a component of interest such as ammonia or sulfuric acid. A supply pipe 6 for supplying pure water into the container 1 is connected to the pure water inlet 4, and a pure water outlet 5 is used to discharge a mixed liquid in which a component of interest is injected into pure water. A discharge pipe 7 is connected, and the discharge pipe 7 is provided with a monitor 8 for measuring the specific resistance and / or pH of the mixed solution.
[0013]
An inlet 9 is formed at the open end of the bottomed cylindrical ceramic membrane filter 3. The inlet 9 is provided with a supply pipe 10 for supplying a concentrated liquid containing a component of interest such as ammonia and sulfuric acid at a higher concentration than that of pure water. Further, the supply pipe 10 is provided with a shut-off valve 11. Yes. In the apparatus shown in FIG. 1, a first chamber 12 that stores pure water outside the ceramic membrane filter 3 is formed inside the container 1, and a second chamber that stores concentrated liquid inside the ceramic membrane filter 3. 13 is formed.
[0014]
In the example shown in FIG. 1, the average pore size of the ceramic filter 3 serving as a porous medium is 0.2 μm or less with a molecular weight cut-off of 3000 or more, preferably 0.1 μm with a molecular weight cut-off of 10,000 or more, which is a narrower range. The following is preferable. Here, as an example of the porous medium, the ceramic membrane filter 3 made of alumina, for example, has been exemplified, but any material having resistance to the liquid to be contacted can be used, and an organic membrane such as a hollow fiber membrane or a metal membrane is also suitable. Can be used for Moreover, although ammonia and sulfuric acid were illustrated as a focused component, ozone, hydrogen, carbonic acid, etc. can also be used suitably.
[0015]
FIG. 2 is a view showing another example of an apparatus for carrying out a two-liquid mixing method using the diffusion injection method of the present invention. In the example shown in FIG. 2, the same members as those in the example shown in FIG. 2 is different from the example shown in FIG. 1 in that a cylindrical ceramic membrane filter 3 is used. Therefore, an outlet 21 is provided through the seal 2 at the end opposite to the side where the inlet 9 of the ceramic membrane filter 3 is provided, and a discharge pipe 22 and an opening / closing valve 23 are provided connected to the outlet 21. Yes. Also in the example shown in FIG. 2, when the on-off valve 23 is closed, the bottomed cylindrical ceramic membrane filter 3 shown in FIG.
[0016]
Next, a two-component mixing method using the above-described apparatus will be described. First, pure water is circulated in the first chamber 12 from the inlet 4 toward the outlet 5 at a constant flow rate (the flow rate can be changed on the way). This distribution of pure water is not essential, and it is not necessary to distribute it. However, it is possible to obtain a mixed liquid containing a trace amount of the component of interest by distributing it. In this state, the concentrated liquid is transferred into the second chamber 13 by controlling the opening degree of the shutoff valve 11. At this time, a part of the concentrated liquid passes through the ceramic membrane filter 3 and is injected into the pure water side by press-fitting. Thereafter, when the pressurization is interrupted, the concentrated liquid in the second chamber 13 moves to the pure water side in the first chamber 12 by diffusion through the ceramic membrane filter 3.
[0017]
The amount of the concentrated liquid to be diffused and injected is limited by the concentration of the concentrated liquid supplied into the second chamber 13 and the diffusion area of the porous medium. At this time, when the concentrated liquid is transferred into the second chamber 13 by pressure, the pressure injection amount of the concentrated liquid into the pure water, and when the concentrated liquid is depressurized after being transferred into the second chamber 13 by pressure. The ratio of the concentrated liquid to the amount of diffusion injection into pure water is preferably 1:10 or more. In other words, it is preferable to carry out diffusion injection with a sufficiently large diffusion area and adjusting the supply frequency of the concentrated liquid. The state of one cycle of the injection is shown in FIG.
[0018]
When the concentration of the concentrated liquid in the second chamber 13 decreases due to diffusion, the concentrated liquid is replenished. In the replenishment of the concentrated liquid, the concentrated liquid having a reduced concentration of the component of interest in the second chamber 13 is pressed into the pure water side in the first chamber 12 through the ceramic membrane filter 3 (the apparatus in FIG. 1). Or in the case of the apparatus shown in FIG. 2, the on-off valve 22 is opened and discharged from the discharge pipe 23 connected to the ceramic membrane filter 3. Replenishment of the concentrated liquid to the ceramic membrane filter 3 is performed intermittently using the on-off valve 22 having an on-off speed of 0.1 seconds or less. The opening and closing speed of the valve affects the deviation from the control value when concentrated liquid is injected under pressure. When a valve with an opening and closing speed of 0.1 seconds or more is used, the control accuracy decreases. It is preferable to use a short one. This open / close control is preferably configured to detect the concentration of the liquid mixture by a sensor provided in the discharge pipe 7 and to perform an open / close signal from a connected control device.
[0019]
Actually, according to the two-liquid mixing method using the diffusion injection method of the present invention using the apparatus having the configuration shown in FIG. 1, ammonia water containing a trace amount of ammonia (target specific resistance value of ammonia water: 0.15 ± 0) .05 MΩ · cm). At that time, ammonia water having a concentration of 5% was used as one of the two liquids, and ultrapure water was used as the other liquid. The pressure when the ammonia water was injected was 0.25 MPa, and the ultrapure water was supplied at a flow rate of 10 → 5 → 1 → 5 → 10 L / min, and the pressure was 0.2 MPa. The ammonia water supply cycle is controlled by observing the specific resistance value of ammonia water containing a small amount of ammonia obtained as treated water with a monitor and supplying ammonia water when it reaches 0.20 MΩ · cm, and 0.19 MΩ · cm. In the following, ON-OFF control was performed by a method of stopping supply, pressure injection was performed, and then diffusion injection was performed. A ceramic membrane filter having an average pore size of 10,000 molecular weight cut off was used. When ammonia water containing a small amount of ammonia was produced under the above conditions, the target low-concentration ammonia water could be obtained continuously. The result is shown in FIG.
[0020]
【The invention's effect】
As is clear from the above description, according to the present invention, since the injection control from the second solution to the first solution is performed by diffusion through the porous medium, the mixing ratio is large and the entire flow rate is high. Even when the amount is small, a mixed solution can be obtained continuously. For example, when the flow rate of the first solution is as small as 5000 L / h, if the mixing ratio is to be 1/1000 or less, the injection amount of the first solution is as small as 0.083 (L / min), and the pipe diameter Since 1 mm or less is required, a commercially available control valve, metering pump, etc. cannot be used. The present invention is particularly effective when the two liquids are mixed under such conditions.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an apparatus for carrying out a two-liquid mixing method using the diffusion injection method of the present invention.
FIG. 2 is a view showing another example of an apparatus for carrying out a two-liquid mixing method using the diffusion injection method of the present invention.
FIG. 3 is a diagram showing one cycle of injection in the present invention.
FIG. 4 is a diagram showing an example of an experimental result when ammonia water is diffusely injected into ultrapure water in the present invention.
[Explanation of symbols]
1 container, 2 seal, 3 ceramic membrane filter, 4 inlet, 5 outlet, 6 supply piping, 7 discharge piping, 8 monitor, 9 inlet, 10 supply piping, 11 shutoff valve, 12 first chamber, 13 first 2 chambers, 21 outlet, 22 discharge piping, 23 on-off valve

