JPH0630260Y2 - External pressure full filtration hollow fiber membrane module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a scrubbing washable external pressure full filtration type hollow fiber membrane module used in a nuclear power plant or the like.

(Prior Art) In nuclear power plants, recently, a suspended hollow fiber membrane module has been used as a condensate filter. These hollow fiber membrane modules are operated by full filtration, and when the filtration pressure difference increases due to clogging, the operation is stopped and air is introduced from the bottom of the hollow fiber membrane module to raise it along the hollow fiber membranes. , The hollow fiber membrane is vibrated to scrub off the solid matter adhering to the membrane. The present inventor has previously disclosed in Japanese Utility Model Laid-Open No. 63-111901, a hollow fiber membrane in which a partition plate having an air distribution hole is arranged in an adhesive fixing portion at a lower portion of a hollow fiber membrane module and communicated with an air collecting recess. Suggested a module. However, the diameter of the hollow fiber membrane module is at most about 5 inches, and the air blowing hole is
In order to uniformly vibrate the hollow fiber membrane, four or more places are required, and in the module having a water permeation rate of 12 m ³ / Hr, 16 holes are required at 26 mmφ and 27 holes are required at 20 mmφ. However, if the undiluted solution supply hole is provided in the middle part of the outer cylinder, the air of the air scrubbing will be lost even in the middle. Further, the undiluted solution inlets need to be located in the upper and lower parts of the module so that the undiluted solution is sucked in when the air is introduced and the air and water are discharged from the upper part of the module.
However, in the known hollow fiber membrane module, air leaks from the undiluted solution supply port at the bottom of the module, and the undiluted solution does not enter, so even if scrubbing, the air lift is not sufficient and the scrubbing effect is poor. There was a problem.

(Problems to be Solved by the Invention) An object of the present invention is to provide a module having a large scrubbing effect during air scrubbing in order to solve the above problems.

(Means for Solving the Problems) That is, the present invention is an external pressure full filtration type in which both ends of a large number of hollow fiber membranes are liquid-tightly fixed to an outer cylinder with an adhesive, and a nozzle for blowing air is provided at the bottom. In the hollow fiber membrane module of No. 3, the holes for supplying the undiluted solution are provided in the upper part and the lower part of the outer cylinder, and the center of the undiluted solution supply hole in the lower part of the outer cylinder is displaced from the center of the air blowing hole by 15 degrees or more. It is an external pressure full filtration type hollow fiber membrane module.

(Example) Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited to this range. In the module of the present invention, as shown in FIG. 1, a large number of hollow fiber membranes (1) whose both ends are open and a water collecting pipe (2) are put in an outer cylinder (3), and the upper and lower parts are bonded by an adhesive section (4). A fixed seal is provided, and a filtrate collection chamber (5) is provided at the lower end of the module in a sealed manner by an o-ring (6). Around the liquid collection chamber (5), there is a skirt-shaped recess (7) that opens at the bottom, and an o-ring (8).
Is provided in an outer cylinder (3) in a hermetically sealed manner. The skirt-shaped recess (7) is open at the bottom, so that the air introduced into the skirt-shaped recess (7) enters the module,
It communicates with the hole (9) of the outer cylinder and the air distribution hole (11) of the partition plate (10) embedded in the adhesive portion (4).

Further, undiluted solution supply holes (12) and (13) are opened in the upper part and the lower part of the outer cylinder, respectively, and as shown in FIG. 2, the center of the undiluted solution supply hole (13) in the lower part of the module is indicated by Y. The −Y ′ line is displaced from the XX ′ line indicating the center of the air distribution hole (11) by 15 degrees or more.

During normal filtration, the undiluted solution enters the module through the undiluted solution supply hole (12) of the module outer cylinder, is filtered by the hollow fiber membrane (1), flows up and down in the hollow fiber membrane, and flows to the lower part. The liquid is withdrawn from the system from the liquid collection chamber (5) through the liquid collection pipe (2) together with the filtrate flowing to the upper part.

When the filtration differential pressure of the hollow fiber membrane module exceeds a certain pressure,
In order to remove the solid content adhering to the hollow fiber membrane, filtration is stopped and air scrubbing is performed. There is an air injection nozzle (not shown) in the lower part of the module, and the introduced air collects in the skirt-shaped recess (7) and the hole (9) of the outer cylinder, the air distribution hole (11) of the partition plate (10). ), Enters the module, rises along the hollow fiber membrane (1), and is discharged to the outside of the module through the hole (12) in the outer cylinder of the module upper part. At the same time, due to the flow of air, the undiluted solution is sucked from the hole (13) in the outer cylinder of the lower part of the module, pushing up the solid content separated from the hollow fiber membrane, and together with the air bubbles, from the hole (12) in the outer cylinder of the module It is discharged outside the module. The positions of the center of the air distribution hole (11) of the partition plate (10) and the center of the hole (13) of the outer cylinder at the lower part of the module may be displaced from the center of the module by 15 ° or more, preferably 20 ° or more. is necessary. When the angle is less than 15 degrees, the introduced air leaks from the hole (13) of the outer cylinder at the lower part of the module, the circulation amount of the undiluted solution in the module due to the air lift effect decreases, and the scrubbing effect decreases. . In addition, the holes (1
2) When (13) is provided as close to the adhesive section (4) as possible, the vibration of the yarn during scrubbing becomes large and the scrubbing effect becomes large. Thus, the module from which the solid content has been removed is used again for filtration.

(Effect of the invention) The center of the air distribution hole of the partition plate embedded in the adhesive part of the module and the center of the hole of the outer cylinder at the bottom of the module are
By shifting it more than once, a hollow fiber type module with good air scrubbing properties can be obtained.

[Brief description of drawings]

1 is a sectional view showing an example of the present invention, and FIG. 2 is a sectional view taken along the line AA 'in FIG. 1 ... Hollow fiber membrane, 8 ... O-ring 2 ... Water collecting pipe, 9 ... Outer cylinder hole 3 ... Outer cylinder 10 ... Partition plate 4 ... Adhesive part, 11 ... Air distribution hole 5 …… Collecting chamber, 12 …… Upper stock solution supply hole 6 …… O-ring, 13 …… Lower stock solution supply hole 7 …… Skirt-shaped recess

Claims (1)

[Scope of utility model registration request] 1. A hollow fiber membrane module of external pressure full filtration type, wherein both ends of a large number of hollow fiber membranes are liquid-tightly fixed to an outer cylinder with an adhesive, and an air blowing nozzle is provided in the lower portion of the hollow fiber membrane module. An external pressure full filtration type hollow fiber, characterized in that holes for supplying the undiluted solution are provided in the upper part and the lower part of the hollow tube, and the center of the undiluted solution supply hole in the lower part of the outer cylinder is displaced by 15 degrees or more from the center of the hole of the air blowing nozzle Membrane module.