JPH0699042A - Hollow fiber membrane filtering device - Google Patents

Abstract

PURPOSE:To provide an improved hollow fiber membrane filtering device capable of easily executing the maintenance working such as the exchange of a hollow fiber membrane module, completely preventing the flow-in of air into a hollow fiber membrane hollow part at the time of back washing by a high pressure back washing water, executing efficient back washing and adequately keeping filtering function. CONSTITUTION:A partition panel 13 is provide at the bottom of a vessel composed of a vessel 4 and a body vessel 3, the hollow fiber membrane module is uprighted on the partition panel 13, an original liquid inlet pipe led from the bottom of the vessel is opened on the upper face of the partition panel 13, an outlet region for treated water from the hollow fiber membrane module is formed by the partition panel 13 and the bottom of the body vessel 3, and the back washing is executed by feeding the high pressure back washing water from a pressurized water tank 8 to the treated water outlet region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane filtering device in which a plurality of hollow fiber membrane modules are housed in a container. The present invention relates to a hollow fiber membrane filtration device capable of efficiently backwashing a membrane.

[0002]

2. Description of the Related Art For example, as a filtering device used in a nuclear power plant for separating and removing condensate existing in a condensate or a radioactive waste liquid, a filter aid such as a powder ion exchange resin has been used as an element in the past. The pre-coating type filtration device which pre-coats on the filter aid and separates and removes the suspended matter by the pre-coating layer was adopted. Devices have come to be adopted.

FIG. 6 shows a schematic structure around a filter of a hollow fiber membrane filtering device. Hollow fiber membrane module 16
Are suspended from the tube sheet 20 sandwiched between the body container 3 and the lid container 4.

Raw water that needs to be filtered is guided to the barrel container 3 through the raw water inlet pipe 1 at the bottom of the container, filtered by the hollow fiber membranes bundled in the hollow fiber membrane module 16, and the container upper lid container. 4 is collected and sent to the downstream system through the treated water outlet pipe 2. When the amount of the suspension captured by the hollow fiber membrane reaches a specified amount, the hollow fiber membrane is backwashed. Backwashing a hollow membrane
Low-pressure air backwashing for vibrating the hollow fiber membrane to remove suspended matter by low-pressure air supplied from the air tank 5, the inlet-side air valve 11, and the inlet-side air pipe 12 into the barrel container 3, and the air tank 5, The treatment liquid retained in the lid container 4 is pressure-fed as high-pressure backwash water by the high-pressure air supplied into the lid container 4 from the outlet-side air valve 7 and the outlet-side air pipe 6, and the hollow fiber membrane is backwashed from the inside to the outside. Backwashing with high pressure air.

Here, in this type of hollow fiber membrane filtration device,
The hollow fiber membrane module 16 has a service life and needs to be replaced regularly, and the inside of the body container 3 also needs to be regularly inspected. In this type of maintenance, first, the lid container 4 is opened and the hollow fiber membrane module 16 installed on the tube sheet 20 is taken out. When opening the lid container 4, the outlet pipe 2 connected to the lid container 4 is temporarily removed. Further, when the maintenance is completed, it is necessary to restore the lid container 4 and reattach the outlet pipe 2.

As a device related to this type, there is, for example, JP-A-63-147506.

[0007]

In the above-mentioned prior art, sufficient consideration has not been given to the work of opening or restoring the lid container 4 in maintenance such as replacement of the hollow fiber membrane module 16. That is, when the lid container 4 is opened for maintenance, the outlet pipe 2 connected to the lid container 4 is removed, and the lid container 4 after the maintenance is completed.
It was necessary to reattach the outlet pipe 2 for restoration of the above. Normally, the outlet pipe 2 is provided with a plurality of flange connection portions, and the flange pipe connection portion is opened and connected to remove the outlet pipe 2, and the mounting work is performed. However, this work requires attention to prevent leakage of the contained fluid. It was inevitable that it was complicated.

Further, when the amount of processing liquid held in the lid container 4 is insufficient during the backwashing with high pressure air in the prior art,
By flowing high-pressure air from the inside to the outside of the hollow fiber membrane,
When such air flows into the hollow fiber membrane, there is a problem that the membrane itself is dried and the hollow portion is clogged with bubbles, which impairs the water permeability after backwashing, that is, the filtering ability.

The present invention solves the above-mentioned problems, and facilitates replacement of the hollow fiber membrane module and efficiently filters raw water and backwashes the hollow fiber membrane module. It is intended to provide.

[0010]

In order to achieve the above object, the hollow fiber membrane filtering apparatus according to the present invention stores a plurality of hollow fiber membrane modules in a container, and uses these as filtration elements for filtering raw water. At the same time as the backwashing, low-pressure air backwashing is performed in which low-pressure air is sent from the raw water supply side to vibrate the hollow fiber membrane to remove the filtration suspension attached to the outside of the hollow fiber membrane. In the hollow fiber membrane filtration device consisting of, a partition plate is provided in the lower part of the container consisting of the lid container and the body container, the hollow fiber membrane module is installed upright on the partition plate, and the raw water inlet pipe led from the lower part of the container is installed. The partition plate and the lower part of the shell container form an opening in the upper surface of the partition plate to form a treated water outlet region from the hollow fiber membrane module, and when backwashing, high-pressure backwash water from a pressurized water tank is used. To the treated water outlet area It is characterized in that to perform the backwash.

