JP2010142710A - Stationary filter and bubbling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized low-cost stationary filter capable of surely and efficiently carrying out the back washing of a hollow yarn membrane and the removal of retained air by supplying treating water in the filter as back washing water to the hollow yarn membrane through a vertical pipe. <P>SOLUTION: In the stationary filter 1 provided with a hollow yarn membrane module 2 comprising the plurality of hollow yarn membranes, a feed pipe 5 for forcibly feeding air for introducing air to a lower part treating water dome 9, a waste liquid feed pipe 6 for introducing a waste liquid to a feed dome 8, a filtrate discharge pipe 7 for discharging the treating water in the lower part treating water dome 9 and the vertical pipe 3 connected to the lower part of the hollow yarn membrane module 2 and supported by a lower part partitioning plate 4, the lower end part of the vertical pipe 3 lies below the connection part of the feed pipe 5 for forcibly feeding air and the lower part treating water dome 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stationary filter and a bubbling device using a hollow fiber membrane as a filtration element.

  Polyethylene hollow fiber membranes having an outer diameter of 270 μm to 410 μm and a large membrane area are used as filtration elements for waste liquid filtration treatment apparatuses of nuclear power plants or thermal power plants. Since the hollow fiber membrane can be regenerated by washing, when a certain amount of the suspension trapped by the hollow fiber membrane reaches a certain amount, the treated water is recirculated and air bubbling is used in combination with the hollow fiber membrane. The yarn membrane is backwashed.

  Conventionally, the waste liquid filtration processing apparatus using the hollow fiber membrane has been generally a suspension type structure filter that suspends the hollow fiber membrane module from the tube plate. Since the replacement work and maintenance of the membrane module are complicated, a stationary filter in which the hollow fiber membrane module is installed on the lower partition plate as shown in FIGS. 8 and 9 has recently been proposed (Patent Document 1). ).

8 and 9, the waste liquid to be treated is introduced into the barrel container 52 through an inlet pipe 51 provided at the lower portion of the filter 50, and treated water treated by the hollow fiber membrane module 53 is discharged from an outlet pipe 54. Discharged. At the time of backwashing, air in the high-pressure air tank 55 is guided from the inlet pipe 51 into the barrel container 52 to perform air bubbling cleaning, while water in the water tank 56 is used as high-pressure backwash water from the outlet pipe 54 to the lower partition plate 57. The hollow fiber membrane is backwashed.
JP-A-6-99042

  In the conventional stationary filtration apparatus described above, high-pressure water is used as backwash water, so a tank for storing high-pressure water must be provided, and a pumping means for sending high-pressure water to the filter is also necessary. Therefore, the equipment is complicated and large, and the operation cost is high.

  The present invention has been made in order to solve the above problems, and by utilizing the treated water in the filter as the backwash water, the hollow fiber membrane can be backwashed efficiently and is small in size. An object of the present invention is to provide a stationary filter that can keep operating costs low.

  Another object of the present invention is to provide a bubbling device that automatically operates with air during backwashing with treated water.

  The stationary filter according to the present invention is made to solve the above-mentioned problems, and includes a hollow fiber membrane module composed of a plurality of hollow fiber membranes, a pneumatic feeding pipe for introducing air into the lower treated water dome, and a waste liquid. Waste liquid supply piping for introducing the waste water into the supply dome, filtered water discharge piping for discharging the treated water in the lower treated water dome to the outside, and vertical piping connected to the lower portion of the hollow fiber membrane module and supported by the lower partition plate The vertical pipe is characterized in that the lower end of the vertical pipe is below the connecting part between the pneumatic feed pipe and the lower treated water dome.

  The stationary filter according to the present invention includes a hollow fiber membrane module comprising a plurality of hollow fiber membranes, a pneumatic feed pipe for introducing high-pressure air into the lower treated water dome, and a waste liquid supply for introducing waste liquid into the supply dome. Piping, filtered water discharge piping for discharging treated water in the upper and lower treated water domes to the outside, an upper partition plate for supporting the upper portion of the hollow fiber membrane module, and a lower partition plate connected to the lower portion of the hollow fiber membrane module In the stationary filter comprising a vertical pipe supported by, a communication pipe is provided between the upper partition plate and the lower partition plate, and the vertical pipe has a lower end portion thereof and the pneumatic feed pipe. It exists below the connection part with a lower treated water dome.

  The bubbling device according to the present invention includes a bubbling air introduction pipe and a driving air pipe fixed to a lower partition plate of a filter, a cylinder that operates by air pressure supplied from the driving air pipe, and a cylinder that is provided in the cylinder. And a bubbling pipe communicating with the bubbling air inflow hole.

