JP2001157805A - Precoat system and precoating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that in order to form a uniform precoat layer on each of precoat-type elements 22, a precoat process conventionally has to be performed in three steps using third piping 13 in addition to first and second pipings 11, 12 in the early stage of the precoat process. SOLUTION: This precoat system S consists of first piping 11 for supplying slurry from a precoat tank 10 to a filter vessel 21, second piping 12 for returning penetrating water from precoat-type elements 22 to the precoat tank 10 and third piping 13 for xtracting diluting water before penetration from the top of the filter vessel 21 and returning the water to the precoat tank 10. In addition, the system S forms an ascending water flow in the filter vessel 21 using the third piping 13 in the early stage and the terminal stage of the precoat process. In this system S, the third piping 13 is omitted and a water passage pipe 27 is installed at a position surrounded by the precoat-type elements 22 in the filter vessel 21. Thus a descending water flow opposed to the ascending water flow from an inlet pipe 21C through the water passage pipe 27 in the filter vessel 21 (an upper chamber 21B) is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precoating system and a precoating method, and more particularly, to a precoating system and a precoating method for precoating a precoating material into a precoating filter widely used in, for example, nuclear power plants and thermal power plants. About the method.

[0002]

2. Description of the Related Art Conventionally, in a power plant such as a nuclear power plant or a thermal power plant, steam is produced by utilizing nuclear power or thermal power, and the steam is used to drive a power generation turbine to generate power. For example, in a boiling water nuclear power plant (BWR), steam generated in a nuclear reactor is sent to a high-pressure turbine and then to a low-pressure turbine in order, and each turbine rotates a generator to generate electric power. It is cooled, sent to the condensate purification system as condensate, and used repeatedly. In the condensate purification system, the condensate is sent in the order of a condensate filtration device and a condensate desalination device, and in both of them, suspended substances such as iron oxide fine particles generated from piping materials such as reactors and piping and Fe and the like. After removing various ion components such as ions and Cu ions, condensate is sent to the reactor. The reactor is provided with a reactor coolant purification system and a fuel pool cooling purification system in addition to the condensate purification system. Also in these purification systems, suspended substances and ionic components generated in the systems are removed using a filtration device.

In a condensate purification system, a reactor coolant purification system or a fuel pool cooling purification system, for example, a precoat type filtration device is installed as a condensate filtration device. A precoat material (for example, a powdery ion exchange resin or the like) is precoated on a precoat element of the filtration device using a precoat system.

As shown in FIGS. 3 and 4, a conventional precoat system S includes an adjustment tank (hereinafter, referred to as a "precoat tank") 10 for adjusting a slurry with a precoat material and dilution water, and this precoat tank. 10 through the first pipe 11 for supplying the slurry from the inlet of the filtration vessel 21 of the precoat filtration device 20 to the inside thereof, and a plurality (for example, several tens to several hundreds) of precoat elements 22 in the filtration vessel 21. A second pipe 12 for returning the diluted water from the outlet of the filtration container 21 to the precoat tank 10, and extracting the dilution water before passing through each precoat type element 22 from the upper opening of the filtration container 21 to the precoat tank 10. And a return third pipe 13.

[0005] A pump 14 is provided in the first pipe 11, and a slurry of the precoat material is supplied from the precoat tank 10 to the inside of the filtration container 21 via the pump 14, and dilution water is supplied from the outside of each precoat type element 22. While passing inward, a precoat material is laminated on the surface of each precoat element 22 to form a precoat layer. The dilution water that has passed through each precoat type element 22 is returned to the precoat tank 10 via the second pipe 12, and a circulation flow of the dilution water is formed between the precoat tank 10 and the filtration container 21. The second pipe 12 branches near the precoat tank 10, and the first branch pipe 12A is connected to the first pipe 11 and the second branch pipe 12B is connected to the third pipe 13
It is connected to the. A discharge pipe 15 for discharging backwash air or the like containing water after backwashing the precoat element 22 to a backwash receiving tank (not shown) is connected to an upper opening of the filtration container 21. . The discharge pipe 15 and the precoat tank 10 are connected via a third pipe 13. In addition, 16 is a pipe through which treated water flows, 17 is a pipe through which water to be treated flows, 18 is an air supply pipe that supplies backwash air, and 19A to 19H are automatic valves.

