JP2017148692A - Pure water production device and method for producing pure water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pure water production device capable of producing high purity pure water, from raw water containing vanadium at a high concentration, by efficiently removing the vanadium.SOLUTION: Provided is a pure water production device 2 comprising: a first cation exchange resin column 3 filled with a high crosslinking degree gel type cation exchange resin; a decarbonation column 4: an anion exchange resin column 5 filled with a gel type anion exchange resin; and a second cation exchange resin column 6 filled with a porous type cation exchange resin. The water W1 to be treated obtained by treating raw water W by a pretreatment system is subjected to downward circulation water treatment by the first cation exchange resin column 3, and next, this cation-treated water W2 is fed to the upper part of the decarbonation column 4. Successively, the decarbonated water W3 is subjected to upward circulation water treatment in the anion exchange resin column 5. Then, the anion-treated water W4 is subjected to downflow circulation water treatment by the second cation exchange resin column 6 to obtain pure water W5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pure water production apparatus and a pure water production method for producing pure water from raw water containing vanadium, and more particularly to pure water production capable of efficiently removing vanadium from raw water containing vanadium at a high concentration. The present invention relates to an apparatus and a method for producing pure water.

  Vanadium is used as a catalyst, and is contained in ash such as coal and petroleum, as well as in certain natural waters. Vanadium-containing water contains various forms of vanadium depending on its origin. Vanadium forms various compounds depending on the valence of -I to + V, and each compound has one in which vanadium dissociates into a cation and one in which it dissociates into an anion. When vanadium is contained in an ionized or ionizable state like a soluble salt, vanadium can be removed by ion exchange.

  When pure water is produced using industrial water or tap water containing 1 to 10 ppb or more of vanadium as described above, cation exchange is performed after pretreatment such as coagulation and filtration and dechlorination with activated carbon. Pure water is produced by removing vanadium by treatment with a pure water production apparatus such as a three-bed, four-column type equipped with a resin tower and an anion exchange resin tower. However, when the vanadium-containing water is treated with an ion exchange device, the resin component is eluted from the ion exchange resin due to the influence of the catalytic action of vanadium, which adversely affects water quality such as an increase in TOC. Accordingly, as described in Patent Document 1, it is known to treat vanadium-containing water using a cation exchange resin having a high degree of crosslinking in the cation exchange resin tower serving as the first tower as a countermeasure. And as a pure water manufacturing apparatus using this highly crosslinked degree cation exchange resin, a highly crosslinked degree gel type cation exchange resin tower, a gel type anion exchange resin tower, and a highly crosslinked degree gel type cation exchange resin tower are provided, if necessary. What provided the decarbonation apparatus is used.

JP 2002-346559 A

  By the way, high water quality is recently demanded mainly in the field of electronic components. For example, high-purity water quality having a specific resistance value of treated water of 18 MΩ · cm or more and TOC of 50 ppb or less has been demanded. However, when vanadium-containing water is used as raw water, even if a three-bed, four-column pure water production apparatus is configured using a highly crosslinked cation exchange resin as described in Patent Document 1, the specific resistance When the value is about 16 to 17 MΩ · cm, it is difficult to obtain a water quality of 18 MΩ · cm or more, and the TOC is not sufficiently reduced.

  The present invention has been made in view of the above problems, and a pure water production apparatus and pure water capable of producing high purity pure water by efficiently removing vanadium from raw water containing a high concentration of vanadium. An object is to provide a manufacturing method.

  In view of the above-mentioned object, first, the present invention provides a first cation exchange resin tower, a decarboxylation apparatus, an anion exchange resin tower, and a second cation exchange resin tower that are brought into contact with water to be treated containing vanadium. In this order, the first cation exchange resin tower is filled with a highly crosslinked gel cation exchange resin, the anion exchange resin tower is filled with a gel anion exchange resin, and a second cation is obtained. Provided is a pure water production apparatus characterized in that an exchange resin tower is filled with a porous cation exchange resin (Invention 1).

  The water quality of 18 MΩ · cm or more is also achieved in a conventional three-bed, four-column pure water production apparatus equipped with a high-crosslinking degree gel-type cation exchange resin tower, a gel-type anion exchange resin tower, and a high-crosslinking degree gel-type cation exchange resin tower. As a result of studying the cause of not being able to obtain, it is caused by a slight eluate from the ion exchange resin due to the effect of vanadium, and in particular, a trace amount of organic matter eluted from the anion exchange resin of the gel type anion exchange resin tower is gel type. It was found that the reason was that it could not be removed by the cation exchange resin tower. Therefore, as a result of examining a method for quickly removing the cationic eluate from the anion exchange resin, a porous cation exchange resin was used as a cation exchange resin to be packed in the cation exchange resin tower at the latter stage of the gel type anion exchange resin tower. It was found that the specific resistance of treated water can be greatly improved if used. Based on these findings, the present inventors have conceived the present invention. According to this invention (Invention 1), vanadium is efficiently removed from raw water containing vanadium at a high concentration to obtain high-purity pure water. Can be manufactured.

