KR20150138940A - Hollow fiber membrane and method of detecting damage of membrane thereof - Google Patents

Abstract

The present invention relates to a hollow fiber membrane filtration device, and to a method for detecting damage on a filtration membrane thereof. The detection method of the present invention is involved in detection of damage on the hollow fiber membrane filtration device having a membrane module and a pipe for transporting a fluid by being connected to the membrane module. To this end, the detection method comprises the following steps: proceeding a membrane filtration process by means of the hollow fiber membrane filtration device; measuring resonance frequencies for an inspection of the hollow fiber membrane filtration device; and determining damage on the membrane module by comparing the measured value of resonance frequencies to a predetermined standard value.

Description

TECHNICAL FIELD [0001] The present invention relates to a hollow fiber membrane filtration device and a filtration membrane damage detection method thereof. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a hollow fiber membrane filtration apparatus and a filtration membrane damage detection method thereof. More particularly, the present invention relates to a hollow fiber membrane filtration device capable of easily detecting damage of a filtration membrane using an unattached sensor and improving the accuracy of damage detection, and a filtration membrane damage detection method thereof.

Due to the serious pollution of the water source, interest in purified water quality has increased and demand for highly purified water treatment is increasing. Accordingly, it is attempted to complement existing water treatment facilities or introduce new filtration devices and filtration processes. However, in order to complement existing water purification facilities or introduce new advanced water treatment facilities, there are various difficulties such as site acquisition and cost. In recent years, advanced water treatment processes using membrane filtration that is easy to operate and maintain as well as stable water quality have been proposed.

In addition, in order to prevent the risk of leakage of substances harmful to humans and the environment contained in the supply water and microorganisms such as cryptosporidium and gyadia, which are contained in the membrane filtration water treatment system using a membrane, the turbidity of the filtrate, (On-line Indirect Integrity Test) is generally applied and widely used.

The membrane filtration and water treatment method is a method of separating contaminants in raw water using a membrane having a selective permeation function (typically, a hollow fiber membrane), and is a method for reliably removing suspended solids There are advantages. On the other hand, the membrane filtration performance may deteriorate due to the presence of contaminants or solids on the surface of the filtration membrane. In this case, physical washing such as backwashing of water or air backwashing, or chemical washing using chemicals to dissolve The membrane filtration performance can be restored by washing the filtration membrane.

In order to prevent such deterioration of the membrane filtration performance, it is important to immediately detect and cope with the membrane filtration damage. In the prior art, a filtration membrane damage detection technique in a membrane filtration process will be described as follows.

' Journal of AWWA , Desalination , membrane Science has disclosed a method of injecting air into the primary side under the condition that the primary side and the secondary side are gas and liquid by a method of detecting the damage of the filtration membrane, and Japanese Unexamined Patent Application Publication No. 2000-342936 2001-269551 and 2007-245060 disclose a method for detecting damage of a filtration membrane by applying a method of injecting air into a primary side or a secondary side by holding a primary side and a secondary side of a hollow fiber membrane module as a gas or a liquid Technology is disclosed.

However, this and previous patents detect damage to the filtration membrane under conditions where the primary and secondary sides of the membrane module are applied in a gas-liquid or liquid-gas state. Under such conditions, the pressurized air is moved from the gas state side to the liquid state side by the pressure difference. In this case, resistance due to the density and the air pressure partial pressure is generated, and the rate of change of the air pressure is not large. Accordingly, even if there is damage to the filtration membrane, it is difficult to accurately determine the filtration membrane damage because the change in air pressure is small. Further, as the membrane filtration proceeds, the total filtration resistance value increases, and the measurement sensitivity is deteriorated. Also, the sensitivity is low and not quantified, so it is highly probable that the confirmation of membrane damage will be misinterpreted. Therefore, in the membrane filtration water treatment system, the pressure maintenance test method, which is a direct (off-line Direct Integrity Test), is used in parallel with the indirect method in order to check whether damage or breakage of the membrane occurs regularly or regularly.

To solve the disadvantages of the related art as described above, there has been proposed a technique of maximizing a change rate of the air pressure by keeping both the primary side and the secondary side in a gaseous state. However, this technique also has a disadvantage in that the accuracy of damage detection is somewhat unreliable because the membrane filtration damage is judged on the basis of the rate of air pressure change as in the related arts.

In addition, we developed a technology to detect the damage of the filter membrane by using the piezoelectric body to easily detect the damage of the filter membrane and to improve the accuracy of the damage detection. However, since there is a disadvantage in that a membrane damage detection method using a piezoelectric body has a disadvantage that a sensor is required to be attached per membrane module, the piezoelectric body attachment and sensor cost are more than necessary when applied to the demonstration plant, It is disadvantageous to replace not only the membrane module but also the piezoelectric body attached to the module.