As shown in FIG. 4, the inside of the filtration container 21 is connected to a lower chamber 21A and an upper chamber 21 via a tube sheet 23.
B. An inlet pipe 21C penetrating through the lower chamber 21A is connected to a central opening of the tube sheet 23, and a baffle plate 24 is opposed to an upper end opening of the inlet pipe 21C. The outlet pipe 2 is located near the inlet pipe 21C.
1D is arranged. The first pipe 21C is provided at the inlet pipe 21C.
Pipe 11 is connected, and the second pipe 1 is connected to the outlet pipe 21D.
2 are connected. A vent nozzle 21E is attached to an upper wall of the upper chamber 21B through an opening, and a third pipe 13 is connected to the vent nozzle 21E via a discharge pipe 15 so as to be able to communicate with the vent nozzle 21E. In addition, in FIG.
Is a nozzle for supplying backwash air, 25 is a lower chamber 21
A tube that communicates A with the upper chamber 21B and supports the precoat-type elements 22 is a support member that supports the upper end of each precoat-type element 22.

When water is sampled for a predetermined period using the filtration device 20, the pressure difference between the outside and inside of each precoat element 22 reaches a predetermined value (for example, 175 kPa), and the pressure difference is measured by a differential pressure gauge (see FIG. (Not shown) and the water sampling process is completed. Next, the water sampling process is switched to the backwashing process by operating the operation panel, backwashing water is supplied in a direction opposite to the time of water sampling, and backwashing air is supplied into the lower chamber 21A, and the air surge backwashing is performed. To remove the precoat material from each precoat type element 22. Subsequently, the backwashing step is switched to the precoating step by operating the operation panel to form a precoating layer of a precoating material on each precoating type element 22. When the precoating step is completed, the precoat material is held on the surface of each precoating type element 22 in the standby preparation step using the holding pump 14A, and the water pressure is gradually increased to the water pressure at the time of water sampling in the standby step.
Switch to the water sampling process.

In the case of the conventional precoating method, the pump 14 is driven in the initial stage of the precoating to form a uniform precoating layer on the precoating type element 22 and the first, second and second pumps are controlled by the control device. 3 piping 1
Automatic valves 19 for each of 1, 12, 13 and discharge pipe 15
A, 19B, 19C, 19D and the automatic valve 19E of the first branch pipe 12A are opened, and the slurry in the precoat tank 10 flows from the first pipe 11 and the inlet pipe 21C to the filtration vessel 21 with the other automatic valves closed. Flows into the upper chamber 21B, and is dispersed throughout the room via the baffle plate 24. Many of the dilution water in the upper chamber 21B (for example, 9 /
10) passes through each precoat type element 22, flows into the lower chamber 21A, and returns to the precoat tank 10 via the outlet pipe 21D and the second pipe 12. Part of the dilution water (for example, 1/10 of the total flow rate) is supplied to the upper vent nozzle 21E, the discharge pipe 15 and the third pipe 13 together with the precoat material.
And returns to the pre-coat tank 10. Third pipe 1
When the diluting water in the upper chamber 21B escapes from the upper chamber 21B together with the pre-coat material via 3, a rising water flow from the lower part to the upper part in the upper chamber 21B is formed, and the pre-coat material on the rising water flow A part is carried to the upper part in the upper chamber 21B, and starts forming a precoat layer on the whole of each precoat type element 22.

After the initial step, the automatic valve 19D of the third pipe 13 is closed, the reflux of the dilution water from the third pipe 13 is stopped, the automatic valve 19F of the second branch pipe 12B is opened, and the second valve 19D is opened. When the dilution water is refluxed using only the pipe 12 of
Since the precoat material is uniformly dispersed in the upper chamber 21B, a uniform precoat layer is formed on each precoat element 22 as a whole.