  In the above invention (Invention 1), at least one of the highly crosslinked gel type cation exchange resin, gel type anion exchange resin, and porous type cation exchange resin is washed in advance so that the TOC elution amount is 30 ppb or less. (Invention 2)

  According to this invention (Invention 2), by washing these ion exchange resins, elution due to the effect of vanadium can be reduced by removing unpolymerized components contained in the ion exchange resin. Can be reduced.

  Secondly, the present invention treats water to be treated containing vanadium with a highly crosslinked gel type cation exchange resin and then decarboxylates the treated water into a gel type anion exchange resin and a porous type cation exchange resin tower in order. Provided is a pure water production method characterized in that pure water is obtained by contact (Invention 3).

  According to this invention (Invention 3), when the water to be treated is treated with a highly crosslinked gel-type cation exchange resin to remove the cation component, the pH becomes less than 7. Therefore, by decarboxylation, inorganic carbonate in the raw water to be treated is removed. The component is removed to some extent to increase the pH to facilitate removal of the anion component, and then the anion component is removed with a gel type anion exchange resin. At this time, a small amount of organic substance is eluted from the gel-type anion exchange resin due to the effect of vanadium in the water to be treated. This organic substance can be quickly removed by the porous cation exchange resin, greatly increasing the specific resistance of the treated water. Can be improved.

  In the said invention (invention 3), at least 1 sort (s) of the said highly crosslinked degree gel type cation exchange resin, a gel type anion exchange resin, and a porous type cation exchange resin was wash | cleaned beforehand so that TOC elution amount might be 30 ppb or less (Invention 4)

  According to this invention (invention 4), by washing these ion exchange resins, elution due to the effect of vanadium can be reduced by removing unpolymerized components contained in the ion exchange resin. Can be reduced.

  In the said invention (invention 3 and 4), it is preferable that the said to-be-processed water contains 1-10ppb of vanadium (invention 5).

  According to this invention (invention 5), high-purity pure water can be produced even if the water to be treated contains vanadium at a high concentration by performing the treatment as described above.

  According to the present invention, treated water containing vanadium is treated with a highly crosslinked gel cation exchange resin and then decarboxylated, and the treated water is sequentially contacted with the gel anion exchange resin and the porous cation exchange resin tower. Since pure water is obtained, cationic and anionic vanadium can be removed, and the eluate of the gel-type anion exchange resin can be quickly removed by the porous cation exchange resin. As a raw water, for example, it is possible to produce high-purity pure water having a specific resistance of 18 MΩ · cm or more and a TOC of 50 ppb or less.

It is a flowchart which shows the pure water manufacturing apparatus by one Embodiment of this invention.

  Hereinafter, a pure water production apparatus and a pure water production method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing a pure water production apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a pretreatment system, 2 is a pure water production apparatus, and the pretreatment system 1 is a general system configuration. For example, it is composed of an agglomeration / pressure levitation device, a filtration device, and an activated carbon tower. The pure water production apparatus 2 includes a first cation exchange resin tower 3 filled with a highly crosslinked gel type cation exchange resin, a decarboxylation tower 4 as a decarboxylation apparatus, and an anion exchange filled with a gel type anion exchange resin. It consists of a resin tower 5 and a second cation exchange resin tower 6 filled with a porous cation exchange resin.

  The first cation exchange resin tower 3 is connected to the pretreatment system 1 via the first flow path 11 at the upper part of the first cation exchange resin tower 3, and the second flow path provided at the lower part. The decarbonation tower 4 is a downward circulating water system for taking out treated water from 12, and is connected to the upper part of the decarbonation tower 4 via the first cation exchange resin tower 3 and the second flow path 12. The water is sprayed from the top to the bottom. The anion exchange resin tower 5 is connected to the decarboxylation tower 4 via the third flow path 13 at the lower part of the anion exchange resin tower 5, and treated water is supplied from the fourth flow path 14 provided at the upper part. It becomes the upward circulation water system to take out. Further, the second cation exchange resin tower 6 is connected to the anion exchange resin tower 5 via the fourth flow path 14 at the upper part of the second cation exchange resin tower 6, and the downward flowing water system is taken out from the lower part. It has become.

