JPH1157703A - Membrane filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of the membrane elements to be mounted by using a precoat filtration tower and its shell plate as they are and suspending the membrane elements such as a large-diameter hollow-fiber membrane and a pleated membrane eccentric to the mounting hole of a precoat filter. SOLUTION: A hole 13' through which a water collecting pipe 11 is passed is provided at the mounting hole 6 for the precoat filter of a shell plate. The water collecting pipe 11 is passed upward through the hole 13', the outer periphery of the pipe 11 is welded to the inner periphery of a mounting seat 12 above the hole 13' and fixed, and a membrane element 10 is suspended below the shell plate 4. Namely, the hole 13' is made eccentric to the center axis of the mounting hole 6 so that a part of the outer periphery of the hole 13' is kept in contact with a part of the inner periphery of the seat 12 when the water collecting pipe is passed upward. Further, the plural membrane elements 10 surrounding the membrane element 10a are radially separated from the elements in respective centers and fixed to the seat 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a filtration tower and a can plate of a precoat filter for filtering condensate of a thermal power plant and a nuclear power plant and drainage drainage, and has a larger diameter than a precoat filter. The present invention relates to a membrane filtration device in which many membrane elements such as a hollow fiber membrane and a pleated membrane are mounted on a can plate.

[0002]

2. Description of the Related Art When a can plate 4 has a diameter of 1800 mm, a pre-coat filter 5 is provided in a can plate 4 which divides a tower 1 of a pre-coat filter into a lower raw water supply chamber 2 and an upper treated water chamber 3. One mounting hole 6 with a diameter of 70 mm is used for hanging and mounting.
96 are set up at a pitch of 60 mm. Since the diameter of the precoat filter 5 is 120 mm, which is smaller than the pitch of the mounting holes, 96 precoat filters can be mounted by suspending the precoat filter to one of the mounting holes 6 (see the left half of FIG. 3).

[0003]

However, the precoat filter is removed, and the pitch of the mounting holes is set to 1 in the mounting hole of the same can plate.
If a membrane element having a diameter larger than 60 mm is to be hung and mounted, it can only be mounted in every other mounting hole as shown in FIG. 4, so that the number of mounted membrane elements is about 30. Since the load applied to the membrane element of the present invention is large, the differential pressure rise speed is increased, and the service life of the membrane is shortened. The only way to prevent this is to remake the can plate so that a larger number of membrane elements can be installed. However, the can plate needs to be thick in order to support the differential pressure generated in the precoat filter and the membrane element, and also needs to have smoothness, which is not easy to manufacture and increases the cost.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention utilizes a can plate on which a pre-coated filter has been mounted as it is, so that a larger number of membrane elements can be mounted than mounting every other mounting hole. Therefore, the water collection pipe of the membrane element was biased to the mounting hole where the precoat filter of the can plate that divides the inside of the precoat filtration tower into the lower raw water supply chamber and the upper treatment water chamber was suspended. It is characterized in that it is attached and suspended with its center in mind.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The water collecting pipe 1 to be hung on a can plate even if the diameter of the membrane element 10 is larger than that of the pre-coated filter.
The diameter of 1 is smaller than the mounting hole 6 for the precoat filter of the can plate. For example, in the case of a pleated membrane element obtained by folding a flat membrane, the diameter of the membrane element is 166 mm, and the outer diameter of the water collecting pipe is 45 mm.

Accordingly, the length of the mounting hole 6 is longer than the thickness of the can plate.
A bottomed cylindrical mounting seat 12 fitted into the inner periphery of the mounting hole 6 having a bottom plate 13 having a diameter larger than the diameter of the bottom plate 13 is used. 6, the nut 15 is screwed into an external thread on the upper outer periphery of the mounting seat 12, and the mounting seat is sealed and fixed to the mounting hole 6.

In FIG. 1A, a hole 13 'is formed in the bottom plate 13 of the mounting seat so as to penetrate the water collecting pipe 11 projecting upward from the membrane element eccentrically with respect to the central axis A of the mounting hole 6. The water collecting pipe 11 is passed through the hole 13 'from below, and the contact portion between the outer circumference of the water collecting pipe and the inner circumference of the mounting seat 12 is fixed on the hole 13' by welding. Hang it down. That is, the hole 13 ′ is opened eccentrically with respect to the center axis of the mounting hole so that a part of the outer circumference thereof contacts a part of the inner circumference of the mounting seat 12 when the water collecting pipe is passed from below. is there. Thus, the amount of eccentricity of the center axis of the membrane element or the center axis B of the water collection pipe with respect to the center axis A of the mounting hole becomes X.

To increase the amount of eccentricity, FIG.
As shown in (B), a water collecting pipe whose part projecting upward from the membrane element is bent in a crank shape is used, and the bent upper part 11a of the water collecting pipe is passed through the hole 13 'of the bottom plate 13 of the mounting seat 12 from below. A portion of the outer periphery of the upper portion 11a and a portion of the inner periphery of the mounting seat may be welded and fixed.

FIG. 1C shows a central membrane element 10a.
Fig. 1 (A), Fig. 1
(B) shows a case where the diacentrically eccentrically mounted members are mounted on the mounting seat so as to be radially separated from the central membrane element. The water collecting pipe of the central membrane element 10a is concentrically passed through a hole formed in the center of the bottom plate of the mounting seat, and is fixed by welding. The mounting hole of the can plate to which the membrane element is not mounted is closed by a closing seat 12 'similar to the mounting seat but having no hole in the bottom plate. In this way, the central membrane element and the seven membrane elements surrounding it are
A set of seven sets and three membrane elements concentrically mounted on the mounting seat at a position distant from each set of nine sets,
52 membrane elements could be mounted in the mounting holes of the six can plates.

