JP4598698B2 - Ozone production method - Google Patents

Description

  The present invention relates to an ozone production method for producing high-purity ozone gas by reducing the concentration of hydrogen gas, which is an impurity in an ozone-containing gas obtained by water electrolysis.

  Conventionally, in the ozone gas production field, in an ozone-generating water electrolyzer, the anode chamber and the cathode chamber are partitioned, and the gas generated from both electrode chambers is not diffused into the counter electrode chamber. An exchange membrane was used (see, for example, Patent Document 1).

  However, in the ozone production method according to the conventional method described above, the thickness of one fluororesin-based ion exchange membrane used as the solid electrolyte decreases as the solid electrolyte is operated for a long time, or the membrane deteriorates. The generated hydrogen gas diffuses into the anode chamber and the hydrogen gas concentration increases as an impurity in the ozone-containing gas.

  In addition, according to the above conventional method, when operated at high electrical density, the decrease in the thickness of the ion exchange membrane for fluororesin and the deterioration of the membrane are accelerated, and the hydrogen gas concentration further increases as an impurity in the ozone-containing gas. There is a tendency. And if hydrogen gas concentration exceeds 4% as an impurity in ozone containing gas, there exists a possibility of exploding.

  Further, according to the above conventional method, the ozone-generating water electrolyzer cannot be stably operated for a long period of time.

JP-A-5-295579

  The object of the present invention is to eliminate the disadvantages of the conventional methods described above, lower the concentration of hydrogen gas, which is an impurity in ozone gas obtained by water electrolysis, obtain high-purity ozone gas, and stabilize the water electrolyzer for ozone generation for a longer time. And providing a way to drive.

In order to achieve the above object, the present invention uses a fluororesin ion exchange membrane as a solid electrolyte, and uses a water electrolyzer for ozone generation partitioned into an anode chamber and a cathode chamber by the fluororesin ion exchange membrane. In the ozone production method of producing ozone-containing gas from the anode chamber and hydrogen gas from the cathode chamber, as the fluororesin ion exchange membrane, a plurality of fluororesin ion exchange membranes are brought into contact with each other and attached to the electrolytic cell, At least one of the plurality of fluororesin ion exchange membranes is a fluororesin ion exchange membrane with cuts penetrating the front and back, and at least one is a fluororesin ion exchange membrane with no cuts, in lowering the hydrogen concentration of the ozone containing the gas generated from the previous SL anode chamber.

Further , the second problem-solving means is that a plurality of cuts of the fluororesin ion exchange membrane having the cuts are formed over the entire surface, and the cuts are linear , lateral, concentric or irregular. It is that it is arranged.

According to the present invention, as a fluororesin ion exchange membrane, a plurality of fluororesin ion exchange membranes are attached to the electrolytic cell in contact with each other, and the hydrogen concentration in the ozone-containing gas generated from the anode chamber is lowered. In addition, the electrolytic cell for generating ozone can be stably operated for a long period of time.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
In the present invention, as shown in FIG. 1, a plurality of fluororesin-based ion exchange membranes used as a solid electrolyte are obtained by bringing ordinary fluororesin-based ion exchange membranes 1, 1, 1 without cuts into contact with each other 3 Using three fluororesin ion exchange membranes, the three fluororesin ion exchange membranes are mounted in an ozone generating water electrolysis tank 6, and the anode 3 and the cathode 4 are connected to both sides via O-rings 5. The anode chamber 7 and the cathode chamber 8 were formed by mounting. The normal fluororesin ion exchange membranes 1, 1, 1 without cuts are all larger than the electrolysis area, and the center of the normal fluororesin ion exchange membranes 1, 1, 1 without cuts is at the center. The fluororesin ion exchange membrane 1 positioned was made larger than the fluororesin ion exchange membranes 1 and 1 in contact with the cathode 3 and the anode 4. Pure water was supplied into the cathode chamber 8, and pure water was electrolyzed in the ozone-generating water electrolysis tank 6, oxygen-containing ozone gas was obtained from the anode chamber 7, and hydrogen gas was obtained from the cathode chamber 8.

  As a result, the concentration of hydrogen gas mixed in the oxygen-containing ozone gas obtained from the anode chamber 7 is extremely low, and the value is less than half that in the case where the normal fluororesin ion exchange membrane 1 is used alone. Thus, the ozone generating water electrolyzer 6 could be stably operated for a long time.

