JPH11315389A - Electrolytic cell for production of ozone and water treating device using that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress temp. increase on the reaction interface and to maximize the current efficiency in the electrolytic synthesis reaction and the concn. of ozone produced by disposing a cooling part which can be cooled with water on the outer face of at least one pole of the anode plate and cathode plate. SOLUTION: In the electrolytic cell 1, water is electrolyzed through a solid polymer electrolyte film 15 between an anode 12 of the anode plate 11 and a cathode 14 of the cathode plate 13 to produce ozone. The cathode plate 13 is equipped with a cooling room 16. The ozone producing device 2 is used for water treatment. Since a bypass water at about 28 deg.C flows from a filter device 31 to the sucking side of a pump 34, about 5% of the water is supplied by a cooling water supply system 36 to the cooling room 16. For example, the cooling water is at 28.2 deg.C when it enters the cooling room 16 and the water is at 32 deg.C at the exit and joined with the bypass water of 28 deg.C to raise the temp. to 28.2 deg.C. A part of the water is supplied to the cooling room 16 by the pump 34 while rest of the water is supplied to the water ejector. The electrolytic reaction part is kept at about 35 deg.C to maximize the ozone gas concn. Thus, cooling water using tap water is not required, thus reducing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic cell for generating ozone by electrolyzing water with a solid polymer electrolyte membrane interposed between an anode formed by an anode plate and a cathode formed by a cathode plate. The present invention also relates to a water treatment apparatus in which ozone obtained by an ozone generator using the electrolytic cell is brought into contact with water to be treated and filtered by a filtration apparatus, and particularly to a technique for cooling an electrolytic cell.

[0002]

2. Description of the Related Art A conventional oxygen / hydrogen generator does not require cooling, so that no cooling means has conventionally been provided. However, when ozone is generated, the operating temperature rises due to heat generation because ozone is generated at the anode in competition with oxygen. When the operating temperature becomes higher than a certain level, the ozone generation efficiency, and thus the ozone generation amount, is greatly reduced.

FIG. 4 shows the relationship between the electrolysis temperature and the ozone concentration when ozone is generated in an electrolytic cell. At a temperature from 35 ° C. to a maximum of about 40 ° C., the ozone concentration is reduced to a maximum value or a value slightly reduced therefrom. Can be maintained. However, when the temperature of the anode water as the operating temperature reaches 45 ° C. to 50 ° C., the generation rate of oxygen increases, the amount of generated ozone is reduced, and the ozone concentration is significantly reduced. In this state, the current efficiency also decreases. Therefore, cooling is important in an electrolytic cell that generates ozone.

[0004] As a cooling method of the electrolytic cell, for example, the fact that the anolyte is circulated between the anode chamber and the gas-liquid separation tank is utilized, and a heat exchanger is interposed on the return side of the circulating liquid to make the anode cool. Conventionally, a method of cooling the liquid has been performed. However, in such a method, since the amount of water circulated by the air lift action is small, the circulating water cooled to a certain temperature and low at the entrance of the electrolytic cell greatly increases in temperature at the reaction interface. Therefore, the reaction interface cannot be sufficiently cooled to maximize the electrolysis efficiency.

In the case of a monopolar electrolytic cell, a Peltier device is mounted on the outer surface of the anode plate, and the outer surface of the Peltier device, which becomes hot, is cooled by a blower, while the anode plate is cooled on the contact surface, which becomes cold. An apparatus designed to perform this operation is also introduced (see Japanese Utility Model Laid-Open No. 6-72695). However, such a cooling device cannot be applied to an intermediate portion of a bipolar electrolytic cell.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and can be applied to a bipolar type apparatus, and suppresses a temperature rise at a reaction interface to efficiently generate ozone. Another object of the present invention is to provide a water treatment apparatus provided with such an electrolytic cell.

[0007]

According to the present invention, in order to solve the above-mentioned problems, a first aspect of the present invention is to provide a solid polymer electrolyte membrane between an anode formed by an anode plate and a cathode formed by a cathode plate. In an electrolytic cell that generates ozone by intervening and electrolyzing water, a cooling unit that enables water cooling is provided on an outer surface of at least one of the anode plate and the cathode plate. It is characterized by.

