JPH0611384B2 - Filtration tower using hollow fiber module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a filtration tower using a hollow fiber module that can be used, for example, when removing clad contained in wastewater for thermal power plants or nuclear power plants. And
In particular, the precoat type filtration tower installed to remove the cladding contained in the waste water for the above is converted into a filtration tower using a hollow fiber module, or the one installed as a filtration tower using a hollow fiber module is a filtration tower. The present invention relates to a filtration tower using a hollow fiber module devised so as to be used as a precoat type filtration tower by slightly changing the inside of the.

<Prior Art> Conventionally, a precoat type filtration tower has been used to remove clads such as iron oxide contained in wastewater for thermal power plants or nuclear power plants, particularly condensate.

As shown in FIG. 6, the structure of the conventional precoat type filtration tower is such that the lower partition plate 2 communicating with the raw water pipe 1 is provided in the filtration tower 3, and the insides of the filtration tower 3 are the upper chamber A and the lower chamber C. And a plurality of filtration elements 4 communicating with the water collection pipe 5 are erected in the upper chamber A, and the lower end of the water collection pipe 5 is lowered by penetrating the water collection pipe 5 in the lower partition plate 2. The treatment water pipe 6 and the cleaning air layer 7 are communicated with the lower chamber, and the baffle plate 8 is attached above the raw water pipe 1 facing the upper chamber A. Reference numeral 9 is an air vent pipe, and 10 to 13 are valves.

The operation in such a conventional precoat type filtration tower is as follows.

That is, when pre-coating the filter element 4 with a filter aid, the raw water pipe 1 and the treated water pipe 6 are closed circulation system through a pre-coat layer (not shown) and a pre-coat pump (not shown), and the powder is put in the pre-coat tank. A slurry liquid of a filter aid such as an ion exchange resin is prepared, the upper chamber A and the lower chamber C of the filtration tower are filled with water, valves 10 and 11 are opened, and the precoat pump is driven to prepare the slurry liquid. Water pipe 1
More inflow. After the slurry liquid flows into the upper chamber A by such an operation, when the slurry liquid passes through each filter element 4, the filter aid in the slurry liquid is pre-coated on the outer periphery of each filter element 4, and the filtrate is Water is collected in the lower chamber C by each water collecting pipe 5, and then circulated through the treated water pipe 6 to the precoat tank.

When the raw water is filtered after pre-coating each filter element 4 with the filter aid by such an operation, it is performed as follows.

That is, the valve 10 and the valve 11 are opened to feed the raw water to the raw water pipe 1.
From the treated water, the raw water is passed through the precoat layer of the filter aid, the clad existing in the raw water is filtered, and the treated water is discharged from the treated water pipe 6.

Further, the following peeling operation of the precoat layer is performed after the completion of filtration.

That is, by opening the valve 13 and the valve 10 to drain the water in the upper chamber A, most of the used filter aid pre-coated on the filter element 4 is peeled off by gravity fall, and the filter aid is removed from the raw water pipe. Eject from 1. Next, by opening the valve 12 and injecting compressed air from the cleaning air pipe 7,
The filtered water existing above the lower end of the raw water pipe 5 is suddenly made to flow back to the filtration element 4 via the water collection pipe 5, and then the backwash water from the treated water pipe 6 and the gas-liquid mixture by the compressed air from the washing air pipe 7 are used. Is flowed back to the filter element 4 to further wash the filter aid remaining on the filter element 4. After the peeling operation of the precoat layer is completed, the precoating operation of the filter aid and the water flow are repeated.

<Problems to be Solved by the Invention> The structure of a conventional precoat type filtration tower is as shown in FIG. 6, and when a powder cation exchange resin and a powder anion exchange resin are used as a filter aid, Although there is an advantage that impurity ions in the raw water can be removed together with the removal of the clad, it has the following drawbacks because a filter aid is used to remove the clad.

That is, when the precoat type filtration tower is used for treating condensate of a boiling water nuclear power plant, for example, when the precoat layer is peeled off, a large amount of used filter aid containing a radioactive solid substance is discharged, Therefore, it needs to be further treated as radioactive waste.