[0010] Some membrane elements have a short length of the water collecting pipe 11 and do not protrude upward from a hole of the cap 16 which is placed on the upper end of the membrane element via an O-ring 17. In that case, the lower part of the mounting aid 18 such as a rod or an angle material is fixed by welding above the inside of the water collecting pipe 11, the auxiliary tool 18 is pulled out from the hole of the cap, and the upper part of the auxiliary tool is attached to the mounting seat 12. The membrane element may be projected upward from the hole 13 'of the bottom plate and welded to the inner periphery of the mounting seat 12, and the membrane element may be hung below the can plate for mounting. Thereby, the center axis B of the membrane element can be eccentric with respect to the center axis A of the mounting hole 6. To increase the amount of eccentricity, use an auxiliary tool bent in a crank shape as shown in FIG.
8a is fixed to the upper inside of the water collecting pipe 11 by welding, and the upper straight portion 18b of the auxiliary tool which has come out from the hole of the cap 16 is projected upward from the hole 13 'of the bottom plate of the mounting seat 12 so that the mounting seat 12
, And the membrane element may be hung below the can plate and attached.

Further, the present invention is not limited to suspending one membrane element eccentrically with respect to one mounting hole 6 of a can plate.
As shown in FIG. 2C, one membrane element may be suspended from two mounting holes 6 and 6 eccentrically. That is, the mounting seats 12 and 12 are fixed to the mounting holes 6 and 6 as described above, and the holes 13 ′ and
13 ′, each upward end 19 ′, 1 of the U-shaped pipe 19.
The pipe 19 is suspended from the bottom of the can plate by welding the portion in contact with the inner periphery of the mounting seat through the bottom of the pipe 9 ′, and the upper end of the concentrated pipe 11 of the membrane element is set in the middle of the pipe 19. It is suspended by welding in a letter shape.
Thereby, the center axis B of the membrane element is eccentric with respect to the center axes A, A of the two mounting holes 6, 6.

As a result, the permeated water permeated through the membrane element and collected in the water collecting pipe 11 flows into the treated water chamber from the two upward ends 19 'and 19' of the U-shaped pipe 19,
The amount of permeated water is increased.

The pleated membrane element 743 described above.
The film area of B is 19 m ² . As shown in FIG. 4, when 30 membrane elements are suspended and mounted concentrically using a mounting seat at every other 96 mounting holes of the can plate, the total membrane area is 19 m. ² × 30 = 570 m ² . When the actual condensate of a thermal power plant of 350 m ³ / hour was treated for one month using this membrane filtration device, the rate of increase of the differential pressure was 0.0012 kg / cm ² per day, and the system allowable differential pressure 1 The estimated membrane life to reach 0.5 kg / cm ² was 3.4 years.

On the other hand, as shown in FIG.
When 52 membrane elements are attached to the attachment holes of the six can plates, the total membrane area is 19 m ² × 52 = 988 m ² .
When the actual condensate of a thermal power plant of 350 m ³ / hour was similarly treated using this membrane filtration device for one month, the load applied to one of the membrane elements was reduced, and the differential pressure increased. The speed was 0.0006 kg / cm ² per day. As a result, the estimated life until the system allowable differential pressure reached 1.5 kg / cm ² was about 6.8 years, which was about twice as long as the case where 30 membrane elements were attached.

[0015]

As apparent from the above, according to the present invention, the pre-coated filtration tower and its can plate are used as they are, and the membrane elements such as hollow fiber membranes and pleated membranes having a diameter larger than that of the pre-coated filter are used. By mounting the pre-coated filter eccentrically to the mounting hole and suspending it, the number of membrane elements to be mounted can be increased, and as a result,
The flow rate (flow rate per unit membrane area) of the membrane of one membrane element per one membrane decreases, and the life of the membrane of the membrane element can be prolonged. Therefore, although the initial investment cost will increase due to the increase in the number of membrane elements installed, the cost of membrane elements due to the extension of the life of the membrane, and the replacement work cost due to halving the frequency of replacement of the membrane elements will decrease, and in the long term Can reduce the total cost.

[Brief description of the drawings]

1A is a cross-sectional view of a first example in which a membrane element is eccentrically mounted in a precoat filter mounting hole of a can plate, FIG. 1B is a cross-sectional view of a second example, and FIG. It is a top view of a part of the can plate which shows the state where the membrane element was attached as mentioned above.

2A is a cross-sectional view of a third example in which a membrane element is eccentrically mounted in a precoat filter mounting hole of a can plate, FIG. 2B is a cross-sectional view of a fourth example, and FIG. It is a sectional view of a 5th example similarly.

FIG. 3 is a diagram illustrating a state in which a precoat filter is hung and attached to a can plate of a precoat filtration tower, and a right half is a diagram illustrating a state in which a membrane element is also hung and mounted.

FIG. 4 is a plan view of a part of a can plate in a state where a membrane element is attached to every other mounting hole of a precoat filter in a can plate of a precoat filtration tower.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Precoat filtration tower 2 Raw water supply chamber below precoat filtration tower 3 Treated water chamber above precoat filtration tower 4 Can plate 5 Precoat filter 6 Prehole filter mounting hole 10 Membrane element 11 Membrane element water collecting pipe 12 Mounting seat 12 ′ Closing seat 13 Bottom plate 13 'Hole eccentrically opened in the bottom plate of the mounting seat 14 Packing 15 Nut 16 Cap 17 O-ring 18 Membrane element mounting aid

Claims (1)

[Claims] 1. A water collection pipe for a membrane element is biased to a mounting hole in which a precoat filter of a can plate which divides the inside of a precoat filtration tower into a lower raw water supply chamber and an upper treatment water chamber is suspended. A membrane filtration device characterized by being attached and suspended with its center in mind.