JP2004081927A - Method of filling condensed water desalting apparatus with ion exchange resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of filling a desalting column of a condensed water desalting apparatus with an ion exchange resin capable of obtaining the effect of reducing a PSS (polystyrene sulphonate) concentration in a desired treated water by certainly forming a target ion exchange resin bed of a two-bed form in the desalting column by suppressing the whirling-up of an anion exchange resin from the resin bed formed in the lower part in the desalting column. <P>SOLUTION: In the method of filling a condensed water desalting apparatus with the ion exchange resin, mutually different two upper and lower layers of ion exchange resin beds, which comprise an upper ion exchange resin bed comprising a mixed resin of a cation exchange resin and an anion exchange resin and a lower ion exchange resin bed comprising an anion exchange resin, are formed in the desalting column. In this case, the desalting column is filled with the anion exchange resin along with transfer water to form the lower ion exchange resin bed and, afte water in the desalting column is drained, the desalting column is filled with the mixed resin along with transfer water to form the upper ion exchange resin bed on the lower ion exchange resin bed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for filling an ion exchange resin into a condensate desalination apparatus provided in a condensate piping system of a nuclear or thermal power plant.
[0002]
[Prior art]
It is known that the treated water of the condensate desalination apparatus contains several kinds of organic impurities. These are mainly impurities eluted from the ion exchange resin packed in the desalting tower, and are generated when the ion exchange resin undergoes oxidative decomposition by dissolved oxygen or an oxidizing agent. Among these, the organic impurities eluted from the cation exchange resin are mainly polystyrene sulfonic acid (hereinafter sometimes abbreviated as PSS), which is decomposed in a nuclear reactor or a steam generator to generate sulfate ions, which has been a problem in recent years. Has become. That is, since sulfuric acid causes corrosion of the structural material and generation of scale, it is desirable to reduce as much as possible, and several methods for reducing the generation of sulfate ions have been proposed.
[0003]
As one of the reduction methods, the ion exchange resin layer formed in the desalting tower is divided into upper and lower layers, and the upper layer is a mixed ion exchange resin obtained by mixing a cation exchange resin and an anion exchange resin, or a layer of the cation exchange resin alone, There has been proposed a method in which the lower layer is formed of a single layer of an anion exchange resin (Japanese Patent Application Laid-Open No. 9-276682). In this method, since the anion exchange resin in the lower part of the desalting tower adsorbs PSS eluted from the upper layer, the PSS concentration in the treated water can be reduced.
[0004]
[Problems to be solved by the invention]
However, when trying to form desired two upper and lower ion exchange resin layers in the desalination tower as described above, there are the following problems. That is, since the specific gravity of the anion exchange resin is generally smaller than that of the cation exchange resin, when filling the ion exchange resin in the desalination tower, the anion exchange resin is first received and the anion exchange resin layer is formed in the lower part of the desalination tower. However, when the mixed ion exchange resin is received thereon, the resin layer in the desalting tower becomes in a fluid state, and the anion exchange resin soars and moves to the upper part of the mixed ion exchange resin layer, thereby desalinating. There is a problem that the amount of anion exchange resin in the lower part of the column is reduced. When the amount of the anion exchange resin in the lower part of the desalination tower decreases, it becomes difficult to capture PSS, the PSS concentration in the treated water increases, and the target PSS concentration reduction effect in the treated water can be obtained by dividing into two layers. Absent.
[0005]
Such a phenomenon occurs, for example, as shown in FIG. As shown in FIG. 5, when filling the desalination tower 101 with the ion exchange resin, first, a slurry of the anion exchange resin and water is supplied from the resin transfer pipe 102 into the desalination tower 101, An anion exchange resin layer 103 is formed on the bottom. At this time, since the transported water transported together with the anion exchange resin also accumulates in the tower, a water layer 104 is formed on the upper portion of the resin layer 103 after the completion of the transport of the anion exchange resin as illustrated. Next, a slurry of a mixed resin of cation and anion exchange resin and water is supplied into the desalting tower 101 from the resin transfer pipe 102 to form a mixed resin layer on the anion exchange resin layer 103. Since the water flow of the slurry introduced from the top of the tower hits the water layer 104, the anion exchange resin layer 103 is fluidized, and a part of the anion exchange resin soars up, in the mixed resin layer being formed or in the mixed resin layer. It moves to the top of the layer. As a result, the amount of the anion exchange resin in the lower part of the column is reduced, for example, as shown in FIG. When the amount of the anion exchange resin in the lower part of the column is reduced, the target PSS concentration reduction effect in the treated water cannot be obtained as described above.