However, most of the solid matter discharged in the precoat type filtration tower is a used filter aid used as a precoating agent, and the precoat type filtration tower has a drawback that it unnecessarily increases the emission amount of radioactive waste. . Therefore, in order to solve the drawbacks of such a precoat type filtration tower, in recent years, when removing the clad in the condensate, a large number of hollow fiber modules bundled with a large number of hollow fibers are installed upright in the filtration tower, It has been attempted to significantly reduce the amount of radioactive waste by directly filtering the clad with each hollow fiber without using an auxiliary agent.

In addition, in a filtration tower using such a hollow fiber module, since impurity ions in the condensate cannot be removed, in order to remove the impurity ions, a cation exchange resin in a particulate form and an anion in a particulate form are provided in the preceding stage or the latter stage of the filtration column. A demineralization tower using an exchange resin is installed, or a conventional precoat type filtration tower using a powder cation exchange resin and a powder anion exchange resin as a filter aid is provided in the latter stage of the filtration tower using a hollow fiber module in some cases. It is usually installed.

The present invention relates to the structure of a filtration tower using such a hollow fiber module, and in particular, a conventionally used precoat type filtration tower as shown in FIG. 6 is comparatively used as a filtration tower using a hollow fiber module. An object of the present invention is to provide a filtration tower using a hollow fiber module having a structure that can be easily modified.

<Means for Solving Problems> The present invention relates to a filtration column using a hollow fiber module in which the original shape of the conventional precoat type filtration column shown in FIG. The element 4 is changed to a hollow fiber module in which a large number of hollow fibers are bundled, the hollow fiber module and the water collecting pipe 5 are connected via a connector, and an upper partition plate is provided at the upper end of the hollow fiber module to provide an inside of a filtration tower. Is divided into an upper chamber, a middle chamber, and a lower chamber, raw water is introduced from the middle chamber, and filtered water is obtained by passing the raw water from the outside to the inside of each hollow fiber of each hollow fiber module installed upright in the hollow, and filtering the filtered water. Be obtained from the lower chamber and / or the upper chamber,
Further, after filtration, a bubble dispersion mechanism and a bubble distribution mechanism for separating the clad adhering to the outer peripheral surface of each hollow fiber by vibrating action of bubbles are installed in the lower part of each hollow fiber module. is there.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory view of a filtration tower showing an example of an embodiment of the present invention. The inside of the filtration tower 3 is divided into an upper chamber A, a hollow B and a lower chamber C by an upper partition plate 14 and a lower partition plate 2, Another number of hollow fiber modules 1 in the middle chamber B via the connector 16 and the water collecting pipe 5.
Set up 5.

The hollow fiber module 15, the connector 16, and the water collection pipe 5
As shown in Fig. 2 in detail, a large number of hollow fibers 17 (three in the drawing are shown, but usually 100 or more are used) with both ends open are bundled, and the hollow fibers at both ends of the hollow fiber bundle are bundled. A hollow fiber module 15 having a fixing portion 18 in which a gap between threads is adhered with an adhesive or the like is constituted, and the hollow fiber module 1
The lower end opening of 5 is housed in the upper part of the connector 16 having the water collecting chamber 19, and the water collecting pipe 5 is provided in the lower part of the connector 16.
Through the upper opening of the.

Reference numeral 20 denotes an outer cylinder of the hollow fiber module 15, which has a water flow port 21 and an air vent port 22, but the outer cylinder 20 may be of a net shape. It is not necessary to attach the circulation port 21 and the air vent port 22.

A bubble passage 23 is provided on the side plate of the connector 16, and the bubble passage 23 is provided below the hollow fiber module 15.
And a bubble dispersion mechanism 25 for dispersing bubbles on the outer peripheral surface of each hollow fiber 17 is provided.
A skirt portion 26 is provided below the connector 16. When the hollow fiber module 15 is erected in the middle chamber B, the upper end of the hollow fiber module 15 is passed through the upper partition plate 14 via the fixture 27, and the upper end opening of each hollow fiber 17 is placed in the upper chamber A.
Further, the water collecting pipe 5 penetrates the lower partition plate 2, and the lower opening of the water collecting pipe 5 communicates with the lower chamber C.

