JP2013010097A - Strong basic anion exchange resin, condensate demineralization method, and condensate demineralizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anion exchange resin which is excellent in an eluate adsorption performance from a cation exchange resin suitably used for a condensate demineralizer, etc., in a power plant requiring a water quality of higher purity, and has a strength that can sufficiently endure the actual use in a plant.SOLUTION: The strong basic anion exchange resin is a gel-type resin, and has an absorption amount of polystyrenesulfonic acid, measured by a specific method, of 0.25 mmol/L-resin or more and an average particle diameter of 300 μm or larger. A BET specific surface area is preferably less than 1 m/g and an absorbance measured by a specific method is 0.10 or more and 0.44 or less.

Description

  The present invention relates to a novel strongly basic anion exchange resin, a method of using this strongly basic anion exchange resin, a mixed bed ion exchange resin containing this strongly basic anion exchange resin, and this strongly basic anion exchange resin. The present invention relates to a condensate demineralization method and a condensate demineralization apparatus using a resin. More specifically, the present invention relates to a strongly basic anion exchange resin suitable for use in a mixed bed form with a cation exchange resin in a condensate desalination apparatus of a power plant, and the strongly basic anion exchange resin. , A mixed bed ion exchange resin containing this strongly basic anion exchange resin, a condensate demineralization method and a condensate demineralization apparatus using this strongly basic anion exchange resin.

  By using the strongly basic anion exchange resin of the present invention for a condensate demineralizer in a power plant that requires high-purity water quality, the operational stability of the plant can be enhanced.

In boilers and power generation facilities, various types of hot water and room temperature water are required to be desalted and purified.
For example, there are two types of nuclear power plants, PWR type (pressurized water type) and BWR type (boiling water type). In either case, the cooling water circulation system is filled with ion exchange resin. A salt device is installed, and this is caused by suspended metal corrosion products that elute from metal materials such as pipes in the desalination treatment by this condensate demineralizer and leakage of seawater used as cooling water. Salt is removed, and the quality of the system water is maintained at high purity.
Even in a thermal power plant, the steam after driving the power generation turbine is cooled to condensate, and this condensate is recycled and used, but the condensate circulating in the system is ionic impurities and suspended metals. Condensate demineralizers are installed to remove these because they are contaminated with corrosion products.

  By the way, ion exchange resins are roughly classified into “gel type” and “porous (porous) type” according to their structural properties, and each includes a cation exchange resin and an anion exchange resin.

  In condensate demineralizers at power plants, cation exchange resins and anion exchange resins are usually used in a mixed bed form. Conventionally, there are various types of condensate demineralizers at each power plant. Combination resins have been proposed. For example, in a PWR (pressurized water) nuclear power plant, a combination of a porous cation exchange resin and a porous anion exchange resin, and in a BWR (boiling water) nuclear power plant, a gel cation exchange resin and a gel. A combination of type anion exchange resins has been mainly used.

However, in recent years, from the viewpoint of plant equipment and safety, it has been required to maintain the quality of the system water with a higher purity. In particular, it is important to manage the ion concentration in the reactor water, especially the sulfate ion concentration. It is becoming.
Much of the origin of this sulfate ion is a cation exchange resin used in condensate demineralizers in power plants. That is, polystyrene sulfonic acid having a molecular weight of several hundred to several tens of thousands elutes from the cation exchange resin due to oxidative deterioration of the base structure, and this polystyrene sulfonic acid becomes a factor for increasing the sulfate ion concentration of the treated water.

For this reason, cation exchange resins have a high degree of crosslinking to increase oxidation resistance and reduce the amount of eluted sulfate ions (for example, Patent Documents 1 and 2). A method of adsorbing an eluate from a resin on an anion exchange resin (for example, Patent Documents 3 and 4) is known.
An anion exchange resin with improved ability to adsorb effluent from the cation exchange resin has also been proposed (for example, Patent Document 5).

Japanese Patent Laid-Open No. 11-352283 JP 2007-64646 A JP 2009-281873 A JP 2009-279519 A Japanese Patent Laid-Open No. 2007-216094

  As seen in Patent Document 5 and the like, the anion exchange resins with improved adsorption ability of the eluate from the cation exchange resin, which have been developed and provided in the past, are porous and practically strong. There was a problem. That is, the porous ion exchange resin has a lower physical strength (resin crushing strength) and a smaller ion exchange capacity than the gel ion exchange resin.

  For this reason, it has been desired to develop a novel anion exchange resin that is excellent in the adsorption performance of the effluent from the cation exchange resin and that has sufficient strength to withstand actual use in a plant. Furthermore, in order to meet the demand for higher water quality, which is increasing year by year, further improvement of the anion exchange resin itself is required.

  The present invention has been devised in view of the above circumstances, and is suitable for use in a condensate demineralizer and the like in a power plant where high-purity water quality is required. It is an object of the present invention to provide a novel anion exchange resin having excellent adsorption performance and strength sufficient to withstand actual use in a plant. The present invention also provides a method of using such a strongly basic anion exchange resin, a mixed bed ion exchange resin containing this strongly basic anion exchange resin, and condensate dewatering using this strongly basic anion exchange resin. A salt method and a condensate demineralizer are provided.

As a result of intensive studies to solve the above problems, the present inventor has found that a specific gel-type strongly basic anion exchange resin can solve the above problems.
That is, the gist of the present invention is the following [1] to [10].