  In the system having the above-described configuration, the cation exchange resin packed in the first cation exchange resin tower 3 includes a strong acid cation exchange resin having a sulfonic group as a cation exchange group and a weak acid cation having a carboxylic acid group. Any exchange resin can be used, and a gel-type resin is used in that the PSA is less eluted. In the cation exchange resin, divinylbenzene serves as a cross-linking agent, and a chain structure is cross-linked to form a network resin. The more divinylbenzene, the more chain branches and the denser the structure, and the smaller the divinylbenzene, the larger the network with less branching. Resins used for normal water treatment have a degree of crosslinking of about 8% and are called standard crosslinked resins. In contrast, in the present embodiment, a highly crosslinked resin having a crosslinking degree of 9% or more, preferably 10 to 50%, particularly preferably 12 to 16% is used. By using such a highly crosslinked gel type cation exchange resin and contacting with vanadium-containing water, even if vanadium is concentrated in the resin, deterioration of the resin is prevented, and the cation exchange ability is not lowered.

  Moreover, as an anion exchange resin with which the anion exchange resin tower 5 is filled, a gel type resin is used in that the elution of PSA is small. Strongly basic anion exchange resin having quaternary ammonium group such as trimethylammonium group or dimethylethanolammonium group on styrene skeleton based on styrene-divinylbenzene copolymer, styrene-divinylbenzene copolymer, etc. Any of weakly basic anion exchange resin anion exchange resin having a primary to tertiary amino group as a functional group can be used for styrene skeleton or polyacrylate ester skeleton, but strong basic anion exchange resin is preferred. Can be used. The exchange group of the anion exchange resin is preferably in the OH form.

  Furthermore, the cation exchange resin filled in the second cation exchange resin tower 6 is a porous cation exchange resin. Porous cation exchange resins have a larger pore diameter formed on the surface or inside of the resin than gel type, and therefore the organic matter adsorption rate is fast, while elution from the resin itself tends to be more elution than the gel type. There is no porous type cation exchange resin having a high degree of crosslinking, and the degree of crosslinking is about 8%.

  As the above-mentioned high cross-linking degree gel type cation exchange resin, gel type anion exchange resin, and porous type cation exchange resin, it is preferable to use those subjected to conditioning (washing). Here, the term “conditioning” refers to washing with a chemical such as an acid, pure water, pure water, etc., because a new ion exchange resin always contains an unpolymerized component. Such conditioning is performed so that the TOC elution amount becomes a certain value (for example, 30 ppb) or less. In particular, since the porous cation exchange resin packed in the second cation exchange resin tower 6 is easily eluted from the resin itself as described above, it is preferable to use a cation exchange resin that is conditioned to reduce elution of unpolymerized components and the like.

  Next, a method for producing pure water using the pure water producing apparatus having the above-described configuration will be described. First, the raw water W is treated with the pretreatment system 1 to be treated water (pretreated water) W1, and this treated water W1 is passed through the first flow path 11 to the upper part of the first cation exchange resin tower 3. The cation is exchanged and adsorbed by passing through a highly crosslinked gel type cation exchange resin bed packed in the first cation exchange resin tower 3 in a downward flow. At this time, the inside of the column becomes acidic with a pH of about 2.5 to 5.5, so that the exchange adsorption efficiency of cationic vanadium is increased. Here, in the present embodiment, the highly crosslinked gel type cation exchange resin packed in the first cation exchange resin tower 3 is less susceptible to deterioration by vanadium, and therefore there is little elution due to modification of the cation exchange resin, The cation exchange capacity is kept high.

  The cation-treated water W2 obtained here is supplied from the second channel 12 to the upper part of the decarboxylation tower 4, and water is sprayed from the upper part of the tower to remove the carbonic acid in the cation-treated water W2 and make the pH weakly acidic. Raise to the area.

  Subsequently, decarbonated water W3 is supplied from the third channel 13 to the lower part of the anion exchange resin tower 5 and passed through the gel type anion exchange resin bed filled in the anion exchange resin tower 5 in an upward flow. , The anion is exchange adsorbed. At this time, since the decarbonated water W3 contains anionic vanadium that could not be removed by the first cation exchange resin tower 3, the gel type anion exchange resin is deteriorated by the vanadium, and this deterioration is caused. TOC is slightly eluted.

  Therefore, the anion-treated water W4 is supplied from the fourth channel 14 to the upper portion of the second cation exchange resin tower 6 and flows downward in the porous cation exchange resin bed filled in the second cation exchange resin tower 6. The gel-type anion exchange resin eluate is removed. Since the porous cation exchange resin has a large pore diameter formed on the surface or inside of the resin, it can quickly adsorb cationic organic substances. The porous cation exchange resin is more easily eluted from the resin itself than the gel cation exchange resin, but the anion-treated water W4 is not only substantially free of vanadium but also has a good water quality. Elution from the cation exchange resin is suppressed. In particular, in the present embodiment, by using a porous cation exchange resin that has been conditioned so that the TOC elution amount is 30 ppb or less as described above, the elution of unpolymerized components and the like can be reduced. preferable.