Between the skirt portion 26 and the lower partition plate 2, each water collecting pipe 5
The perforated plate 28 is installed so as to surround the above, and the tubular body 30 having the air outlet 29 is communicated below the perforated plate 28 to form the bubble distribution mechanism 31.

Since the bubble distribution mechanism 31 is provided for introducing bubbles into the skirt portion 26, the structure is not limited to the structure shown in FIG. 2 as long as it achieves this purpose.

Further, as shown in FIG. 1, an air blow pipe 33 having a valve 32 is provided in the side trunk of the filtration tower 3 below the upper partition plate 14, and an air inflow pipe having a valve 34 is provided in the raw water pipe 1. 35
Is provided by branching. The other configurations of the pipes and valves are similar to those of the conventional precoat type filtration tower shown in FIG.

<Operation> The operation of the present filtration tower is as follows.

First, when filtering the raw water, the valve 10 and the valve 11 are opened, and the raw water flows in from the raw water pipe 1. The raw water that has flowed into the inner chamber B via the raw water pipe 1 has a flow port 21 of each hollow fiber module.
To reach the outer peripheral surface of each hollow fiber 17, and when raw water passes from the outer side to the inner side of each hollow fiber 17, solid matter such as clad in raw water is filtered on the outer peripheral surface of each hollow fiber 17 to obtain filtered water. Reaches the lower chamber C via the connector 16 and the water collection pipe 5, and is then taken out of the filtration tower 3 through the treated water pipe 6. In addition, in the said filtration, the valve 13 can be opened and filtered water can also be taken in from the air vent pipe 9 via the upper chamber A.

By continuing such filtration, the pressure loss of each hollow fiber module 15 increases, or after performing a specified amount of filtration, the following washing operation is performed.

First, the valves 10 and 11 are closed, and while the upper chamber A and the lower chamber C are filled with the filtered water, and the middle chamber B is filled with the collected water, the valves 32 and 34 are opened and the compressed air is introduced from the air inflow pipe 35. Then, each hollow fiber module 15 is agitated with air.

That is, the compressed air flowing in from the air inflow pipe 35 collides with the perforated plate 28, then rises in the form of bubbles from the air outlet 29, and the bubbles are received by the skirt portion 26.
It reaches the bubble passage 23 and the bubble dispersion portion 24, reaches the upper part of the hollow fiber module 15 while vibrating the outer peripheral surface of each hollow fiber 17, and then is discharged to the outside of the filtration tower through the air vent port 22 and the air blow pipe 33. It

By such air agitation, each hollow fiber 17 is vibrated by the bubbles, so that the solid matter such as the clad adhered to the outer peripheral surface of each hollow fiber 17 is effectively peeled off.

After the air stirring is completed, the valve 34 is closed, the valve 10 is opened, and the water in the middle chamber B is drained. By removing the water, a concentrated liquid containing a large amount of solids is obtained outside the filtration tower 3.

Next, the following back washing is performed.

That is, compressed air flows in from the washing air pipe 7, and filtered water existing in the lower chamber C and above the water collecting pipe 5 is passed through the water collecting pipe 5 and the water collecting chamber 19 of the connector 16 to each hollow fiber 17
Backwash by passing from the inside to the outside of each hollow fiber 17
The solid substance remaining on the outer periphery of is removed, and drainage containing the solid substance is similarly taken out by opening the valve 10.

In the above-mentioned reverse cleaning, the compressed air flows in from the cleaning air pipe 7, the compressed air also flows in from the air vent pipe 9 by opening the valve 13, and the filtered water existing in the upper chamber A is also hollow fibers 17. It can also be passed from the inside to the outside.