According to a second aspect of the present invention, in addition to the above, the cooling portion is formed as a disk-shaped space portion having a certain width inside an annular portion provided on the outer diameter side. An inlet passage and an outlet passage formed in the cooling water, the inlet passage and the outlet passage being radially formed substantially symmetrically from each other from the center of the space portion, and the inlet passage and the outlet passage being provided over the entire width. A guide member that is open at a portion facing the outlet passage and is disposed at a distance from an inner end of the annular portion to guide a flow of cooling water.

A third aspect of the present invention is directed to a water treatment apparatus in which ozone obtained by an ozone generator is brought into contact with water to be treated and filtered by a filtration apparatus, wherein the ozone generation apparatus has an anode and a cathode formed by an anode plate. An electrolytic cell that generates ozone by electrolyzing water with a solid polymer electrolyte membrane interposed between a cathode formed of a plate and at least one of the anode plate and the cathode plate Having an electrolytic cell provided with a cooling unit that allows water cooling on the outer surface of the electrode plate,
A cooling water supply system that guides water filtered by the filtration device to the cooling unit and a cooling water return system that returns water that has flowed out of the cooling unit to the filtration device are provided.

According to a fourth aspect of the present invention, in addition to the above, there is provided a water ejector for inhaling and supplying ozone generated from the ozone generator and a pump for supplying driving water to the water ejector. The supply system is configured to include the pump and a supply-side branch system that branches from the discharge side of the pump to the cooling unit, and the cooling water return system is configured to include the pump and the cooling unit from the suction side of the pump. , And is configured to include a return-side branch system reaching

A fifth aspect of the present invention is characterized in that, in addition to the features of any one of the first to fourth aspects, the electrolytic cell is a bipolar electrolytic cell in which a plurality of electrolytic cells are combined.

[0012]

FIG. 1 shows an example of the structure of an electrolytic cell to which the present invention is applied and an example of the configuration of a part of a water treatment apparatus equipped with the same. The electrolytic cell 1 is a device that generates ozone by electrolyzing water with a solid polymer electrolyte membrane 15 interposed between an anode 12 formed by an anode plate 11 and a cathode 14 formed by a cathode plate 13. And a cooling chamber 16 as a cooling unit that enables water cooling. Symbols 12a and 14
a is an outlet of ozone, oxygen and circulating water and a hydrogen outlet, respectively.

The cooling chamber 16 includes an anode plate 11 or a cathode plate 13.
Is provided on the outer surface of at least one of the plates. In this example, the electrolytic cell 1 is of a bipolar type in which unit electrolytic cells are combined, and the cathode plates 13-1 at both left and right ends in the figure.
Outer surface of anode plate 11-1 and central anode plate 11-2
And 16-1, 16-2, 16-3 at three positions on the outer surface of the cathode plate 13-2 and between them. The cooling chambers 16-1 and 16-2 at both ends are formed by electrode plates at both ends and side plates 17 at both ends. The right side plate 17-1 on the right end side has the same structure as the cathode plate 13.
In FIG. 1, illustration of the internal structure of the cooling chamber 16 is omitted. Reference numeral 18 denotes a packing for sealing between the respective electrode plates and between the side plates.

If cooling chambers are provided at both ends in addition to the intermediate portion as in this embodiment, a sufficient cooling effect can be efficiently achieved by water cooling. However, depending on the surrounding environmental conditions, the cooling condition of the central cooling chamber 16-3, etc., the cooling chambers 16-1 and 16-2 at both ends may be omitted, and the function may depend on the natural heat radiation from the electrode plate surface. It is. Further, in order to reduce the amount of cooling water, it is also possible to use other cooling methods such as air cooling or a Peltier element for the pole plates at both ends.

FIG. 2 shows a schematic structure of the cathode plate 13 and the right side plate 17-1 forming the cooling chamber 16. Since both plates have the same structure, the cathode plate 13 will be described below. Note that the right side plate 17-1 is not provided with a portion for forming the concave cathode chamber 14. However, both plates may have the same structure in view of the commonality of parts.

