JP2016080624A - Adsorption removal system and adsorption removal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorption removal system capable of increasing the amount of adsorption of all nuclides when decontaminating simultaneously plural kinds of radionuclides.SOLUTION: The adsorption removal system includes: an adsorption tower 3 which has an ion exchange type adsorbent which is capable of adsorbing plural kinds of radionuclides from radioactive contaminated water including sea water; a feed pipe 11 for feeding polluted water including sea water to the adsorption tower 3; a fresh water generation section 5 that generates fresh water from polluted water which has passed through the adsorption tower 3 and includes the sea water; and a dilution pipe 15 which is connected to the feed pipe 11 for allowing the generated fresh water to flow into the feed pipe 11 to dilute the polluted water which includes the sea water in the feed pipe 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adsorption removal apparatus and an adsorption removal method.

  A radionuclide decontamination system that individually removes Cs and Sr from radioactively contaminated water including seawater and then removes salt from seawater has been proposed (see, for example, Patent Document 1). The system is configured to return fresh water generated by the salt removal device to the nuclear reactor.

JP 2014-001952 A Japanese Patent No. 5285183

  By the way, in order to reduce the adsorbent to be discarded, an adsorbent that simultaneously decontaminates a plurality of radionuclides has been proposed (see, for example, Patent Document 2). However, generally, when simultaneously decontaminating a plurality of radionuclides, breakthrough starts from multivalent ions having a small distribution coefficient, and the plurality of radionuclides cannot be sufficiently decontaminated.

  Then, the objective of this invention is providing the technique which can increase the adsorption amount of all the nuclide, when decontaminating several radionuclide simultaneously.

  In order to solve the above-mentioned problem, an adsorption removal apparatus is an ion exchange type and includes an adsorption tower having an adsorbent capable of adsorbing multiple types of radionuclides from radioactively contaminated water containing seawater, and the adsorption tower contains the seawater. A supply pipe that supplies radioactive contaminated water, a fresh water generating unit that generates fresh water from the radioactive contaminated water including the seawater that has passed through the adsorption tower, and the fresh water that is connected to the supply pipe and flows into the supply pipe And a dilution pipe for diluting radioactive contaminated water including the seawater in the supply pipe.

  ADVANTAGE OF THE INVENTION According to this invention, when decontaminating several radionuclide simultaneously, the technique which can increase the adsorption amount of all the nuclide can be provided.

The block diagram of the adsorption removal apparatus which concerns on the 1st Embodiment of this invention is shown. The block diagram of the adsorption removal apparatus which concerns on the 2nd Embodiment of this invention is shown. The block diagram of the adsorption removal apparatus which concerns on the 3rd Embodiment of this invention is shown.

  A suction removal apparatus according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an adsorption removal apparatus 1 according to the first embodiment. The adsorption removal apparatus 1 includes a water pump 2, an adsorption tower 3, a high-pressure pump 4, a fresh water generation unit 5, an introduction pipe 10, a supply pipe 11, a discharge pipe 12, and a plurality of connection pipes 13, 14. And a dilution tube 15.

  The water pump 2 supplies the contaminated water P including seawater from the introduction pipe 10 to the adsorption tower 3.

  The adsorption tower 3 is filled with an adsorbent capable of adsorbing radionuclide strontium (hereinafter referred to as Sr) and cesium (hereinafter referred to as Cs), and Sr and Cs are removed by the filler. To do. It is converted into treated water T from which this adsorption tower 3s has been removed.

  The adsorbent is an ion exchange type adsorbent, and a single adsorbent capable of simultaneously adsorbing Cs and Sr is used. Examples of the adsorbent that simultaneously adsorbs Cs and Sr include an adsorbent obtained by caustic treatment of a titanium silicate compound (for example, CST).

  The high pressure pump 4 pressurizes the contaminated water P from the adsorption tower 3 and supplies it to the reverse osmosis membrane 5.

  The fresh water production | generation part 5 is equipped with a reverse osmosis membrane, and produces | generates fresh water from the contaminated water P containing seawater. Examples of the structure of the reverse osmosis membrane include a spiral type and a hollow fiber type. Examples of the material for the reverse osmosis membrane 5 include cellulose and polyamide.

  Next, a process for adsorbing Sr and Cs from the contaminated water P including seawater by the adsorption removal apparatus 1 will be described.