  According to the present invention, the treated water in the filter is used as the backwash water, supplied to the hollow fiber membrane through the vertical pipe, and the bubbling washing device is automatically operated to reverse the hollow fiber membrane. Washing and removal of stored air can be performed reliably and efficiently, and a small and low-cost stationary filter can be provided.

Hereinafter, an embodiment of a stationary filter according to the present invention will be described with reference to the drawings.
(First embodiment)
A stationary filtration apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an overall configuration diagram of a stationary filter. In FIG. 1, a stationary filter 1 includes a hollow fiber membrane module 2 composed of a plurality of hollow fiber membranes, a vertical pipe 3 connected to the lower part of the hollow fiber membrane module 2, and high-pressure air to a treated water dome 9. The pneumatic feed pipe 5 to be introduced, the waste liquid supply pipe 6 for introducing the waste liquid into the supply dome 8, the filtered water discharge pipe 7 for discharging the treated water 10 in the treated water dome 9 to the outside, and the vertical pipe 3 are supported and fixed. And a lower partition plate 4. As the hollow fiber membrane, for example, a hollow fiber membrane made of polyethylene and having an outer diameter of about 270 μm is used.

Next, the lower structure of the hollow fiber membrane module 2 will be described with reference to FIG.
In FIG. 2, the hollow fiber membrane module 2 is connected to the upper part of the vertical pipe 3 via the module support 13, and the lower end of the vertical pipe 3 is below the connection part between the pneumatic feed pipe 5 and the treated water dome 9. It is extended.

  Further, in the vertical pipe 3, a step 14 is provided immediately below the connecting portion with the hollow fiber membrane module 2, and the diameter 18 of the vertical pipe 3 is small below the step.

  In addition, the pneumatic feed pipe 5 is connected to the treated water dome 9 at a position above the lower end of the vertical pipe 3 and in the vicinity of the lower part of the partition plate 4.

  When the stationary filter 1 configured as described above is subjected to a filtration treatment operation, first, waste liquid is introduced into the supply dome 8 from the waste liquid supply pipe 6 and treated by the hollow fiber membrane module 2, and then treated water. 10 is introduced into the treated water dome 9 through the vertical pipe 3 and then discharged to the outside through the filtered water discharge pipe 7.

Next, the backwashing operation for recovering the differential pressure of the hollow fiber membrane module 2 will be described.
First, about 3.0 kg / cm ² of air is pumped from the pneumatic feed pipe 5 to the upper portion of the treated water dome 9, and the treated water 10 stored in the treated water dome 9 is pushed down by the air pressure. Next, the treated water 10 flows upward through the vertical pipe 3 and is sent to the hollow fiber membrane of the hollow fiber membrane module 2 for backwashing.

  As described above, since the pneumatic feeding pipe 5 is connected to the treated water dome 9 above the lower end of the vertical pipe 3 and in the vicinity of the lower part of the lower partition plate 4, a predetermined amount of treatment necessary for backwashing is performed. It becomes possible to feed the water 10 into the hollow fiber membrane module 2.

  Note that the lower end position of the vertical pipe 3 can be appropriately changed to a position near the bottom of the treated water dome 9 according to the amount of treated water necessary for backwashing.

  FIG. 7 is a diagram showing a result of an experiment conducted by repeatedly performing backwashing using the stationary filter having the above configuration. According to FIG. 7, it can be seen that the differential pressure is restored each time backwashing is performed, and the clad adhering to the hollow fiber membrane is efficiently removed by backwashing.

  According to the first embodiment, by configuring the vertical pipe as described above, the treated water in the filter can be used as the backwash water, and the hollow fiber membrane can be backwashed efficiently. In addition, it is possible to provide a stationary filter that is small in size and can be operated at a low cost.

In the above embodiment, the air introduced from the pneumatic feeding pipe 5 is shown as 3.0 kg / cm ² , but is appropriately selected according to the capacity of the stationary filter 1 and the internal pressure. In addition, although the gas to be injected is shown as an example of air, it is needless to say that a gas such as nitrogen and carbon dioxide which is difficult to deteriorate can be used.

(Second Embodiment)
A stationary filtration apparatus according to a second embodiment of the present invention will be described with reference to FIG.
This 2nd Embodiment is related with the structure and its mechanism for removing the air which accumulated in the hollow fiber membrane module 2 at the time of backwashing.

  After the hollow fiber membrane module 2 is backwashed by the procedure described in the first embodiment, the hollow fiber membrane does not transmit air, and therefore air is stored at the tip of the hollow fiber membrane module 2. Therefore, when normal filtration operation is resumed after backwashing, it is necessary to discharge the stored air from the lower part of the vertical pipe with treated water. Usually, since the maximum rising speed of air in water is 1112 m / h, the flow rate of treated water in the vertical pipe needs to be higher than the maximum rising speed of bubbles in order to eliminate air in the hollow fiber membrane. .