The cathode plate 13 is formed in a disk shape. Although not shown, the same applies to the anode plate 11. The cooling chamber 16 is formed as a disk-shaped space portion having a certain width B inside the ring portion 13a outside the cathode plate 13 in this example, which is an annular portion on the outer diameter side, and is formed in the ring portion 13a. Inlet tubular portion 16 as an inlet passage and an outlet passage for the cooling water
a and an outlet tubular portion 16b, and two support guides 16c as guide portions disposed at an interval from the inside of the ring portion, that is, the inner diameter side end. In addition, a cylindrical center support guide 16d is provided in the center C portion inside these.

The inlet and outlet tubular portions 16a, 16b are formed radially in a direction substantially symmetrical to each other from the center C of the space portion, that is, in the present example, formed up and down in the diameter direction. The two support guides 16c are spaced from each other at portions facing the entrance / exit tubular portions 16a and 16b, and are provided over the entire width B. The cooling water is divided into and out of the spaces as indicated by arrows. In this example, the shape is an arc so as to guide the sink. When the entire electrolytic cell 1 is tightened, the cooling chamber 16
It also has the function of maintaining the shape. In addition, the support guide 1
The shape of 6c may be any shape that can appropriately guide the cooling water, such as a U-shape or a polygon. Center support guide 16
d keeps the center interval with respect to the external clamping force. It may be rectangular or the like. According to such a structure, the support guide 16c allows the cooling water to flow uniformly over the entire surface of the cathode plate 13 so as to efficiently cool the internal electrolytic reaction section, and the electrolytic cell is fastened with a coupling bolt (not shown). Sometimes it has the dual effect of retaining its shape.

The electrolytic cell 1 as described above is provided with an ozone generator 2
Is configured. That is, an outlet pipe 21 for extracting ozone and oxygen generated from the anode 12 of the electrolytic cell 1 and circulating raw water, a gas-liquid separation tank 22, a return pipe 23 for circulating water, and the like are provided. Ozone gas is taken out from an outlet pipe 24 at the top of the gas-liquid separation tank 22. Although not shown, raw water is supplied to the gas-liquid separation tank 22 via an ion-exchange type pure water device or the like.

Such an ozone generator 2 is used in a water treatment apparatus 3 for bringing ozone generated therefrom into contact with water to be treated and filtering the same through a filtration device. The water treatment device 3 is, for example, a device that circulates and filters pool water. As a normal configuration, the water treatment device 3 has a filter 31 serving as a filtration device having a sand filtration unit 31a, and dissolves ozone in water to supply ozone. It has a water ejector 33 which draws ozone from the tank 32 and the gas-liquid separation tank 22 and sends it out together with the driving water, a pump 34 for supplying the driving water, an ozone water supply system 35 and the like. In this example, a cooling water supply system 36 and a cooling water return system 37 to which the present invention is applied are provided.

In the ozone water supply system 35 as described above, the cooling water supply system 36 guides the water filtered by the filter 31 to the cooling chamber 16 of the electrolytic cell. In this embodiment, the cooling water is supplied from the pump 34 and the discharge side thereof. It is configured to include a supply-side branch system 36a that branches into the cooling chamber 16. Cooling water return system 3
Numeral 7 returns the water that has flowed out of the cooling chamber 16 to the filter 31. In this example, the water 7 includes a pump 36 and a return-side branch system 37a that extends from the cooling chamber 16 to the suction side of the pump 36. According to this structure, the pump of the ozone water production system of the water treatment apparatus can be used for supplying the cooling water of the electrolytic cell, so that an independent cooling water pump can be omitted and the pipe system can be simplified. However, an independent cooling water circulation pump may be provided.

The above-described electrolytic cell, the ozone generator including the same, and the water treatment apparatus are used as follows. Although not shown, water at the bottom of the pool or overflow water is taken, sent to the filter 31 by the circulating water pump, filtered, and returned to the pool again. The temperature of this water is usually 28
It is about ° C. High-concentration ozone water of 10 to 15% is introduced into the filter 31 for sterilization and improvement of filtration performance. That is, the ozone and oxygen generated from the anode 12 of the electrolytic cell 1 and the circulated raw water enter the gas-liquid separation tank 22 and are separated from each other. The ozone is sucked by the water ejector 33 and the ozone is dissolved together with the driving water. The ozone water enters the filter 31 at a high concentration and is dissolved in water at a high concentration. In addition, the pump 34 is operating, and the filtered water circulated from the filter 31 is supplied to the water ejector 33 as drive water.