  First, the contaminated water P including seawater introduced through the introduction pipe 10 is supplied to the adsorption tower 3 through the supply pipe 11 by the water pump 2. The contaminated water P that has passed through the adsorption tower 3 passes through the connecting pipe 13, is pressurized by the high-pressure pump 4, and is supplied to the fresh water generator 5 through the connecting pipe 14. In the fresh water generation unit 5, fresh water F is generated by passing the contaminated water P including seawater through the reverse osmosis membrane, and the generated fresh water F flows into the supply pipe 11 through the dilution pipe 15.

  The fresh water F flowing into the supply pipe 11 is mixed with the contaminated water P introduced from the introduction pipe 10, and the contaminated water P is diluted. That is, the seawater concentration of the contaminated water P is reduced. Then, the contaminated water having a reduced seawater concentration flows into the adsorption tower 3, and Sr and Cs are adsorbed by the adsorbent. Thereafter, the contaminated water P that has passed through the adsorption tower 3 and whose nuclide concentration has been reduced is discharged as treated water T from a discharge pipe 12 connected to the fresh water generation unit 5. The seawater concentration of the introduced contaminated water P and the seawater concentration of the discharged treated water T are equal.

  As described above, in the adsorption removal apparatus 1 of the present embodiment, the adsorption tower 3 has an ion exchange type adsorbent, and adsorbs and removes cesium and strontium from contaminated water including seawater. The fresh water generation unit 5 generates fresh water F from the contaminated water P including seawater that has passed through the adsorption tower 3, and flows the generated fresh water F into the supply pipe 11, thereby diluting the contaminated water P including seawater in the supply pipe 11. To do.

  Thereby, the seawater concentration of the contaminated water P supplied to the adsorption tower 3 is reduced. And as described in Teresia Moller: "Ion exchange of 85Sr, 134Cs and 57Co in sodium titanosilicate and the effect of crystallinity on selectivity", Separation and Purification Technology 28 (2002) 13-23, the distribution coefficient of radionuclides is It is inversely proportional to the ionic valence power of the concentration. Therefore, for example, when the contaminated water P is diluted twice with the fresh water F, the seawater concentration is halved and the distribution coefficient of Sr, which is a divalent ion, is four times. By diluting the contaminated water P twice, the concentration of Sr in the contaminated water P is halved, but the distribution coefficient is quadrupled. Therefore, theoretically, the adsorption amount of Sr can be doubled. it can. Thus, when the seawater concentration of the contaminated water P supplied to the adsorption tower 3 is reduced, it is possible to increase the amount of adsorption of Sr, which is a divalent ion (multivalent ion), on the adsorbent.

  For Cs, which is a monovalent ion, the distribution coefficient increases, but the concentration decreases, so the amount of adsorption on the adsorbent does not change. That is, by diluting the contaminated water P twice, the distribution coefficient is doubled. However, since the concentration of Cs in the contaminated water P is halved, the adsorption amount does not change.

  In addition, the fresh water generation unit 5 generates fresh water F from the contaminated water P including seawater that has passed through the adsorption tower 3, causes the generated fresh water F to flow into the supply pipe 11, and the contaminated water P including seawater in the supply pipe 11. Dilute. Thus, since fresh water is not injected from the outside but generated from the contaminated water P, adsorption of multiply charged ions (Sr) from the contaminated water P including seawater without increasing the total amount of the contaminated water P. The amount of adsorption to the material can be increased.

  Further, in Sr and Cs, Sr has a smaller distribution coefficient, and breakthrough starts from Sr. However, the start of breakthrough of Sr can be delayed by the configuration as described above. As a result, the adsorption amount of Cs can be increased. Therefore, the decontamination amount of all the radionuclides (Sr, Cs) can be increased without increasing the total amount of the contaminated water P.

  Since the adsorbent packed in the adsorption tower 3 is an adsorbent capable of simultaneously adsorbing a plurality of types of radionuclides (Sr, Cs), the adsorbent to be discarded can be reduced.

  Next, a suction removal apparatus 101 according to a second embodiment of the present invention will be described with reference to the drawings. In addition, about the same structure as the adsorption removal apparatus 1 which concerns on 1st Embodiment, the same reference number is attached | subjected and description is abbreviate | omitted and only a different part is demonstrated.