[0011]

The partition plate provided in the barrel container holds the hollow fiber membrane module and divides the barrel container into two parts, the raw water side and the treated water side, and the raw water coming from the lower part of the barrel container by the raw water inlet pipe. To the upper part of the partition plate, and also to guide the treated water filtered by the hollow fiber membrane module and discharged to the treated water outlet pipe to the treated water outlet region under the partition plate.
In addition, the pressurized water tank used during backwashing functions to supply water to be pumped from the treated water outlet region side of the hollow fiber membrane module to the raw water side during high pressure air backwashing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The function of filtering the stock solution with the hollow fiber membrane module is no different from the conventional one.

FIG. 1 shows the overall construction of the filtration device. In the lower part of the body container 3, an inlet pipe 1 and an outlet pipe 2 are provided.
Are connected. An air pipe 12 from an air tank 5 is connected to the inlet pipe 1. The air pressure in the air tank 5 is set to be higher than the inward fluid pressure in the inlet pipe 1 and the outlet pipe 2, and the air in the air tank 5 is opened by opening the valve 11 provided in the air pipe 12. It is sent to the 1st side. The air tank 5 is connected to a water tank 8 by an air pipe 6, and the water tank 8 is connected to an outlet pipe 2 by a water pipe 9. The water tank 8 is filled with water leaving a space above it.
After closing 0, the valve 7 is opened to pressurize the water tank 8.
Then, by opening the valve 10, the water in the water tank 8 is pumped to the outlet pipe 2 side. These containers, tanks, pipes, valves, etc. are made of a structural material having sufficient corrosion resistance to the inclusion fluid, such as stainless steel, and may be made of plastic or the like depending on the pressure of the inclusion fluid.

FIG. 2 shows the structure of the body container 3. A partition plate 13 is installed inside the body container 3, and the inlet pipe 1 enters from the lower portion of the body container 3 and is open above the partition plate 13. The outlet pipe 2 is connected to the lower portion of the body container 3 below the partition plate 13. A hollow fiber membrane module 16 is vertically installed on the partition plate 13 via a conducting tube 15 and a module support 14, and an upper portion of the hollow fiber membrane module 16 is held by a steady rest plate 17.

FIG. 3 shows details around the hollow fiber membrane module 16. A plurality of hollow fiber membranes 18 are housed inside the hollow fiber membrane module 16, and the hollow portion of the end surface thereof is open to the lower end surface of the hollow fiber membrane module 16. Raw water from the outside of the hollow fiber membrane module 16 has a hole 1
9 through the hollow fiber membrane module 16 and the hollow fiber membrane 1
The filtration process is performed by flowing from the outer side of 8 to the inner hollow part. The filtered treated water is the hollow fiber membrane module 16
Go out from the lower end of the module support 14 and conduit tube 15
And flows out into the treated water outlet region below the partition plate 13.

Operations such as removal and replacement of the hollow fiber membrane module 16 are performed as follows.

First, the lid container 4 is opened, and the steady rest 17
After removing the hollow fiber membrane module 16, the hollow fiber membrane module 16 is pulled out from the module support 14 and taken out of the body container 3 through the upper opening of the body container 3. Loading of the new hollow fiber membrane module 16 for replacement is performed in the reverse procedure.

Next, the operation of this filtering device is performed as follows.

First, with the valve 10 and the valve 11 closed, the raw water is made to flow from the inlet pipe 1 to the barrel container 3, the treated water is taken out from the outlet pipe 2, and the filtration treatment operation is performed. Along with this filtration operation, insoluble impurities in the raw water are additionally accumulated on the outer surface of the hollow fiber membrane 18, and the filtration capacity is reduced. In this case, the following backwashing operation is performed. First, after stopping the passage of raw water, the valve 11 is opened to introduce the air in the air tank 5 from the inlet pipe 1 into the body container 3, and the bubbles of this air rise in the water in the body container 3 by the vibration. The hollow fiber membrane 18 is shaken to remove impurities accumulated on its surface. Next, after closing the valve 11, the valve 10 is opened and the water in the pressurized water tank 8 is introduced as high-pressure backwash water from the outlet pipe 2 into the treated water outlet region under the partition plate 13 and further conducted. This water is flowed from the hollow portion of the hollow fiber membrane 18 in the hollow fiber membrane module 16 through the pipe 15 to the outer surface side to wash the hollow fiber membrane 18. in this way,
High-pressure water for backwashing is passed through the pressurized water tank 8 to the container 3
The following can be cited as the effect of flowing into the lower part of the.
That is, when the pressurized air is directly guided to the lower portion of the body container 3, even if the treated water exists in this portion, the air flows into the hollow portion of the hollow fiber membrane 18, and the air flows in the hollow fiber membrane. 18 will pass from the inside to the outside. The hollow fiber membrane 18 is usually made of a synthetic resin such as a polyolefin resin and has a hydrophobic property. Therefore, once dried, it becomes difficult for water to pass through. For this reason, when the air flows in as described above, the membrane itself is dried and the hollow portion is clogged with air bubbles, which impairs the water permeability after the backwash, that is, the filtering ability. By using the pressurized water tank 8, it is possible to prevent such a decrease in filtration capacity and properly maintain the function of the filtration device.

