JP5025021B2 - Deoxygenation decarboxylation device - Google Patents

Description

  The present invention relates to a deoxygenation decarboxylation device that removes in advance oxygen components and carbonic acid components in raw water supplied to a boiler or the like, and in particular, deoxygenation decarboxylation treatment by adjusting pH of water to be treated and contact treatment with nitrogen gas. The present invention relates to a deoxygenation decarboxylation apparatus.

  In the water treatment field such as boiler feed water, dissolved oxygen in the feed water causes corrosion of the boiler and piping. Further, carbon dioxide gas in feed water and carbon dioxide gas generated by thermal decomposition of bicarbonate ions and carbonate ions also cause corrosion of boilers and piping. For this reason, deoxygenation and decarboxylation treatment is performed on boiler feed water, etc., one of which is a combination treatment of pH adjustment and contact with nitrogen gas as described in Patent Documents 1 and 2. is there. Further, Patent Document 3 describes one of deoxygenation devices by contact with nitrogen gas.

JP 2001-129305 A JP 2003-047950 A JP 2005-95791 A

  The conventional deoxygenation and decarboxylation treatment by pH adjustment and contact treatment with nitrogen gas is performed as follows. As oxygen components and carbonate components in the raw water, there are bicarbonate ions and carbonate ions in addition to dissolved oxygen and carbon dioxide gas. Dissolved oxygen and carbon dioxide are removed by contact with nitrogen gas, but ions are not removed by contact with nitrogen gas.

  Therefore, first, before sending the raw water to the degassing treatment tower using nitrogen gas, the raw water is adjusted to an acidic pH of 6.5 or less. Then, as shown in Chemical Formula 1, bicarbonate ions and carbonate ions in the raw water become free carbon dioxide gas.

  In this state, the raw water is sent to a degassing treatment tower using nitrogen gas. In the degassing tower, a large amount of nitrogen gas is brought into contact with the raw water. As a result, the carbon dioxide gas and dissolved oxygen in the raw water are replaced with nitrogen gas and removed from the raw water. In the deoxygenation / decarboxylation treatment described in Patent Documents 1 and 2, deoxygenation / decarboxylation treatment is performed according to this procedure.

  On the other hand, the deoxygenation device described in Patent Document 3 removes dissolved oxygen in raw water by bringing the raw water into contact with nitrogen gas, and is a counter flow type in which a gas-liquid contact tube is connected to the water tank. In addition to using the above treatment tower, high-efficiency deoxygenation treatment is performed by circulating water to be treated and nitrogen gas in the tower.

  However, as described in Patent Documents 1 and 2, if the deoxygenation and decarboxylation treatment is performed in order in the order of pH adjustment and nitrogen gas contact, there are the following problems. In order to mix a pH reducing agent such as sulfuric acid with raw water, a large-scale pH adjusting tank equipped with an injection stirring mechanism is required on the upstream side of the deaeration treatment tower, and the equipment scale and equipment cost increase.

  An object of the present invention is to provide a high-efficiency deoxygenation and decarboxylation apparatus that can obtain high deoxygenation and decarboxylation performance on a small scale and at low cost.

  In order to achieve the above object, the present inventor considers that the root of the above-mentioned problems lies in pH adjustment and permutation treatment of nitrogen gas contact, and direct injection of a pH lowering agent into a degassing treatment tower that performs nitrogen gas contact A comparative study was conducted on the type of deaeration tower suitable for direct injection and the injection location. As a result, it is effective to supply the pH lowering agent directly into the treatment tower of the deoxygenation apparatus described in Patent Document 3, particularly the water tank of the counter-flow treatment tower in which the gas-liquid contact tube is connected to the water tank. Turned out to be very high.

  That is, in the deoxygenation device described in Patent Document 3, a gas-liquid contact cylinder is connected to the water tank, and water to be treated is introduced into the gas-liquid contact cylinder and discharged to the outside through the lower water tank, A counter-flow type processing tower is used in which nitrogen gas is introduced into the water tank and discharged to the outside through the gas-liquid contact cylinder. Then, part of the used nitrogen gas discharged from the gas-liquid contact cylinder of the processing tower is diffused and introduced into the water to be treated that stays in the water tank, circulates in the tower, and the covered nitrogen gas in the water tank of the processing tower. The treated water is reintroduced into the gas-liquid contact cylinder and circulates in the tower.