Claims (5)

When the first solution and the second solution having a concentration of the component of interest higher than that of the first solution are brought into contact with each other through the porous medium, the second solution is injected into the first solution by diffusion. A first chamber for storing the first solution is formed in one of the porous media, a second chamber for storing the second solution is formed in the other of the porous media, and the second solution is stored in the second chamber. When the pressure is transferred into the pressure chamber and then depressurized, the pressure injection amount of the second solution into the first solution and the second pressure when the second solution is depressurized after being transferred into the second chamber by pressure. Two liquids using a diffusion injection method characterized by injecting the second solution into the first solution by setting the ratio of the diffusion injection amount to the first solution to be 1:10 or more. Mixing method. The two-component mixing method using the diffusion injection method according to claim 1, wherein the first solution does not contain a component of interest. The two-component solution using the diffusion injection method according to claim 1 or 2, wherein the average pore size of the porous medium is a fractional molecular weight of 3000 or more and 0.2 µm or less, preferably a fractional molecular weight of 10,000 or more and 0.1 µm or less. Mixing method. The porous medium has a bottomed cylindrical shape with one end closed, a first chamber is formed outside the bottomed cylindrical porous medium, and a second chamber is formed inside the bottomed cylindrical porous medium. The two-component mixing method using the diffusion injection method according to any one of claims 1 to 3 , wherein a chamber is formed. The porous medium has a cylindrical shape, the first chamber is formed outside the cylindrical porous medium, the second chamber is formed inside the cylindrical porous medium, and the cylindrical porous A two-component mixing method using the diffusion injection method according to any one of claims 1 to 3 , wherein one end of the porous medium is closed.

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