FIG. 3 shows a state of the cooling system of the electrolytic cell 1. In the electrolytic cell 1, in order to generate ozone as described above, an electrosynthesis reaction of ozone occurs and heat is generated around the reaction interface. Therefore, a part of the water of the pump 34 flows to the supply side branch system 36a, passes through the cooling chamber 16, and is returned to the suction side of the pump 34 from the return side branch system 37a. The temperature around the electrolytic cell at this time is as shown in the figure.

That is, the filter 31 is provided on the suction side of the pump 34.
Since the bypass water having a temperature of about 28 ° C. flows into the cooling chamber 16 of the electrolytic cell 1 by flowing about 5% of this water into the cooling chamber 16, for example, the cooling water flows into the cooling chamber at 28.2 ° C. And the temperature rises by cooling the electrolytic reaction section,
At the outlet of the cooling chamber, the temperature becomes 32 ° C., and the water merges with the bypass water at 28 ° C. to reach 28.2 ° C., and is sent out from the pump 34. You. As a result, the temperature of the electrolytic reaction section is maintained at about 35 ° C. As a result, the electrolysis efficiency became 18%, and as shown in FIG.
It can be as high as 40 g / Nm ³ .

In this case, since the water flowing into the cooling chamber 16 is the water filtered by the filter 31, it does not contain dirt or dust, and usually removes a small amount of residual ozone of about 0.01 to 0.05 ppm. It has the effect of preventing the generation of bacteria and slime. As a result, the cost of cooling water due to the use of tap water is not required, and dirt and clogging of the cooling system can be eliminated to facilitate maintenance. For example, an apparatus that generates 100 g / h of ozone can save about 4000 m ³ of tap water annually.

In the case of the cooling method of the prior art, as shown in FIG.
Even if the temperature is reduced from 35 ° C. to 35 ° C., the temperature of the electrolytic reaction section of the electrolytic cell 1 ′ rises to about 42 ° C. because it is not cooled, the current efficiency is 13%, and the ozone gas concentration is 18%.
It is about 0 g / Nm ³ , and those values are considerably lower than those in the case of the water cooling system of the present invention.

[0026]

As described above, according to the present invention, according to the first aspect of the present invention, water cooling can be performed on the outer surface of at least one of the anode plate and the cathode plate constituting the electrolytic cell. Since a cooling section is provided, a required amount of cooling water can be supplied to this section to achieve a desired cooling action. As a result, the place where the electrolytic synthesis reaction is occurring can be reliably and efficiently cooled. Then, the current efficiency and the generated ozone concentration in the electrolytic synthesis reaction can be maximized.

According to the second aspect of the present invention, the cooling portion is formed as a disk-shaped space having a certain width inside the annular portion on the outer diameter side, and the inlet passage and the outlet of the cooling water formed in the annular portion. Since the passages are formed radially from the center of the hollow portion in a direction substantially symmetric to each other, and the passages facing the passages are spaced apart from each other and the guide members are arranged so as to guide the flow of the cooling water in a state in which the passages are open, Cooling water is introduced into the space from the inlet passage, is diverted into and out of the space between the guide members, and is joined at the outlet passage while guiding these flows by the guide member. Can be discharged from As a result, the heat generated in the electrolytic reaction portion can be absorbed from the entire surface through at least one of the anode plate and the cathode plate, and this portion can be efficiently cooled.

According to a third aspect of the present invention, there is provided a water treatment apparatus in which ozone obtained by an ozone generator is brought into contact with water to be treated and filtered by a filtration apparatus. The cooling water supply system that guides the water filtered by the filtration device to the cooling unit and the cooling water return system that returns the water discharged from the cooling unit to the filtration device are provided for cooling. In addition, the cost of cooling water required when using tap water can be reduced to almost zero. And in this case, since the water filtered by the filtration device does not contain dirt and dust, and a small amount of ozone remains in the filtered water due to the combined use of ozone treatment, the generation of bacteria and slime is also prevented, The cooling unit does not get dirty or clogged. As a result, maintenance of the cooling system becomes easy.