  In the present invention, as shown in FIG. 2, a plurality of fluororesin-based ion exchange membranes used as solid electrolytes have a plurality of cuts on both sides of a normal fluororesin-based ion exchange membrane 1 having no cuts. Three fluororesin ion exchange membranes in which the provided fluororesin ion exchange membranes 2 and 2 are in contact with each other are used, and these three fluororesin ion exchange membranes are mounted in an ozone generation water electrolyzer 6. The anode 3 and the cathode 4 were mounted on both sides via the O-ring 5 to form the anode chamber 7 and the cathode chamber 8. Pure water was supplied into the cathode chamber 8, and pure water was electrolyzed in the ozone-generating water electrolysis tank 6, oxygen-containing ozone gas was obtained from the anode chamber 7, and hydrogen gas was obtained from the cathode chamber 8.

  As a result, the concentration of hydrogen gas mixed in the oxygen-containing ozone gas obtained from the anode chamber 7 is even lower than when all the fluororesin ion exchange membranes 1, 1, 1 are used in contact with each other. As compared with the case where the normal fluororesin ion exchange membrane 1 is used alone, the amount is less than half, and the ozone generating water electrolyzer 6 can be stably operated for a long period of time.

  In addition, when a fluororesin-based on-exchange membrane with cuts is used in this way, liquid or gas does not accumulate between the membranes, and this liquid or gas can be exchanged with fluororesin ion exchange with cuts. Since it is easily discharged out of the system through the cut of the film 2, an increase in the cell voltage can be prevented without causing a phenomenon like a void.

  Further, according to the present invention, a plurality of cuts of the fluororesin ion exchange membrane 2 having the cuts may be formed in the lateral direction as shown in FIG. Without being limited to the shape, a plurality of the entire surface is formed, and the cuts are arranged linearly or circularly in a vertical direction, a horizontal direction, a concentric circle shape, or irregularly, thereby obtaining the above effect. It can be further improved.

  Further, in the above example, three fluororesin ion exchanges in which the fluororesin ion exchange membranes 2 and 2 having cuts are brought into contact with each other on both sides of a normal fluororesin ion exchange membrane 1 without a cut. Although the membrane is used, the number of the three membranes may be two, or four or more. According to the present invention, at least one of the plurality of fluororesin ion exchange membranes has a slit. By using the fluororesin ion exchange membrane 2 that has entered, it is possible to further prevent the liquid and gas from staying between the membranes, and the cell voltage becomes very large or the value fluctuates greatly. In addition, since water does not accumulate between the membranes, a phenomenon such as a void can be prevented.

  Furthermore, according to the present invention, the cut of the fluororesin ion exchange membrane with the cut is a cut that penetrates the front and back, thereby further reducing the hydrogen concentration in the ozone-containing gas generated from the previous anode chamber. It is possible to lower the cell voltage and prevent the cell voltage from rising.

  Further, according to the present invention, all of the plurality of fluororesin ion exchange membranes use a membrane having a size larger than the electrolysis area, and at least one of the plurality of fluororesin ion exchange membranes, A fluororesin ion exchange membrane having a larger size than other fluororesin ion exchange membranes can be used to prevent liquid leakage between a plurality of membranes, and the above effects can be further improved.

  Next, the present invention will be specifically described with reference to examples and comparative examples. However, the present invention is not limited to these examples.

< Reference Examples 1 and 2 and Comparative Example 1>
As the reference example 1, the ozone-generating water electrolyzer 6 shown in FIG. 1 is used, and as a solid electrolyte, two normal fluororesin-based ion exchange membranes ( reference example 1) or three ( reference example 2) without cuts. Were used in contact with each other. The effective electrolysis area of the water electrolyzer for ozone generation 6 was 1 dm ² , and the current density was 100 A / dm ² . Nafion N-117 (registered trademark) manufactured by DuPont was used as the lead 3 for the anode 3, the platinum powder for the cathode 4, and the fluororesin ion exchange membranes 1 and 2 that are stationary electrolytes. Further, as Comparative Example 1, instead of the three fluororesin ion exchange membranes, a single ordinary fluororesin ion exchange membrane 1 (thickness, 0.18 mm) without a cut was used.

As a result, as shown in Table 1, in Reference Example 1 in which two films are stacked and in Reference Example 2 in which three films are stacked, the hydrogen concentration in the ozone-containing gas generated from the anode chamber 7 is extremely reduced. Compared with the case where one film was used, it was less than half. As a result, it has been found that even when there is no cut in the film, by stacking a plurality of films, there is an effect of reducing the hydrogen concentration in the ozone-containing gas.

