JPH11207159A - Production of separation membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a separation membrane module high in safety and reliability and made compatible to each application by solving a problem that the leak is generated in a practical operation when a defective hollow yarn membrane having latent defective part, which does not result in the leakage yet, remains. SOLUTION: In the separation membrane module at least having an original liquid supply port and a permeated liquid outlet and loading the hollow yarn membrane, the defective membrane is detected by alternately passing a liquid from the original liquid supply port and the permeated liquid outlet under a pressure 1-2 times of the normal operation pressure of the separation membrane module to impress pressure shock and by sealing the detected defective membrane to make compatible to each application, the separation membrane module having high safety and reliability is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a separation membrane module using a hollow fiber membrane, and more particularly, to applying a pressure shock to a separation membrane module with a liquid to cause a defective hollow fiber membrane to leak. By detecting this and repairing the detected defective hollow fiber membrane in advance, it is possible to prevent initial troubles such as leaks caused by breakage of the defective membrane etc. at the time of actual use of the separation membrane module, and to secure safety. The present invention relates to a method for producing a separation membrane module that enables highly reliable and reliable separation operation.

[0002]

2. Description of the Related Art Separation membrane modules using hollow fiber membranes are:
Generally, it is manufactured by inserting a hollow fiber membrane bundle into a storage case and bonding and sealing the end portion with an adhesive. Is generated. Defects may occur during the spinning of the hollow fiber membrane, but it is difficult to completely remove the defect before the step of bonding and sealing the ends of the hollow fiber membrane bundle. Further, even if the yarn bundle has no defective portion at the stage when the hollow fiber membranes are bundled, a defect may occur in the step of bonding and sealing the end with the case using an adhesive.

[0003] Therefore, conventionally, as a method of detecting a hollow fiber membrane having such a leak defect portion after bonding and sealing,
In general, a method of immersing an adhesive sealing portion in a liquid such as water or alcohol and applying a gas pressure equal to or lower than a bubble point to confirm whether or not bubbles are generated is detected. Further, even when a leak film is detected, an initial trouble that the film leaks during the actual liquid operation may occur. As a cause of this, there is no leak, but a defective film having a potential defect portion leading to the leak remains, which is considered to cause a leak at the time of actual liquid operation, and is disclosed in JP-A-7-299341. Has proposed a method in which a gas pressure is applied to a separation membrane module for a long time to cause a defective membrane having a potential defect to leak, and this is detected in advance.

[0004]

However, these conventional detection methods use the normal operating pressure of the separation membrane module of one to one.
Gas is aerated at 1.6 times the pressure, and pressurization of this gas alone will only detect a leaky hollow fiber membrane, and will not lead to a leak in the method of JP-A-7-299341. A defective film having a latent defect portion remains, and complete detection is not possible. In either case, a leak may occur during actual liquid operation. In other words, if a defective membrane having a latent defect remains, the suspended substance on the stock solution leaks to the permeation side when the separation membrane module is actually used, and further, fungi and pyrogen on the stock solution leak to the permeation side. And other problems may occur.

Therefore, when the pressure of the gas is further increased in order to complete the detection of the defective membrane, the pressure resistance of the separation membrane module itself becomes a problem, and the gas being pressurized due to breakage or destruction at one time. There is a risk of being released outside the separation membrane module. In particular, when a large separation membrane module is used, such danger is large.

When the leaked undiluted solution component is contained in the permeate treated by the separation membrane module as described above,
Depending on the application, it may not conform to the standard or cause problems such as trouble occurrence. In particular, applications for pharmaceuticals, ultrapure water, foods, and clean water are fields where standards are often strictly defined, which poses a problem. As described above, in order to manufacture a separation membrane module according to a use, it is necessary to devise a manufacturing process.

In view of such circumstances, there is a strong demand for the development of a highly reliable method of manufacturing a separation membrane module that does not include a defective film by using a method for reliably and safely detecting a defective film.

[0008]

In view of the above, the present inventor has proposed that a liquid is alternately pressurized and passed from a module stock solution supply port and a permeate solution outlet under specific conditions to a separation membrane module, and the stock solution side and the permeate solution side of the membrane. By repeating the operation of applying a pressure shock alternately from the above, a defective film having a latent defect part is reliably detected,
By using the method of repairing the module, it was found that a separation membrane module having high safety and high reliability could be manufactured, and the present invention was completed.

