CN116212643A - Sealing Technology of Hollow Fiber Membrane - Google Patents

Abstract

The invention belongs to the field of membrane preparation, and in particular relates to a hollow fiber membrane sealing process, comprising the following steps: 1) aligning one end of a membrane filament bundle formed by a plurality of membrane filaments and then putting them into a membrane shell; 2) placing a liquid colloid Inject a certain distance into the membrane shell and be able to cover the end of the membrane tow; 3) After the liquid colloid in step 2) is solidified and becomes solid or semi-solid, add potting glue; 4) Wait for the filling in step 3) After the encapsulant is cured, the pouring end that constrains the membrane tow is formed; 6) After the film tow at both ends forms a constrained pouring end under the action of the encapsulant, the colloid is liquefied and discharged from the membrane shell. The technical protection scheme of the present application replaces the sealant or sealing mixture required for traditional sealing, greatly reducing production loss. Its unique phase limit change reduces the technical requirements for the alignment step, and reduces the risk of quality change caused by insufficient technical personnel in the production increase stage.

Description

Sealing Technology of Hollow Fiber Membrane

technical field

The invention belongs to the field of membrane preparation, and in particular relates to a hollow fiber membrane sealing process.

Background technique

In the existing traditional technology, the standard hollow fiber membranes have open hollows at both ends without sealing. Therefore, in the process of casting the membrane filaments with the sealant, it is necessary to seal the ends of the membrane filaments first to prevent the entry of the sealant from damaging the performance of the membrane filaments; The end of the filament is cut so that the hollow part of the membrane filament becomes an open end to complete its function; however, this process is relatively cumbersome and affects the construction period;

The applicant adopted a new technology (2022116417353) in the existing specific gravity sealing technology, which uses the difference in specific gravity between the liquid head material and the packaging resin material (namely, sealant) to form layers to complete the sealing, but because both are In liquid state, during the feeding and curing process of the sealant, the sealing material will be displaced, resulting in the risk of the potting compound entering the hollow fiber membrane. In addition, because they are all liquid, the feeding speed of the potting compound is required to be slow. In actual production Secondary pouring is required to avoid the slow feed rate causing the potting compound to not fully enter the membrane shell and become solidified, resulting in low production efficiency and not easy to use in mass production.

It should be noted that the background technology in this application is only used to illustrate its research and development background, and is not judged as prior art.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings in the prior art and provide a hollow fiber membrane sealing process.

To achieve the above object, the technical solution adopted in the present invention is:

A sealing process for hollow fiber membranes, comprising the steps of:

1) Align one end of the membrane filament bundle formed by a plurality of membrane filaments and put it into the membrane shell;

2) inject liquid colloid into the membrane shell for a certain distance, and be able to cover the end of the membrane filament bundle;

3) After the liquid colloid in step 2) solidifies and becomes solid or semi-solid, add the potting glue;

4) After the potting glue in step 3) is cured, the pouring end that constrains the membrane tow is formed;

5) repeat step 1)-step 4) to the other end of film tow;

6) After the membrane filament bundles at both ends form a constrained pouring end under the action of the potting glue, the colloid is liquefied and discharged from the membrane shell. At this time, the hollow part of the end of the membrane filament is opened to form a The sealing of the hollow fiber membrane can be completed by connecting the channel.

The colloid is gelatin solution or thixotrope.

When the colloid is gelatin solution, the gelatin solution is liquid at 26-50°C, and semi-solid or solid at ≤25°C.

In the gelatin solution, the volume to mass ratio of water to gelatin is 1:600-1:50L/g.

The thixotrope is liquid at ≤50°C, becomes solid or semi-solid after standing for ≥30 minutes, and changes from solid or semi-solid to sol after mechanical shaking.

The thixotrope is a mixture of sodium hexametaphosphate and sodium citrate, and the mass ratio of the two is 1:0.8-1:1.2.

The height at which the membrane tow is put into the membrane shell is 40-100mm.

In step 2), the liquid colloid is injected into the membrane shell at a height of 5-50 mm.

The colloid undergoes a phase transition at -40°C to 100°C.

The colloid is solid or semi-solid at -40°C-25°C; liquid at 25°C-100°C.

Or the colloid is solid or semi-solid at -40°C-50°C; liquid at 50°C-100°C.

Or the colloid is solid or semi-solid at -40°C-30°C; liquid at 30°C-100°C.

Compared with prior art, the beneficial effect of the present invention is:

This application utilizes the phase limit variability of the colloid to form the colloid into a solid or semi-solid state, and then pours the potting compound into the membrane shell. If the flow rate is too fast, the liquid layer of the colloid will be impacted, which will cause the sealant to block the hollow part of the membrane filament. After the pouring is completed, the phase limit variability of the colloid is used to remove the colloid from the membrane shell, thereby completing the production of the hollow fiber membrane module. This method is simple and convenient, and saves the production cycle.