  When a pH lowering agent for decarboxylating the water to be treated is supplied into the water tank of the treatment tower, nitrogen gas is diffused and introduced into the water to be treated in the water tank, and the water to be treated is stirred. Therefore, the mixing of the pH lowering agent proceeds in the same manner as when the pH lowering agent was added to the stirring and mixing tank without using a special stirring and mixing tank, and the bicarbonate ions and carbonate ions in the water to be treated were free of carbonate. It becomes gas. Then, the carbon dioxide gas is replaced with nitrogen gas together with dissolved oxygen and separated and discharged. At this time, nitrogen gas and water to be treated are circulated in the treatment tower and gas-liquid contact is repeated, so that the separation and discharge efficiency of carbon dioxide gas and oxygen gas is also high.

  By the way, when the water to be treated is not circulated and the pH reducing agent is supplied into the water tank of the treatment tower, the carbon dioxide gas separated and removed from the water to be treated in the water tank by the diffusion injection of nitrogen gas is converted into nitrogen gas. At the same time, in the process of rising in the gas-liquid contact cylinder, the carbon dioxide gas is reabsorbed into the water to be treated by coming into contact with the neutral newly introduced water, and the carbon dioxide separation and discharge effect is particularly reduced. However, when the water to be treated is circulated, newly introduced water and acidic circulating water are mixed in the gas-liquid contact cylinder and become acidic water to be treated, so that reabsorption of carbon dioxide gas is prevented. The circulation operation of the water to be treated when supplying the pH lowering agent directly to the water tank of the treatment tower is not only repeated gas-liquid contact, but also from the point of preventing carbon dioxide reabsorption due to pH increase in the gas-liquid contact cylinder. It is also important.

  The deoxygenation decarboxylation apparatus of the present invention has been developed on the basis of such knowledge, and is attached to a water supply system that supplies raw water to be deoxygenated and decarboxylated from the raw water tank to the raw water consumption section, to the raw water consumption section. A deoxygenation and decarboxylation device that removes in advance oxygen components and carbonic acid components in the raw water to be supplied, wherein a gas-liquid contact cylinder is connected to the water tank, and the water to be treated descends in the gas-liquid contact cylinder, and the lower water tank The counterflow type treatment tower in which the nitrogen gas is exhausted to the outside through the gas-liquid contact cylinder and exhausted to the outside, and the used nitrogen gas discharged from the gas-liquid contact cylinder of the treatment tower A nitrogen gas circulation system in which a part of the water is diffused and introduced into the treated water staying in the water tank and circulated in the tower, and the treated water in the water tank of the treatment tower is reintroduced into the gas-liquid contact cylinder. A circulation system for circulating the water to be treated for decarboxylation of the water to be treated The pH-lowering agent for adjusting water to be treated is acidified, the nitrogen gas in the water tank is adopted a configuration to be injected into the water to be treated is introduced diffused.

  In the deoxygenation decarbonization apparatus of the present invention, the water to be treated introduced into the gas-liquid contact cylinder of the treatment tower temporarily stays in the lower water tank through the gas-liquid contact cylinder. A part of the water to be treated in the water tank is discharged as treated water to the outside of the tower, and the rest is reintroduced into the gas-liquid contact tube and circulates in the tower. At the same time, nitrogen gas rises in the gas-liquid contact cylinder of the treatment tower and makes countercurrent contact with the water to be treated. Part of the nitrogen gas that has risen in the gas-liquid contact cylinder is discharged outside the tower, and the rest is diffused and introduced into the water to be treated in the water tank, rises again in the gas-liquid contact cylinder, and circulates in the tower. In this state, a pH lowering agent is injected into the water to be treated in the water tank.

  The water to be treated in the water tank is agitated by the diffusion and introduction of nitrogen gas, and in this state, the pH lowering agent is injected to promote the mixing of both. By stirring and mixing the pH lowering agent in the water tank, carbonate ions and bicarbonate ions in the water to be treated become free carbon dioxide gas. This water to be treated is introduced into the gas-liquid contact cylinder and comes into contact with nitrogen gas. By repeating this, carbon dioxide gas and dissolved oxygen in the water to be treated are replaced with nitrogen gas, and separated and removed from the water to be treated. The treated water from which carbon dioxide gas and dissolved oxygen are removed is discharged out of the treatment tower as treated water.