  The conditions for water flow in the pure water production process as described above can be the same as those in the treatment by normal ion exchange. The water flow rate varies depending on the vanadium concentration of the water to be treated W1, the required water quality, and the like, but is generally 5 to 100 L / L-Resin / hr, particularly 5 to 50 L / L-Resin / hr.

  By performing such treatment, it is possible to obtain pure water W5 having high purity. Specifically, it is possible to produce high-purity pure water having a specific resistance of 18 MΩ · cm or more and a TOC of 50 ppb or less.

  Such a method for producing pure water according to this embodiment is suitable for treating raw water containing vanadium at a high concentration, and particularly suitable for treating raw water containing vanadium in an amount of 1 to 10 ppb or 10 ppb or more.

  As mentioned above, although this invention has been demonstrated based on the said embodiment, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible. For example, the first cation exchange resin tower 3 may be a mixed bed of a strong acid cation exchange resin and a weak acid cation exchange resin, or in some cases, a strong base anion exchange resin is disposed after the strong acid cation exchange resin. It may be a mixed floor. The anion exchange resin tower 5 may be a mixed bed of a strong basic anion exchange resin and a weak basic anion exchange resin. Furthermore, the decarboxylation apparatus does not need to be the decarboxylation tower 4 as in this embodiment, and a degassing membrane or the like can be used.

  EXAMPLES Hereinafter, although a comparative example and an Example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.

[Example 1]
In the three-bed, four-column type pure water production apparatus shown in FIG. 1, the first cation exchange resin column 3 is filled with a highly crosslinked gel type cation exchange resin (UPK-12 manufactured by Kurita Kogyo Co., Ltd.), and an anion exchange resin is obtained. The column 5 was filled with a gel-type anion exchange resin (UPA11 manufactured by Kurita Kogyo Co., Ltd.), and the second cation exchange resin tower 6 was filled with a porous cation exchange resin (UPK-14 manufactured by Kurita Kogyo Co., Ltd.). . The porous cation exchange resin was conditioned in advance so that the TOC elution amount was 30 ppb or less.

  Kumamoto Prefecture water (raw water) W containing 1 to 10 ppb of vanadium was treated with a pretreatment system 1 composed of an agglomeration / pressure flotation device, a filtration device and an activated carbon tower to obtain treated water W1. When this treated water W1 was subjected to water treatment at a water flow rate of 20 L / L-Resin / hr with the above-described three-bed, four-column pure water device, pure water W5 having a specific resistance of 18 MΩ · cm or more and TOC of 50 ppb or less was obtained. It was possible to manufacture stably.

[Comparative Example 1]
In Example 1, a pure water production apparatus was configured in the same manner except that the second cation exchange resin tower 6 was filled with a highly crosslinked gel type cation exchange resin (UPK-14 manufactured by Kurita Kogyo Co., Ltd.). The water W1 was passed through. The water quality of the pure water W5 produced by this pure water device is about TOC 70-100 ppb with a specific resistance value of about 16-17 MΩ · cm, and water quality with a specific resistance value of 18 MΩ · cm or more could not be stably obtained. .

DESCRIPTION OF SYMBOLS 1 ... Pretreatment system 2 ... Pure water manufacturing apparatus 3 ... 1st cation exchange resin tower 4 ... Decarbonation tower 5 ... Anion exchange resin tower 6 ... 2nd cation exchange resin tower W ... Raw water W1 ... Water to be treated (previous Treated water)
W2 ... Cation treated water W3 ... Decarbonated water W4 ... Anion treated water W5 ... Pure water

Claims (5)

A pure water production apparatus comprising a first cation exchange resin tower in contact with water to be treated containing vanadium, a decarboxylation apparatus, an anion exchange resin tower, and a second cation exchange resin tower in this order,
The first cation exchange resin tower is filled with a highly crosslinked gel cation exchange resin, the anion exchange resin tower is filled with a gel anion exchange resin, and the second cation exchange resin tower is filled with a porous cation exchange resin. An apparatus for producing pure water.   The at least one of the highly crosslinked gel type cation exchange resin, gel type anion exchange resin, and porous type cation exchange resin is washed in advance so that the TOC elution amount is 30 ppb or less. The pure water manufacturing apparatus according to 1.   The treated water containing vanadium is treated with a highly crosslinked gel cation exchange resin and then decarboxylated, and the treated water is sequentially brought into contact with the gel anion exchange resin and the porous cation exchange resin tower to obtain pure water. A method for producing pure water.   The at least one of the highly crosslinked gel type cation exchange resin, gel type anion exchange resin, and porous type cation exchange resin is washed in advance so that the TOC elution amount is 30 ppb or less. 3. The method for producing pure water according to 3.   The method for producing pure water according to claim 4 or 5, wherein the water to be treated contains 1 to 10 ppb of vanadium.

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