[1] Strongly basic anion which is a gel-type resin and has an adsorption amount of polystyrenesulfonic acid measured by the following method of 0.25 mmol / L-resin or more and an average particle diameter of 300 μm or more Exchange resin.
<Measurement method of polystyrene sulfonic acid adsorption amount>
Polystyrene sulfonic acid “Polynas PS-1” manufactured by Tosoh Organic Chemical Co., Ltd. was passed through a strongly acidic cation exchange resin to form H, and then the polystyrene sulfonic acid was adjusted to a concentration of 0.01 mmol / L as the H concentration. Adjust the aqueous solution.
The column is filled with a strongly basic anion exchange resin that has been adjusted to OH form by treatment with an aqueous sodium hydroxide solution, washed with water, and then passed through a polystyrenesulfonic acid aqueous solution with a concentration adjusted to give polystyrene equivalent to 50% breakthrough. The amount of sulfonic acid adsorbed is determined and taken as the amount of polystyrene sulfonic acid adsorbed by the strongly basic anion exchange resin.

[2] The strongly basic anion exchange resin according to [1], wherein a specific surface area measured by the following method is less than 1 m ² / g.
<Method for measuring specific surface area>
The strongly basic anion exchange resin is dried by heating under reduced pressure under a vacuum of 50 ° C., an adsorption isotherm (adsorbed gas: krypton) is measured under liquid nitrogen, and a specific surface area is calculated by performing a BET plot.

[3] The strongly basic anion exchange resin according to [1] or [2], wherein the absorbance measured by the following method is 0.10 or more and 0.44 or less.
<Measurement method of absorbance>
In an ultraviolet / visible spectrum measuring apparatus using an integrating sphere as a detector, a cylindrical cell with a screw cap is densely filled with a strongly basic anion exchange resin, and the reflectance of light having a wavelength of 800 nm is measured. Absorbance is determined by Munch conversion. Separately, the same cell is filled with barium sulfate, the same measurement and conversion are performed, and the calculated absorbance is taken as the absorbance of the cell. A value obtained by subtracting the absorbance of the cell from the absorbance when the cell is filled with the strongly basic anion exchange resin is determined as the absorbance of the strongly basic anion exchange resin.

[4] A method for using a strongly basic anion exchange resin, wherein the strongly basic anion exchange resin according to any one of [1] to [3] is used in a mixed bed form with a cation exchange resin.

[5] A mixed bed ion exchange resin comprising the strongly basic anion exchange resin according to any one of [1] to [3] and a cation exchange resin.

[6] The mixed bed ion exchange resin according to [5], wherein the degree of crosslinking of the cation exchange resin is 8 to 20% by weight.

[7] In a condensate desalination method for desalinating condensate of a power plant with an ion exchange resin, the strongly basic anion exchange resin according to any one of [1] to [3] is used as the ion exchange resin. Condensate desalination method to be used.

[8] In a condensate demineralization method in which the condensate of the power plant is demineralized with an ion exchange resin, the mixed bed ion exchange resin according to [5] or [6] is used as the ion exchange resin. Desalination method.

[9] In a condensate demineralizer comprising an ion exchange resin tower for desalting the condensate of a power plant, the ion exchange resin tower is a strongly basic anion according to any one of [1] to [3] Condensate demineralizer containing exchange resin.

[10] In a condensate demineralization apparatus including an ion exchange resin tower for desalinating condensate in a power plant, the ion exchange resin tower includes the mixed bed ion exchange resin according to [5] or [6]. Condensate demineralizer.

The strongly basic anion exchange resin of the present invention has the advantages of a gel-type resin that has a large ion exchange capacity per volume and a high physical strength (crushing strength of the resin) as compared with the porous type. It also has the advantage of a porous resin that the amount of adsorbate adsorbed from a cation exchange resin such as the above is high. For this reason, the strongly basic anion exchange resin of the present invention has sufficient strength for use in various plants. By using this together with the cation exchange resin, polystyrene sulfone from the cation exchange resin can be obtained. The eluate such as acid can be efficiently adsorbed and removed to improve the quality of the treated water.
Therefore, the use of the strongly basic anion exchange resin of the present invention in a condensate demineralizer in a power plant that requires high-purity water quality can sufficiently enhance the operation efficiency of the plant and its stability. Can do.

  Hereinafter, embodiments of the present invention will be described in detail.

[Strongly basic anion exchange resin]
The strongly basic anion exchange resin of the present invention is a gel-type resin, and the polystyrenesulfonic acid adsorption amount measured by a specific method is 0.25 mmol / L-resin or more, and the average particle size is 300 μm. It is the above.

  As described above, ion exchange resins are roughly classified into “gel type” and “porous (porous) type” types according to their structural properties. As a method for discriminating them, there is a method of visually discriminating transparent spheres as gel type resins and opaque spheres as porous type resins as described in JP-A-2009-279519.

The gel type resin has the advantages that the ion exchange capacity per volume is large and the physical strength (crushing strength of the resin) is high as compared with the porous type.
On the other hand, since the gel type resin generally has a specific surface area smaller than that of the porous type resin, there is no problem in adsorbing ordinary inorganic ions (such as chloride ions). Is disadvantageous. That is, as described above, polystyrene sulfonic acid having a molecular weight of several hundred to several tens of thousands elutes from the cation exchange resin due to oxidative degradation of the base structure, etc., but the ability to adsorb and remove this is a gel type resin. Low compared to