  Thus, in the deoxygenation decarboxylation apparatus of the present invention, not only the contact of the treated water and nitrogen gas is repeated in the gas-liquid contact tube of the treatment tower, but also the diffusion of nitrogen gas in the water tank of the treatment tower. By the introduction, contact between the water to be treated and nitrogen gas is repeated, and deoxygenation / decarboxylation treatment is performed. In addition, the pH lowering agent is injected into the water to be vigorously stirred by the introduction of carbon dioxide gas, so that the pH lowering agent can be stirred efficiently without using a dedicated pH adjusting tank having a stirring and mixing function. Mixing is performed and gas release of bicarbonate ions and carbonate ions in the water to be treated is promoted.

  That is, in the deoxygenation and decarbonization apparatus of the present invention, the water tank of the treatment tower also serves as a pH adjustment tank, a deoxygenation tank and a decarbonization tank, and a gas-liquid contact cylinder which is an original deoxygenation apparatus and decarbonation apparatus is added. Thus, highly efficient deoxygenation and decarboxylation is performed with a small facility. The further importance of the circulation operation of the water to be treated when the pH reducing agent is directly supplied to the water tank of the treatment tower is as described above. In addition, since pH adjustment is performed in the treatment tower, the response is good and the control accuracy is high.

  As the treatment tower in the deoxygenation decarboxylation apparatus of the present invention, a two-column tower having a treatment tower comprising a first treatment tower and a second treatment tower is preferable because of high deoxygenation efficiency. In this case, in the first treatment tower and the second treatment tower, the water to be treated from the water supply system is introduced into the gas-liquid contact cylinder of the first treatment tower and the gas-liquid contact cylinder of the second treatment tower is introduced. Nitrogen gas is introduced, and the nitrogen gas circulation system diffuses and introduces used nitrogen gas discharged from the gas-liquid contact tube of the second treatment tower into the treated water in the water tank of the first treatment tower, and the treated water circulation system It is desirable that the water to be treated in the water tank of the first treatment tower is introduced into the gas-liquid contact cylinder of the first treatment tower and the gas-liquid contact cylinder of the second treatment tower. The water to be treated in the water tank of the first treatment tower is pH adjusted to be acidic. On the other hand, the water to be treated from the water supply system is basically neutral. When both are introduced into the gas-liquid contact cylinder of the first treatment tower, both are mixed and become acidic, so that the carbon dioxide gas in the nitrogen gas rising in the gas-liquid contact cylinder enters the water to be treated. Reabsorption is prevented.

  About pH meter for pH adjustment of to-be-processed water, it is preferable to provide a pH meter in a water tank or a to-be-processed water circulation system for pH adjustment of to-be-processed water staying in a tank of a to-be-treated water, It is particularly preferable to provide it. This is because it is less likely to be affected by hunting caused by nitrogen gas bubbles on the electrode in the pH meter if it is provided in the treated water circulation system.

  The deoxygenation decarboxylation apparatus of the present invention circulates nitrogen gas and water to be treated in a counter-flow type treatment tower having a gas-liquid contact tube connected to a water tank, and circulates the nitrogen gas to be treated in the water to be treated in the water tank. In the degassing apparatus of the type introduced into diffusion, since the pH reducing agent for adjusting the water to be treated is injected into the water to be treated in the water tank, the water tank of the treatment tower is a pH adjusting tank and a deoxygenating tank. In addition, since a gas-liquid contact cylinder which is also an original deoxygenation device and decarbonation device is added to serve as a decarbonization tank, high deoxygenation and decarboxylation performance can be obtained on a small scale and at low cost.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a deoxygenation decarboxylation apparatus showing an embodiment of the present invention.

  The deoxygenation decarboxylation apparatus of the present embodiment performs deoxygenation decarboxylation treatment of raw water such as boiler feed water by pH adjustment and nitrogen gas from a nitrogen source. A nitrogen gas circulation system 20 that circulates nitrogen gas in the tower 10, a treatment water circulation system 30 that circulates the treatment water in the treatment tower 10, and a pH adjustment system 40 that adjusts the pH of the treatment water are provided. .

  The processing tower 10 is a two-column type in which a first processing tower 10a and a second processing tower 10b are installed in parallel. The 1st processing tower 10a is the structure by which the perpendicular | vertical gas-liquid contact cylinder 12a was connected on the water tank 11a which stores a to-be-processed water. Similarly to the first treatment tower 10a, the second treatment tower 10b has a configuration in which a vertical gas-liquid contact cylinder 12b is connected to a water tank 11b for storing water to be treated. The water tanks 11a and 11b are arranged in parallel. It is installed and integrated, and communicates at the lower part of the partition wall 13 that partitions the two. The gas-liquid contact cylinders 12a and 12b are filled with a stationary contact promoting member (reactor) made of a Raschig ring material or the like in order to increase the contact area and contact time between the water to be treated and nitrogen gas.