FIG. 4 shows an example of the performance of this filtration device. This figure shows the relationship between the operating time of this device and the filtration differential pressure. The horizontal axis represents the operating time, and the vertical axis represents the inlet pipe 1
And the pressure difference between the contained fluids in the outlet pipe 2, that is, the filtration pressure difference. As shown in curve a, with the passage of operating time,
The filtration differential pressure is gradually increasing. This is because impurities are accumulated on the surface of the hollow fiber membrane 18 and the filtration resistance of the hollow fiber membrane 18 increases. At point B, the filtration process is stopped, backwashing is performed by opening the valve 11, and the lowered differential pressure is point C. Further, the second point is the reduced pressure difference caused by backwashing by opening the valve 10. The differential pressures at the points B and C are measured by temporarily restarting the filtration process and recording the filtration differential pressure at that time. It is shown that the backwashing efficiently reduces the differential pressure, the backwashing of the hollow fiber membranes 18 is efficiently performed, and there is no reduction in the filtration capacity.

FIG. 5 shows another embodiment of the present invention. There is no difference from the embodiment of FIG. 1 except that the water pipe 9 is directly connected to the body container 3 below the partition plate 13. Also in this example, the effect and safety of backwashing by opening the valve 10 are the same as those in the embodiment of FIG.

[0023]

EFFECT OF THE INVENTION The hollow fiber membrane filtering apparatus of the present invention is provided with a partition plate in the lower part of the container consisting of a lid container and a body container, and the hollow fiber membrane module is installed on the partition plate in an upright state. Open the raw water inlet piping derived from the above to the upper surface of the partition plate,
The partition plate and the lower part of the body container form a treated water outlet region from the hollow fiber membrane module, and during backwashing, high-pressure backwash water from a pressurized water tank is sent to the treated water outlet region. Since it is designed to be backwashed,
Since there is no piping to connect to this, maintenance work such as replacement of the hollow fiber membrane module can be easily performed by simply removing the lid container from the barrel container, and it is also possible to reverse the high pressure backwash water from the pressurized water tank. At the time of washing, the inflow of air into the hollow portion of the hollow fiber membrane is completely prevented, the back washing is effectively performed, and the proper maintenance of the filtration function can be achieved.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a hollow fiber membrane filtering device according to the present invention.

FIG. 2 is a view showing a structure of a container of a hollow fiber membrane filtration device according to the present invention.

FIG. 3 is a diagram showing a configuration around a hollow fiber membrane module of a hollow fiber membrane filtration device according to the present invention.

FIG. 4 is a diagram showing the performance of the hollow fiber membrane filtration device according to the present invention.

FIG. 5 is a view showing another embodiment of the hollow fiber membrane filtration device according to the present invention.

FIG. 6 is a diagram showing a configuration of a conventional hollow fiber membrane filtration device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inlet piping 2 ... Outlet piping 3 ... Body container 4 ... Lid container 5 ... Air tank 8 ... Water tank 13 ... Partition plate 36 ... End member 40 ... Hollow fiber membrane 41 ... Conventional hollow fiber membrane module 16 ... Hollow fiber membrane Module 14 ... Module support 15 ... Conduction tube 17 ... Steady plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Kazama 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Yoshihiro Shiozawa 3--2, Saiwaicho, Hitachi, Ibaraki No. 1 in Hitachi Engineering Co., Ltd. (72) Inventor Taketoshi Kurita 3-10-2 Bentencho, Hitachi City, Ibaraki Prefecture Hitachi Kyowa Industry Co., Ltd.

Claims (1)

[Claims] 1. A hollow fiber membrane module comprising a plurality of hollow fiber membrane modules housed in a container for filtering raw water using these as filtration elements, and at the time of backwashing, low pressure air is fed from the raw water supply side. In a hollow fiber membrane filtration device that performs low-pressure air backwash to remove the filtration suspension attached to the outside of the hollow fiber membrane by vibrating the membrane, a partition is formed in the lower part of the container consisting of a lid container and a body container. Set up a board,
The hollow fiber membrane module is installed upright on the partition plate, the raw water inlet pipe led from the lower part of the container is opened to the upper surface of the partition plate, and the treatment from the hollow fiber membrane module is performed between the partition plate and the lower part of the barrel container. A hollow fiber membrane filtration characterized in that a water outlet region is formed, and at the time of backwashing, high-pressure backwash water from a pressurized water tank is sent to the treated water outlet region for backwashing. apparatus.