In addition, there is a problem in that the time and cost due to the double measurement are consumed since the conventional one or more membrane modules must be tested by indirect method or direct method, and then the faulty series or unit must be measured by direct method for each module again.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow fiber membrane filtration apparatus and a filtration membrane damage detection method which can easily detect whether a filtration membrane is damaged or not, and can improve the accuracy of damage detection.

Another object of the present invention is to provide a hollow fiber membrane filtration device and a filtration membrane damage detection method which can overcome the problem of test time, cost and labor consumed in double testing.

Another object of the present invention is to provide a hollow fiber membrane filtration device and a filtration membrane damage detection method which do not need to replace a sensor when a membrane module is replaced because a sensor is not attached per membrane module by applying a non-affixed sensor, .

One aspect of the present invention relates to a method for detecting filter membrane damage in a hollow fiber membrane filtration apparatus. The method includes the steps of: performing a membrane filtration process using the hollow fiber membrane filtration device, the membrane module having a membrane module and a pipe connected to the membrane module and carrying a fluid; Measuring a resonance frequency of the hollow fiber membrane filter apparatus; And comparing the measured resonance frequency value with a preset reference value to determine whether the membrane module is damaged.

In one embodiment, the step of measuring the resonance frequency comprises injecting a fluid into the hollow fiber membrane filter; A process in which the mechanical vibration due to the fluid injection is converted into an electrical signal by the unattached sensor; And measuring a reference resonance frequency or a test resonance frequency from the electrical signal, wherein the unattached sensor is installed apart from the hollow fiber membrane filter apparatus.

The membrane module includes a housing accommodating a plurality of filtration membranes and the plurality of filtration membranes, wherein a non-affixed sensor is spaced apart from the housing surface, the filtration membrane including a first surface through which raw water flows, And the test resonance frequency can be measured by injecting a fluid into the first surface or the second surface.

In one embodiment, the unattached sensor may be formed spaced apart from the piping surface.

In another embodiment, the unattached sensor may be formed separately on the membrane module and the pipe surface.

The unattached sensor may comprise a piezoelectric material. The piezoelectric material may include lead zirconate titanate (PZT).

Another aspect of the invention relates to a hollow fiber membrane filtration device. The apparatus comprising: a membrane module including a housing housing a plurality of filtration membranes and the plurality of filtration membranes; And a pipe connected to the membrane module for transferring a fluid, wherein a non-affixed sensor is spaced apart from the hollow fiber membrane filtration device, and the unattached sensor measures the resonance frequency of the hollow fiber membrane filtration device, And judges whether or not it is damaged.

The present invention can easily detect damage to the filtration membrane, improve the accuracy of damage detection, overcome problems with conventional test time, cost and labor consumed in conventional double testing, There is no need to replace the sensor when the membrane module is replaced because the sensor is not attached to the membrane module, and the cost can be saved. The present invention has the effect of providing a hollow fiber membrane filtration device and a filtration membrane damage detection method.

1 is a schematic view of a hollow fiber membrane filtration apparatus according to one embodiment of the present invention.
2 is a schematic view of a hollow fiber membrane filtration apparatus according to another embodiment of the present invention.
3 is a schematic view of a hollow fiber membrane filtration apparatus according to another embodiment of the present invention.

1 is a schematic view of a hollow fiber membrane filtration apparatus according to one embodiment of the present invention. As shown in FIG. 1, a hollow fiber membrane filtration apparatus according to an embodiment of the present invention includes a membrane module 10 and piping 21, 22 connected to the membrane module for transferring fluids.

The membrane module 10 includes a plurality of filtration membranes 12 and a housing 11 for receiving the plurality of filtration membranes.

The filtration membrane includes, but is not necessarily limited to, microfiltration, ultrafiltration, and the like used for various water treatments such as water treatment and seawater desalination. In an embodiment, the filtration membrane may have a hollow fiber shape.

The membrane module includes a first surface through which raw water flows and a second surface through which process water is discharged on the basis of the surface of the filtration membrane. For example, the first surface may be formed outside the filtration membrane, and the second surface may be formed inside the filtration membrane. One end of the membrane module may be connected to the source water tank, and the other end may be connected to the treatment water tank. In this case, the raw water of the raw water tank is supplied to the first surface of the membrane module through the raw water supply pipe, the raw water supplied to the first surface is filtered by the filtration membrane so that the contaminants in the raw water are filtered, And is supplied to the second surface which is the inner space of the filtration membrane. The treated water discharged from the second surface is finally discharged to the treated water tank through the treated water discharge pipe 22.