As a result of intensive studies, the present inventor has combined the advantage that the gel type resin has a large ion exchange capacity and a high physical strength (resin crushing strength) and the advantage that the porous type polystyrene sulfonic acid has a high adsorption capacity. We have developed a resin that has led to the present invention.
That is, a general gel type resin synthesizes a cross-linked copolymer by copolymerizing a monovinyl aromatic monomer such as styrene and a cross-linkable aromatic monomer such as divinylbenzene by suspension polymerization or the like. Introduced and manufactured. On the other hand, although the method for synthesizing the porous resin differs depending on each manufacturer, in general, an inert substance (hereinafter sometimes referred to as “porous agent”) is added during suspension polymerization, and after the polymerization, A method of removing this is adopted. Examples of the porosifying agent include organic solvents such as toluene, pentanol, s-butanol, heptane, and isooctane, or dilutions of linear polymers, specifically, toluene in which polystyrene is dissolved. At this time, the abundance of the porous portion is determined by the balance between the degree of crosslinking (% by weight of the crosslinkable aromatic monomer with respect to the total weight of the monovinyl aromatic monomer and the crosslinkable aromatic monomer), the kind of the porous agent, and the amount added. It is determined.
The present inventor adds a general porous resin when synthesizing a crosslinked copolymer by polymerizing a monovinyl aromatic monomer such as styrene and a crosslinkable aromatic monomer such as divinylbenzene. A strongly basic anion that combines the advantages of using a porosifying agent as described above and adjusting the amount of addition, which is a gel-type resin and has a high ability to adsorb polystyrene sulfonic acid in a porous resin. It led to the development of exchange resin.

<Gel type>
The strongly basic anion exchange resin of the present invention is characterized by being a gel type.

As described above, ion exchange resins are roughly classified into “gel type” and “porous type” types according to their structural properties.
Since the strongly basic anion exchange resin of the present invention is a gel type, the ion exchange capacity per volume is larger and the physical strength (crushing strength) is higher than that of the porous resin.

<Average particle size>
The strongly basic anion exchange resin of the present invention is characterized by having an average particle size of 300 μm or more.

If the average particle size of the strongly basic anion exchange resin is smaller than 300 μm, the pressure loss during water flow in the resin packed bed will increase, and a large-capacity pump will be required for liquid feeding, or a pressure vessel should be used. The average particle size needs to be 300 μm or more. However, if the average particle size of the strongly basic anion exchange resin is too large, there is a problem that the surface area per volume is reduced and the reaction rate of ion exchange is reduced, or it is difficult to maintain the strength of the resin. For this reason, the average particle size of the strongly basic anion exchange resin is preferably 300 to 1000 μm, particularly preferably 400 to 800 μm.
In addition, the average particle diameter of the strongly basic anion exchange resin is a value measured by the method described in the section of Examples described later.

<Polystyrenesulfonic acid adsorption amount>
The strongly basic anion exchange resin of the present invention is characterized in that the polystyrenesulfonic acid adsorption amount measured by a specific method is 0.25 mmol / L-resin or more.

  When the polystyrenesulfonic acid adsorption amount of the strongly basic anion exchange resin is less than 0.25 mmol / L-resin, the adsorption removal performance of the effluent from the cation exchange resin is insufficient. When the polystyrene sulfonic acid adsorption amount is 0.25 mmol / L-resin or more, the effluent such as polystyrene sulfonic acid from the cation exchange resin can be efficiently adsorbed and removed to improve the quality of the treated water.

  The polystyrene sulfonic acid adsorption amount of the strongly basic anion exchange resin is preferably as high as possible, and more preferably 0.27 mmol / L-resin or more, and particularly preferably 0.29 mmol / L-resin or more. Furthermore, this polystyrene sulfonic acid adsorption amount is usually 0.5 mmol / L-resin or less.

  In addition, the polystyrene sulfonic acid adsorption amount of the strongly basic anion exchange resin is more specifically measured by the method described in the section of Examples described later.

<Specific surface area>
The strongly basic anion exchange resin of the present invention preferably has a specific surface area of less than 1 m ² / g.

When the specific surface area of the strongly basic anion exchange resin is 1 m ² / g or more, the physical strength (crushing strength) of the resin is lowered due to its porosity. When the specific surface area of the strongly basic anion exchange resin is less than 1 m ² / g, the physical strength of the resin is secured, which is preferable. Further, the lower limit of the specific surface area of the strongly basic anion exchange resin is not particularly limited, but is the measurement limit (usually 0.01 m ² / g).

  The specific surface area of the strongly basic anion exchange resin is a value measured by the method described in the Examples section described later.

<Absorbance>
The strongly basic anion exchange resin of the present invention preferably has an absorbance (hereinafter sometimes referred to as “specific absorbance”) measured by a specific method of 0.10 to 0.44.

  If the specific absorbance of the strongly basic anion exchange resin is too small, the transparency is low, which means that it is a porous type rather than a gel type. On the other hand, the one having a large specific absorbance has the transparency of the gel type resin, but if the specific absorbance is too large, the polystyrene sulfonic acid adsorption amount decreases. When the specific absorbance of the strongly basic anion exchange resin is in the above range, the polystyrenesulfonic acid adsorption amount and physical strength (resin crushing strength) can be made sufficient, which is preferable. The specific absorbance of the strongly basic anion exchange resin is more preferably 0.20 to 0.42, and particularly preferably 0.30 to 0.40.

  The specific absorbance of the strongly basic anion exchange resin is more specifically measured by the method described in the Examples section described later.

In the examples described later, the sample having a particle size adjusted to about 600 μm is used as a sample for specific absorbance measurement. However, in the case of a sample having a particle size other than 600 μm (however, it must be a uniform particle size) The value of the converted absorbance obtained from the particle size Rμm and the actually measured absorbance by the following formula may be used as the specific absorbance.
For example, an anion exchange resin having an average particle size (R) of 450 μm or less and a highly uniform particle size distribution, such as an anion exchange resin that is difficult to adjust the particle size to about 600 μm, can be calculated using the following formula: The measured absorbance can be corrected to the specific absorbance of the sized product of about 600 μm.
Equivalent absorbance = actual absorbance × (600 / R)

<Physical strength (resin crushing strength)>
The strong basic anion exchange resin of the present invention has a practical requirement that the physical strength (crushing strength of the resin) measured by the method described in the section of Examples below is 350 g / grain or more. It is preferable for satisfying the strength. The crushing strength is preferably as large as possible, and more preferably 400 g / grain or more.