  The capacity of the first processing tower 10a is larger than the capacity of the second processing tower 10b, and is about 1.5 times here. A self-priming air diffuser 14 called an aerator is attached to the side wall of the water tank 11a of the first treatment tower 10a on the side opposite to the water tank 31b. The self-priming diffuser 14 is composed of a rotating blade in the water tank 11a supported by a horizontal axis and a blade driving motor outside the tank. The rotating blade is driven to rotate in the water to be treated in the water tank 11a. The gas is sucked and diffused and injected into the water to be treated in the tank.

  In this deoxygenation decarboxylation apparatus, raw water is introduced into the gas-liquid contact cylinder 11a of the first treatment tower 10a from above by a raw water supply system 50 having a supply pump (not shown). On the other hand, nitrogen gas for removing gases such as dissolved oxygen and carbon dioxide gas is supplied from a nitrogen source (not shown) by the nitrogen gas supply system 60 in the water tank 11b of the second treatment tower 10b, particularly from the surface of the water to be treated in the water tank 11b. It introduce | transduces into the upper tank space, and introduce | transduces into the gas-liquid contact cylinder 11b of the 2nd processing tower 10b from this lowest part via this space part. The treated water that has been subjected to the deoxygenation and decarboxylation treatment is discharged from the lower portion of the water tank 11b of the second treatment tower 10b to the outside of the tower by the treated water discharge system 70 including the treated water pump 71.

  The nitrogen gas circulation system 20 equipped in the processing tower 10 is a self-supporting system in which all of the nitrogen gas discharged from the top of the gas-liquid contact cylinder 11b of the second processing tower 10b is attached to the water tank 11a of the first processing tower 10a. It supplies to the suction type diffuser 14. A part of nitrogen gas is supplied to the self-priming diffuser 14 from the tank space above the liquid level in the water tank 11a of the first processing tower 10a and the upper part of the gas-liquid contact cylinder 12a. The treated water circulation system 30 equipped in the treatment tower 10 together with the nitrogen gas circulation system 20 draws treated water from the bottom of the water tank 11a of the first treatment tower 10a from the circulation pump 31, and makes the gas-liquid contact of the second treatment tower 10b. It introduce | transduces into the upper part of the pipe | tube 12b, and the upper part of the gas-liquid contact pipe | tube 12a of the 1st processing tower 10a.

  The pH adjustment system 40 is capable of adjusting a flow rate of injecting the pH lowering agent in the tank 41 containing a known pH lowering agent such as an aqueous sulfuric acid solution into the water to be treated in the water tank 11a of the first treatment tower 10a. And a pH meter 43 for measuring the pH value of the water to be treated in the water tank 11a. The pH meter 43 measures the pH of the water to be treated which is diverted from the downstream side of the circulation pump 31 in the water to be treated circulation system 30. The water to be treated after the pH measurement is returned to the water tank 31a of the first treatment tower 30a. The output signal of the pH meter 43 is sent to a controller 44 called a mass flow controller. The controller 44 controls the capacity of the pump 42 so that the measured pH value matches the target value. Thereby, the pH value of the to-be-processed water in the water tank 31a of the 1st processing tower 30a is managed by the target acidic value of 6.5 or less, for example.

  Next, the function of the deoxygenation decarboxylation apparatus of this embodiment will be described.

  During operation of the deoxygenation decarboxylation apparatus of the present embodiment, raw water is introduced from above into the gas-liquid contact cylinder 12a of the first treatment tower 10a via the raw water introduction system 50. The introduced water to be treated flows down in the gas-liquid contact cylinder 12a and stays in the water tank 11a. The water to be treated in the water tank 11a is managed by the pH adjustment system 40 to have a target acidity of pH 6.5 or less. The treated water that has been treated is discharged by the treated water discharge system 70 from the water tank 11b of the second treatment tower 10b. The amount of raw water introduced and treated water discharged are substantially the same.

  In addition, when the circulation pump 31 in the treated water circulation system 30 is operated, the treated water in the water tank 11a, the gas-liquid contact cylinder 12b of the second treatment tower 10b, and the gas-liquid contact cylinder of the first treatment tank 10a. Each is introduced into 11a from above. The water to be treated introduced into the gas-liquid contact cylinder 12b of the second treatment tower 10b flows down in the gas-liquid contact cylinder 12b and stays in the water tank 11b. The water to be treated introduced into the gas-liquid contact cylinder 12a of the first treatment tower 10a flows down in the gas-liquid contact cylinder 12a together with the raw water and stays in the water tank 11a. Since the water tanks 11a and 11b communicate with each other at the lower part, they have the same liquid level. Thus, the water to be treated circulates in the treatment tower 10. The amount of water to be treated is usually 0.5 to 5 times the amount of raw water introduced (treated water discharge amount).