That is, the present invention relates to a separation membrane module having at least a stock solution supply port and a permeate solution outlet, and having a hollow fiber membrane loaded therein, wherein the separation membrane module is used alternately from the stock solution supply port and the permeate solution outlet. A separation membrane module characterized in that a liquid is passed at a pressure in the range of 1 to 2 times the pressure, a defective membrane is detected by applying a pressure shock between the hollow fiber membranes, and the detected defective membrane is sealed. Is provided. In the method for producing a separation membrane module, the pressure of the liquid passing therethrough is in a range of 1 to 1.6 times the normal use pressure of the separation membrane module, and the time of the liquid passing is in a range of 1 to 600 seconds. It is characterized in that the operation of alternately applying pressure from a stock solution supply port and a permeate solution outlet is continuously repeated. In addition, the liquid passing through is water, causing fouling in the hollow fiber membrane when a pressure shock due to water is applied, removing a fouling substance after sealing a defective membrane detected by the pressure shock, and removing the hollow fiber membrane. And a method for manufacturing a separation membrane module characterized by recovering the performance of the separation membrane module.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a pressure shock operation and a repairing process of a detection film performed thereafter are usually performed by detecting and detecting a leak film by a general liquid immersion bubble detection method.
This is performed after the repair process.

In the present invention, the liquid used for pressure shock for detecting a defective hollow fiber membrane includes glycerin, propylene glycol, polyethylene glycol, and the like.
Examples thereof include aqueous solutions and water.

The temperature of the liquid passing therethrough is about 1-99.
Although the range of ° C. can be used, it must be selected according to the specification of the module, and it is more effective to perform the process at a high temperature close to the upper limit of the specification of the module.

In the present invention, to apply a pressure shock by alternately passing a pressurized liquid from a stock solution supply port and a permeate solution outlet means that the solution is pressurized from the stock solution supply port, that is, the stock solution side of the membrane, and the membrane is permeated. After the pressure is released, the liquid is then passed through the permeate outlet, that is, the permeate side on the opposite side of the membrane, to allow reverse permeation and release the pressure. Needless to say, the order of the flow-through pressurization may be performed first from the permeate outlet.

As described above, in the present invention, a strong pressure shock is applied to the membrane by alternately applying the pressure from the stock solution side and the permeated solution side of the membrane, thereby making it easy for a defective membrane to leak. It is.

As a specific method of applying a liquid to a separation membrane module in which this pressure shock is repeatedly operated,
The method may be appropriately selected and performed depending on the form of the separation membrane module and the like, and is not particularly limited.

For example, in the case of a separation membrane module having two undiluted solution supply ports and two permeate outlets, one undiluted solution supply port and one permeate exit are closed, and the remaining undiluted solution supply port and the permeate exit are alternately turned on. Liquid feed pressurization may be performed, or liquid pressurization alternately performed from the undiluted solution supply port and the permeate outlet may be alternately performed on the two undiluted solution supply ports and the permeate exit. Further, the method of passing the liquid may be a dead end filtration method or a cross flow filtration method.

The liquid passing pressure through the hollow fiber membrane is preferably 1 to 2 times, more preferably 1 to 1.6 times, the normal operating pressure of the separation membrane module.

The ordinary operating pressure of a separation membrane module using a hollow fiber membrane is generally 0.1 to 3 kg / cm ² (differential pressure between membranes). The pressure may be set to be equal to or less than the individual withstand pressure, but generally, it is preferably set to 3 kg / cm ² or less.

In the present invention, the method of applying a pressure shock to the membrane is such that the liquid is passed for 1 to 600 seconds and the pressure is released for 0 to 600 seconds as one pressure shock, and is alternately repeated from the stock solution side and the permeate solution side, respectively. In this case, when pressure is alternately applied from the stock solution side and the permeate solution side, two pressure shocks are applied.

In the present invention, this pressure shock is applied to 2 to 10
It may be repeated 000 times. However, if the time for passing the liquid or the number of repetitions of such a membrane is too short or the number of times is too small, the hollow fiber membrane which is liable to cause a defect remains completely without a defect. Reliability is reduced. Further, if the time is too long or the number of times is too large, the efficiency is reduced or the module is damaged. Furthermore, since the processing per module is performed in several hours, the liquid passing time is 10 hours.
~ 60 seconds is preferred. The number of repetitions is 1
About 00 to 30,000 times is preferable, and 3,000 to
More preferably, 5,000 times.

However, depending on the liquid used for the pressure shock, if the liquid is passed at a pressure in the range of 1 to 2 times the actual working pressure of the module, the permeation flow rate exceeds the design of the module, and the hollow fiber membrane may be damaged. Adverse effects are expected.