<Other physical properties>
The strong basic anion exchange resin of the present invention has a water content of 40 to 60% measured by the method described in the Examples section described later, and ensures the desalting performance of the ion exchange resin. Is preferable. If the water content is too small, the substance diffusion in the ion exchange resin is suppressed, so that the desalting property is inhibited. If it is too much, the exchange capacity per volume of the ion exchange resin is lowered and the desalting ability is lowered. A more preferable water content of the strongly basic anion exchange resin is 45 to 55%.

  The strongly basic anion exchange resin of the present invention preferably has an anion exchange performance with a neutral salt decomposition ability of 1.1 meq / mL or more as measured by the method described in the Examples section below. The neutral salt decomposition ability is preferably as large as possible, more preferably 1.2 meq / mL or more.

<Manufacturing method>
The method for producing a strongly basic anion exchange resin of the present invention is a method capable of producing a gel-type strongly basic anion exchange resin satisfying the polystyrene sulfonic acid adsorption amount and the average particle size defined in the present invention. There is no particular limitation, but a specific example is as follows.

  The production process of the strongly basic anion exchange resin of the present invention is roughly divided into (a) a polymerization process, (b) a haloalkylation process, and (c) an amination process.

  (A) In the polymerization step, when a cross-linked copolymer is produced by copolymerizing a mixture of a monovinyl aromatic monomer and a cross-linkable aromatic monomer (hereinafter sometimes referred to as “monomer mixture”), Copolymerization is performed by adding an agent.

  Examples of the monovinyl aromatic monomer include alkyl-substituted styrenes such as styrene, methylstyrene, and ethylstyrene, and halogen-substituted styrenes such as bromostyrene. These may be used alone or in combination of two or more. Among the monovinyl aromatic monomers, styrene or a monomer mainly composed of styrene is preferable.

  Moreover, as a crosslinkable aromatic monomer, divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, divinylxylene, divinylbiphenyl, bis (vinylphenyl) methane, bis (vinylphenyl) ethane, bis (vinylphenyl) propane, And bis (vinylphenyl) butane. These may be used alone or in combination of two or more. Among them, divinylbenzene is preferable as the crosslinkable aromatic monomer. In addition, although industrially produced divinylbenzene usually contains a large amount of ethyl vinylbenzene (ethylstyrene) as a by-product, such divinylbenzene can also be used in the present invention.

The use amount of the crosslinkable aromatic monomer is usually 0.5 to 30% by weight, preferably 2.5 to 12% by weight, more preferably based on the weight of the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer. 4 to 10% by weight. As the amount of the crosslinkable aromatic monomer used increases and the degree of crosslinking increases, there is a problem that the amount of ion exchange groups introduced into the resulting anion exchange resin decreases. In addition, the crushing strength of the anion exchange resin particles tends to be low.
In order to adjust the degree of crosslinking, there is also a method of using a post-crosslinking reaction as a side reaction of haloalkylation in the latter (b) haloalkylation step.

  The copolymerization reaction of the monovinyl aromatic monomer and the crosslinkable aromatic monomer can be performed based on a known technique using a radical polymerization initiator.

  As the radical polymerization initiator, one or more of dibenzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile and the like are used, and the amount used is usually monovinyl aromatic. It is 0.05 weight% or more and 5 weight% or less with respect to the weight of the mixture of a monomer and a crosslinkable aromatic monomer.

  As the porosifying agent, it dissolves in the monomer mixture, but the obtained cross-linked copolymer does not swell (hereinafter sometimes referred to as “poor solvent”), or is dissolved in the monomer mixture. A substance that swells the resulting crosslinked copolymer (hereinafter sometimes referred to as “good solvent”) can be used.

  Specifically, a water-insoluble organic compound can be used as the substance (poor solvent) that dissolves in the monomer mixture but does not swell the resulting crosslinked copolymer. Examples of the water-insoluble organic compound include linear or branched hydrocarbons, linear or branched water-insoluble alcohols, polymers and copolymers. Examples of linear or branched hydrocarbons include pentane, hexane, heptane, octane, nonane, decane, dodecane, isooctane, gasoline, mineral oil, and the like. Examples of water-insoluble alcohols include alcohols having 4 or more carbon atoms and linear or branched alkyl chains, such as n-butanol, s-butanol, t-butanol, pentanol, hexanol, and octanol. And methyl isobutyl carbinol. Examples of the polymer include polystyrene, polyethylene, polypropylene, polyester, polyurethane and the like. Block copolymers can also be used. These may be used alone or in combination of two or more.

  Further, as a substance (good solvent) that dissolves in the monomer mixture and swells the resulting crosslinked copolymer, specifically, aromatic hydrocarbons such as toluene, xylene (ortho, meta, para) Aromatic hydrocarbons, such as benzene, chlorobenzene, dichlorobenzene, nitrobenzene, bromobenzene, aniline, ethylbenzene, and diethylbenzene, in which the aromatic ring may be substituted can be used. In addition, halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane, and the like can be used. These may be used alone or in combination of two or more.