In the final step, the automatic valve 19F of the second branch pipe 12B is closed again, the automatic valve 19D of the third pipe 13 is opened, and the dilution water in the upper chamber 21B is passed through the third pipe 13. It is returned to the precoat tank 10. At this time, the precoat material remaining in the discharge pipe 15 and the third pipe 13 at the time of the initial step is removed and returned to the upper chamber 21B via the precoat tank 10, and the remaining precoat material is removed from each precoat mold. The element 22 is pre-coated, and finally all the pre-coat materials are pre-coated.

[0011]

However, in the case of the conventional pre-coating method, the first and second pre-coating processes are performed at the beginning of the pre-coating process in order to form a uniform pre-coat layer on each pre-coat type element 22 as described above. Piping 11,
A rising water flow must be formed in the upper chamber 21B using the third piping 13 in addition to the second piping 12, and the third piping 13 is used at the end of the precoating process as in the initial case. Then, the residual pre-coat material in the pipe 13 and the discharge pipe 15 must be removed, and the pre-coat process is complicated in three steps. In the case of the conventional pre-coating system S, the third and the third
The auxiliary equipment such as the piping 13 and the automatic valve 19D is required, which not only complicates the piping structure but also increases the cost, and also requires maintenance of the auxiliary equipment such as the automatic valve 19D.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a pre-coat system capable of simplifying a pre-coat piping structure to reduce initial costs and maintenance costs. It is an object of the present invention to provide a pre-coating method that can be used.

[0013]

According to a first aspect of the present invention, there is provided a precoat system comprising: an adjustment tank for adjusting a slurry with a precoat material and dilution water; A first pipe for supplying the slurry to the inside thereof; and a second pipe for returning diluting water permeated by precoating a plurality of precoat-type elements in the filtration container with a precoat material from an outlet of the filtration container to the adjustment tank. And a third pipe for extracting the dilution water before passing through each of the precoat-type elements from the upper opening of the filtration container and returning the diluted water to the adjustment tank. In the pre-coating system for forming a rising water flow from the inlet side to the opening side in the filtration vessel using the pipe of the third pipe, while the third pipe is omitted, A water pipe extending from a position slightly above the inlet of the filtration container to at least the upper end of each of the pre-coated elements is provided at a position surrounded by each of the pre-coated elements in the filtration container, and the water pipe is provided in the filtration container. And forming a water flow that is opposed to the water flow from the inlet through the air inlet.

According to a second aspect of the present invention, there is provided a precoating method for adjusting a slurry with a precoating material and diluting water, and from the adjusting tank to the inside of a filtration vessel of a precoat type filtration device from an inlet of the filtration vessel. A first pipe for supplying the slurry, a second pipe for returning a dilution water that has been permeated by precoating a plurality of precoat elements in the filtration container with a precoat material from an outlet of the filtration container to the adjustment tank, A third pipe for extracting the dilution water before passing through each of the precoat elements from the opening at the top of the filtration vessel and returning the diluted water to the adjustment tank, and using the third pipe at the beginning and end of the precoat. Then, each of the pre-coated elements is pre-coated using a pre-coating system that forms a rising water flow reaching from the inlet side to the opening side in the filtration container. In the method, a water pipe extending from a position slightly above the inlet to at least a position of an upper end of each of the precoat elements in the filtration container is provided at a position surrounded by each of the precoat elements, while the third pipe is provided. Omitting, when pre-coating each of the pre-coated elements using the first and second pipes, forming a water flow facing the water flow from the inlet through the water pipe in the filtration container. It is a feature.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, based on the embodiment shown in FIG. 1 and FIG. In each figure,
FIG. 1 is a configuration diagram showing an embodiment of the precoat system of the present invention, and FIG. 2 is a cross-sectional view showing an example of a filtration device used in the precoat system shown in FIG.

In the present embodiment, for example, a precoat system S installed in a reactor coolant purification system of a nuclear power plant will be described. As shown in FIG. 1, the pre-coating system S includes a third pipe 13 shown in FIG.
And its attached devices are omitted. Further, as shown in FIG. 2, the internal structure of the filtration container 21 is improved. Others are conventionally configured according to the precoat system.

