JP4797485B2 - Method for producing zeolite membrane - Google Patents

Description

  The present invention relates to a method for producing a zeolite membrane.

  Zeolite, which is representative of a crystalline porous material, is a material that has solid acidity, ion exchange capacity, adsorption separation capacity, molecular level pores and the like due to its pore structure. In recent years, attention has been focused on the use of this zeolite as a membrane to separate water in an organic solvent.

  As the method for producing the zeolite membrane, the surface of the support is obtained by bringing the support into contact with a reaction solution containing a raw material of the zeolite membrane mainly composed of a silica source and an alumina source, and reacting the reaction solution with the support. A so-called “hydrothermal synthesis” method in which a zeolite membrane is formed is well known (see Patent Document 1).

However, in the hydrothermal synthesis method, when a zeolite membrane body is formed on the surface of the support, deposits such as unreacted substances, zeolite particles, or amorphous components are observed on the surface of the zeolite membrane body. . In this case, when the zeolite membrane body is used as it is as a separation membrane, there arises a problem that the permeation flux Q of the permeation component that permeates the zeolite membrane decreases or the separation performance α of the zeolite membrane decreases.

In order to suppress such a situation, in the method for producing a zeolite membrane, the zeolite membrane element is washed after being lifted from the reaction solution. The washing of the zeolite membrane element at this time is performed, for example, by the operator rubbing each part with a brush for each zeolite membrane element (hereinafter referred to as “hand washing”).
Japanese Patent Laid-Open No. 2004-82008

  However, when the zeolite membrane body is cleaned by the above-described manual cleaning, it takes time to clean each zeolite membrane body, resulting in poor workability. Further, in the manual cleaning, there is a possibility that the degree of cleaning differs for each zeolite membrane element, and the deposits on the uncleaned portion may solidify during the cleaning. Moreover, this differs depending on the skill level of the operator. For this reason, when producing a plurality of zeolite membranes, it is difficult to make the zeolite membrane homogeneous.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the zeolite membrane which can manufacture a homogeneous zeolite membrane efficiently irrespective of a skill level.

In order to solve the above problems, the present invention provides a membrane element forming step of reacting a support and a reaction solution containing a raw material for a zeolite membrane to form a zeolite membrane element on the surface of the support, and a zeolite membrane element A separation step for separating the body and the reaction liquid, and washing water having an injection pressure of 1 MPa to 10 MPa from the spray nozzle in the plane orthogonal to the extending direction of the zeolite membrane body. Water is sprayed so as to spread toward the zeolite membrane element, and the spray nozzle is applied to the support while maintaining the distance between the zeolite membrane element and the tip of the spray nozzle at 100 cm or less. by relatively moving, the zeolite membrane element was washed to remove deposits on the surface of the zeolite membrane permeation flux and zeolite membrane separation performance is improved A cleaning step that is a method for producing a zeolite membrane containing. In the present invention, the support means the support element body itself when the zeolite membrane element seed crystal is attached on the surface of the support element body or when the seed crystal is not attached. The spray pressure refers to the pressure displayed by the gauge when the gauge is installed in the spray nozzle.

According to the method for producing a zeolite membrane of the present invention, in the washing step, washing water having an injection pressure of 1 MPa to 10 MPa from the spray nozzle is orthogonal to the extending direction of the zeolite membrane element. The washing water is sprayed in a plane so as to spread toward the zeolite membrane body, and the distance between the zeolite membrane body and the tip of the spray nozzle is kept to 100 cm or less with respect to the support. Since the spray nozzle is relatively moved, the zeolite membrane body separated from the reaction solution can always be washed under the same conditions. For this reason, the removal of the deposits from the surface of the zeolite membrane element is performed to the same extent. Therefore, when producing a plurality of zeolite membranes, it is possible to produce a homogeneous zeolite membrane regardless of the skill level of the operator. Moreover, in the said washing | cleaning process, since removal of a deposit | attachment is performed by injecting washing water to the whole zeolite membrane body, it can prevent that an unwashed part arises. Therefore, a homogeneous zeolite membrane can be obtained throughout.