Therefore, in the present invention, for the purpose of suppressing the permeation flow rate and further increasing the efficiency of pressure shock, after the hollow fiber membrane is caused to appropriately foul in advance, the pressure due to the passage of the liquid is increased. It has been found that a method of detecting a defective film by repeating a shock operation is preferable.

The fouling substance used in the present invention is removed by washing with a chemical after detecting a defective film.
It is preferable that the film can recover the initial performance of the film. Examples of such a material include low-concentration organic polymer solutions such as albumins and humic substances, and fine particle dispersions such as silicas.In the present invention, decomposition with a chemical solution, washing and removal are simple and easy. Certain ovalbumin aqueous solutions are optimally used.

The concentration of this ovalbumin is 0.0
5 to 1% by weight is suitable. If it is less than 0.05% by weight,
This is because fouling is unlikely to occur, and if the content exceeds 1% by weight, the initial performance will not be restored unless washing is performed several times. Is also completed once.

In order to foul the hollow fiber membrane, for example, an appropriate amount of a fouling substance in the above-mentioned concentration range may be mixed into the liquid used for the pressure shock and permeated through the membrane.

A solution causing such fouling is stored in a tank as a liquid for pressure shock, and the solution is adjusted from one side of the membrane by a cross-flow filtration method.
After the pressure is released and the pressure is released, the liquid from the other side which has a liquid containing no fouling substance from the opposite side of the membrane and receives the membrane permeated liquid is reversely permeated while adjusting the pressure by the cross-flow filtration method. A pressure shock method in which a permeate is received in a tank storing a solution causing a ring and pressure is released is also an embodiment of the present invention.

It is also possible that the fouling liquid and the pressure shock liquid containing no fouling substance are separated, fouled in advance, and then switched to the pressure shock liquid to perform the pressure shock. Of course.

As described above, in the present invention, a sufficient effect can be obtained when the liquid passing pressure is equal to or lower than the pressure resistance of the separation membrane module, and high safety can be ensured.

Next, the defective film leaked due to the pressure shock is detected by a normal liquid immersion bubble detection method and sealed.
The sealing of the leak film may be performed before or after the removal of the fouling substance. However, in the present invention, in order to ensure the operation of removing the fouling substance, the sealing is performed before the fouling substance is removed. Is preferred.

When a defective film is detected, the defective film can be repaired by a method of repairing the defective film by pouring an adhesive into the hollow portion of the hollow fiber membrane in which the defect has occurred, or by sealing a metal or plastic pin. And a method of welding and sealing an end face of the hollow fiber membrane.

For recovery of the initial performance of the membrane, ovalbumin, which is preferably used as a fouling substance, is removed by washing with a chemical solution. For example, a chemical solution used for washing is, for example, 10 to 500 mg / L of hypochlorous acid. Circulation washing may be performed using a sodium aqueous solution or a 0.1 to 2% by weight aqueous solution of an enzyme detergent.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings and embodiments, but the present invention is not limited thereto.

(Example 1) Inner diameter 800 μm, outer diameter 1, 3
Cellulose acetate hollow fiber membrane 2 having a separation performance of 00 μm
Twenty defective hollow fiber membranes having dents crushed by intentionally pressing down to 4,000 are mixed, and after centrifugal bonding is performed by a centrifugal sealing device, the sealing portion is cut to open the hollow fiber membrane. Then, a hollow fiber type separation membrane module for a model was manufactured.

The hollow fiber type separation membrane module (15) is assembled in the system shown in FIG. 1, and the permeate side inlet solenoid valve (9) and the raw water side outlet solenoid valve (8) are closed, and the raw water side inlet solenoid valve (7) is closed. ) And the permeate side outlet solenoid valve (10) are opened, and the raw water side inlet pressure gauge (11) is supplied with a 0.1 wt% aqueous solution of egg white albumin in the raw water tank (1) by the liquid feed pump (3).
The 2.4 kg / cm ^2, an outlet-side return pipe of the ball valve of the raw water side inlet flowmeter (5) of the liquid feed pump (3) (16)
The solution was adjusted to 10 m ³ / hr by squeezing, and the solution was passed through a hollow fiber type separation membrane module (15) for 15 seconds to carry out filtration and fouling of ovalbumin. Permeate side outlet pressure gauge at this time (14) is 0.3 kg / cm ^2, as the transmembrane pressure was 2.1 kg / cm ^2.
Thereafter, the liquid sending pump (3) was stopped, all valves were opened, and pressure was released for 2 seconds. Next, the permeate side inlet solenoid valve (9) and the raw water side outlet solenoid valve (8) are opened, the raw water side inlet solenoid valve (7) and the permeate side outlet solenoid valve (10) are closed, and the permeate water tank (2) is permeated. The permeate-side inlet pressure gauge (13) is set at 2.4 kg / cm ² by water and the permeate-side inlet flowmeter (6) is ball-pumped with a liquid feed pump (4). 17), 10m ³ / h
r, and add 15 to the hollow fiber type separation membrane module (15).
The solution was passed for 2 seconds to perform filtration. The raw water side outlet pressure gauge at this time (12) is 0.3 kg / cm ^2, as the transmembrane pressure was 2.1 kg / cm ^2. The pressure shock caused by such an operation is applied to the hollow fiber type separation membrane module (1).
After repeating 5,000 times continuously in 5), the hollow fiber type separation membrane module (15) was removed from the apparatus, immersed in a water tank, and inspected by applying an air pressure of ² kg / cm ² from the permeation side. , All 20 defective hollow fiber membranes mixed were detected.

