JPS6159196B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a multi-tube over-desalination apparatus for over-desalting by passing introduced water through a over-element whose cylindrical surface is pre-coated with a super-aid agent.

[Prior art]

Figure 1 shows the water treatment systems of the condensate purification system and reactor water purification system of a nuclear power plant using a boiling water reactor (BWR). In Figure 1, the temperature generated in the reactor 10 is 280℃, and the pressure is 70℃.
The high-temperature, high-pressure steam of Kg/cm ² is sent to the turbine 14 through the main steam pipe 12, rotates the turbine 14, and then flows into the condenser 16 where it is condensed and returned to water. The condensate condensed in the condenser 16 is sucked into the condensate pump 18 and sent to the super-demineralizer 22 via the condensate pipe 20. The condensate in the super-desalinator 22 is treated with crud (usually consisting mainly of corrosion products such as Fe ₂ O ₃ and Fe ₃ O _{4 )} generated in the condensate purification system.
Fine suspensions that do not pass through a 0.45μm bore filter) and nuclide ions are subjected to excessive desalination.
Sent to 4.

This demineralizer 24 has a layered layer of granular cation exchange resin and anion exchange resin, and is designed to capture and desalinate residual crat and nuclide ions in the condensate that were not removed in the overdemineralizer 22. ing. The condensate purified in the over-desalinators 22 and 24 is warmed in a low-pressure feedwater heater 26 and then sent to a high-pressure feedwater heater 30 by a pump 28. The condensate heated in the high-pressure feedwater heater 30 is then supplied to the nuclear reactor 10 via the water supply pipe 32.

On the other hand, the reactor water inside the nuclear reactor 10 is circulated through the circulation pump 34.
Therefore, the water is circulated through a circulation path 36. A part of the reactor water is then transferred to the reactor water purification system piping 3.
8 and cooled in the cooler 40,
It is purified by a reactor water purifier 44 via a pump 42 and returned to atomic Hz 10 via a water supply pipe 32.

The super desalination device 22 used in such atomic Hz power generation equipment has a structure as shown in FIG. In FIG. 2, the over-demineralizer 22 has an over-chamber 52 formed in the middle of a container body 46 by a bottom plate 48 and a ceiling plate 50. An introduced water inlet 54 is formed in the center of the bottom plate 48, so that introduced water 56 can be injected into the overchamber 52 via the condensate pipe 20 connected to the introduced water inlet 54. In addition, the inside of the overchamber 52 has an outer diameter of about 50 mm,
Approximately 200 cylindrical over-elements 58 having a total length of approximately 1.5 m are provided at intervals of approximately 80 mm. The over-element 58 is provided upright on the bottom plate 48, and its lower end extends through the bottom plate 48 to protrude a chamber 62 in which the over-demineralized water 60 is collected. And furthermore,
The upper end of the over-element 58 is supported by the ceiling plate 50 with a hanging fitting (not shown). In addition, above the introduction water inlet 54, umbrella-shaped guide plates 64, 66 are provided.
is provided, and the introduced water 56 is passed through each element 5.
8 It is designed to lead evenly downward.

As shown in FIG. 3, the over-element 58 has a cylindrical support plate 68 with a large number of pores in its center, and around this cylindrical support plate 68 are an over-support layer 70 and an auxiliary over-layer 72. is formed. The super-support layer 70 is made by bundling and twisting ultra-fine fiber threads and wrapping it around the cylindrical support plate 68 to a thickness of about 10 mm, and can remove fine particles on the micron order by itself. It's becoming like that. In addition, the auxiliary agent overlayer 72 formed on the surface of the cylindrical support layer 70 is composed of several resins in which fine powders of a cation exchange resin and an anion exchange resin with an average particle size of several tens of micrometers are mixed in a specific ratio. It is pre-coated with a thickness of mm.

In the over-demineralizer 22 configured as described above, over-demineralization of introduced water and precoating with an auxiliary agent overlayer are performed in the following manner.