In the cleaning step, cleaning water having an injection pressure of 1 MPa to 10 MPa from the spray nozzle is applied to the plurality of zeolite membrane bodies separated in the separation step in an in-plane direction orthogonal to the extending direction of the zeolite membrane body. The washing water is sprayed so as to spread toward the zeolite membrane element, and the distance between each zeolite membrane element and the tip of the spray nozzle is maintained at 100 cm or less with respect to the support. It is preferable to obtain a zeolite membrane by moving a spray nozzle relatively to wash a plurality of zeolite membrane bodies.

Thus, when there are a plurality of zeolite membrane elements, washing water is simultaneously sprayed from the spray nozzles to each of the zeolite membrane elements. Also in this case, washing water having a spray pressure of 1 MPa to 10 MPa is sprayed from a spray nozzle to a plurality of zeolite membrane elements , and the distance between each zeolite membrane element and the tip of the spray nozzle is maintained at 100 cm or less . However, since the spray nozzle is moved relative to the support, the obtained plurality of zeolite membranes can be made homogeneous. In addition, since the plurality of zeolite membrane bodies are simultaneously cleaned, the cleaning is performed extremely efficiently, and the zeolite membrane can be manufactured more efficiently.

As described above, in the cleaning process, injection pressure of the washing water jetted from the spray nozzle is not more than 1 MPa to 10 MPa, a distance between the zeolite membrane element and the tip portion of the spray nozzle Ru der less 100 cm. In this case, deposits adhering to the surface of the zeolite membrane body are more effectively removed, and a homogeneous zeolite membrane having sufficient permeation flux and separation performance can be produced.

Here, “permeation flux (kg / m ² h)” refers to the amount of liquid permeating the zeolite membrane per unit time. For example, when water is to be separated from a mixed solution of ethanol and water, when a zeolite membrane is used as the separation membrane, the amount of water passing through the zeolite membrane per unit time.

“Separation performance” means, for example, in the case of a mixed solution of ethanol and water, when a zeolite membrane is used as a separation membrane, the concentration of water before separation is A1% by mass and the concentration of ethanol is A2% by mass. When the concentration of water in the liquid or gas that has passed through the zeolite membrane is B1% by mass and the concentration of ethanol is B2% by mass, the following formula (1):
α = (B1 / B2) / (A1 / A2) (1)
It is represented by. In addition, it becomes possible to isolate | separate a specific liquid with higher concentration from a liquid mixture, so that this value is large.

The present invention also includes a membrane element forming step of reacting a support and a reaction solution containing a raw material of the zeolite membrane to form a zeolite membrane element on the surface of the support, the zeolite membrane element and the reaction A separation step of separating the liquid, washing water with a spray pressure of 1 MPa to 10 MPa from the spray nozzle for the zeolite membrane element, and a distance between the zeolite membrane element and the tip of the spray nozzle of 100 cm While maintaining the following, by spraying so that the washing water spreads toward the zeolite membrane body in a plane parallel to the extension direction of the zeolite membrane body and parallel to the extension direction of the spray nozzle, this include a washing step, the obtaining the zeolite membrane element was washed to remove deposits on the surface of the zeolite membrane permeation flux and zeolite membrane separation performance is improved Which is a method for manufacturing a zeolite membrane according to claim.

According to the method for producing a zeolite membrane of the present invention, in the cleaning step, washing water having an injection pressure of 1 MPa to 10 MPa is applied to the zeolite membrane element from the spray nozzle, and the zeolite membrane element and the tip of the spray nozzle are provided. While being maintained at a distance of 100 cm or less , the washing water is sprayed so as to spread in the plane parallel to the extending direction of the zeolite membrane body and parallel to the extending direction of the spray nozzle as it goes to the zeolite membrane body. Thus, the zeolite membrane body is washed, so that it is possible to always wash the zeolite membrane body separated from the reaction solution under the same conditions. For this reason, the removal of the deposits from the surface of the zeolite membrane element is performed to the same extent. Therefore, when producing a plurality of zeolite membranes, it is possible to produce a homogeneous zeolite membrane regardless of the skill level of the operator. Moreover, in the said washing | cleaning process, since removal of a deposit | attachment is performed by injecting washing water to the whole zeolite membrane element body, it can prevent that an unwashed part arises. Therefore, a homogeneous zeolite membrane can be obtained throughout. Furthermore, in the production method of the present invention, since the washing water is brought into contact with the entire zeolite membrane body at once, solidification of the deposits due to the washing water not contacting for a long time during washing can be more sufficiently suppressed. , Can effectively remove deposits. For this reason, sufficient permeation flux and sufficient separation performance can be obtained.

