JP2001137867A - Oxidant removing device and seawater treating device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxidant treating device which does not possess a problem of generation of fresh wastes, or the like, and a seawater treating device equipped therewith. SOLUTION: The seawater treating device is a device to treat the seawater of a water tank 100 with ozone and comprises an electrolytic ozone generator 1, an ozone treating system 2, an oxidant removing device 3 consisting of a hydrogen reaction column 4, and the like. The hydrogen reaction column 4 has a reaction section 41 packed with palladium as a catalyst. The seawater in which the oxidant remains and the hydrogen generated in the ozone generator are introduced to the reaction section. Accordingly, the oxidant is reduced by he hydrogen and is treated as bromine ions. The effective utilization of the hydrogen which is the by-product of the ozone generator is made possible and the running cost for the oxidant removal in the ozone treatment of the seawater does not occur. The fresh wastes like used active carbon are not generated either.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidant removing device for removing oxidants from water to be treated containing oxidants, and a seawater treatment device for treating seawater with ozone using the oxidant removing device.

[0002]

2. Description of the Related Art Ozone is required to sterilize or inactivate microorganisms and viruses in seawater to produce clean seawater, and to prevent sea organisms from adhering to seawater intake facilities and heat exchangers to cause adverse effects. It is effective to use an oxidizing agent such as That is, although ozone has a strong oxidizing power, it decomposes into oxygen, so it has no persistence like chlorine and sodium hypochlorite, and is a useful substance that is indispensable for environmentally friendly systems. .

However, when ozone is used for seawater,
Brom ions present in sea water at about 60 to 70 ppm are oxidized to form oxidant brom oxide. This oxidant is important because it has a bactericidal activity and breaks down ammonium ions and has a relatively high chemical stability, so it plays a complementary role in ozone disinfection systems, but on the other hand, it has persistence and is environmentally friendly. May be a problem. For example, in aquariums and fishery facilities, the effect of oxidants on seafood is a problem.

In order to solve such a problem, a device for removing residual oxidant with activated carbon has been used (for example, JP-A-3-143596, JP-A-9-29).
No. 9935). However, when activated carbon is used, there is a problem that activated carbon is consumed and needs to be replenished, and the used activated carbon becomes new waste and must be disposed of.

As an apparatus that does not use activated carbon, in a filter, zeolite or barley stone that is inexpensive and inexpensive, such as activated carbon, is used instead of filter sand that is usually used, so that oxidants can be removed. A seawater purification device has been proposed (Japanese Patent Laid-Open No. 6-285483).
Reference). However, zeolite or barley stone has a problem that it is inferior to filter sand in terms of availability, cost and general filtration performance as a filter material of a filter.

In the purification of seawater with ozone, ammonia is treated with an oxidant generated by ozone, the concentration of ozone is controlled by detecting the concentration of residual oxidant, and the oxidant does not affect more than half of the sand filtration layer. A breeding facility for fish and shellfish is also proposed (see JP-A-6-233990). However, in such a device, the effect of ozone purification may be limited and insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, does not generate new waste, and has no restriction on the filter material when a filter is used in a water purification system. It is an object of the present invention to provide an oxidant removing device whose effect is not limited when purifying ozone and a seawater purifying device provided with the oxidant removing device.

[0008]

According to the present invention, there is provided an oxidant removing apparatus for removing an oxidant from water to be treated containing an oxidant, the invention comprising a hydrogen reaction vessel. A reaction section filled with a catalyst, a water introduction section and a hydrogen introduction section in which the water to be treated and the hydrogen are introduced so that the water to be treated and hydrogen are brought into contact with each other in the reaction section, And a treated water discharge unit for discharging treated water as treated water by contacting the treated water with the hydrogen.

According to a second aspect of the present invention, in addition to the above, the water to be treated is composed of a first water to be treated and a second water to be treated, and is an aeration vessel, wherein the first water to be treated, air and A first treated water introduction unit and an air introduction unit, into which the first treated water and the air are introduced so that the first treated water and the air are brought into contact with each other and become the second treated water;
An aeration container provided with a second treated water discharge section for discharging the second treated water, and an air discharge section for discharging the air after contacting the first treated water; The second treated water is introduced into the treated water inlet of the reaction vessel.