Introduced water 56, which is water to be treated, is introduced into the overchamber 52 from below the overdemineralizer 22 via the condensate pipe 20 and the inlet water inlet 54, as shown in FIG.
The introduced water 56 that has entered the filter chamber 52 collides with the umbrella-shaped guide plates 64 and 66, flows along the bottom plate 48, and then rises along the filter element 58 from below the filter element 58. As shown in FIG. 3, the introduced water 56 is passed through the auxiliary agent overlayer 72 and the oversupport layer 70 made of ion exchange resin to remove nuclide ions and cracks.
8 and is collected in a chamber 62 as super-demineralized water 60. In addition, when precoating the auxiliary overlayer 72 on the surface of the oversupporting layer 70, the precoating liquid containing the powdered ion exchange resin is applied to the condensate pipe 20.
The pre-coat liquid is supplied into the filter chamber 52 from above, and is caused to rise along the filter element 58. and,
The precoat liquid permeates into the cylindrical support plate 68 while forming an auxiliary agent overlayer 72 on the surface of the oversupport layer 70 .

This precoat has a resin concentration of 0.5-1.0% by weight
The linear velocity (LV) obtained by dividing the powder ion exchange resin slurry by the element surface area is usually 3 to 4 m/
h. However, in the conventional over-desalination device 22 having the above-described structure, the pre-coat forming layer of the auxiliary agent cannot be formed to have a uniform thickness over the entire length of the over-element 58, as shown in FIG. . i.e. LV of 4m/h
In the case of precoating with
When the thickness exceeds 1000 mm, the thickness of the auxiliary agent overlayer 72 becomes extremely thin. Then, when the LV is increased to 6.5 and 10 m/h, the auxiliary agent overlayer 72 at the top of the element
However, the formation of the auxiliary agent overlayer 72 at the lower end of the element is worsened by the increased retardation of the powdered ion-exchange resin ceramic and is susceptible to delamination.

If excessive demineralization treatment is performed in a state where the thickness of the auxiliary agent overlayer 72 is uneven, the overdemineralization rate of the treated water will decrease in the thinner layer thickness. Moreover, the volumetric overflow in the overlayer mechanism (auxiliary agent overlayer 72
Due to poor adsorption within the auxiliary agent layer 72
If the formation of is uniform, the differential pressure increases rapidly rather than gradually, shortening the overlife. Then, when the differential pressure reaches the set pressure or higher, the pre-coated auxiliary agent overlayer 72 is peeled off, and a new auxiliary agent overlayer 72 is formed. Therefore, there are disadvantages in that the number of replacements of the auxiliary agent layer 72 increases and the amount of used waste resin, that is, the amount of radioactive waste increases.

[Purpose of the invention]

The present invention was made in order to eliminate the drawbacks of the prior art, and an object of the present invention is to provide a multi-tube excessive demineralization device that can uniformly form an auxiliary agent overlayer.

[Summary of the invention]

The present invention makes it possible to ensure that the flow rate of the powdered ion exchange resin slurry that forms the auxiliary agent overlayer in the upper part of the over-element installed upright in the container body of a conventional multi-tube over-desalination apparatus is equal to or lower than the sedimentation rate of the resin. Based on the findings, a flow pipe was formed along the axis in the center of the container body, and a part of the introduced water was configured to pass through a large number of over-element pipes and the flow pipe. , the auxiliary agent overlayer can be uniformly formed on the surface of the overelement.

[Embodiments of the invention]

Figure 5 shows the conventional multi-tube over-desalination equipment.
These are the results of pre-coating the auxiliary powder resin onto the over-element with a LV of 4 m/h, then collecting the pre-coating auxiliary agent from each position of the over-element, and measuring the sedimentation rate of the auxiliary agent in still water. The horizontal axis is the position from the lower end of the filter element, and the vertical axis is the sedimentation rate of the collected auxiliary agent. As is clear from the figure, the sedimentation speed of the pre-coated auxiliary agent is 1000mm from the bottom of the filter element.
Above that, it decreases rapidly. This means that the resin having a low specific gravity is thinly precoated at the upper position of the over-element, and it is thought that this is caused by the resin having a high specific gravity not being able to reach the upper position of the over-element. It has become clear that in order to form a sufficient auxiliary agent overlayer, it is necessary to pre-coat the resin with a sedimentation velocity of about 36 m/h or more.