According to a fourth aspect of the present invention, a pump for supplying driving water to a water ejector for inhaling and supplying ozone generated from an ozone generator is used, and the pump and a supply side between the driving water system and the cooling unit are used. Since the cooling water supply system and the return system are configured to include the branch system and the return side branch system, an independent pump for cooling the cooling unit and an independent piping system from the filtration device are omitted, and cooling is performed. The system can be simplified and the cost can be reduced.

According to the fifth aspect of the present invention, the above-described electrolytic cell and the water treatment apparatus including the same are applied to a bipolar electrolytic cell in which a plurality of unit electrolytic cells are connected. In addition, the cooling unit provided between the combined unit electrolytic cells enables more effective water cooling.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration example of an electrolytic cell and a water treatment device to which the present invention is applied.

FIGS. 2A and 2B show a structure of a cooling portion of the electrolytic cell, wherein FIG. 2A is a front view and FIG. 2B is a longitudinal sectional view.

FIG. 3 is an explanatory view showing a state of a cooling portion of the electrolytic cell.

FIG. 4 is a curve diagram showing a relationship between electrolysis temperature and ozone gas concentration.

FIG. 5 is an explanatory diagram showing a state of a cooling portion of a conventional electrolytic cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolyzer, bipolar electrolyzer 2 Ozone generator 3 Water treatment apparatus 11 Anode plate 12 Anode 13 Cathode plate 14 Cathode 15 Solid polymer electrolyte membrane 16 Cooling room (cooling part) 13a, 17a Ring part (annular part) 16a Inlet tubular part (inlet passage) 16b Outlet tubular part (outlet passage) 16c Support guide (guide part) 31 Filter (filter) 33 Water ejector 33 34 Pump 36 Cooling water supply system 36a Supply side branch system 37 Cooling water return system 37a Return side branch system B width

Claims (5)

[Claims] An electrolytic cell that generates ozone by electrolyzing water by interposing a solid polymer electrolyte membrane between an anode formed by an anode plate and a cathode formed by a cathode plate, wherein the anode plate or An electrolytic cell, wherein a cooling unit that allows water cooling is provided on an outer surface of at least one of the cathode plates. 2. The cooling part is formed as a disk-shaped space part having a certain width inside an annular part provided on the outer diameter side, and a cooling water inlet passage formed in the annular part and An outlet passage, an inlet passage and an outlet passage radially formed from the center of the space portion in a substantially symmetrical direction with each other, and a portion provided over the entire width and facing the inlet passage and the outlet passage is open. 2. The electrolytic cell according to claim 1, further comprising: a guide member disposed at a distance from an inner end of the annular portion to guide a flow of cooling water. 3. 3. A water treatment apparatus in which ozone obtained by an ozone generator and water to be treated are brought into contact with each other and filtered by a filtration apparatus, wherein the ozone generator has an anode formed by an anode plate and a cathode formed by a cathode plate. An electrolytic cell that generates ozone by electrolyzing water with a solid polymer electrolyte membrane interposed between the anode plate and the outer surface of at least one of the cathode plates of the cathode plate A cooling water supply system that guides water filtered by the filtration device to the cooling unit, and cooling that returns water that has flowed out of the cooling unit to the filtration device; A water treatment apparatus comprising a water return system. 4. A water ejector for inhaling and supplying ozone generated from the ozone generator and a pump for supplying driving water to the water ejector, wherein the cooling water supply system includes the pump and a discharge of the pump. The cooling water return system is configured to include a supply-side branch system that branches from the side to reach the cooling unit, and the cooling water return system includes a return-side branch system that extends from the pump and the cooling unit to the suction side of the pump. The water treatment apparatus according to claim 3, wherein the water treatment apparatus is configured as follows. 5. The electrolyzer according to claim 1, wherein the electrolyzer is a bipolar electrolyzer combined with a plurality of electrolyzers.
An electrolytic cell or a water treatment apparatus according to item 1.