  The method for producing a zeolite membrane preferably further includes a cooling step for cooling the zeolite membrane body after the separation step.

  After the separation step, since the zeolite membrane element is generally at a high temperature, the zeolite membrane element is easily dried. That is, when the zeolite membrane element is separated from the reaction solution, the moisture on the surface of the zeolite membrane element is evaporated and dried. In this case, the deposit on the surface of the zeolite membrane element is solidified, and it tends to be difficult to remove the deposit in the washing step. Therefore, by cooling the zeolite membrane body after the separation step, the zeolite membrane body becomes difficult to dry and the solidification of the deposits can be suppressed.

  According to the method for producing a zeolite membrane of the present invention, a homogeneous zeolite membrane can be efficiently produced regardless of the degree of skill.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In addition, the dimensional ratio of drawing is not restricted to the ratio of illustration.

(First embodiment)
The method for producing a zeolite membrane according to the present embodiment includes a seed attachment step in which a seed crystal is attached to a support element and reacting a reaction liquid containing a raw material of the support and the zeolite membrane on the surface of the support. A membrane element forming step for forming a zeolite membrane element, a separation step for separating the zeolite membrane element and the reaction solution, and washing water with a constant injection pressure from the spray nozzle to the zeolite membrane element. The cleaning water is sprayed so as to spread toward the zeolite membrane body in a plane perpendicular to the extending direction of the membrane body, and the distance between the zeolite membrane body and the tip of the spray nozzle is kept constant and supported. A washing step of washing the zeolite membrane body to obtain a zeolite membrane by moving the spray nozzle relative to the body.

  According to the method for producing a zeolite membrane, in the washing step, washing water having a constant injection pressure is applied to the zeolite membrane element from a spray nozzle within a plane perpendicular to the extending direction of the zeolite membrane element. In order to spread toward the zeolite membrane body, in order to move the spray nozzle relative to the support while maintaining a constant distance between the zeolite membrane body and the tip of the spray nozzle, It becomes possible to always wash the zeolite membrane body separated from the reaction solution under the same conditions. For this reason, the removal of the deposits from the surface of the zeolite membrane element is performed to the same extent. Therefore, when producing a plurality of zeolite membranes, it is possible to produce a homogeneous zeolite membrane regardless of the skill level of the operator. Moreover, in the said washing | cleaning process, since removal of a deposit | attachment is performed by injecting washing water to the whole zeolite membrane element body, it can prevent that an unwashed part arises. Therefore, a homogeneous zeolite membrane can be obtained throughout.

  Hereinafter, each step will be described in detail.

[Seed adhesion process]
The seed attachment step is a step of attaching a seed crystal to a support element to form a support.

  By performing the seed deposition step, it becomes possible to form a more uniform zeolite membrane body on the support in the membrane body forming step described later, and more uniform on the support also in the cleaning step described later. It becomes possible to form a zeolite membrane element.

  The seed crystal differs depending on the type of zeolite of the target zeolite membrane. For example, the same type of zeolite as the zeolite to be formed may be used, or the crystal structure may be similar.

  In the solution containing the seed crystal, the concentration of the seed crystal in the solution is preferably 0.01% by mass to 20% by mass, and more preferably 0.1% by mass to 10% by mass. When the concentration of the seed crystal is less than 0.01% by mass, the seed crystal does not sufficiently adhere to the support element and there are defects such as pinholes in the zeolite membrane as compared with the case where the concentration is in the above range. If the concentration of the seed crystal exceeds 20% by mass, the layer containing the seed crystal becomes too thick as compared with the case where the concentration is in the above range, and the seed crystal in the outer portion is crystallized. Since the inner seed crystal is retained without being sufficiently crystallized, the zeolite membrane tends to be peeled off or defective.