  At the same time, nitrogen gas is introduced into the space above the liquid level in the water tank 11b of the second processing tower 10b by the nitrogen gas supply system 20, and is self-priming attached to the water tank 11a of the first processing tower 10a. The air diffuser 14 is activated. Nitrogen gas introduced into the space in the water tank 11b rises in the gas-liquid contact cylinder 12b of the second treatment tank 10b and comes into counterflow contact with the circulating water to be treated flowing down in the gas-liquid contact cylinder 12b. Nitrogen gas discharged from the gas-liquid contact cylinder 12b of the second treatment tank 10b is sucked into the self-priming diffuser 14 provided in the water tank 11a of the first treatment tower 10a, and into the treated water in the water tank 11a. Diffusion injection. Thus, nitrogen gas is also circulated in the processing tower 10. The circulation amount of nitrogen gas is usually 1.5 to 20 times the nitrogen gas supply amount (nitrogen gas discharge amount).

  As a result of such operation, the water to be treated is subjected to deoxygenation / decarboxylation treatment through the following process.

  A pH lowering agent is injected by the pH adjusting system 40 into the water to be treated that stays in the water tank 11a of the first treatment tower 10a. The water to be treated in the water tank 11 a is agitated by the diffusion and introduction of nitrogen gas from the self-priming diffuser 14. For this reason, a pH lowering agent is stirred and mixed with the to-be-processed water in the water tank 11a, without using a special stirring and mixing apparatus. Thereby, it becomes carbon dioxide gas from which carbonate ions and bicarbonate ions in the water to be treated are liberated.

  The treated water flows down through the treated water circulation system 30 and in the gas-liquid contact tubes 12a and 12b. At this time, the gas-liquid contact cylinders 12a and 12b come into countercurrent contact with the rising nitrogen gas. Thereby, the carbon dioxide gas and dissolved oxygen in the water to be treated flowing down in the gas-liquid contact cylinders 12a and 12b are replaced with nitrogen gas and separated and removed from the water to be treated. In the gas-liquid contact cylinder 12a, the raw water also flows down, but is mixed with the water to be treated whose pH has been adjusted to become an acidic mixed solution, so that carbon dioxide does not reabsorb.

  In the water tank 11a of the first treatment tower 10a, nitrogen gas becomes fine bubbles from the self-priming diffuser 14 and is injected into the treated water whose pH has been adjusted. The dissolved oxygen is separated and removed. The carbon dioxide gas and oxygen gas separated and removed are discharged out of the tower together with the nitrogen gas discharged from the gas-liquid contact cylinder 12a of the first processing tower 10a.

  Thus, in the deoxygenation decarboxylation apparatus of this embodiment, nitrogen gas is repeatedly used for contact with the water to be treated. Since the contact is performed not only by the gas-liquid contact cylinders 12a and 12b of the processing tower 10, but also by diffusion injection by the self-priming air diffuser 33 in the water tank 11a of the first processing tower 10a, the contact efficiency is high. Moreover, in the water tank 11a, the water to be treated is stirred by diffusion injection of nitrogen gas. Since the pH lowering agent is injected into the water to be treated, the pH lowering agent is uniformly mixed in the water to be treated without using a special stirring and mixing device. Moreover, since it is mixing in the processing tower 10, responsiveness is high and control accuracy is also high.

  The self-priming diffuser 14 is an injection device for circulating nitrogen gas, and is also a stirrer for water to be treated in the water tank 11a. The water tank 11a of the first treatment tower 10a also serves as a pH adjusting tank for mixing a pH lowering agent with the water to be treated and a degassing tank (deoxygenation tank and decarbonation tank) by nitrogen gas diffusion injection.

  Therefore, although the deoxygenation decarboxylation apparatus of this embodiment is small and economical, it exhibits high deoxygenation decarboxylation efficiency. Specifically, the amount of nitrogen gas used is basically an amount commensurate with the amount of raw water introduced and the amount of treated water discharged, but the gas-liquid contact cylinder 12a is circulated by using a self-priming diffuser 14. , 12b and the water tank 11a, it can be reduced.