A third aspect of the present invention is characterized in that, in addition to the features of the first or second aspect, the hydrogen is hydrogen generated from an electrolytic ozone generator.

According to a fourth aspect of the present invention, in the seawater treatment apparatus for treating seawater with ozone, an electrolytic ozone generator for generating the ozone, a seawater treatment section for bringing the ozone into contact with the seawater, and a seawater treatment section. An oxidant removing device for removing the generated and remaining oxidant, wherein the oxidant removing device is a hydrogen reaction vessel, and a reaction section filled with a catalyst, and the water to be treated and hydrogen are mixed in the reaction section. A treated water introduction unit and a hydrogen introduction unit into which the treated water and the hydrogen are introduced so as to be in contact with each other, and a treated water discharge unit that is discharged as the treated water when the treated water comes into contact with the hydrogen. Wherein the hydrogen is hydrogen generated from the electrolytic ozone generator.

[0012]

FIG. 1 shows an example of the overall configuration of a seawater treatment apparatus including an oxidant removal apparatus to which the present invention is applied. The seawater treatment device is a device that treats seawater in a water tank 100 for breeding fish and shellfish with ozone, an electrolytic ozone generator 1 that generates ozone, and an ozone treatment system that is a seawater treatment unit that contacts ozone with seawater. 2. An oxidant removing device 3 for removing oxidants in the water to be treated remaining with oxidants generated by the ozone treatment. The oxidant removing device 3 of the present example includes a hydrogen reaction tower 4 which is a hydrogen reaction vessel.

The electrolytic ozone generator 1 has an anode side 11a
Cell section 11 having a gas-liquid separation tank 12 for oxygen and ozone, a gas-liquid separation tank 1 for hydrogen, and a cathode side 11b and a solid polymer electrolyte membrane 11c interposed therebetween.
3, etc. In this apparatus, oxygen and ozone are extracted together with circulating water from the anode side and hydrogen is discharged from the cathode side by electrolyzing pure water supplied and circulated from a pure water supply system (not shown). According to such an ozone gas generator, 10 to 15% by weight
High concentration ozone gas can be generated.

The ozone treatment system 2 includes a booster pump 21 for increasing and circulating ozone water, an eductor 22 for inhaling generated ozone and mixing it with seawater, and a gas-liquid separator 23a.
And an ozone dissolving tank 23 for dissolving ozone in seawater, provided with a waste ozone decomposer 23b, a filter 24 with built-in filter sand,
And so on. The seawater in the water tank 100 is purified by the circulation pump 5 via the filter 24 and returned to the water tank 100.

The hydrogen reaction tower 4 has a reaction section 41 filled with a catalyst, and a seawater inlet serving as a treated water introduction section into which treated water and hydrogen are introduced so that the treated water and hydrogen come into contact with each other. The system includes a unit 43, a hydrogen inlet unit 42 serving as a hydrogen introduction unit, a seawater outlet unit 44 serving as a treated water discharge unit from which treated water comes into contact with hydrogen and is discharged as treated water.

The hydrogen reaction tower 4 of the present embodiment is provided with a diffuser pipe 45 for blowing hydrogen into small bubbles and a float valve 46 for separating and discharging only hydrogen from seawater when unreacted hydrogen is generated. ing. Further, in order to treat the surplus hydrogen discharged from the float valve 46, a hydrogen processor (not shown) including a hydrogen combustion device or the like is provided as needed. As the catalyst to be filled in the reaction section 41, palladium is usually used, and for example, the catalyst is filled in a state of being supported on a pellet-shaped ceramic having a diameter of about 3 mm and a length of about 3 mm.