[0006]
In order to suppress the movement of the anion exchange resin as described above, a method of adjusting the particle size of the resin, that is, a method of using a large particle size anion exchange resin or a small particle size cation exchange resin can be considered. At this time, it becomes difficult to perform a separation operation in a regeneration facility for separating a cation exchange resin having a large specific gravity downward and an anion exchange resin having a small specific gravity upward. If the resin cannot be separated, it will be impossible to regenerate the chemicals, and it will be difficult to refill the resin after extracting it from the desalting tower during regular inspection. Therefore, such adjustment of the particle size of the resin cannot be practically adopted.
[0007]
An object of the present invention is to suppress the rising of the anion exchange resin from the resin layer formed in the lower part of the desalination tower, and to form the target two-layer ion exchange resin layer in the tower without fail, thereby achieving the desired treatment. It is an object of the present invention to provide a method of filling an ion exchange resin into a desalination tower of a condensate desalination apparatus, which is capable of obtaining a PSS concentration reduction effect in water.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for filling an ion exchange resin in a condensate deionization apparatus according to the present invention comprises: an upper ion exchange resin layer comprising a mixed resin A of a cation exchange resin and an anion exchange resin in a desalination tower. When forming two different upper and lower ion exchange resin layers of the anion exchange resin alone or the lower ion exchange resin layer composed of the mixed resin B having a higher proportion of the anion exchange resin than the mixed resin A, In the salt tower, after filling the anion exchange resin or the mixed resin B with the transfer water to form the lower ion exchange resin layer, drain the water in the desalting tower, and then fill the mixed resin A with the transfer water. Forming an upper ion-exchange resin layer on the lower ion-exchange resin layer.
[0009]
In this method, after the upper ion exchange resin layer is further formed, the inside of the desalting tower can be filled with water, and the inside of the desalting tower can be pressurized. Pressurization may be performed by supplying pressurized water at the time of filling with water and keeping the supply valve of the pressurized water open even after filling, or by pressurizing water by supplying pressurized water after filling the inside of the tower. The pressurizing pressure may be about the pressure of make-up water or condensate of the power plant, and for example, 0.3 to 0.8 MPa is appropriate. By maintaining the pressurized state in the desalting tower for a certain period of time, even when bubbles exist in the ion exchange resin layer formed in the tower, the bubbles can be dissolved in water. Further, by replacing the water in the tower with new water after pressurizing for a certain time and pressurizing again, bubbles in the tower can be effectively removed. Incidentally, at this time, as water for transferring the ion exchange resin into the desalination tower and water for filling the desalination tower after the transfer, the gas dissolving power is strong, as described below. It is desirable to use degassed water, for example, degassed pure water or condensed water can be used.
[0010]
Further, in the above method, after forming the upper ion-exchange resin layer, continuously supply degassed water from which dissolved gases such as dissolved oxygen and dissolved nitrogen have been removed in advance in the desalting tower, in other words, Deaerated water may be passed through the desalination tower to remove bubbles in the desalination tower. The degassed water may be either pressurized water or non-pressurized water. By replacement with degassed water, even when bubbles exist in the ion exchange resin layer, the bubbles can be dissolved in water, and preparation for the start of the desalting process can be made.
[0011]
In order to drain (drain) water in the desalination tower after forming the lower ion exchange resin layer, a method of simply draining using a height difference may be used. It may be introduced and forcedly drained. With forced drain, the water in the tower can be drained faster.