  The support element used in the present invention is not particularly limited, but is preferably porous, and is made of, for example, ceramics, organic polymer, or metal. Examples of ceramics include mullite, alumina, silica, titania, zirconia, and the like. Examples of metals include stainless steel, sintered nickel, and a mixture of sintered nickel and iron. Among these, it is preferable to use alumina as a support element. When alumina is used as the support element, elution of the material of the support element can be suppressed. Note that the support element may be made by sintering zeolite.

When the support element is porous, the average pore diameter of the pores is preferably 0.1 μm to 20 μm, and more preferably 0.1 μm to 5 μm. In this case, a zeolite membrane with few pinholes can be formed, and a zeolite membrane with high separation performance can be obtained. Moreover, it is preferable that a porosity is 5 to 50%, and it is more preferable that it is 30 to 50%. In this case, since the gas permeation amount of the support element is high, a zeolite membrane having a high permeation flux can be obtained.

When the average pore diameter is less than 0.1 μm, compared to the case where the average pore diameter is in the above range, the seed crystal does not sufficiently adhere in the support element pores, and therefore tends to be easily peeled off. When the average pore diameter exceeds 20 μm, compared to the case where the average pore diameter is in the above range, the pores cannot be filled with zeolite crystals, pinholes are generated, and the separation performance tends to be lowered. Further, when the porosity is less than 5%, compared with the case where the porosity is in the above range, the gas permeation rate is low, and thus there is a tendency that a high permeation flux cannot be obtained, and the porosity is 50 If it exceeds%, the mechanical strength of the support is low compared to the case where the porosity is in the above range, and thus the product tends to be unusable.

The shape of the support element is not particularly limited, and examples thereof include a hollow shape such as a cylindrical shape, a hollow fiber shape, and a tube shape, a plate shape, a honeycomb shape (honeycomb shape), and a pellet shape. Such a shape can be changed according to the use for which the zeolite membrane is used. For example, when a zeolite membrane is used as a separation membrane for water and an organic solvent, it is preferably hollow. In this case, washing described later can be performed more uniformly, and a zeolite membrane having a sufficient permeation flux and separation performance can be produced.

  The seed attaching step is performed by bringing the support element into contact with a solution containing the seed crystal. Examples of the contacting method include an impregnation method, a dip coating method, a spray coating method, a coating method, and a filtration method.

  Note that the solution containing the seed crystal may contain an additive such as a surfactant.

  After passing through the seed attaching step, it is preferable to dry the seed crystal. In this case, the seed crystal can be sufficiently attached to the support element.

[Film body forming process]
The membrane element forming step is a step of forming a zeolite membrane element on the surface of the support by reacting the support and a reaction solution containing the raw material of the zeolite membrane. The membrane element forming step is performed by bringing the support to which the seed crystals are attached into contact with a reaction solution containing a raw material for the zeolite membrane.

  The synthesis of the zeolite membrane can be performed, for example, by a hydrothermal synthesis method, a dry gel conversion method, or the like. Of these, the zeolite membrane is preferably synthesized by a hydrothermal synthesis method.

  First, in the membrane element forming step, the raw material of the zeolite membrane is added to water and stirred to prepare a reaction solution used for the zeolite synthesis reaction. Then, a zeolite membrane is formed on the surface of the support by impregnating the support with the reaction solution.

  The raw material of the zeolite membrane is an alumina source and a silica source, and may contain an alkali metal source and / or an alkaline earth metal source as necessary. Examples of the alumina source include aluminum powder, aluminum aluminate, aluminum sulfate, aluminum nitrate, aluminum chloride, alumina powder, colloidal alumina, and the like. Silica sources include sodium silicate, water glass, alkali metal silicates such as potassium silicate, silica powder, silicic acid, colloidal silica, acid clay, kaolin, silicon alkoxide (aluminum isopropoxide, etc.), etc. Can be mentioned. Examples of the alkali (earth) metal source include sodium chloride, potassium chloride, calcium chloride, magnesium chloride and the like. In addition, alkali metal silicate can be used as a silica source and an alkali metal source.