  In the production of the strongly basic anion exchange resin of the present invention, as the porous agent, a substance (poor solvent) that dissolves in the monomer mixture but does not swell the obtained cross-linked copolymer may be used. It is preferable in terms of operability at the time, separability between the porous agent after the reaction and the crosslinked copolymer, and the like. Among the poor solvents, linear or branched hydrocarbons are particularly preferable, and hexane, heptane, and octanes are particularly preferable.

  The porosifying agent is usually 1% by weight or more and 100% by weight or less, preferably 5% by weight or more and 80% by weight or less, more preferably 10% by weight, based on the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer. It is used in an amount of 60% by weight or less. If the amount of the porous agent is too large, an excessively porous polymer is formed to cause a decrease in physical strength, which is not suitable. If the amount of the porous agent is too small, the polystyrene sulfonic acid adsorption amount does not increase. That is, in the production of the strongly basic anion exchange resin of the present invention, a porosifying agent that is not used in the production of the gel type anion exchange resin is used in the production of a normal porous type anion exchange resin. A gel-type anion exchange resin is produced in which the amount of polystyrene sulfonic acid adsorbed is increased by using less than the amount of the porous agent used.

  In general, in the production of a porous anion exchange resin, as described in Example 1 and Example 2 of Japanese Patent Publication No. 37-13792, a mixture of a monovinyl aromatic monomer and a crosslinkable aromatic monomer is used. When the use amount of the crosslinkable aromatic monomer is 12% by weight or more, the porosifying agent is used by 50% by weight or more based on the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer.

  In the production of the strongly basic anion exchange resin of the present invention, when the use amount of the crosslinkable aromatic monomer to the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer is 12% by weight or less, the use of the porosifying agent is used. The amount is preferably 50% by weight or less based on the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer. Further, when the use amount of the crosslinkable aromatic monomer to the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer is 10% by weight or less, the use amount of the porosifying agent is changed between the monovinyl aromatic monomer and the crosslinkable aromatic monomer. The amount is preferably 60% by weight or less based on the mixture. In addition, when the amount of the crosslinkable aromatic monomer used in the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer is 8% by weight or less, the amount of the porous agent used is that of the monovinyl aromatic monomer and the crosslinkable aromatic monomer. It is preferable that it is 70 weight% or less with respect to a mixture. The amount of the crosslinkable aromatic monomer and the amount of the porous agent used for the mixture of the monovinyl aromatic monomer and the crosslinkable aromatic monomer are within a range where a gel-type anion exchange resin having an increased polystyrenesulfonic acid adsorption amount can be obtained. Therefore, it is necessary to set an optimum range so that an anion exchange resin satisfying the strength required for handling in the subsequent process can be obtained.

  The polymerization mode is not particularly limited, and the polymerization can be carried out in various modes such as solution polymerization, emulsion polymerization, suspension polymerization, etc. Among them, suspension in which a uniform bead-shaped copolymer is obtained. A polymerization method is preferably employed. The suspension polymerization method can be carried out by selecting a known reaction condition using a solvent, a dispersion stabilizer or the like generally used for the production of this type of copolymer.

  The polymerization temperature in the copolymerization reaction is usually room temperature (about 18 ° C. to 25 ° C.) or more, preferably 40 ° C. or more, more preferably 70 ° C. or more, and usually 250 ° C. or less, preferably 150 ° C. or less. Preferably it is 140 degrees C or less. If the polymerization temperature is too high, depolymerization occurs at the same time, and the degree of polymerization completion is lowered. If the polymerization temperature is too low, the degree of polymerization completion will be insufficient.

The polymerization atmosphere can be carried out under air or under an inert gas, and nitrogen, carbon dioxide, argon or the like can be used as the inert gas. Moreover, the polymerization method described in JP-A-2006-328290 can also be suitably used. Moreover, the well-known method of obtaining the crosslinked copolymer of a uniform particle size can also be used conveniently. For example, methods disclosed in JP 2002-35560 A, JP 2001-294602 A, JP 57-102905 A, and JP 3-249931 A can be suitably used.
The aforementioned porosifying agent is removed from the reaction system by washing with a solvent or heating distillation after completion of the polymerization reaction to obtain a crosslinked copolymer.

  (B) The haloalkylation step is a step in which (a) the crosslinked copolymer obtained in the polymerization step is swelled and reacted with a haloalkylating agent in the presence of a Friedel-Crafts reaction catalyst to haloalkylate. .

  In order to swell the crosslinked copolymer, a swelling solvent such as dichloroethane can be used. Moreover, depending on the kind of haloalkylating agent, it can be swollen only with the haloalkylating agent.

  Examples of the haloalkylating agent include halogen compounds such as chloromethyl methyl ether, methylene chloride, bis (chloromethyl) ether, vinyl chloride, bis (chloromethyl) benzene, and these may be used alone. Two or more kinds may be mixed and used, but chloromethyl methyl ether is more preferable.

  The amount of the haloalkylating agent used is selected from a wide range depending on the degree of crosslinking of the crosslinked copolymer and other conditions, but is preferably an amount that at least sufficiently swells the crosslinked copolymer. It is 1 weight times or more, preferably 2 weight times or more, usually 20 weight times or less, preferably 10 weight times or less.

  Examples of Friedel-Crafts reaction catalysts include Lewis acid catalysts such as zinc chloride, iron (III) chloride, tin (IV) chloride, and aluminum chloride. These catalysts may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The amount of Friedel-Crafts reaction catalyst used is usually 0.001 to 10 times, preferably 0.1 to 2 times, more preferably 0.2 to 1 times the weight of the cross-linked copolymer. It is.

  The reaction temperature varies depending on the type of Friedel-Crafts reaction catalyst to be employed, but is usually 0 ° C. or higher and preferably 55 ° C. or lower.