The oxygen component and the carbonic acid component in boiler feed water were removed using the deoxygenation decarboxylation apparatus shown in FIG. The raw water temperature is 25 ° C., the pH is 7.5, the dissolved oxygen concentration in the raw water is 7.8 mg / L, and the carbonate / bicarbonate ion concentration is 60 mg / L in terms of M alkalinity. The effective capacity of the water tank in the first treatment tower is 100L, and the effective capacity of the water tank in the second treatment tower is 75L. The raw water treatment amount (raw water supply amount / treated water discharge amount) per unit time was 3.0 m ³ / h, and the circulation amount in the treatment tower was 6.0 m ³ / h. The nitrogen gas amount was 0.45 Nm ³ / h per unit time, 0.15 Nm ³ / m ³ per unit processing amount, and the circulation rate was 4.5 Nm ³ / h. A sulfuric acid aqueous solution was used as the pH lowering agent, and the pH adjustment value was 5.5.

  The dissolved oxygen concentration in the treated water was 0.25 mg / L and the carbonate / bicarbonate ion concentration was 7 mg / L in terms of M alkalinity, even though the stirring agent tank for the pH lowering agent was not used.

  FIG. 2 shows the relationship between the adjusted pH value and the carbonate / bicarbonate ion concentration in the treated water when the deoxygenation / decarboxylation treatment of the boiler feed water is performed using the deoxygenation / decarboxylation device shown in FIG. Conditions other than the pH adjustment value are the same as above. In spite of not using the stirring and mixing tank of the pH lowering agent, the concentration of carbonate / bicarbonate ions in the treated water decreases as the pH of the treated water decreases.

It is a block diagram of the deoxygenation decarboxylation apparatus which shows one Embodiment of this invention. The performance diagram of the deoxygenation decarboxylation apparatus shows the relationship between the adjusted pH value and the carbonate / bicarbonate ion concentration in the treated water.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Treatment tower 10a 1st treatment tower 10b 2nd treatment tower 11a, 11b Water tank 12a, 12b Gas-liquid contact cylinder 13 Partition wall 14 Self-priming air diffuser 20 Nitrogen gas circulation system 30 Water to be treated circulation system 31 Circulation pump 40 pH adjustment System 41 Tank 42 Pump 43 pH meter 44 Controller 50 Raw water supply system 60 Nitrogen gas supply system 70 Treated water discharge system 71 Treated water pump

Claims (3)

A deoxygenation decarboxylation device that is attached to the water supply system that supplies raw water to be deoxygenated and decarboxylated from the raw water tank to the raw water consumption unit, and removes oxygen components and carbonic acid components in the raw water supplied to the raw water consumption unit in advance. There,
A gas-liquid contact cylinder is connected to the water tank, and the treated water descends in the gas-liquid contact cylinder and is discharged to the outside through the lower water tank, and nitrogen gas rises in the gas-liquid contact cylinder and is discharged to the outside. A counter-flow type processing tower,
A nitrogen gas circulation system in which a part of used nitrogen gas discharged from the gas-liquid contact cylinder of the treatment tower is diffused and introduced into the treated water staying in the water tank and circulated in the tower;
A treated water circulation system for re-introducing treated water in the water tank of the treated tower into the gas-liquid contact cylinder and circulating in the tower;
Deoxygenation dehydrogenation characterized in that a pH lowering agent that adjusts the water to be treated to be acidic in order to decarboxylate the water to be treated is injected into the water to be treated in which nitrogen gas in the water tank is diffusely introduced. Carbonic acid equipment.   2. The deoxygenation decarboxylation apparatus according to claim 1, wherein the processing tower includes a first processing tower and a second processing tower, and in the first processing tower and the second processing tower, the gas-liquid contact tube of the first processing tower. Water to be treated from the feed water system is introduced into the gas, nitrogen gas is introduced into the gas-liquid contact cylinder of the second treatment tower, and the nitrogen gas circulation system is discharged from the gas-liquid contact cylinder of the second treatment tower. Used nitrogen gas is diffused and introduced into the water to be treated in the water tank of the first treatment tower, and the water circulation system for treatment of the water to be treated in the water tank of the first treatment tower and in the gas-liquid contact cylinder of the first treatment tower and A deoxygenation decarboxylation apparatus, which is introduced into a gas-liquid contact cylinder of a second treatment tower. The deoxygenation decarboxylation apparatus according to claim 1 or 2, wherein a pH meter for adjusting the pH of the water to be treated staying in the water tank of the treatment tank is provided in the water circulation system. Carbonic acid equipment.

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