The molar ratio (converted to SiO ₂ / Al ₂ O ₃ ) between the silica source and the alumina source in the reaction solution can be appropriately determined depending on the type of zeolite of the target zeolite membrane.

  Moreover, the density | concentration of the said silica source and an alumina source is not specifically limited. That is, in the film body forming step, the concentration of the silica source or the alumina source may be increased to make the reaction liquid gel, which may be brought into contact with the support, and the concentration of the silica source or the alumina source should be reduced. Thus, the low viscosity reaction liquid may be brought into contact (impregnated) with the support.

  That is, the composition of the reaction solution, the reaction temperature, the reaction time, and the like vary depending on the zeolite type of the target zeolite membrane.

  Note that the reaction solution may contain an additive such as a crystallization accelerator. Examples of the crystallization accelerator include tetrapropylammonium bromide, tetrabutylammonium bromide and the like.

[Separation process]
The separation step is a step of separating the zeolite membrane body and the reaction liquid. Separation methods include, for example, a method in which a support on which a zeolite membrane element is formed is pulled out from the reaction solution, and a support in which the zeolite membrane element is formed is immersed in the reaction solution. For example, a method of removing from a discharge port provided at the bottom of the container, a method of moving the container together with the reaction liquid from a state where the support on which the zeolite membrane element is formed is immersed in the reaction liquid, Etc.

  In addition, it is preferable to perform a isolation | separation process immediately from the state which the support body in which the zeolite membrane element was formed is immersed in the reaction liquid. In this case, it can suppress that a zeolite membrane body dries and a deposit | attachment solidifies.

[Washing process]
After separating the reaction solution and the zeolite membrane element, the zeolite membrane element is washed to remove deposits such as unreacted substances, zeolite particles, or amorphous components formed on the zeolite membrane element. Specifically, with respect to the zeolite membrane element, the washing water having a constant injection pressure is spread from the spray nozzle so that the washing water spreads toward the zeolite membrane element in a plane orthogonal to the extending direction of the zeolite membrane element. The zeolite membrane is washed by spraying and moving the spray nozzle relative to the support while maintaining a constant distance between the zeolite membrane and the tip of the spray nozzle (hereinafter referred to as necessary) (Referred to as “spray cleaning”). A zeolite membrane is thus obtained.

  The reason for washing the zeolite membrane body after the separation step is as follows.

  After the separation step, since the zeolite membrane body is at a high temperature, the zeolite membrane body is easily dried. That is, when the zeolite membrane element is separated from the reaction solution, the moisture on the surface of the zeolite membrane element is evaporated and dried. In this case, when the surface of the zeolite membrane element is dried, the deposit on the surface of the zeolite membrane element is solidified, and it tends to be difficult to remove the deposit in the washing step. For the above reason, the zeolite membrane is washed after the separation step.

  The washing step is preferably performed immediately after the separation step. Here, the reason why the washing step is performed immediately after the separation step is to perform washing before the zeolite membrane is dried, and specifically, it is preferably within 30 minutes.

  Hereinafter, the washing process of the zeolite membrane body will be specifically described with reference to FIG.

  FIG. 1 is a schematic view showing a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies in the cleaning step of the present embodiment. In the cleaning process of the embodiment, a schematic view of a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies, as viewed from the extending direction side of the support, (b) It is the schematic seen from the arrow C direction of (a).

  As shown in FIGS. 1A and 1B, in the cleaning process of the present embodiment, a plurality (four in the present embodiment) of zeolite membrane elements 2 are arranged in parallel and linearly with each other. The spray nozzle 1 is arranged at a position where the washing water 3 can be sprayed onto all of the plurality of zeolite membrane bodies 2. Here, as the spray nozzle 1, a nozzle capable of spraying the cleaning water 3 at the spray angle θ in a plane orthogonal to the extending direction of the zeolite membrane body 2 is used. The spray angle θ is an angle representing the spread of the sprayed cleaning water 3 when the cleaning water 3 is sprayed from one spray nozzle 1, and is applied to all the plurality of zeolite membrane bodies 2 to be cleaned. The angle at which the cleaning water 3 can be sprayed.