  By performing the haloalkylation reaction, a haloalkylated crosslinked copolymer can be obtained.

  (C) In the amination step, the haloalkylated crosslinked copolymer obtained in (b) is reacted with an amine compound to introduce an amino group to produce an anion exchange resin. Can also be carried out using known methods.

  For example, a method in which a haloalkylated cross-linked copolymer is suspended in a solvent and reacted with an amine compound such as trimethylamine or dimethylethanolamine can be mentioned. As a solvent used in the amino group introduction reaction, for example, one kind of water, toluene, dioxane, dimethylformamide, dichloroethane and the like can be used alone or in admixture of two or more kinds. After the amination step, an anion exchange resin can be obtained by changing the salt form into various anion forms by a known method. As the salt form, Cl form, OH form, carbonic acid form, sulfuric acid form and the like are used.

<How to use>
The strong base anion exchange resin of the present invention is particularly suitable for use in a mixed bed form with a cation exchange resin because of its excellent polystyrene sulfonic acid adsorption performance. However, the present invention is not limited to use in a mixed bed form with a cation exchange resin, and the strongly basic anion exchange resin of the present invention can be used in any form such as use alone or in combination with other catalyst resins. it can.

  Examples of the cation exchange resin used in combination with the strongly basic anion exchange resin of the present invention include gel type and porous type strongly acidic cation exchange resins. Preferably, a cation exchange resin having a high oxidation resistance and a high degree of crosslinking is used, and the degree of crosslinking is preferably 8 to 20% by weight, more preferably 12 to 16% by weight. Within the above range, when the degree of crosslinking of the cation exchange resin is not less than the lower limit value, the elution amount of the eluate from the cation exchange resin tends to be reduced. In the present invention, the cation exchange resin to be used is not particularly limited, but usually a strong acid cation exchange resin having a sulfonic acid group as an exchange group is used.

  The ratio of use of these cation exchange resins and the strongly basic anion exchange resin of the present invention is appropriately determined according to the application, but in the demineralization treatment of power plant condensate, the strong base of the present invention is used. It is preferable to use the anionic exchange resin: strongly acidic cation exchange resin in a volume ratio of 1: 5 to 5: 1, particularly 1: 3 to 3: 1.

[Condensate demineralization method and condensate demineralization apparatus]
The condensate desalination method of the present invention is a method for desalinating the condensate of a power plant such as a nuclear power plant or a thermal power plant using the strongly basic anion exchange resin of the present invention. The water desalination apparatus is a condensate desalination apparatus for a power plant including an ion exchange resin tower containing the strongly basic anion exchange resin of the present invention.

  In the condensate demineralization method and condensate demineralization apparatus of the present invention, the strongly basic anion exchange resin of the present invention is preferably used in the mixed bed form with the above-mentioned cation exchange resin at the above-mentioned use ratio.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

  The measuring methods of various physical properties of strongly basic anion exchange resins in the following examples and comparative examples are as follows.

<Measuring method of average particle diameter>
The average particle size is Diaion (registered trademark) (ion exchange resin / synthetic adsorbent manual 1) revised edition 4th edition (issued February 26, 2010), No. 140 edited by Mitsubishi Chemical Corporation Ion Exchange Resin Division. It was calculated by the method described on page 142.

<Method for measuring moisture content>
The moisture content is the third edition of the Diaion (registered trademark) (Ion Exchange Resin / Synthetic Adsorbent Manual 1) Revised Edition, 3rd edition (issued February 26, 2010) edited by the Mitsubishi Chemical Corporation Ion Exchange Resin Division. Measured by the method described on page 132.

<Method for measuring neutral salt decomposition ability>
Neutral salt decomposition capacity is the third edition of the 4th edition of Diaion (registered trademark) (Ion Exchange Resin / Synthetic Adsorbent Manual 1) edited by the Mitsubishi Chemical Corporation Ion Exchange Resin Division (issued February 26, 2010) ) Measured by the method described on pages 135-137.

<Measurement method of polystyrene sulfonic acid adsorption amount>
Tosoh Organic Chemical Co., Ltd. polystyrene sodium sulfonate “Polynas PS-1” is passed through a strongly acidic cation resin to form H, and then water is added to dilute to 0.01 mmol / L as H concentration. Thus, a polystyrene sulfonic acid aqueous solution whose concentration was adjusted was prepared.
After treating the strongly basic anion exchange resin with aqueous sodium hydroxide to adjust the salt form to OH form, tap method (put the resin in a graduated cylinder with water, tap the bottom, 10 mL of the resin was collected in a state in which the volume was read in a state where it did not sink, and the column was packed, and then washed thoroughly with water until the organic elution component derived from the resin disappeared.
Subsequently, the polystyrene sulfonic acid solution having the above concentration adjusted was passed at SV (space velocity) = 20 hr ⁻¹ , the absorbance of the polystyrene sulfonic acid solution eluted with a UV detector (wavelength 225 nm) was measured, and a breakthrough curve was obtained. Recorded. The total amount of polystyrene sulfonic acid adsorbed on the strongly basic anion exchange resin by the time when the UV absorbance of the eluted polystyrene sulfonic acid solution reached 50% with respect to the UV absorbance of the polystyrene sulfonic acid solution whose concentration was adjusted. The adsorption amount was calculated as the adsorption amount of polystyrene sulfonic acid.

<Method for measuring specific surface area>
The strongly basic anion exchange resin was dried by heating under reduced pressure under a vacuum of 50 ° C., then the adsorption isotherm (adsorbed gas: krypton) was measured under liquid nitrogen, and the BET plot was calculated to calculate the specific surface area. The adsorption isotherm was measured using an autosorb 1MP manufactured by Canterchrome.