The hydrogen introduced into the hydrogen reaction tower 4 may be supplied from a hydrogen cylinder or the like, but is supplied from the electrolytic ozone generator 1 in this embodiment. In this case, as will be described later, the amount of hydrogen generated from the cathode side 11b of the electrolytic ozone generator is usually much larger than the amount required to react with the oxidant. Therefore, when it is necessary to keep the amount of dissolved oxygen in the treated water at a level maintained by ordinary seawater, it is necessary to limit the amount of hydrogen introduced into the hydrogen reactor 4. Therefore, in the apparatus of the present example, the regulating valves 47 and 48 are provided so that the amount of hydrogen supplied to the hydrogen reaction tower 4 can be adjusted while checking the oxidant amount, the residual oxidant concentration, and the like.

The above-described seawater treatment apparatus is operated as follows and exerts its operational effects. The seawater in the aquarium 100 is
It is taken out by the circulation pump 5 and returned to the water tank 100 again via the ozone treatment system 2 and the oxidant removing device 3 constituting the internal circulation path, and is circulated and cleaned. In the ozone treatment system 2, seawater is circulated in the system by the booster pump 21 as described above, and the electrolytic ozone generator 1
The ozone generated in the water is introduced into the ozone dissolving tank 23 and dissolved in the circulating water. This ozone directly kills harmful microorganisms in the seawater, and the ozone reacts with bromine ions in the seawater to form bromooxide. Oxidant is generated, thereby further bactericidal action is performed and ammonium ion which is a dirt component in seawater is decomposed,
Including these, the filter 24 can obtain a comprehensive seawater purification effect.

The seawater that has passed through the filter 24 is introduced into the hydrogen reaction tower 4 that constitutes the oxidant removing device 3. In the above-mentioned ozone treatment system, it is desirable to supply sufficient ozone to increase the sterilizing / purifying effect.In such a case, when the dirt components in the seawater are small, the generated oxidant becomes excessive and the It remains.

On the other hand, in the electrolytic ozone generator 1, hydrogen is generated from the cathode side along with the generation of ozone and oxygen on the anode side, and this hydrogen is introduced into the hydrogen reaction tower 4 and becomes small bubbles from the air diffuser 45. Is blown out into the seawater. Then, it reacts with the oxidant in the seawater in the reaction section 41 filled with the palladium catalyst, and acts to reduce this to return to the original bromide ion. As a result, the seawater that has passed through the hydrogen reaction tower 4 is sterilized and purified and becomes harmless seawater that does not affect fish and the like, and is returned to the water tank 100. Thereby, the tank water is circulated and cleaned well.

In the above, bromine ions in seawater are oxidized by ozone to form oxidants, bromooxides, which are reduced by hydrogen to form the original bromine ions. Therefore, if all ozone is used in this reaction, Then, hydrogen is needed in the same molar amount as ozone. On the other hand, in the electrolytic ozone generator, high concentration ozone is generated. However, oxygen is generated about 7 to 8 times as much as ozone, and its molar amount is about 11 to 12 times as large as ozone. Since water is electrolyzed, hydrogen has twice the molar amount of oxygen. Accordingly, hydrogen is generated in a molar amount of about 22 to 24 times that of ozone, and even considering the efficiency of hydrogen contacting and reducing the oxidant, it is considerably more than the amount required for the oxidant treatment. It has occurred. As a result, the oxidant can be treated only with hydrogen generated by the electrolytic ozone generator as described above, and in such a case, it is not necessary to consume expensive hydrogen produced separately. Then, the oxidant can be treated without increasing the operation cost of the seawater purification device.

FIG. 2 shows another example of the overall configuration of a seawater treatment apparatus including an oxidant removing apparatus to which the present invention is applied. This example is an apparatus for sterilizing a seawater system of a heat exchanger 6 cooled with seawater in various plants and the like with ozone, and includes an electrolytic ozone generator 1, an ozone treatment system 2, and residual oxidants in treated seawater. Oxidant removing device 3
, And a hydrogen reaction tower 4. Reference numeral 7a,
7b and 7c are a seawater intake unit, a seawater supply pump, and a seawater drainage unit, respectively. In addition, devices having the same functions as those in FIG. 1 are denoted by the same reference numerals. In addition, the hydrogen reaction tower 4 of this example is of an open type. Reference numeral 46 'denotes an outlet for discharging excess hydrogen.