After such backwashing is completed, the valve 10, the valve 32, the valve 1
2. Open the valve 13 to let the raw water flow from the raw water pipe 1 into the middle chamber B, discharge the air in the middle chamber B from the air blow pipe 33 to fill the middle chamber B with the raw water, and then close the valve 32. Each hollow fiber 1
The air in the upper chamber A is evacuated by the filtered water obtained by performing the filtration in 7 and the air in the lower chamber C is evacuated to fill each chamber, and then the valves 12 and 13 are closed and the valve 11 is opened. And continue the filtration described above.

As described above, the filtered water during the filtration can be obtained from the treated water pipe 6 or the air vent pipe 9.
It is possible to increase the flow velocity in the hollow fiber 17 and to increase the processing capacity of the filtration tower 3 as a result of obtaining the air from the air vent tube 9 rather than obtaining it alone.

Because the inner diameter of the hollow fiber 17 is usually as thin as 0.2 to 1.2 mm, the pressure loss when passing through the hollow fiber 17 is significantly affected by the length of the hollow fiber 17, and therefore Rather than taking out the filtered water from the ends of the hollow fiber 17, the passage length of the filtered water in the hollow fiber becomes 1/2 and the pressure loss becomes almost 1/2 when the filtered water is taken out from both ends. In other words, when the pressure loss of each hollow fiber 17 is constant, the amount of filtered water can be made larger by taking out the filtered water from one end of each hollow fiber 17 than by taking out the filtered water from both ends.

In this way, it is more advantageous to let the filtered water flow out from both ends of the hollow fibers 17 than to let it flow out from one end.
However, in this case, the filtration tower 3
There is a problem that the surrounding piping becomes a little complicated.

Therefore, as a means for solving this inconvenience, as shown in FIG. 3, one or a plurality of communication pipes 36 for communicating the upper chamber A and the lower chamber C are provided outside the filtration tower 3, or FIG. As shown in FIG. 1, one or a plurality of communication pipes 36 for the same purpose can be provided inside the filtration tower 3.

By providing such a communication pipe 36, the filtered water in the upper chamber A can flow out from the single treated water pipe 6 via the lower chamber C, so that the above-mentioned piping around the filtration tower does not become complicated. .

Further, as shown in FIG. 5, the communication pipe 36 may be provided in the hollow fiber module 15.

That is, each hollow fiber 1 having both ends open around the communication pipe 36
7 are arranged, and the hollow fibers 17 and the end faces of the communication pipes 36 are bonded to each other with an adhesive or the like to form a hollow fiber module 15 as the fixing portion 18, and the upper end of the hollow fiber module 15 is attached via the fixture 27. 14, the upper end opening of each hollow fiber 17 and the upper end opening of the communication pipe 36 communicate with the upper chamber A, and the lower end thereof,
That is, the lower end opening of each hollow fiber and the lower end opening of the communication pipe 36 are housed in the upper portion of the connector 16. The structure of other parts is similar to that of FIG.

In the hollow fiber module 15 shown in FIG. 5, the filtered water that has risen in each hollow fiber 17 and reaches the upper chamber A is passed through a communication pipe 36 provided in the hollow fiber module 15 to collect water.
9. It can flow out to the lower chamber C via the water collecting pipe 5. It goes without saying that the filtered water descending in each hollow fiber 17 flows out to the lower chamber C via the water collecting chamber 19 and the water collecting pipe 5.

By providing the communication pipe 36 in the hollow fiber module 15 in this way, the filtered water in the lower chamber A is independently passed through the lower chamber C without providing the independent communication pipe 36 outside or inside the filtration tower 3. Since it can flow out from the treated water pipe 6, the structure of the filtration tower 3 can be further simplified.

<Effect> As described above, the filtration tower using the hollow fiber of the present invention is
A filtration tower 3, a lower partition plate 2, a raw water pipe 1, a treated water pipe 6, a water collection pipe 5, an air vent pipe 9 in a conventional precoat type filtration tower,
All the valves 10, 11, 12, 13 and the like can be used, and it is extremely excellent in that the conventional precoat type filtration tower is remodeled as a filtration tower using hollow fibers.