<Measurement method of absorbance>
In an ultraviolet / visible (UV-Vis) spectrum measuring apparatus (“UV2400PC” manufactured by Shimadzu Corporation) using an integrating sphere as a detector, a sample (prepared according to the following method and having a particle size of about 600 μm is placed in a cylindrical cell with a screw cap. The adjusted wet base anion exchange resin (Cl form) was densely packed, the reflectance of light having a wavelength of 800 nm was measured, and the absorbance was determined by Kubelka-Munk conversion.
A sample (a strongly strong basic anion exchange resin in a wet state in which the particle size was adjusted to about 600 μm) was prepared by the method described below.
That is, a strongly basic anion exchange resin (Cl form) was passed through a 600 μm sieve to remove the sieve (fine powder), and the residue on the sieve was removed with demineralized water. Next, the particles clogged with a 600 μm sieve were collected in a vat with pressurized water of demineralized water. The collected product was wrapped in a cloth and centrifuged to remove adhering water. Centrifugation was performed for 7 minutes at a cage diameter of 15 cm and a rotational speed of 3000 rpm.
Integrating sphere manufactured by Shimadzu Corporation (detector: photomaru, inner diameter: 60 mmφ, entrance window: 12 (W) × 20 (H) mm, exit window: 12 (W) × 24 (H) mm, photomaru window: 16 mmφ, integral Sphere aperture ratio: about 11%) was used. However, the optical path diameter of ultraviolet / visible light is 4 mm × 6 mm. As the cylindrical cell with a screw cap, a cylindrical cell with a screw cap (manufactured by synthetic quartz glass, optical path length: 5 mm, optical path surface size: 22 mmφ) manufactured by GL Science Co., Ltd. was used.
The slit width was 5 nm. The calibration of the apparatus was performed by directly contacting the opening of the integrating sphere with barium sulfate packed in a dedicated holder (one opening 27 mmφ).
The reflectance was measured by placing a sample (a wet basic anion exchange resin in a wet state adjusted to a particle size of about 600 μm (Cl type)) behind the integrating sphere. A black plate was placed on the back of the sample. After the reflectance measurement, Kubelka-Munk conversion was performed with the attached software to determine the absorbance.
Separately, the same cell was filled with barium sulfate (manufactured by Wako Pure Chemicals, Wako Grade 1), and the same measurement was performed. The values were used as the reflectance and absorbance of the cell itself.
A value obtained by subtracting the absorbance of the cell from the absorbance when the cell was filled with the strongly basic anion exchange resin was calculated as the absorbance of the strongly basic anion exchange resin. The measurement was performed three times or more on the same sample, and the average value was taken.

<Measurement method of crushing strength>
A sodium hydroxide aqueous solution was passed through a strongly basic anion exchange resin to adjust the salt form to OH form, and then collected through a 600 μm sieve in the same manner as in the above absorbance measurement, and the particle size was adjusted to about 600 μm. Several hundred particles were collected from the particles, and 60 particles were randomly selected from the particles, and the strength was measured with a Chatillon tester or equivalent. Furthermore, it was set as the physical strength per resin particle | grain (= crushing strength) by taking the average value. The crushing strength is preferably larger than 250 g / grain.

<Example 1>
As monomers, 311 g of styrene and 51 g of divinylbenzene having a purity of 57% by weight (divinylbenzene: 29 g, monovinyl aromatic monomer: 22 g), 181 g of isooctane and 4.91 g of dibenzoyl peroxide (purity 75% by weight, wet product) were used. A monomer phase was obtained by mixing. A 0.13% by weight aqueous solution of polyvinyl alcohol was used as the aqueous phase, and this was mixed with the monomer phase to obtain a monomer suspension. The suspension was reacted at 75 ° C. for 6 hours with stirring, then heated to 80 ° C. and reacted for 3 hours to obtain a copolymer (1).
100 g of the copolymer (1) was put in a round bottom flask, and 500 g of chloromethyl methyl ether was added to sufficiently swell the copolymer. Thereafter, 50 g of zinc chloride was added as a Friedel-Crafts reaction catalyst, the temperature of the bath was set to 50 ° C., and the mixture was reacted for 10 hours with stirring to obtain a chloromethylated copolymer (2).
150 g of the above chloromethylated copolymer (2) is placed in a round bottom flask, 319 mL of demineralized water, 256 g of toluene, and 183 mL of 30% by weight trimethylamine aqueous solution are added, and the mixture is reacted at 50 ° C. for 8 hours with stirring. An ion exchange resin (Cl form) (Sample A) was obtained. Table 1 shows the evaluation results of the obtained strongly basic anion exchange resin.

<Example 2>
In Example 1, the monomer phase was 291 g of styrene, 48 g of divinylbenzene having a purity of 57% by weight (divinylbenzene: 27 g, monovinyl aromatic monomer: 21 g), 203 g of isooctane, dibenzoyl peroxide (purity 75% by weight, wet product). A strongly basic anion exchange resin (Cl form) (sample B) was obtained in the same manner as in Example 1, except that the mixture was 54 g. Table 1 shows the evaluation results of the obtained strongly basic anion exchange resin.

<Comparative Examples 1-4>
As Comparative Examples 1 to 4, commercially available strongly basic anion exchange resins, ie, “SA10DL” and “PA316” manufactured by Mitsubishi Chemical Corporation, “IRA400J” and “IRA900” manufactured by Rohm and Haas, Inc. were used. . Table 1 shows the results of the same evaluation.