3, the horizontal axis is the diameter X of the vertical pipe (m ^2), the vertical axis as the flow rate Y (L / h) per unit time flowing in vertical pipes, different for a plurality of vertical pipes cross-sectional areas, hollow It is the figure which plotted the point (* mark) where it became possible to exclude stored air from a thread membrane module, and the point (x mark) which remained without removing stored air. From this figure, it can be seen that if (X, Y) is above the primary straight line represented by Y> 80 Log ₁₀ (X) +320, the stored air is excluded.

For example, from the processing capacity of the filter, when the treated water flows at a flow rate of 40 l / h flowing down the vertical pipe, the cross-sectional area of the vertical pipe may be about 5 × 10 ⁻⁴ m ² or less.

  Moreover, the level | step difference 14 is provided in the vertical piping 3 connected to the hollow fiber membrane module 2, and the diameter of a lower vertical piping is made small. Thereby, it becomes possible to remove air more rapidly by improving the entrainment efficiency of the air by the treated water and making a slag flow of a two-phase state flow.

  According to the second embodiment, by appropriately designing the vertical piping, the air staying in the hollow fiber membrane module can be efficiently removed, and the stationary filtration that can be reduced in size and reduced in operating cost. A processor can be provided.

(Third embodiment)
An automatic opening and closing type bubbling device according to a third embodiment of the present invention will be described with reference to FIGS.

  The third embodiment relates to an automatic opening / closing type bubbling device that automatically supplies bubbles into the supply dome 8 during backwashing. Bubbling cleaning with bubbles is usually performed in combination with backwashing with treated water. That is, in the present invention, the back washing of the hollow fiber membrane module is performed by pumping the treated water into the hollow fiber membrane and back washing, and at the same time, the bubbling device is automatically operated to bubble and wash the hollow fiber membrane.

  FIG. 4 is an overall configuration diagram of the stationary filter 1 in which the bubbling device 22 is installed, and FIG. 5 is a detailed view of the automatic opening / closing type bubbling device 22.

  The bubbling device 22 includes a bubbling air introduction pipe 23 fixed to the lower partition plate 4, a driving air pipe 31 fixed to the lower partition plate 4, a cylinder 24 operated by air pressure supplied from the driving air pipe 31, bubbling An air inflow hole 29, a spring 30, a check valve 25 for preventing water from entering, and a rising pipe 27 for preventing water from entering.

Next, the operation of the bubbling device 22 configured as described above will be described.
When air is pumped from the pneumatic feeding pipe 5 to the upper part of the treated water dome 9 and the stored treated water 10 is pushed down to create an air space above the treated water dome 9, the cylinder 24 shown in FIG. Air is sent to the drive air piping 31, and the cylinder 24 operates in the left direction in the figure. As a result, the air inflow hole 29 opens in communication with the bubbling air introduction pipe 23, air is sent to the bubbling pipe 26 having a large number of minute holes (not shown), and a large amount of bubbles rise upward. Then, the hollow fiber membrane is washed by bubbling.

  In order to drive the cylinder 24, it is desirable to design the cross-sectional area A where the cylinder 24 contacts the driving air to be 2 to 5 times larger than the cross-sectional area B of the air intrusion hole 31 a of the cylinder 24.

  According to the third embodiment, by simply sending air having a pressure higher than the pressure of the treated water dome 9 into the treated water dome of the filter, it becomes possible to perform automatic washing by backwashing using treated water and air bubbling. In addition, a bubbling stationary apparatus having high cleaning efficiency, a compact size, and a low cost can be provided.

(Fourth embodiment)
A stationary filter according to a fourth embodiment of the present invention will be described with reference to FIG.
This stationary filter has a structure in which treated water is collected from both ends of the hollow fiber membrane module.

  In FIG. 6, the hollow fiber membrane module 2 is fixed to the lower partition plate 4a and the upper partition plate 4b, and a communication pipe 33 is provided between the lower treated water dome 9a and the upper treated water dome 9b. The lower structure of the hollow fiber membrane module 2 is the same as that of the first embodiment.

  In normal filtration processing operation, waste liquid is introduced into the supply dome 8 from the waste liquid supply pipe 6 and processed by the hollow fiber membrane module 2, and then the treated water is discharged to the upper and lower treated water domes 9a and 9b, Next, the water is discharged to the outside through the filtered water discharge pipe 32.