On the other hand, for the purpose of the present invention, a fluid of a certain pressure, for example, a gas (e.g., air) or a liquid (e.g., water) is supplied to the first or second surface And a pneumatic system and a hydraulic system for measuring the pressure of the supplied fluid may be provided. At this time, the gas and the liquid may be supplied from the gas injection means and the liquid injection means, respectively. When the gas is supplied, separate first and second gas supply pipes may be provided. When the liquid is supplied, the first surface may be the liquid tank and the second surface may be the liquid tank. Further, in addition to the raw water tank and the treated water, a separate liquid injecting means may be provided to inject liquid into the first surface and the second surface, respectively.

The unattached sensor S is formed on the surface of the housing 11 so as to be spaced apart from the housing 11, and it is possible to determine whether the membrane module is damaged by measuring the resonance frequency. In another embodiment, the unattached sensor S may be formed on the pipe surface as shown in Fig. In another embodiment, the unattached sensor S may be formed on both the hinging and the piping surfaces as shown in Fig.

The non-affixed sensor S is spaced apart from the object to be measured, and includes a resonance frequency measuring means and control means for comparing the measured value with a reference value to determine whether the non-affixed sensor S is damaged.

The non-affixed sensor S serves to convert the mechanical vibration into an electrical signal, and the resonance frequency measuring means analyzes the electrical signal to measure the resonance frequency. At this time, the mechanical vibration of the membrane module and the piping is generated by the supply of a certain pressure of the fluid, that is, the gas or the liquid, to the first surface or the second surface.

The non-affixed sensor may be any piezoelectric material having a piezoelectric effect. In one embodiment, the non-affixed sensor may include a first electrode (+) and a second electrode (-) on both sides of the piezoelectric polymer film It is possible to constitute a piezoelectric body. The unattached sensor may be manufactured by a conventional method using PZT (lead zirconate titanate) as an element.

The resonance frequency measuring means analyzes the electrical signal transmitted from the unattached sensor and measures the resonance frequency. As described above, the unattached sensor is installed on the surface of the membrane module or piping. When gas or liquid is supplied to the inside of the membrane module and mechanical vibration is generated in the membrane module and the pipe, The resonance frequency measuring means measures the resonance frequency of the membrane module and the pipe through the electrical signal of the non-affixing sensor by measuring the resonance frequency from the electric signal.

The resonance frequency of the membrane module and the pipe is measured by comparing the resonance frequency (reference resonance frequency) of the membrane module and the pipe in the steady state with the resonance frequency (inspection resonance frequency) of the damaged membrane module and the pipe, This is to judge whether the module is damaged or not.

Therefore, if it is intended to determine whether the filter membranes are damaged with respect to a plurality of membrane modules and pipes, the reference resonance frequencies of the plurality of membrane modules and the respective pipes must be measured in advance. In the measured state, the resonance frequency of each of the membrane modules and the pipe is measured and compared with the reference resonance frequency, so that it is possible to detect the damage of each of the membrane modules and the pipe.

The control means performs such functions as ensuring the reference resonance frequency, comparing the examination resonance frequency with the reference resonance frequency, and judging whether it is damaged. That is, the control unit receives the specific resonance frequency of the specific membrane module and the pipe, which are measured through the resonance frequency measuring unit, in the state where the resonance frequency of the steady state of the plurality of membrane modules and the pipe, And comparing the inspection resonance frequency of the pipe with the reference reference resonance frequency to determine whether the corresponding membrane module and the pipe are damaged.

Another aspect of the present invention relates to a method for detecting a filter membrane damage in a hollow fiber membrane filtration apparatus.

The method comprises the steps of: performing a membrane filtration process using the hollow fiber membrane filtration apparatus described above; measuring a resonance frequency of the hollow fiber membrane filtration apparatus; And comparing the measured resonance frequency value with a preset reference value to determine whether the membrane module is damaged.

Here, the membrane filtration process is a process of treating raw water with treated water using a membrane module, and a membrane filtration apparatus in a state where the membrane filtration process is completed means that raw water and treated water exist on the first and second surfaces of the membrane module That is, a state in which the membrane module maintains an empty space.

In this state, the reference resonance frequency for the membrane module and the pipe in the steady state is measured. Specifically, a gas or liquid of a certain pressure is supplied to the inside of the membrane module. A gas or liquid at a constant pressure can be supplied to the first surface or the second surface of the membrane module and the piping. The pressure of the gas or the liquid supplied to the inside of the membrane module and the pipe is preferably maintained at a constant level. Specifically, the pressure or the critical pressure at the time when the gas or liquid supplied to the first surface diffuses to the second surface, It is preferable that the gas or liquid supplied to the two surfaces is maintained at a critical pressure at the time when the gas or liquid is diffused to the first surface. The reason why the critical pressure is applied is to check whether the filter membrane is damaged or not. When the filtration membrane is damaged, the gas or liquid supplied as the critical pressure falls rapidly below the critical pressure due to the filter membrane damage. , Resulting in corresponding mechanical vibrations. Of course, pressure below the critical pressure may be applied to meet the device configuration and other conditions.