  In this state, the washing water 3 is sprayed from the spray nozzle 1 at a constant spray pressure, and the zeolite membrane 2 is moved along the central axis 5 along the extending direction. At this time, the zeolite membrane element 2 is moved while keeping the distance between the zeolite membrane element 2 and the tip 1a of the spray nozzle 1 constant. At this time, the washing water 3 is sprayed from one spray nozzle 1 to the zeolite membrane bodies 2 arranged in a straight line. By using the spray nozzle 1, a plurality of zeolite membrane bodies 2 are used. On the other hand, the washing water 3 can be applied with an equal pressure. In other words, the outer water pressure can be made higher than the inner water pressure by the spray nozzle 1. At this time, without moving the zeolite membrane element 2, the tip 1a of the spray nozzle 1 is kept along the length direction of the zeolite membrane element 2 while keeping the distance from the zeolite membrane element 2 constant. May be moved.

At this time, the relative moving speed of the zeolite membrane to the spray nozzle 1 is preferably 5 cm / s or less. When the moving speed exceeds 5 cm / s, compared with the case where the moving speed is in the above range, the spray is not sufficiently applied to the same place, so that the washing becomes insufficient, and sufficient membrane performance (permeation flux , separation performance) ) Will not be obtained.

  Further, after the zeolite membrane element 2 is spray-washed while being moved, the zeolite membrane element 2 itself is rotated around the central axis 5 of the zeolite membrane element 2 and spray-washing is again performed in the same manner. In this case, each zeolite membrane body 2 can be made uniform throughout. The zeolite membrane element 2 may be rotated while spray cleaning, that is, while moving the zeolite membrane element 2, not after the zeolite membrane element 2 is spray-cleaned.

In the present embodiment, the distance between the zeolite membrane element 2 and the tip 1a of the spray nozzle 1 is preferably 100 cm or less, more preferably 1 to 20 cm. In the present embodiment having a plurality of zeolite membrane elements 2, the distance between each zeolite membrane element 2 and the tip 1a of the spray nozzle 1 is within the above range. If this distance is less than 1 cm, the zeolite membrane body 2 tends to be damaged, and it is sufficient even if the spray pressure of the washing water sprayed from the spray nozzle 1 is lowered so that the zeolite membrane body 2 is not damaged. However, the zeolite membrane 2 tends not to be washed. On the other hand, when the distance exceeds 100 cm, compared with the case where the distance is 100 cm or less, the pressure of the washing water when reaching the zeolite membrane body 2 is low, the washing becomes insufficient, and sufficient permeation flux and sufficient There is a tendency that it becomes impossible to obtain a zeolite membrane having excellent separation performance.

When the distance between the zeolite membrane element 2 and the tip 1a of the spray nozzle 1 is 100 cm or less, the spray pressure of the cleaning water 3 in the spray nozzle 1 is preferably 10 MPa or less. In this case, deposits adhering to the surface of the zeolite membrane element 2 are more effectively removed, and a homogeneous zeolite membrane having sufficient permeation flux and separation performance can be produced. When the injection pressure exceeds 10 MPa, the zeolite membrane body 2 tends to be damaged.

  Here, the injection pressure is more preferably 200 kPa to 10 MPa, and further preferably 1 MPa to 10 MPa. When the injection pressure is less than 200 kPa, the deposits on the surface of the zeolite membrane body 2 tend not to be sufficiently removed as compared with the case where the injection pressure is 200 kPa or more.

  In the present embodiment, the washing water is usually composed mainly of water, preferably pure water. The washing water may contain additives such as a surfactant and alcohol.

  The pH of the washing water is preferably 4-9. When the pH of the washing water is less than 4, the zeolite crystals tend to be decomposed and the separation performance tends to be lower than when the pH is in the above range, and when the pH exceeds 9, the pH is above. Compared with the case of being in the range, it tends to be difficult to remove the deposits.