However, when the continuous fluororesin ion exchange membrane shown in Reference Examples 1 and 2 is used as described above, liquid or gas may stay between the membranes, which may increase the cell voltage. .

<Example 1 >
As Example 1 , the ozone-generating water electrolyzer 6 shown in FIG. 2 was used, and a fluororesin ion exchange membrane 2 provided with cuts on both sides of a normal fluororesin ion exchange membrane 1 having no cuts as a solid electrolyte. Three fluororesin ion exchange membranes were used in which 2 were brought into contact with each other. As shown in FIG. 3, a plurality of cuts in the fluororesin ion exchange membrane 2 with the cuts were formed in the lateral direction. The electrolysis effective area of the ozone-generating water electrolyzer 6 is 1 dm ² , lead dioxide powder is used for the anode 3, platinum powder is used for the cathode 4, and fluororesin-based ion exchange membranes 1 and 2, which are stationary electrolytes. Registered trademark). Further, as Comparative Example 1, instead of the three fluororesin ion exchange membranes, a single ordinary fluororesin ion exchange membrane 1 (thickness, 0.18 mm) without a cut was used.

As a result, as shown in Table 2, in Example 1 , the hydrogen concentration in the ozone-containing gas generated from the anode chamber 7 is extremely reduced, and is less than half compared to the case where one film is used. The values were lower than those shown in Reference Examples 1 and 2.

Furthermore, according to the first embodiment, the liquid or gas is easily discharged out of the system through the cut of the fluororesin ion exchange membrane 2 provided with the cut, so that a phenomenon like a void occurs. No increase in cell voltage could be prevented.

<Example 2 >
In the method of Reference Example 1, two fluororesin ion exchange membranes in which a normal fluororesin ion exchange membrane 1 without cut and a fluororesin ion exchange membrane 2 provided with a cut are in contact with each other are used as solid electrolytes. Used and electrolyzed under the same conditions as in Reference Example 1.

As a result, as shown in Table 3, in Example 2 , the hydrogen concentration in the ozone-containing gas generated from the anode chamber 4 is extremely reduced, and is less than half compared to the case where one film is used, The values were lower than those shown in Reference Examples 1 and 2.

  Furthermore, according to the present embodiment, since the liquid and gas are easily discharged out of the system through the cut of the fluororesin ion exchange membrane 2 provided with the cut, a phenomenon like a void does not occur. It was possible to prevent the cell voltage from rising.

  ADVANTAGE OF THE INVENTION According to this invention, it can use in the field | area which requires the high purity ozone gas by reducing the hydrogen gas concentration which is an impurity in the ozone gas obtained by water electrolysis.

The figure which shows the schematic diagram of an example of the water electrolyzer for ozone generation used for the ozone manufacturing method at the time of laminating | stacking two or more uncut films | membranes by the reference example of this invention. The figure which shows the schematic diagram of an example of the water electrolyzer for ozone generation used for an ozone manufacturing method at the time of laminating | stacking the film | membrane with a cut | disconnection and the film | membrane with a notch | cut according to this invention. The figure which shows the schematic diagram of an example of the cut of the fluororesin ion-exchange membrane 2 with a cut in the ozone manufacturing method by this invention.

Explanation of symbols

1: Fluororesin ion exchange membrane without cut 2: Fluororesin ion exchange membrane with cut 3: Anode 4: Cathode 5: O-ring 6: Water electrolyzer for ozone generation 7: Anode chamber 8: Cathode chamber

Claims (2)

A fluorine resin ion exchange membrane is used as a solid electrolyte, and ozone-containing gas and cathode chamber hydrogen gas are supplied from the anode chamber using a water electrolyzer for ozone generation partitioned into an anode chamber and a cathode chamber by the fluorine resin ion exchange membrane. In the ozone manufacturing method to be manufactured, as the fluororesin ion exchange membrane, a plurality of fluororesin ion exchange membranes are attached to the electrolytic cell in contact with each other , and at least one of the fluororesin ion exchange membranes Like is fluorine resin based ion exchange membrane that contains the cuts penetrating the front and back, a fluorine resin based ion exchange membrane that does not contain at least one is a notch, the hydrogen before Symbol ozone-containing the gas generated from the anode chamber A method for producing ozone, comprising reducing the concentration. A plurality of cuts of the fluororesin ion exchange membrane with the cuts are formed over the entire surface, and the cuts are linearly , laterally, concentrically or irregularly arranged. The ozone production method according to claim 1 .

Images