As shown in FIG. 2, the filtering device 20 includes:
A filter container 21, a precoat element 22, a tube sheet 23, a baffle plate 24, a tube 25, and a support member 26 are provided. Further, the inside of the filtration container 21 is divided into a lower chamber 21A and an upper chamber 21B via a tube sheet 23. In the present embodiment, a water pipe (hereinafter, referred to as a draft tube) 27 and a rectifying plate 28 are provided in the upper chamber 21B. Draft tube 27
2 extends from a position slightly above the inlet pipe 21C to a position at the upper end of each precoat element 22 as shown in FIG. 2, and the precoat element is disposed therearound. The lower end of the draft tube 27 is connected to the center of the baffle plate 24, and the upper end is supported by a support member 26.

Therefore, most of the inflowing water from the inlet pipe 21C is dispersed throughout the upper chamber 21B by the baffle plate 24 to form a rising water flow, while a part of the inflowing water rises in the draft tube 27 to reach the upper end. It flows out from the opening toward the upper wall surface of the upper chamber 21B, and forms a downward rain flow through the upper wall surface to the entire upper chamber 21B, thereby suppressing the rising water flow formed by the baffle plate 24. At this time, most of the precoat material rises as indicated by an arrow A in FIG. 2 on the rising water flow formed by the baffle plate 24 in the upper chamber 21B, and the remaining precoat material is transferred to the upper chamber 21B by the draft tube 27. As shown by an arrow B in FIG. 2, it descends on the descending water flow formed by the upper wall surface flowing toward the upper wall surface and suppresses the rise of the precoat material from below. As described above, since the precoat material is carried on the water flow from both the upper and lower sides, the precoat material is evenly distributed throughout the upper chamber 21B, and a uniform precoat layer is formed over the entire length of each precoat type element 22.

As described above, in this embodiment, the filtration container 2
1, the draft tube 27 is provided, so that a rising water flow and a descending water flow can be formed so that the pre-coated material can be evenly distributed in the entire upper chamber 21B. , It is not necessary to extract the water to the outside to create a rising water flow, so that it is possible to omit the conventional third piping and auxiliary equipment such as an automatic valve attached thereto. Therefore, it is not necessary to perform complicated control in the precoating step as described later.

Therefore, a precoat method of the present invention using the precoat system of the present embodiment will be described. When the pump 14 is driven under the control of the control device, the automatic valves 19A and 19B of the first and second pipes 11 and 12 and the first and second
The automatic valves 19E and 19F of the branch pipes 12A and 12B are opened, and the other pre-coat tank 1 is closed.
The slurry in the tube 0 flows from the first pipe 11 and the inlet pipe 21C into the upper chamber 21B of the filtration container 21. Most of the pre-coated material rises from the lower part of the upper chamber 21B on the rising water flow dispersed in the upper chamber 21B via the baffle plate 24, and the remaining pre-coated material rises in the draft tube 27 and the upper end of the draft tube 27. From upper opening 21B
Flows out toward the upper wall surface and descends from the upper part of the current plate 28 on the descending water flow formed in the upper chamber 21B by the upper wall surface. As described above, the precoat material spreads over the entire length of each precoat element 22 due to the rising water flow from the lower part and the downward precipitation flow from the upper part in the upper chamber 21 </ b> B, and the dilution water of the precoat material flows from the outside to the inside of each precoat element 22. During the passage, the precoat material is uniformly laminated over the entire length of each of the precoat elements 22 to form a uniform precoat layer. Then, when the pre-coat material in the pre-coat tank 10 is exhausted, the process is switched from the pre-coat process to the standby preparation process, and after this process, the process is switched to the water sampling process through the same process as the conventional one.

As described above, according to the present embodiment,
Since the draft tube 27 is provided in the upper chamber 21B of the filtration container 21 and the lower precipitation flow is formed from the upper part in the upper chamber 21B using the draft tube 27, the first and second pipes 11, 12 are connected. By simply using the upper chamber 21B, a rising water flow from the lower part and a lower precipitation flow from the upper part are formed in the upper chamber 21B.
B can be evenly distributed over the entirety of B, a uniform precoat layer can be formed over the entire length of each precoat element 22, and the control operation of the precoat process can be simplified.