After washing the zeolite membrane element 2 as described above, it is preferable to wash the inside of the zeolite membrane element. By further washing the inside of the zeolite membrane element, the adhering matter adhering to the inside of the zeolite membrane element is removed, so that the zeolite membrane can be further improved in permeation flux and separation performance. Moreover, when using a zeolite membrane as a separation membrane, it can also fully suppress that a deposit | attachment mixes in a permeate. Examples of the method for washing the inside of the zeolite membrane element include a method of spraying water inside the zeolite membrane element, a method of rubbing with a brush or the like.

  Zeolite membranes having various compositions and structures such as MFI type, X type, Y type, A type, and T type can be produced by the above-described method for producing a zeolite membrane of the present invention. These zeolite membranes can be used as separation membranes.

(Second Embodiment)
Next, a second embodiment of the method for producing a zeolite membrane according to the present invention will be described.

  In the present embodiment, in the cleaning process, the cleaning water 3 is sprayed onto one zeolite membrane body 2 in a state where the spray nozzle 1 is rotated by 90 ° about the central axis 6 along the extending direction. This is different from the first embodiment.

  The cleaning process of this embodiment will be specifically described with reference to FIGS. 2 (a) and 2 (b).

  FIG. 2 is a schematic view showing a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies in the cleaning step of the present embodiment. In the cleaning process of the embodiment, a schematic view of a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies, as viewed from the extending direction side of the support, (b) It is the schematic seen from the arrow D direction of (a).

  As shown in FIGS. 2 (a) and 2 (b), in the cleaning step of the present embodiment, one zeolite in a state in which the spray nozzle 1 is rotated by 90 ° about the central axis 6 along its extending direction. Washing water is jetted onto the membrane element 2. That is, the cleaning water 3 sprayed from the spray nozzle 1 is in a plane including the central axis 6 along the extending direction of the nozzle 1 and the central axis 5 along the extending direction of the zeolite membrane body 2, in other words, Injection is performed so as to spread by a predetermined injection angle θ in a plane parallel to the extending direction of the nozzle 1 and parallel to the extending direction of the zeolite membrane body 2.

  In this case, the entire zeolite membrane body 2 is washed without moving the zeolite membrane body 2 or the spray nozzle 1. At this time, the washing water can be applied to the surface of the zeolite membrane body 2 with an equal pressure along the extending direction. For this reason, a zeolite membrane from which deposits are uniformly removed as a whole is obtained. In addition, by performing the same operation on other zeolite membrane bodies, it is possible to suppress the degree of washing differing as in the case of hand washing on a plurality of zeolite membrane bodies. Each of the zeolite membranes can be homogeneous. Therefore, according to the method for producing a zeolite membrane, it is possible to efficiently produce a homogeneous zeolite membrane regardless of the skill level.

  Moreover, in the manufacturing method of this embodiment, since the washing water is brought into contact with the entire zeolite membrane body 2 at once, solidification of deposits due to the washing water not contacting for a long time during washing is more sufficiently suppressed. It is possible to remove deposits effectively. For this reason, a sufficient permeation flow rate and a sufficient separation performance can be obtained.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the first embodiment described above, the plurality of zeolite membrane elements 2 are arranged linearly with respect to the spray nozzle 1, but may be arranged in an arc. In this case, the distance between the tip of the spray nozzle 1 and the plurality of zeolite membrane elements 2 can be made the same.

  In the first embodiment described above, the central axis along the extending direction of the spray nozzle 1 is perpendicular to the surface including the central axis along the extending direction of the plurality of zeolite membrane bodies 2. The angle of the central axis of the nozzle with respect to may be an acute angle or an obtuse angle.