In the seawater treatment apparatus of this embodiment, the ozone dissolving tank 2
The seawater is sterilized and washed with ozone and oxidant in the piping system 3 and the piping and the heat exchanger 6 to prevent adhesion of microorganisms and dirt components to the piping system and the heat exchanger, and to provide good water permeability and heat of the entire seawater cooling system. Exchange performance is maintained. Then, the seawater thus treated by sufficient ozone supply is introduced into the hydrogen reaction tower 4, and even if the oxidant remains in the seawater, it is decomposed by hydrogen and the seawater does not affect fish and shellfishes. It becomes harmless and is discharged into the sea again. Also in the apparatus of this example, by using the hydrogen of the ozone generator, the oxidant can be treated without generating industrial waste such as used activated carbon and without increasing the operation cost.

FIG. 3 shows a partial configuration of a seawater treatment apparatus including another oxidant removing apparatus to which the present invention is applied. In the oxidant removing apparatus of this example, an aeration tower 7 is additionally provided to the apparatus shown in FIGS. The water to be treated containing the oxidant is composed of the first water to be treated and the second water to be treated in the aeration tower 7, and the second water to be treated is introduced into the hydrogen reaction tower 4.

The aeration tower 7 is provided with a seawater inlet 71, which is a first treated water introduction part, into which the first treated water and the air come into contact and become the second treated water. An air inlet 72, which is an introduction part, a seawater outlet 73, which is a second treated water discharging part for discharging the second treated water, and an air discharging part, which discharges air after contacting the first treated water. An air outlet 74 is provided. The air is supplied from a compressed air system or the like, and is blown out from the air diffuser 75 as small bubbles. A float valve 76 is provided at the air outlet, and air is separated from seawater and discharged.

In this apparatus, the ozone supplied to the ozone treatment system 2 may be supplied from an electrolytic ozone generator as in the apparatus shown in FIGS. 1 and 2, or may be produced by a silent discharge method. You may. The hydrogen supplied to the hydrogen reaction tower 4 may be commercially available in a cylinder or the like, or may be hydrogen generated from an electrolytic ozone generator. In an apparatus in which the ozone generator is constituted only by a silent discharge type, commercially available hydrogen is naturally used. When the electrolytic ozone generator is included in the seawater treatment device, the hydrogen generated from this is used. In this case, since a large amount of hydrogen is generated in a molar amount as compared with the amount of generated ozone as described above, there is a possibility that the oxidant generated by silent discharge type ozone can be treated. In such a case, it is effective to reduce the amount of the residual oxidant by half by the aeration tower 7.

If the aeration tower 7 is provided in this manner, in seawater having a high residual oxidant concentration, the value can be reduced by half and supplied to the hydrogen reaction tower 4 to reduce the hydrogen consumption. As a result, when using commercially available hydrogen, the cost can be reduced, and the operating cost for removing the oxidant can be reduced.

The inventors of the present invention have proposed an ozone dissolving tank 23 as a seawater treatment apparatus having the oxidant removing apparatus shown in FIG.
The aeration tower 7 and the hydrogen reaction tower 4 were made into cylindrical shapes, and experiments were performed using those having sizes (diameter mm × height m) of 150 × 1.5, 250 × 2, and 250 × 2, respectively. The results were obtained (the figures are also shown in the figure): Flow rate of treated seawater: 4 m ³ / h Ozone supply amount: 8 g / h (1/6 mol / h) Supply ozone concentration: 210 g / Nm ³ ozone dissolving tank Ozone discharge amount of float valve: 0.01 g / h (micro amount) Air supply amount to aeration tower: 40 L / min Hydrogen supply amount to hydrogen reaction tower: 1.5 L / mim (approximately 3.75 mol / h) Dissolved ozone concentration Ozone dissolution tank outlet: 0.05 ppm Aeration tower outlet: 0.000 ppm Oxidant concentration (O ₃ equivalent value) Ozone dissolution tank outlet: 1.6 ppm Aeration tower outlet: 0.7 ppm Hydrogen reaction tower outlet: 0.02 ppm For example, by aerating seawater containing oxidants and reacting with hydrogen, Decomposing Kishidanto the bromine ions, it was demonstrated that sufficient removal below the extent not affecting at all the marine organisms. In this experiment,
In order to perform the test with the most practical method, ozone and hydrogen generated by an electrolytic ozone generator are supplied in the same amount. Therefore, although not measured, hydrogen was supplied in an excessive amount, and more than half of the supplied amount of hydrogen was discharged from the float valve 46 of the hydrogen reaction tower. Therefore, it was also found that the oxidant can be sufficiently removed with the above-mentioned hydrogen supply amount even when the aeration tower is not provided. In this regard, an experiment was conducted in which the supply of air to the aeration tower was stopped, and it was confirmed that the oxidant concentration at the outlet of the hydrogen reaction tower was substantially the same as the above.