Further, since the bubble dispersion mechanism and the bubble distribution mechanism are provided, the hollow fiber cleaning effect is excellent, and by providing a communication pipe outside or inside the filtration tower or inside the hollow fiber module, the hollow fibers can pass through each hollow fiber. The flow rate of filtered water that should be used can be increased, and the filtration capacity can be increased.

[Brief description of drawings]

1 to 5 are drawings showing an embodiment of the present invention. FIG. 1 is a cross-sectional explanatory view of a filtration tower, and FIG. 2 is a hollow fiber module used in the filtration tower, a connector, and a water collecting pipe. An enlarged explanatory view, FIGS. 3 and 4 are sectional explanatory views of a filtration tower which is another embodiment, and FIG. 5 is an enlarged explanatory view of a hollow fiber module, a connector, and a water collecting pipe which are another embodiment, FIG. 6 is a cross-sectional explanatory view of a conventional precoat type filtration tower. 1 ... Raw water pipe, 2 ... Lower partition plate 3 ... Filtration tower, 4 ... Filtration element 5 ... Water collection pipe, 6 ... Treated water pipe 7 ... Washing air pipe, 8 ... Baffle plate 9 ... Air vent pipe 10, 11, 12, 13 ... Valve 14 ... Upper partition plate, 15 ... Hollow fiber module 16 ... Connector, 17 ... Hollow fiber 18 ... Fixed part, 19 ... Water collection chamber 20 ... ... Outer cylinder, 21 ... Flow port 22 ... Air vent port, 23 ... Bubble passage 24 ... Bubble dispersion part, 25 ... Bubble dispersion mechanism 26 ... Skirt part, 27 ... Attachment 28 ... Perforated plate, 29 ... Air outlet 30 ... Cylindrical body, 31 ... Bubble distribution mechanism 32 ... Valve, 33 ... Air blow pipe 34 ... Valve, 35 ... Air inflow pipe 36 ... Communication pipe

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasuo Taniguchi 5-5-16 Hongo, Bunkyo-ku, Tokyo Organo Co., Ltd. (72) Masahiko Saito 5-5-16 Hongo, Bunkyo-ku, Tokyo Organo Incorporated (72) Inventor Aramaki Politics 5-5-16 Hongo, Bunkyo-ku, Tokyo Organo Incorporated

Claims (4)

[Claims] 1. A lower partition plate and an upper partition plate are provided internally.
The inside was divided into an upper chamber, a middle chamber, and a lower chamber, and both ends were open.
A hollow fiber module that bundles a large number of hollow fibers is erected in the middle chamber,
The raw water flows into the inner chamber and is fed from the outside to the inside of each hollow fiber.
The filtered water obtained by flowing in is passed through the openings at both ends of each hollow fiber,
It is a filtration tower that flows out from the lower chamber and / or the upper chamber to the outside.
The lower end opening of each hollow fiber of the hollow fiber module.
It is stored in the upper part of the nectar, and the water collecting pipe is in the lower part of the connector.
Through the top opening of the
The hollow section is provided, and the
The air bubbles received by the air passage part from the lower part of each hollow fiber
A bubble dispersion mechanism for dispersing on the outer peripheral surface is attached,
By passing the upper end of the empty fiber module through the upper partition plate
The upper end of each hollow fiber is connected to the upper chamber, and the water collection pipe is
The lower end opening of the water collection pipe is
And the skirt provided on the connector.
For introducing air bubbles into the skirt between the lower partition plates
Hollow fiber module characterized by having a bubble distribution mechanism
Filtration tower using 2. A filtration tower using the hollow fiber module according to claim 1, wherein a communication pipe that connects the upper chamber and the lower chamber is installed outside the filtration tower. 3. A filtration tower using the hollow fiber module according to claim 1, wherein a communication pipe that connects the upper chamber and the lower chamber is installed inside the filtration tower. 4. A communication pipe is installed inside the hollow fiber module so that an upper end opening of the communication pipe communicates with an upper chamber and a lower end opening of the communication pipe communicates with a connector. A filtration tower using the hollow fiber module according to item 1.