FIG. 2 shows the results of a model experiment showing the relationship between the number of pressure shocks and the defective film detection rate. When the number of pressure shocks is less than 3,000, the detection of defective films is insufficient.
If it is 00 times or more, 100% of the defective film is detected, and it is understood that 3,000 to 5,000 times of pressure shock is sufficient.

Air was blown to the detected defective hollow fiber membrane to blow off moisture, and then 0.1 g of a urethane adhesive was injected into each hollow fiber and cured and sealed. When a leak test was performed, no leak was detected from the 20 defective hollow fiber membranes detected, and the film was completely sealed.

After the sealing of the defective hollow fiber membrane, the hollow fiber membrane fouled with the ovalbumin aqueous solution recovered its initial performance by circulating and washing with a 50 mg / L aqueous sodium hypochlorite solution.

(Comparative Example 1) A hollow fiber type separation membrane module manufactured in the same manner as in Example 1 was used.
When a ventilation load was applied for 2 minutes by air at cm ² , only three out of the 20 defective hollow fiber membranes mixed were detected.

Comparative Example 2 Using a hollow fiber type separation membrane module produced in the same manner as in Example 1, a transmembrane pressure difference of 3 kg /
When a continuous ventilation load was applied for 7 hours using air at cm ² , only 9 out of the 20 defective hollow fiber membranes mixed were detected.

[0040]

According to the present invention, there is a possibility that the module may be damaged during the actual use of the separation membrane module by repeatedly subjecting the separation membrane module to a positive pressure, a pressure release, and a reverse pressure, and a pressure shock for applying pressure to the membrane. Can be reliably detected by forcibly leaking a defective hollow fiber membrane in advance, and by performing repairs, reliability that does not include the defective hollow fiber membrane,
A highly safe separation membrane module can be manufactured.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a pressure shock device used in the present invention.

FIG. 2 is an explanatory diagram showing the relationship between the number of pressure shocks and the defective film detection rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw water tank 2 Permeated water tank 3 Liquid feed pump 4 Liquid feed pump 5 Flow meter 6 Flow meter 7 Solenoid valve 8 Solenoid valve 9 Solenoid valve 10 Solenoid valve 11 Pressure gauge 12 Pressure gauge 13 Pressure gauge 14 Pressure gauge 15 Hollow fiber type separation Membrane module 16 Ball valve 17 Ball valve

Claims (3)

[Claims] 1. A separation membrane module having at least a stock solution supply port and a permeate solution outlet, and having a hollow fiber membrane loaded therein.
A defective membrane is detected by alternately passing a liquid at a pressure in the range of 1 to 2 times the normal operating pressure of the separation membrane module from the stock solution supply port and the permeate solution outlet, and applying a pressure shock between the hollow fiber membranes. And sealing the detected defective film. 2. The liquid supply port and the permeated liquid, wherein the pressure of the liquid passing therethrough is in the range of 1 to 1.6 times the normal operating pressure of the separation membrane module, and the time of liquid passing is in the range of 1 to 600 seconds. The method for producing a separation membrane module according to claim 1, wherein the pressure shock operation in which the liquid is alternately passed from the outlet is repeatedly performed. 3. A liquid passing therethrough is water, and fouling is caused in the hollow fiber membrane when a pressure shock by water is applied, and a fouling substance is removed after sealing a defective membrane detected by the pressure shock. 3. The method for producing a separation membrane module according to claim 1, wherein the performance of the hollow fiber membrane is recovered.