  FIG. 2 is a configuration diagram of the adsorption removal apparatus 101 according to the first embodiment. The adsorption / removal device 101 is an adsorption / removal device 101 of a multi-tower system, and includes a water supply pump 2, a 5-column adsorption tower 3, a high-pressure pump 4, a fresh water generation unit 5, an introduction pipe 10, a supply pipe 11, A discharge pipe 12 and a plurality of connection pipes 13 to 19 are provided.

  In the adsorption removal apparatus 101, the contaminated water P is supplied from the second-stage adsorption tower 3 to the fresh water generation unit 5 via the connection pipe 16 to generate fresh water F. The generated fresh water F passes through the dilution pipe 15. Flow into the supply pipe 11. Further, the remaining contaminated water P that has not been desalinated is concentrated in the fresh water generation unit 5, returned to the seawater concentration of the contaminated water P in the introduction pipe 10, and further decontaminated in the adsorption tower 3 of the subsequent three towers.

  Also in the adsorption removal apparatus 101 of this embodiment, there exists an effect similar to the adsorption removal apparatus 1 of 1st Embodiment. Furthermore, since it is the adsorption removal apparatus 101 of a multi-tower system, the adsorption amount (decontamination amount) of the radionuclide (Sr, Cs) can be increased.

  Next, a suction removal apparatus 201 according to a third embodiment of the present invention will be described with reference to the drawings. In addition, about the same structure as the adsorption removal apparatus 101 which concerns on 2nd Embodiment, the same reference number is attached | subjected and description is abbreviate | omitted and only a different part is demonstrated.

  In the adsorption removal apparatus 201, the water pump 2, the high-pressure pump 4, the fresh water generator 5, the introduction pipe 10, the supply pipe 11, the connection pipes 14 and 17, and the dilution pipe 15 are configured as a composite module 20. ing. In the adsorption removal apparatus 201, the merry-go-round method is used. FIG. 3 is a diagram for explaining a method of operating the adsorption removal apparatus 201 by the merry-go-round method. In FIG. 3, the adsorption tower 3 is represented by a circle, and the first adsorption tower 3 is represented by a thick line.

  In the merry-go-round method, a plurality of adsorption towers 3 are connected in series and decontamination is sequentially performed from the preceding adsorption tower 3 toward the latter adsorption tower 3, and the first adsorption tower 3 can sufficiently absorb the nuclides. When performed, the adsorbent of the first stage adsorption tower 3 is replaced with an unused adsorbent, and the second stage adsorption tower 3 is changed to the first stage adsorption tower 3, and the adsorption tower 3 is replaced with the adsorbent. Is a method of performing decontamination as the last-stage adsorption tower 3 and repeating this sequentially.

  In this embodiment, as shown in FIG. 3 (a), among the five adsorption towers 3, the leftmost adsorption tower 3 is the first stage, and the rightmost adsorption tower 3 is the last stage. . In the first and second two-stage adsorption towers 3, the composite module 20 decontaminates the radionuclides (Cs, Sr) from the contaminated water P diluted with the contaminated water P to reduce the seawater concentration. In the 3rd to 5th stage adsorption tower 3, the decontamination of the contaminated water P returned to the seawater concentration of the original contaminated water P is performed. When the adsorption amount of the radionuclide reaches a predetermined amount in the first-stage adsorption tower 3, the water flow is stopped and the adsorbent of the adsorption tower 3 is replaced with an unused one. Then, as shown in FIG. 3B, the adsorption tower 3 in the second stage (second from the left) is designated as the first adsorption tower 3, and the adsorption tower 3 in the first stage (leftmost). Is used as the last adsorption tower 3 to decontaminate the contaminated water P. As in FIG. 3A, in the two-stage adsorption tower 3 of the first and second stages, the radionuclide (Cs, Sr) is obtained from the contaminated water P diluted with the composite module 20 to reduce the concentration of seawater. ) Decontamination. In the 3rd to 5th stage adsorption tower 3, the decontamination of the contaminated water P returned to the seawater concentration of the original contaminated water P is performed.