[0012]
In the method for charging the ion exchange resin into the condensate desalination apparatus according to the present invention as described above, first, the anion exchange resin or the mixed resin B rich in the anion exchange resin is supplied and charged into the desalination tower together with the transfer water. Then, a lower ion exchange resin layer is formed at a lower portion in the desalination tower. In the conventional method, the mixed resin A was subsequently supplied and filled into the desalination tower together with the transfer water. However, in the method of the present invention, the water in the desalination tower is then drained (drained). In a state where the water in the desalting tower is drained, the anion exchange resin of the lower ion exchange resin layer formed in the desalting tower is in a substantially non-flowable state. In this state, the mixed resin A of the cation exchange resin and the anion exchange resin is supplied and filled together with the transfer water onto the upper part of the lower ion exchange resin layer in the desalination tower. Therefore, at the time of this packing, the lower ion exchange resin layer is prevented from being in a fluidized state, the anion exchange resin is prevented from rising, and the anion exchange resin stays in the lower portion in the column. When the mixed resin A is supplied into the tower, the transport water also flows into the tower at the same time, so that the water level in the desalination tower gradually rises, but the water level rises to the surface of the lower ion exchange resin layer. At this point, since a predetermined mixed resin layer can be already formed on the upper part of the lower ion exchange resin layer, the anion exchange resin of the lower ion exchange resin layer is appropriately prevented from rising and moving upward. You. As a result, both the lower ion-exchange resin layer made of the anion exchange resin or the mixed resin B and the upper ion-exchange resin layer made of the mixed resin A are formed in layers of a predetermined form, so that a target two-layer form is reliably formed. As a result, the intended effect of reducing the PSS concentration in the treated water can be reliably obtained.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings, together with examples performed as tests for confirming the effects.
The present invention relates to a method for filling an ion exchange resin into a desalination tower in a condensate desalination apparatus. However, the form of the desalination tower to which the present invention can be applied is not particularly limited. The present invention can be applied to any type of desalination tower shown. In the desalination tower 1 shown in FIG. 1, a resin inlet pipe 7 for supplying an ion exchange resin is provided on an upper portion thereof. A water inlet pipe 2 is provided above the desalination tower 1, and a distributor 3 is provided at the tip thereof. A water collector 4 is provided in the lower part of the desalination tower 1, and the water collector 4 is connected to a water outlet pipe 5. In the desalination tower 1, an ion exchange resin is supplied together with transfer water from a resin inlet pipe 7, and the ion exchange resin is filled up to the design resin surface 6 in the tower. In the present invention, in the desalting tower 1, the ratio of the upper ion exchange resin layer composed of the mixed resin A of the cation exchange resin and the anion exchange resin and the ratio of the anion exchange resin alone or the anion exchange resin is higher than that of the mixed resin A. Two upper and lower ion exchange resin layers different from the lower ion exchange resin layer made of the mixed resin B are formed. In FIG. 1, reference numeral 8 denotes a resin outlet pipe used for transferring the ion exchange resin in the desalination tower 1 to a regeneration facility (not shown).
[0014]
In the desalination tower 11 shown in FIG. 2, a resin inlet pipe 18 for supplying an ion exchange resin is provided at an upper portion thereof. The resin inlet pipe 18 extends to a position below the current plate 14 through a current plate 14 to be described later, and a baffle plate 19 is provided below a distal end portion of the resin inlet pipe 18. A water inlet pipe 12 is connected to the upper part of the desalination tower 11, a baffle plate 13 is provided below the water inlet pipe 12 in the tower, and a baffle plate 14 is provided below the water inlet pipe 12 so as to cross the inside of the tower. ing. A screen 15 is provided in the lower part of the desalination tower 11, and a water outlet pipe 16 is connected to the bottom of the desalination tower 11. In the desalination tower 11, the ion exchange resin is supplied together with the transfer water from the resin inlet pipe 18, and the ion exchange resin fills up to the design resin surface 17 on the screen 15 in the tower. In the present invention, in the desalting tower 11, the ratio of the upper ion exchange resin layer composed of the mixed resin A of the cation exchange resin and the anion exchange resin and the ratio of the anion exchange resin alone or the anion exchange resin is higher than that of the mixed resin A. Two upper and lower ion exchange resin layers different from the lower ion exchange resin layer made of the mixed resin B are formed. In FIG. 2, reference numeral 20 denotes a resin outlet tube.