<Example 3>
A commercially available strong acid cation exchange resin “SK1B” (gel-type strongly acidic cation exchange resin having a sulfonic acid group as an exchange group, crosslinking degree: 8% by weight) manufactured by Mitsubishi Chemical Corporation by the tap method. 50 mL was collected. Similarly, 0.5 mL of strongly basic anion exchange resin (Cl form) “Sample A” obtained in Example 1 was collected, and both resins were put into a 300 mL Erlenmeyer flask. Further, 100 mL of ultrapure water was added to the Erlenmeyer flask, and then set in a WATER BATH SHAKER MM-10 (manufactured by TAITEC) and shaken at a water temperature of 80 ° C. and 100 spm for 20 hours. The supernatant was collected, and the absorbance at a wavelength of 225 nm was measured with UV-1600 GLP (manufactured by Shimadzu Corporation). The results are shown in Table 2.
As described in JP-A-2001-293181, the amount of polystyrene sulfonic acid eluted from the cation exchange resin can be analyzed by measuring the UV absorbance at a wavelength of 225 nm. It shows that the polystyrenesulfonic acid concentration in the eluate (supernatant) is high. For this reason, the lower the absorbance, the more preferably the polystyrene sulfonic acid has been removed by the resin.

<Example 4>
In Example 3, the same evaluation was performed except that the strongly basic anion exchange resin (Cl form) “Sample B” obtained in Example 2 was used as the strongly basic anion exchange resin (Cl form). did. The results are shown in Table 2.

<Comparative Example 5>
In Example 3, the same operation was performed except that the evaluation was carried out only with “SK1B” manufactured by Mitsubishi Chemical Corporation without using a strongly basic anion exchange resin (Cl form). The results are shown in Table 2.

<Evaluation>
From Table 1 and Table 2, the strongly basic anion exchange resin of the present invention is excellent in the adsorption performance of the effluent from the cation exchange resin, and has a strength that can sufficiently withstand use in an actual plant, It can be seen that the desalination treatment of the condensate at the power plant can be performed stably and efficiently over a long period of time.

  The strongly basic anion exchange resin of the present invention is excellent in the eluate adsorption performance from the cation exchange resin and has a strength sufficient to withstand use in an actual plant, and requires high-purity water quality. It can be suitably used for a condensate desalination apparatus in a power plant, and its industrial applicability is extremely high.

Claims (10)

A strongly basic anion exchange resin which is a gel-type resin and has an adsorption amount of polystyrenesulfonic acid measured by the following method of 0.25 mmol / L-resin or more and an average particle diameter of 300 μm or more.
<Measurement method of polystyrene sulfonic acid adsorption amount>
Polystyrene sulfonic acid “Polynas PS-1” manufactured by Tosoh Organic Chemical Co., Ltd. was passed through a strongly acidic cation exchange resin to form H, and then the polystyrene sulfonic acid was adjusted to a concentration of 0.01 mmol / L as the H concentration. Prepare an aqueous solution.
The column is filled with a strongly basic anion exchange resin that has been adjusted to OH form by treatment with an aqueous sodium hydroxide solution, washed with water, and then passed through a polystyrenesulfonic acid aqueous solution with a concentration adjusted to give polystyrene equivalent to 50% breakthrough. The amount of sulfonic acid adsorbed is determined and taken as the amount of polystyrene sulfonic acid adsorbed by the strongly basic anion exchange resin. The strongly basic anion exchange resin according to claim 1, wherein the specific surface area measured by the following method is less than 1 m ² / g.
<Method for measuring specific surface area>
The strongly basic anion exchange resin is dried by heating under reduced pressure under a vacuum of 50 ° C., an adsorption isotherm (adsorbed gas: krypton) is measured under liquid nitrogen, and a specific surface area is calculated by performing a BET plot. The strongly basic anion exchange resin according to claim 1 or 2, wherein the absorbance measured by the following method is 0.10 or more and 0.44 or less.
<Measurement method of absorbance>
In an ultraviolet / visible spectrum measuring apparatus using an integrating sphere as a detector, a cylindrical cell with a screw cap is densely filled with a strongly basic anion exchange resin, and the reflectance of light having a wavelength of 800 nm is measured. Absorbance is determined by Munch conversion. Separately, the same cell is filled with barium sulfate, the same measurement and conversion are performed, and the calculated absorbance is taken as the absorbance of the cell. A value obtained by subtracting the absorbance of the cell from the absorbance when the cell is filled with the strongly basic anion exchange resin is determined as the absorbance of the strongly basic anion exchange resin.   A method for using a strongly basic anion exchange resin, wherein the strongly basic anion exchange resin according to any one of claims 1 to 3 is used in a mixed bed form with a cation exchange resin.   A mixed bed ion exchange resin comprising the strongly basic anion exchange resin according to any one of claims 1 to 3 and a cation exchange resin.   The mixed bed ion exchange resin according to claim 5, wherein the degree of crosslinking of the cation exchange resin is 8 to 20% by weight.   In the condensate desalination method for desalinating condensate of a power plant with an ion exchange resin, the strongly basic anion exchange resin according to any one of claims 1 to 3 is used as the ion exchange resin. Condensate desalination method.   A condensate desalination method in which the mixed bed ion exchange resin according to claim 5 or 6 is used as the ion exchange resin in a condensate desalination method in which the condensate of a power plant is desalted with an ion exchange resin.   A condensate demineralizer comprising an ion exchange resin tower for desalinating the condensate of a power plant, wherein the ion exchange resin tower comprises the strongly basic anion exchange resin according to any one of claims 1 to 3. Including condensate desalination equipment.   A condensate demineralizer comprising an ion exchange resin tower for demineralizing condensate of a power plant, wherein the ion exchange resin tower comprises the mixed bed ion exchange resin according to claim 5 or 6. .