FIG. 4 shows another example of the configuration of the hydrogen supply unit to the hydrogen reaction tower in FIGS. In this example, a water eductor 49 for sucking and pressurizing hydrogen is provided. To the water eductor 49, for example, circulating seawater that has passed through the filter 24 in FIG. 1 is supplied as driving water, and hydrogen generated from an electrolytic ozone generator is supplied, and the mixed water is supplied to the hydrogen reaction tower 4. Supplied. FIG. 4 shows an example in which seawater diverted from the main line is used as driving water when the amount of circulating seawater is large, but the entire amount of circulating seawater may be used as driving water. In the apparatus of the present example, the hydrogen inlet 42 and the seawater inlet 43, which are the water introduction part and the hydrogen introduction part, can be made common. In addition, in the bypass line of the circulating seawater,
A valve that can adjust the amount of water as needed is provided.

According to such a device, when the seawater pressure in the hydrogen reaction tower 4 is high or when the pressure of hydrogen supplied from the electrolytic ozone generator is relatively low, the pressure of hydrogen is easily increased. To the hydrogen reactor 4.

[0031]

As described above, according to the present invention, in the first aspect of the present invention, the oxidant removing device for removing the oxidant from the water to be treated containing the oxidant has a hydrogen reaction vessel, and the hydrogen reaction vessel has a reaction section. And the treated water introduction section, the hydrogen introduction section, and the treated water discharge section, so that the oxidant in the treated water contacts the hydrogen in the reaction section under the action of the charged catalyst. The oxidant can be reduced with hydrogen and converted back to the bromide ion. The bromide is a component generally present in seawater and is not particularly harmful to marine life.

As a result, for example, seawater from an aquarium or a cultivation fishing ground is taken out and treated with ozone to generate an oxidant.
In addition to purifying seawater by disinfecting seawater and decomposing dirt components such as ammonia, etc., it is possible to remove residual oxidants to make seawater harmless to marine organisms such as fish and shellfish, thereby performing seawater circulation treatment.

According to such treatment, since no activated carbon is used, generation of new waste can be prevented, and it is possible to contribute to environmental conservation. In addition, since it is not a device that treats oxidants using zeolite or barley stone as a filter medium of a filter, equipment that is equipped with a filter for circulating purification of seawater is inexpensive, easily available, and generally available. Filter sand with good filtration performance can be used. Further, when seawater is subjected to ozone treatment, even if a considerable amount of residual oxidant is generated, a sufficient amount of ozone can be supplied and treated without limiting the amount of ozone, so that a sufficient seawater purification effect can be reliably obtained. be able to.

According to the second aspect of the present invention, since an aeration vessel is provided as an oxidant removing device in addition to the hydrogen reaction vessel, water to be treated containing residual oxidant generated by ozone treatment or the like is used as the first water to be treated. The oxidant concentration is reduced by bringing the oxidant concentration into contact with air in the container, and the oxidant concentration is reduced to second treated water, which can be treated in the hydrogen reaction vessel. As a result, the concentration of the oxidant to be treated with hydrogen can be reduced, and hydrogen consumption can be reduced.