[0015]
The lower ion exchange resin layer and the upper ion exchange resin layer are formed as follows. First, the anion exchange resin or the mixed resin B is supplied together with the transfer water into the desalination towers 1 and 11 via the resin inlet pipes 7 and 18, and the resin is filled in the lower part of the tower to form the lower ion exchange resin layer. It is formed. After the formation of the lower ion-exchange resin layer, water accumulated in the desalting towers 1 and 11 is drained through the water outlet pipes 5 and 16 (drained). Due to this drain, the lower ion exchange resin layer is brought into a substantially non-flowable state. Next, in this state, the mixed resin A is supplied to the desalination towers 1 and 11 via the resin inlet pipes 7 and 18 together with the transfer water, and is charged into the towers and is placed on the lower ion exchange resin layer. An ion exchange resin layer is formed. During the formation of the upper ion-exchange resin layer, the water used for transporting the mixed resin A gradually accumulates in the desalination towers 1 and 11, and the water level gradually rises. When the surface of the ion-exchange resin layer is reached, the layer of the mixed resin A has already been formed on the lower ion-exchange resin layer. The rising of the anion exchange resin in the resin layer and the upward movement are prevented. Therefore, the lower ion-exchange resin layer composed of the anion exchange resin or the mixed resin B remains substantially in the same layer form, and the anion-exchange resin in the lower ion-exchange resin layer moves upward, in particular, moves upward. Movement of the ion exchange resin layer to the upper part is prevented. Even if the lower ion-exchange resin layer is disordered in the layer form, the surface form of the lower ion-exchange resin layer (boundary form with the upper ion-exchange resin layer) is suppressed to a degree at most.
[0016]
As a result, the lower ion-exchange resin layer having the desired height and the upper ion-exchange resin layer having the desired height are each reliably formed, and the target two-layer structure in the tower is formed. Due to this two-layer configuration, at the time of desalination treatment, PSS eluted from the cation exchange resin in the upper ion exchange resin layer is appropriately captured by the anion exchange resin in the lower ion exchange resin layer, and PSS in the desired treated water is obtained. It is possible to obtain a concentration reduction effect.
[0017]
At the start of the actual desalination treatment, as described above, after the upper ion exchange resin layer is formed, the inside of the desalination tower is filled with water, and the inside of the desalination tower is pressurized for a certain time, or the upper ion exchange resin layer is removed. After the formation, degassing water is continuously supplied into the desalting tower to continuously replace the inside of the desalting tower with degassed water, even when bubbles are present in the ion exchange resin layer. After dissolving the bubbles in water, desalting treatment is preferably started.
[0018]
In order to confirm the effect of preventing the upward movement of the anion exchange resin in the lower ion exchange resin layer according to the present invention, the following test was performed as an example.
As a test apparatus, a desalination tower was made of a transparent material, and the state of the ion-exchange resin layer formed in the tower was visually observed, and the transfer of the ion-exchange resin and the filling state in the tower were confirmed.
[0019]
The outline of the test equipment is shown below.
・ Inner diameter of desalting tower: 500mm
-Resin transfer tube inner diameter: 10 mm
・ Transfer flow rate: 40 L / h
-Lower ion exchange resin layer: Strongly basic anion exchange resin "Amberlite" (registered trademark) IRA400T 9L
-Upper ion exchange resin layer: Mixed resin of cation exchange resin and anion exchange resin Strongly acidic cation exchange resin; "Amberlite" 200C 7.5L
Strongly basic anion exchange resin; "Amberlite" IRA400T 7.5L
[0020]
FIG. 3 shows a transfer and filling state of the embodiment according to the present invention. An anion exchange resin is supplied into the transparent desalination tower 21 via a resin transfer pipe 22 and a baffle plate 23 together with the transfer water, and is placed on a plate 24 provided at a lower part in the tower as a lower ion exchange resin layer. After the formation of the anion exchange resin layer 25, water in the tower is drained through the outlet pipe 26, and thereafter, a mixed resin of the cation exchange resin and the anion exchange resin is supplied together with the transfer water, and the upper ion A mixed ion exchange resin layer 27 as an exchange resin layer was formed. At this time, as shown in FIG. 3, the water level 28 in the tower due to the transfer water reached the upper part of the mixed ion-exchange resin layer 27, but the anion exchange resin layer 25 in the lower part of the tower showed a slight change in the boundary surface, It was held at a substantially predetermined height in the lower part of the inner part.