Further, according to the present embodiment, the precoating step can be performed only by using the first and second pipes 11 and 12, thereby eliminating the need for the conventional third pipe and its attached equipment. In addition, the construction cost can be reduced by simplifying the pre-coating piping structure, and the maintenance cost of auxiliary equipment such as an automatic valve can be reduced.

In the above embodiment, a powdery ion-exchange resin has been described as an example of the precoat material. However, the precoat material may be a filter aid such as cellulose. In the above embodiment, the reactor coolant purification system of a nuclear power plant has been described as an example.However, the present invention can also be applied to a condensate purification system or a fuel pool cooling purification system of a nuclear power plant. It can be widely applied to condensate purification systems of thermal power plants and other filtration purification systems.

[0024]

According to the first aspect of the present invention, it is possible to provide a precoat system which can simplify the precoat piping structure and reduce initial costs and maintenance costs.

Further, according to the second aspect of the present invention, it is possible to provide a precoating method capable of simplifying the control operation of the precoating step.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a precoat system of the present invention.

FIG. 2 is a sectional view showing an example of a filtration device used in the precoat system shown in FIG.

FIG. 3 is a configuration diagram illustrating an example of a conventional precoat system.

FIG. 4 is a sectional view showing an example of a filtration device used in the precoat system shown in FIG.

[Explanation of symbols]

 S Precoat system 10 Precoat tank (adjustment tank) 11 First pipe 12 Second pipe 13 Third pipe 20 Filtration device 21 Filtration vessel 21C Inlet pipe 21D Outlet pipe 21E Vent nozzle (opening on upper wall surface) 27 Draft tube (Water pipe)

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuru Yoda 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation F-term (reference) 4D066 BA01 CA12 CA17 CB08 CB11

Claims (2)

[Claims] 1. An adjusting tank for adjusting a slurry with a precoat material and diluting water, a first pipe for supplying the slurry from an inlet of a filtration container of a precoat type filtration device to the inside of the adjusting tank from the adjusting tank, A second pipe for returning the diluted water permeated by pre-coating the pre-coated material to the plurality of pre-coated elements in the container from the outlet of the filtration container to the adjustment tank, and diluting water before passing through each of the pre-coated elements. A third pipe drawn out from an upper opening of the filtration container and returned to the adjustment tank, wherein the opening is formed from the inlet side in the filtration container using the third pipe at an early stage and a final stage of precoating. In the pre-coating system for forming the rising water flow reaching the part side, the third pipe is omitted, and at least each of the pre-coating molds is positioned from a position slightly above the inlet of the filtration container. A water pipe extending to the position of the upper end of the element is provided at a position surrounded by each of the pre-coated elements in the filtration container, and forms a water flow that faces the water flow from the inlet via the water pipe in the filtration container. A precoat system characterized by the following. 2. An adjusting tank for adjusting a slurry with a precoat material and diluting water, a first pipe for supplying the slurry from an inlet of a filtration container of a precoat type filtration device to the inside of the adjusting tank from the adjusting tank; A second pipe for returning the diluted water permeated by pre-coating the pre-coated material to the plurality of pre-coated elements in the container from the outlet of the filtration container to the adjustment tank, and diluting water before passing through each of the pre-coated elements. A third pipe drawn out from an upper opening of the filtration container and returned to the adjustment tank, wherein the opening is formed from the inlet side in the filtration container using the third pipe at an early stage and a final stage of precoating. In the method of pre-coating each of the pre-coating type elements using a pre-coating system that forms a rising water flow reaching the part side, the above-mentioned inlet in the filter vessel is provided slightly above the inlet. While providing a water pipe extending from the position to at least the upper end of each of the pre-coated elements at a position surrounded by each of the pre-coated elements,
When omitting the third pipe and using the first and second pipes to precoat each of the precoated elements,
A pre-coating method, wherein a water flow is formed in the filtration container, the water flow being opposed to the water flow from the inlet via the water pipe.