According to the third aspect of the present invention, the hydrogen supplied to the hydrogen reaction vessel is hydrogen generated from the electrolytic ozone generator. Hydrogen released into the atmosphere or burned as unnecessary matter can be effectively used for oxidant removal. As a result, it is not necessary to use expensive hydrogen sold in a cylinder or the like, and it is possible to eliminate additional operating costs for removing oxidants.

According to a fourth aspect of the present invention, a seawater treatment apparatus for treating seawater with ozone is configured to include an electrolytic ozone generator, a seawater treatment section using the generated ozone, and an oxidant remover. Has the same structure as that of the first aspect of the present invention, and the hydrogen used is hydrogen generated from the electrolytic ozone generator, so that a sufficient amount of ozone and the oxidant generated thereby increase the sterilization and purification effect of seawater. At the same time, the remaining oxidant can be removed to return the seawater to something harmless to marine life.

In this case, since the hydrogen generated by the electrolytic ozone generator for generating ozone is used for the oxidant treatment, the operation cost for removing the oxidant is unnecessary, and the operation cost for the seawater treatment device is eliminated. Can be reduced. As a result, the seawater treatment apparatus can be optimized in terms of functionality, economy, and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of the overall configuration of a seawater treatment apparatus to which the present invention has been applied.

FIG. 2 is an explanatory diagram showing another example of the overall configuration of a seawater treatment apparatus to which the present invention has been applied.

FIG. 3 is an explanatory view showing a configuration of a part of a seawater treatment apparatus including another oxidant removing apparatus to which the present invention is applied.

FIG. 4 is an explanatory diagram showing another configuration example of the hydrogen supply unit in the seawater treatment device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrolytic ozone generator 2 ozone treatment system (seawater treatment unit) 3 oxidant removal device 4 hydrogen reaction tower (hydrogen reaction vessel) 7 aeration tower 41 reaction unit 42 seawater inlet (treatment water introduction unit) 43 hydrogen inlet ( Hydrogen introduction part) 44 Treated seawater outlet part (treated water discharge part) 71 Seawater inlet part (first treated water introduction part) 72 Air inlet part (air introduction part) 73 Seawater outlet part (second treated water discharge part) 74 Air outlet part (air discharge part)

Claims (4)

[Claims] 1. An oxidant removing apparatus for removing said oxidant from water to be treated containing oxidant, comprising: a hydrogen reaction vessel, wherein a reaction section filled with a catalyst and said water and hydrogen are mixed in said reaction section. A treated water introduction unit and a hydrogen introduction unit into which the treated water and the hydrogen are introduced so as to be in contact with each other, and a treated water discharge unit that is discharged as the treated water when the treated water comes into contact with the hydrogen. An oxidant removal device comprising a hydrogen reaction vessel provided with: 2. The water to be treated is composed of a first water to be treated and a second water to be treated, and is an aeration container, wherein the first water to be treated contacts air and the second water to be treated. A first treated water introduction section and an air introduction section into which the first treated water and the air are introduced, and a second discharge section for discharging the second treated water.
An aeration container having a treated water discharge unit and an air discharge unit configured to discharge the air after contacting the first treated water, wherein the treated water inlet of the hydrogen reaction vessel has Second
The oxidant removal device according to claim 1, wherein water to be treated is introduced. 3. The oxidant removing device according to claim 1, wherein the hydrogen is hydrogen generated from an electrolytic ozone generator. 4. A seawater treatment apparatus for treating seawater with ozone, comprising: an electrolytic ozone generator for producing the ozone; a seawater treatment section for bringing the ozone into contact with the seawater; and an oxidant generated and remaining in the seawater treatment section. And an oxidant removing device for removing the oxidant, wherein the oxidant removing device is a hydrogen reaction vessel,
A reaction section filled with a catalyst, a treated water introduction section and a hydrogen introduction section into which the treated water and the hydrogen are introduced so that the treated water and the hydrogen come into contact with each other in the reaction section; And a treated water discharge unit for discharging treated water as treated water by contacting the treated hydrogen with the hydrogen, wherein the hydrogen is hydrogen generated from the electrolytic ozone generator. A seawater treatment apparatus characterized by the above-mentioned.