  Next, at the time of backwashing operation, air from the pneumatic feed pipe 5 is pumped to the upper part of the treated water dome 9a, and the treated water stored in the treated water dome 9a is pushed down by the air pressure, and the vertical pipe 3 and Treated water is introduced into the hollow fiber membrane from both ends of the hollow fiber membrane module 22 through the communication pipe 33, and backwashing is performed.

  With the above configuration, since water can be collected from both ends of the hollow fiber membrane module, the pressure loss of the hollow fiber membrane and the connection portion is greatly reduced, high-flow rate processing is possible, and the amount of filtration treatment can be increased. Since the back washing can be performed from both ends of the hollow fiber membrane module, the washing efficiency can be further increased.

  According to the fourth embodiment, since the treated water is collected from both ends of the hollow fiber membrane module, the filtration throughput can be increased and the washing efficiency can be greatly increased. It is possible to provide a stationary filter that is higher, more compact, and lower in cost.

The whole block diagram of the stationary filter which concerns on the 1st Embodiment of this invention. The lower structure figure of the hollow fiber membrane module which concerns on the 1st Embodiment of this invention. The discharge characteristic figure of hollow fiber membrane module residence air concerning a 2nd embodiment of the present invention. The whole block diagram of the automatic opening-and-closing type bubbling apparatus which concerns on the 3rd Embodiment of this invention. Detailed drawing of the automatic opening-and-closing type bubbling apparatus which concerns on the 3rd Embodiment of this invention. The whole block diagram of the stationary filter which concerns on the 4th Embodiment of this invention. The backwash performance test figure of the stationary filter which concerns on the 1st Embodiment of this invention. System diagram of a conventional stationary filter. The whole block diagram of the conventional stationary filter.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Deferment type filter, 2 ... Hollow fiber membrane module, 3 ... Vertical piping, 4, 4a ... Lower partition plate, 4b ... Upper partition plate, 5 ... Pneumatic feed piping, 6 ... Waste liquid supply piping, 7 ... Filtration water Discharge piping, 8 ... supply dome, 9 ... treated water dome, 13 ... module support, 14 ... step, 22 ... bubbling device, 23 ... air introduction piping, 24 ... cylinder, 25 ... check valve, 26 ... bubbling piping, 27 ... Rising pipe, 28 ... Air discharge path outlet, 29 ... Air inflow hole, 30 ... Spring, 31 ... Drive air pipe, 50 ... Filter, 51 ... Inlet pipe, 52 ... Trunk container, 53 ... Hollow fiber membrane module, 54 ... Outlet piping, 55 ... High pressure air tank, 56 ... Water tank, 57 ... Lower partition plate.

Claims (8)

A hollow fiber membrane module comprising a plurality of hollow fiber membranes, a pneumatic feed pipe for introducing air into the lower treated water dome, a waste liquid supply pipe for introducing waste liquid into the supply dome, and treated water in the lower treated water dome. In a stationary filter comprising a filtrate drain pipe for discharging to the outside and a vertical pipe connected to the lower part of the hollow fiber membrane module and supported by the lower partition plate,
The vertical pipe has a lower end part below a connection part between the pneumatic feed pipe and the lower treated water dome. A hollow fiber membrane module comprising a plurality of hollow fiber membranes, a pneumatic feed pipe for introducing air into the lower treated water dome, a waste liquid supply pipe for introducing waste liquid into the supply dome, and treated water in the upper and lower treated water domes And a vertical pipe that is connected to the lower part of the hollow fiber membrane module and supported by the lower part of the hollow fiber membrane module. In the filter,
A communication pipe is provided between the upper partition plate and the lower partition plate, and the vertical pipe has a lower end portion below a connection portion between the pneumatic feed pipe and the lower treated water dome. A stationary filter.   The stationary filter according to claim 1 or 2, wherein a lower end portion of the vertical pipe is located near a bottom surface of the lower treated water dome. ^2. Y> 80 Log ₁₀ (X) +320, where X (m ² ) is a cross-sectional area of the vertical pipe and Y (L / h) is a flow rate of treated water flowing through the vertical pipe. The stationary filter of any one of thru | or 3.   The stationary filter according to any one of claims 1 to 4, wherein a step is provided in an upper part of the vertical pipe, and a diameter of the vertical pipe lower than the step is made smaller than that of the upper part.   A bubbling air introduction pipe and a driving air pipe fixed to the lower partition plate of the filter, a cylinder operated by air pressure supplied from the driving air pipe, a bubbling air inflow hole provided in the cylinder, and the bubbling And a bubbling pipe communicating with the air inflow hole.   The stationary filter according to claim 6, wherein the bubbling pipe further includes a check valve for preventing water from entering and a rising pipe for preventing water from entering.   A stationary filter, wherein the bubbling device according to claim 6 or 7 is mounted on the stationary filter according to any one of claims 1 to 5.

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