Description of drawings

Fig. 1 is a schematic diagram of the device used in the hollow fiber membrane sealing process of the present application.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

A sealing process for hollow fiber membranes, comprising the steps of:

1) Align one end of the membrane filament bundle formed by a plurality of membrane filaments 1 and put it into the membrane shell 3 (shown in FIG. 1 ); taking the existing mature fiber membrane as an example, the height of the membrane filament bundle into the membrane shell is 40 -100mm.

2) The liquid colloid 2 is injected into the membrane shell 3 for a certain distance, and can cover the ends of the membrane filaments; the height of the liquid colloid injected into the membrane shell is 5-50mm. The colloid can be added from the top of the membrane shell 3, or it can be added from the liquid discharge port 4 of the membrane shell 3; for the thermal phase change colloid, after standing for not less than 10 minutes, because the ambient temperature is lower than its phase transition temperature, the colloid 2 Exothermic, changing from liquid to solid or semi-solid; for thixotropic colloids, it can change from liquid to solid or semi-solid by standing still;

3) After the liquid colloid in step 2) solidifies and becomes solid or semi-solid, add the potting glue 5; the potting glue 5 is in direct contact with the membrane shell 3, the colloid 2, and the membrane filament 1;

4) After the potting glue in step 3) is cured, the membrane tow and the membrane shell are in close contact to form a permanently constrained pouring end;

5) repeat step 1)-step 4) to the other end of film tow;

6) After the membrane filaments at both ends form a constrained pouring end under the action of the potting glue, the colloid is liquefied and discharged from the liquid discharge port 4 of the membrane shell. At this time, the hollow part of the end of the membrane filament is opened The sealing of the hollow fiber membrane can be completed by forming a communication channel with the membrane shell. For the thermal phase change colloid, the liquefied form can be to move the whole into a container whose temperature range is greater than the phase transition temperature. For the thixotropic colloid, it can be shaken Turn it into a liquid over a period of time.

The gist of this application is to realize the phase change of the colloid before adding the potting compound into a solid state, and after completing the curing of the potting compound, it can be turned into a liquid state by heating or other forms such as thixotropy to facilitate its discharge. Therefore, the application does not further limit the type of colloid.

Combined with the actual application scenario, the thermal phase change colloid described in this application is preferably at -40°C

Phase transition occurs at -100°C; in view of the normal room temperature conditions; therefore, the colloid can be selected to be solid or semi-solid at -40°C to 25°C; liquid at 25°C-100°C. Or the colloid is preferably solid or semi-solid at -40°C to 50°C; liquid at 50°C-100°C. Or the colloid is preferably solid or semi-solid at -40°C-30°C; liquid at 30°C-100°C.

In order to facilitate the description of the technical solution of the present application, the colloid is exemplified by gelatin solution or thixotrope.

When the colloid is a gelatin solution, the gelatin solution is liquid at 26-50°C, and semi-solid or solid at ≤25°C. Specifically, in the gelatin solution, the volume-to-mass ratio of water to gelatin is 1:600-1:300L/g.

When the colloid is a thixotrope, the thixotrope is liquid at ≤50°C, becomes solid or semi-solid after standing for ≥30 minutes, and changes from solid or semi-solid to sol after mechanical shaking . Specifically, the thixotrope is a mixture of sodium hexametaphosphate and sodium citrate, and the mass ratio of the two is 1:0.8-1:1.2.

One end of the standard hollow fiber membrane 1 in the membrane shell 3 has been inserted into the membrane shell 3, the insertion length is 40-100mm, and then the colloid 2 is added to cover the hollow fiber membrane 1 at a height of 5-100mm, and the colloid can be added from the top of the membrane shell 3 , can also be added from the water outlet 4 of the membrane shell 3. After standing for not less than 10 minutes, since the ambient temperature is less than 10-30 ° C, the colloid 2 will release heat and change from liquid to solid or semi-solid, and then add the potting glue 5. The potting glue 5 is in direct contact with the membrane shell 3, the colloid 2, and the hollow fiber membrane 1. After curing, it is in close contact with the hollow fiber membrane 1 and the membrane shell 3 to form a permanent seal. Move the membrane module that has been poured and solidified at both ends into a container with a temperature range of 30-50°C, and open the seal of the water outlet 4 of the membrane shell 3. The colloid 2 will change into a liquid and flow out in this temperature range, while the potting glue 5 will also accelerate curing to complete curing due to the temperature range of the container. Because the encapsulant 5 is in direct contact with the colloid 2 and the membrane shell 3, its curing and exothermic process is easier, and its rise on the outer wall of the hollow fiber membrane 1 becomes smaller, which is more conducive to the subsequent use of the hollow fiber membrane module.