[0021]
As a comparative example, FIG. 4 shows a transfer situation by a conventional method. That is, after forming the anion exchange resin layer 25, the mixed resin is supplied together with the transfer water without extracting the water in the tower, and the mixed ion exchange resin as the upper ion exchange resin layer is formed on the anion exchange resin layer 25. An attempt was made to form layer 27. As a result, as shown in FIG. 4, most of the anion exchange resin in the anion exchange resin layer 25 formed in the lower part of the column has moved upward, and part of the anion exchange resin has moved to the mixed ion exchange resin layer 27. It moved to the upper part to form the upper anion exchange resin layer 25a.
[0022]
From the comparative tests shown in FIGS. 3 and 4, a remarkable effect of draining water after the formation of the lower ion exchange resin layer according to the present invention was confirmed.
[0023]
【The invention's effect】
As described above, according to the method of filling the condensate deionization apparatus with the ion exchange resin according to the present invention, the undesired upward flow of the anion exchange resin from the resin layer formed in the lower part of the desalination tower is suppressed. Thus, the ion exchange resin layer in the upper and lower two-layer form having the target height can be reliably formed in the desalination tower. As a result, the PSS eluted from the cation exchange resin in the upper ion exchange resin layer can be more reliably adsorbed to the anion exchange resin in the lower ion exchange resin layer during the desalination treatment, and the target treated water The effect of reducing the PSS concentration can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a desalination tower to which the method of the present invention can be applied.
FIG. 2 is a schematic configuration diagram showing another example of a desalination tower to which the method of the present invention can be applied.
FIG. 3 is a schematic configuration diagram of a test apparatus showing results of a test (example) performed to confirm an effect of the present invention.
FIG. 4 is a schematic configuration diagram of a test apparatus showing results of a test (comparative example) performed for comparison with a conventional method.
FIG. 5 is a schematic configuration diagram of a desalination tower for explaining a problem in a conventional method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11 Demineralization tower 2, 12 Water inlet pipe 3 Distributor 4 Water collecting collector 5, 16 Water outlet pipe 6, 17 Design resin surface 7, 18 Resin inlet pipe 8, 20 Resin outlet pipe 13 Baffle plate 14, Rectifying plate 15 Screen 19 Baffle plate 21 Desalination tower 22 Resin transfer tube 23 Baffle plate 24 Eye plate 25 Anion exchange resin layer 25a as lower ion exchange resin layer Upper anion exchange resin layer 26 Outlet tube 27 Mixed ion exchange as upper ion exchange resin layer Resin layer 28 Water level in tower

Claims (3)

In the desalting tower, an upper ion-exchange resin layer composed of a mixed resin A of a cation exchange resin and an anion exchange resin, and a lower layer composed of an anion exchange resin alone or a mixed resin B having a higher anion exchange resin ratio than the mixed resin A. In forming the upper and lower two-layer ion exchange resin layers different from each other with the side ion exchange resin layer, the anion exchange resin or the mixed resin B is filled together with the transfer water into the desalination tower to form the lower ion exchange resin layer. After the formation, the water in the desalting tower is drained, and then the mixed resin A is filled together with the transfer water to form an upper ion exchange resin layer on the lower ion exchange resin layer. A method for filling an ion exchange resin into a salt device. 2. The method according to claim 1, wherein after forming the upper ion exchange resin layer, the inside of the desalination tower is filled with water and the inside of the desalination tower is pressurized. 2. The method according to claim 1, wherein the water in the desalting tower is replaced with degassed water after forming the upper ion exchange resin layer.

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