  In FIG. 3 (b), when the adsorption amount of the radionuclide reaches a predetermined adsorption amount in the first stage adsorption tower 3, the adsorbent of the adsorption tower 3 is replaced with an unused one. Then, as shown in FIG. 3 (c), the adsorption tower 3 in the second stage (third from the left) is designated as the first adsorption tower 3, and the adsorption in the first stage (second from the left). Contaminated water P is decontaminated using the tower 3 as the last adsorption tower 3. Similarly to FIG. 3 (b), the radionuclide (Cs, Sr) is decontaminated from the contaminated water P with reduced seawater concentration in the first and second adsorption towers 3 in the first and second stages. In the eye adsorption tower 3, the contaminated water P returned to the seawater concentration of the original contaminated water P is decontaminated. The predetermined adsorption amount may be the adsorption amount of Sr that is adsorbed before the first stage adsorption tower 3 starts to break through Sr, and is determined based on the flow rate and time of the contaminated water P. May be.

  Thus, by decontaminating the contaminated water P by the merry-go-round method, the radionuclide can be efficiently adsorbed and removed. Moreover, the water quality of the treated water T can be stabilized. Further, the water pump 2, the high-pressure pump 4, the fresh water generator 5, the introduction pipe 10, the supply pipe 11, the connection pipes 14 and 17, and the dilution pipe 15 are modularized as a composite module 20. Therefore, the operation | work at the time of changing the adsorption tower 3 to connect by a merry-go-round system becomes easy. Also, the adsorption removal apparatus 201 of the present embodiment has the same effects as the adsorption removal apparatus 101 of the second embodiment.

  In addition, this invention is not limited to the Example mentioned above. A person skilled in the art can make various additions and changes within the scope of the present invention.

  For example, in the second embodiment, the number of adsorption towers 3 for treating the contaminated water P with reduced seawater concentration was two, but it may be one or more than three. May be. Moreover, although the number of the some adsorption tower 3 was five towers, the number of the adsorption towers 3 is not restricted to this.

  Moreover, although the fresh water production | generation part 5 was equipped with the reverse osmosis membrane and produced | generated fresh water by this, you may produce | generate fresh water by distilling the contaminated water P containing seawater with a multistage flash. In the above embodiment, the case where Sr and Cs are adsorbed as a plurality of radionuclides has been described, but other radionuclides may be used.

DESCRIPTION OF SYMBOLS 1, 101, 201: Adsorption removal apparatus, 3: Adsorption tower, 5: Fresh water production | generation part, 11: Supply pipe, 15: Dilution pipe

Claims (5)

An adsorption tower having an adsorbent that is capable of adsorbing multiple types of radionuclides from radioactively contaminated water that is ion-exchanged and includes seawater;
A supply pipe for supplying radioactive contaminated water containing the seawater to the adsorption tower;
A fresh water generating unit that generates fresh water from the radioactively contaminated water containing the seawater that has passed through the adsorption tower;
An adsorption / removal device comprising: a dilution pipe connected to the supply pipe and allowing the generated fresh water to flow into the supply pipe and diluting radioactive contaminated water including the seawater in the supply pipe. The radionuclide includes Sr and Cs;
The adsorption removal apparatus according to claim 1, wherein the adsorbent is an adsorbent that adsorbs Sr and Cs simultaneously. The adsorption tower is composed of a plurality of adsorption towers connected in series,
The supply pipe is connected to a first stage adsorption tower among the plurality of adsorption towers,
The fresh water generation unit generates fresh water from radioactive contaminated water including seawater that has passed through at least the first adsorption tower of the plurality of adsorption towers, and supplies the generated fresh water through the dilution pipe. The adsorption / removal device according to claim 1 or 2, wherein the adsorption / removal device is caused to flow into the pipe. An adsorption removal method executed in the adsorption removal apparatus according to claim 3,
When the radioactive polluted water is passed in order from the first stage adsorption tower and the adsorption amount of the radionuclide of the first stage adsorption tower reaches a predetermined adsorption quantity, the water flow is stopped and the first stage adsorption tower The adsorbent in the adsorption tower is replaced with an unused adsorbent, and the second stage adsorption tower is used as the first stage adsorption tower, and the adsorption tower in which the adsorbent is exchanged is used as the last stage adsorption tower. An adsorption removal method that performs adsorption removal of radionuclides by a merry-go-round system that repeats the process of passing water sequentially. The adsorption removal method according to claim 4, wherein the supply pipe, the fresh water generation unit, and the dilution pipe are modularized.

Images