The sealing technology involved in the present invention, because it can realize the solid-liquid separation of the potting glue and the colloid, can reduce the steps of cutting and bonding in the middle, reduce the use of manpower, and avoid the use of other liquid specific gravity difference sealing methods The cumbersome operations involved in it are more suitable for mass production. After the colloid enters the membrane shell from the liquid state, it can quickly diffuse to the inside and outside of the membrane shell and the hollow fiber membrane. The feed flow rate (40g/s) only takes 30-120s to complete the feeding of the liquid colloid.

The colloid forms a solid or semi-solid colloid on the inner and outer walls of the hollow fiber membrane. The upper limit of the flow rate of the potting glue only needs to consider the diffusion rate of the potting glue (the measured diffusion speed of the hollow fiber membrane potting glue is 4800g/H), and it does not need to be considered. The risk of displacement of the sealing material due to the high flow rate of the potting compound, the flow rate of the potting compound is much higher than the flow rate of the potting compound involved in the sealing method using the difference in specific gravity (usually 60g/H), and will not be caused by excessive flow rate Large, resulting in the displacement of the sealing material in the inner cavity of the membrane filament, affecting the potting area of the potting compound, greatly reducing the difficulty of sealing, and improving the efficiency of mass production.

Its colloidal solid or semi-solid sealing membrane filaments, the sealing material will not be displaced on the outer wall of the membrane filament, avoiding the risk that the potting compound will be poured into the inside of the sealing material due to the high flow rate during the adding process, making the sealing technology safer. more reliable.

At the same time, the potting compound will heat up and swell during the curing process, and the pouring space will become larger. The inside and outside of the potting compound are solid or semi-solid sealing film filaments, which will not cause displacement of the sealing material, and will not cause a large sinking. The requirement for the length of the membrane filament of the hollow fiber membrane is much lower than that of other sealing methods, which effectively improves the utilization rate of the hollow fiber membrane.

The technical protection scheme of the present application replaces the sealant or sealing mixture required for traditional sealing, greatly reducing production loss. Its unique phase limit change reduces the technical requirements for the alignment step, and reduces the risk of quality change caused by insufficient technical personnel in the production increase stage.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A sealing process for a hollow fiber membrane, comprising the steps of:

1) Aligning one end of a membrane silk bundle formed by a plurality of membrane silk and then placing the membrane silk bundle into a membrane shell;

2) Injecting liquid colloid into the membrane shell for a certain distance and covering the end part of the membrane tows;

3) After the liquid colloid in the step 2) is solidified into a solid or semi-solid state, pouring sealant is added;

4) Forming a constrained pouring end for the membrane tows after the pouring sealant in the step 3) is solidified;

5) Repeating steps 1) -4) for the other end of the membrane strand;

6) After the membrane tows at the two ends form constrained pouring ends under the action of pouring sealant, the colloid is discharged from the membrane shell after being liquefied, and at the moment, the hollow parts at the ends of the membrane tows are opened to form a communication channel with the membrane shell, so that the sealing of the hollow fiber membrane can be completed.

2. The sealing process for hollow fiber membranes according to claim 1, wherein the colloid is a gelatin solution or a thixotrope.

3. The sealing process for hollow fiber membranes according to claim 2, wherein when the colloid is a gelatin solution, the gelatin solution is in a liquid state at 26-50 ℃ and is in a semi-solid state or solid state at 25 ℃ or less.

4. A sealing process for hollow fiber membranes according to claim 3 wherein the volume to mass ratio of water to gelatin in the gelatin solution is 1:600 to 1:50l/g.

5. The sealing process for hollow fiber membranes according to claim 2 wherein said thixotrope is liquid at a temperature of 50 ℃ or less, becomes solid or semi-solid after standing for 30 minutes or more, and becomes sol from solid or semi-solid after mechanical shaking.

6. The sealing process for hollow fiber membranes according to claim 5 wherein said thixotrope is a mixture of sodium hexametaphosphate and sodium citrate in a mass ratio of 1:0.8-1:1.2.

7. The sealing process for hollow fiber membranes according to claim 1, wherein the height of the membrane tows put into the membrane shell is 40-100mm.

8. The sealing process for hollow fiber membranes according to claim 1, wherein the height of the liquid colloid injection into the membrane shell in step 2) is 5-50mm.

9. The sealing process for hollow fiber membranes according to claim 1 wherein said colloid undergoes a phase change at-40 ℃ to 100 ℃.

10. The sealing process for hollow fiber membranes according to claim 1 wherein said colloid is solid or semi-solid at-40 ℃ to 25 ℃; the liquid state is at 25-100 ℃.

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