Therefore, we measured the rate of increase in water flow in the inter-element region for each LV. The results are shown in FIG. As shown in Figure 6, LV is 4m/h
In the case of , when the position of the over-element is 1000mm or more, the upward flow velocity in the area between the over-elements becomes less than the sedimentation speed of the resin, 36 m/h, and at positions beyond that, the amount of resin reaching is small. The thickness of the precoat forming layer becomes thinner.
Also, if the LV is increased to 6m/h and 10m/h,
The position where the rising flow velocity in the inter-element region remains higher than the sedimentation velocity of the resin moves further upward. However, it has been found that it is not possible to maintain the upward flow rate above the sedimentation rate of the resin over the entire length of the flow element. Therefore, in order to make the thickness of the resin precoat layer uniform over the entire over-element, it is necessary to maintain the rising speed of the resin slurry at a value greater than the sedimentation speed of the resin even at the upper end of the over-element. It is a condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the multi-tube over-desalination apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. In addition,
Portions corresponding to those described in the prior art are given the same reference numerals and their description will be omitted.

FIG. 7 shows the internal structure of an embodiment of the multi-tube over-desalination apparatus according to the present invention, which was made in consideration of the above experimental results. As shown in FIG. 7, in the over-desalination device 22, an introduced water inlet 74 to which the condensate pipe 20 is connected is narrowed, and the introduced water inlet 74 is narrowed.
A disk-shaped guide 76 having a substantially diamond-shaped cross section is provided above 4 to narrow the flow path of the introduced water 56 and increase the flow velocity. A flow pipe 78 is provided above the guide 76, that is, in the center of the excessive desalination device 22. The flow path pipe 78 is opened so as to gradually expand at the upper and lower ends, so that the introduced water 56 can smoothly flow in and out. A guide 80 is formed along the guide 76 at the lower end of the flow pipe 78, and a guide 80 is formed at the upper end of the flow pipe 78.
A disk-shaped guide plate 82 having a diameter approximately half of the container body 46 extending in the radial direction of 8 is provided. Further, near the upper end of the flow pipe 78 and below the guide plate 82, a guide 84 having a substantially inverted trapezoidal shape is formed. Further, a guide 86 is appropriately provided below the filter chamber 52, that is, near the bottom plate 48, so that the introduced water 56 flows evenly into the area between the filter elements 58.

The over-element 58 is erected to penetrate through the bottom plate 48, and its upper end is hermetically fixed to the ceiling plate 50.

Formation of the auxiliary agent overlayer 72 in the over-desalination apparatus 22 configured as described above is performed as follows. After filling the overchamber 52 with water, a powder ion exchange resin slurry adjusted to a predetermined concentration is injected into the overchamber 52 from a resin mixing tank (not shown) via the condensate pipe 20 using a pump. The injection speed of the resin slurry is determined by the pre-coat to the element 58.
The LV should normally be 3 to 4 m/h. The resin slurry becomes introduced water 56 and enters the introduced water inlet section 74.
It is accelerated in the narrow channel formed by the bottom plate 48 and the guide 76, and diffuses along the bottom plate 48 in the circumferential direction of the overchamber 52. When the resin slurry that has entered the filter chamber 52 passes through the flow path formed by the bottom plate 48 and the guide 76, it sucks the fluid in the flow path pipe 78, and is further spread uniformly in the area between the filter elements 58 by the guide 86. It is rectified so that it flows in.

The resin slurry is then applied to each filter element 58.
rise between. At this time, as shown in FIG. 3, a part of the slurry water passes through the filter element 58,
Powdered resin is captured and precoated on the surface of the overlayer element 58 to form an auxiliary overlayer 72 . The resin slurry that has not passed through the over-element 58 reaches the upper end area of the over-element 58, changes its traveling direction horizontally, and moves toward the center of the over-chamber 52. In this way, the resin slurry directed toward the center of the chamber 52 is guided into the flow pipe 78 by the guide plate 82 and the guide 84, and flows down the flow pipe 78. After that, as described above, the introduction water inlet section 7
The resin slurry flowing from 4 is sucked into the excess chamber 5.
2 will be cycled. Therefore, by setting the suction flow rate to the flow path formed by the guides 76 and 80 so that the rising speed of the resin slurry in the area between each over-element at the upper end of the over-element is equal to or higher than the resin settling speed, it is possible to element 58
The resin will be in uniform contact with the entire length of the
The auxiliary agent overlayer 72 can be formed uniformly.
After forming the auxiliary agent overlayer 72 to a predetermined thickness, the introduction of the resin slurry from the resin mixing tank is stopped, and the precoating is completed.