When a gas or liquid of a certain pressure is supplied to the membrane module and piping in a steady state, corresponding mechanical vibration is generated, and the corresponding mechanical vibration is converted into a non-attached sensor signal installed in the membrane module and piping, do. The resonance frequency measuring means measures the resonance frequency from the transmitted electrical signal, and the measured resonance frequency is stored in the control means as the resonance frequency for the membrane module and the pipe in the steady state, that is, the reference resonance frequency. When a plurality of membrane modules and pipes are provided, a reference resonance frequency measurement process is applied to each of the membrane modules and the pipes. Meanwhile, the reference resonance frequency measurement process may be performed before the membrane filtration process.

In the state where the reference resonance frequency is measured in this manner, the test resonance frequency of each membrane module and the pipe is measured by applying the same condition as the condition in which the reference resonance frequency is measured. That is, a membrane filtering apparatus in a state in which the membrane filtration process is completed is prepared, gas or liquid of a predetermined pressure is supplied into each of the membrane modules and the piping, the mechanical vibration at this time is converted into an electrical signal through the non- The resonance frequency is measured from the electrical signal converted by using the resonance frequency measuring means. At this time, the pressure of the gas or liquid pressurized inside the membrane module and the piping is the same as that of the reference resonance frequency measurement, and may correspond to the critical pressure in one embodiment.

The test resonance frequency of each of the measured membrane modules and piping is transmitted to the control means. The control means compares the reference resonance frequency and the test resonance frequency, Is damaged. When the filtration membrane of the membrane module and the piping is damaged, the mechanical vibration of the membrane module and the piping is also different from the mechanical vibration of the normal state as the pressure of the gas or liquid injected at a constant pressure into the membrane module and the piping is reduced , And the corresponding resonance frequency is also different from the reference resonance frequency.

In the filtration membrane damage detection method of the present invention, irrespective of the submerged membrane and the pressurized membrane, if one of hundreds of membranes is broken during the membrane filtration step, the membrane filtration resistance is reduced. So that it is possible to confirm whether the membrane is damaged without actually affecting the filtration process on-line.

Claims (13)

A method for detecting a filter membrane damage in a hollow fiber membrane filtration device having a membrane module and a pipe connected to the membrane module and carrying a fluid,
Conducting a membrane filtration process using the hollow fiber membrane filtration apparatus;
Measuring a resonance frequency of the hollow fiber membrane filter apparatus;
Comparing the measured resonance frequency value with a preset reference value to determine whether the membrane module is damaged;
The method of claim 1 or 2,
The method of claim 1, wherein measuring the examination resonance frequency comprises:
Injecting a fluid into the hollow fiber membrane filter;
A process in which the mechanical vibration due to the fluid injection is converted into an electrical signal by the unattached sensor; And
And measuring a reference resonance frequency or a test resonance frequency from the electrical signal,
Wherein the unattached sensor is installed to be spaced apart from the hollow fiber membrane filtration device.
The membrane module according to claim 2, wherein the membrane module includes a housing for housing a plurality of filtration membranes and the plurality of filtration membranes, wherein a non-affixed sensor is formed on the housing surface, And a second surface through which treated water is discharged,
And injecting a fluid into the first surface or the second surface to measure a resonance frequency of the filter.
The method as claimed in claim 2, wherein the unattached sensor is formed on a surface of the pipe.
3. The method of claim 2, wherein the unattached sensor is spaced apart from the membrane module and the pipe surface.
3. The method of claim 2, wherein the unattached sensor comprises a piezoelectric material.
The method of claim 6, wherein the piezoelectric material includes lead zirconate titanate (PZT).
A membrane module including a plurality of filtration membranes and a housing for accommodating the plurality of filtration membranes; And
And a pipe connected to the membrane module for transferring the fluid, the hollow fiber membrane filtration device comprising:
In the hollow fiber membrane filtration device, a non-affixed sensor is formed spaced apart,
Wherein the unattached sensor measures the resonance frequency of the hollow fiber membrane filtration device to determine whether the membrane module is damaged.
9. The hollow fiber membrane filtration apparatus according to claim 8, wherein the unattached sensor is formed on a surface of the housing.
The apparatus of claim 8, wherein the unattached sensor is spaced apart from the piping surface.
9. The hollow fiber membrane filtration apparatus according to claim 8, wherein the unattached sensor is spaced apart from the membrane module and the pipe surface.
The apparatus of claim 8, wherein the unattached sensor comprises a piezoelectric material.
13. The hollow fiber membrane filtration apparatus according to claim 12, wherein the piezoelectric material is lead zirconate titanate (PZT).

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