FIG. 8 shows the experimental results of the precoat forming layer when the rate of rise of the resin slurry at the upper end of the over-element 58 was varied. (A) is the case where the upward flow rate of the resin slurry at the upper end of the over-element is 0, and (B) is the case where the upward flow rate is 30 m/h.
(C) is the case where the upward flow velocity is 48 m/h. As is clear from the figure, when the upward flow velocity of the resin slurry at the upper end of the over-element 58 is 48 m/h, which is higher than the sedimentation speed of the resin, 36 m/h, that is, in the case of FIG. A uniform precoat layer can be formed.

After forming the auxiliary agent overlayer 72, the process is switched to over-desalination treatment. In this case, the introduced water 56 has a LV of 4 m/h with respect to the excess element 58 during precoating.
It is gradually raised from the top and is normally supplied to the overchamber 52 at a rate of 8 to 10 m/h. In this embodiment, a portion of the introduced water 56 is constantly circulated between the filter elements 58 via the flow pipe 78, so that the water is uniformly filtered over the entire length of the filter element 58. Can be desalinated. Therefore, it is possible to prevent the conventional method in which the amount of permeation of the treated water locally increases near the lower end of the overlayer element 58, which increases local contamination of the overlayer, and improves over-desalination performance. can be achieved. Further, since the volume excess portion increases, the differential pressure rises more slowly, and the time required to reach the set pressure as the overlife is lengthened, making it possible to extend the overlife. In addition, when the differential pressure reaches the set value, the auxiliary agent layer 72 is peeled off in the same manner as before, the inside of the layer element 58 and the layer 52 is cleaned, and the precoat is performed again with new resin. I can do it.

〔Effect of the invention〕

As explained above, by forming a flow path in the center of the container body and circulating introduced water, a uniform auxiliary agent overlayer can be formed on the surface of the overelement.

[Brief explanation of the drawing]

Figure 1 is a system diagram of the condensate purification system and reactor water purification system of a boiling water nuclear power plant, Figure 2 is an explanatory diagram of a conventional multi-tube over-desalination equipment, and Figure 3 is a multi-tube over-desalination system. Fig. 4 is a cross-sectional view of the over-element used in the salting equipment, and Fig. 5 is a diagram showing the formation thickness of the auxiliary agent over-layer for various linear speeds of the powder ion exchange resin slurry in a conventional multi-tube over-desalting equipment. 6 is a diagram showing the relationship between the longitudinal position of the over-element and the resin sedimentation velocity in a conventional multi-tube over-desalination equipment, and Figure 6 shows the relationship between the longitudinal position of the over-element and the sedimentation velocity of the resin in a conventional multi-tube over-desalination equipment for various linear velocities. A diagram showing the relationship between the direction and the rising speed of the resin slurry, FIG. 7 is an explanatory diagram of the multi-tube over-desalination apparatus according to the present invention, and FIGS. 8A to C
FIG. 3 is a diagram showing the formation state of an auxiliary agent overlayer with respect to the slurry rising speed at the upper end of the overlayer element. 22... Over desalination device, 46... Container body, 5
4... Introducing water inlet, 58... Passing element, 7
4...Introduction water inlet section, 76, 80, 84, 86...
...Guide, 78...Flow path pipe, 82...Guidance plate.

Claims (1)

[Claims] 1. A multi-tube over-desalination apparatus having a container body, a large number of approximately cylindrical over-desalination elements erected in the axial direction within the container body, and an introduction water inlet provided at the lower part of the container body; A channel pipe is provided in the center of the container body along the axis and has upper and lower ends open, so that a portion of the introduced water passes between the plurality of over-elements and inside the channel pipe. A multi-tube over-desalination device characterized by the following configuration.