  In the first embodiment, one spray nozzle 1 is arranged on one side of the surface including the central axis along the extending direction of the plurality of zeolite membrane elements 2, and the plurality of zeolite membrane elements are used in the cleaning process. The body 2 is rotated around the central axis along the extending direction, and one spray nozzle 1 is arranged on each side of the surface including the central axis along the extending direction of the plurality of zeolite membrane bodies 2. May be. In this case, the same spray nozzle 1 is arranged at a symmetrical position with respect to the surface. In this case, the zeolite membrane body 2 can be uniformly washed throughout the entire process without rotating the plurality of zeolite membrane bodies 2 around the central axis along the extending direction.

  Further, in the first embodiment, the cleaning water is sprayed to the plurality of zeolite membrane bodies 2 at once, but the cleaning water is sequentially jetted to the single zeolite membrane body 2. Also good.

  Furthermore, the manufacturing method of the present invention preferably further includes a cooling step for cooling the zeolite membrane body after the separation step in the above embodiment. By performing the cooling step in this way, it is difficult to dry the zeolite membrane body and the deposits can be prevented from solidifying. Then, in the spray cleaning, deposits on the zeolite membrane body can be easily removed, and a homogeneous zeolite membrane having a sufficient permeation flow rate and separation performance can be obtained.

  In addition, if it is after a separation process, the said cooling process may be performed simultaneously with a washing | cleaning process, and may be performed between a separation process and a washing | cleaning process. When the cooling step and the washing step are performed simultaneously, the washing water is cooled to a low temperature (for example, 10 ° C. to 40 ° C.), and the zeolite membrane is washed while being cooled with the washing water. In this case, since the number of steps can be reduced, the working time can be shortened. Further, when the cooling step is performed between the separation step and the washing step, for example, in a container storing the reaction solution, the reaction solution is extracted from the state in which the zeolite membrane element is immersed in the reaction solution, and then cooled. Pure water is introduced. Thereby, the reaction liquid adhering to the zeolite membrane element is diluted, and the ratio of the reaction liquid mixed in the liquid in the cleaning step can be reduced.

  In the cooling step, the method for cooling the zeolite membrane is not particularly limited. Examples of the cooling method include a method of immersing the zeolite membrane element in water, a method of spraying water onto the zeolite membrane element, and a method of dropping water onto the zeolite membrane element.

  Moreover, the seed attachment process in the said embodiment is arbitrary, and is not necessarily an essential process for this invention. In addition, when not performing a seed adhesion process, a support element | base_body becomes a support body.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to the Example given below.

(Examples 1-3)
[Seed adhesion process]
A type A zeolite fine particles (seed crystals, particle size 100 nm) were placed in water and stirred to prepare a solution having a concentration of 0.5 mass%. A tubular porous support body (average pore diameter 1.3 μm, outer diameter 10 mm, inner diameter 6 mm, length 13 cm) made of α-alumina is immersed in this solution for 3 minutes and then pulled up at a rate of about 0.2 cm / s. It was. This was dried in a constant temperature bath at 25 ° C. for 2 hours and then dried in a constant temperature bath at 70 ° C. for 16 hours to obtain a support.

[Film body forming process]
Next, 1 mol part of alumina (Al ₂ O ₃ ), 2 mol parts of silicon dioxide (SiO ₂ ), and 2 mol parts of sodium oxide (Na ₂ O) were added to 150 mol parts of water to obtain a reaction solution. The support was immersed in this reaction solution and held at 100 ° C. for 4 hours to form a zeolite membrane element on the surface of the support. The same operation was repeated to obtain four zeolite membrane bodies.

[Washing process]
As shown in FIG. 1, four zeolite membrane bodies were arranged on a straight line, and both were installed so that the direction of this arrangement and the direction of extension of the spray nozzle (manufactured by Ikeuchi) were perpendicular. The shortest distance between the spray nozzle and the straight line formed by the zeolite membrane element was 10 cm, and the distance between each zeolite membrane element was 1 cm.

Next, the cleaning water was injected into a tank directly connected to the spray nozzle, and the cleaning water was sprayed from the spray nozzle onto the zeolite membrane body at a spray pressure of 3 MPa. The injection angle θ and the flow rate at this time were as shown in Table 1 below. In addition, the spray pressure of the washing water was a value displayed by a gauge installed on the spray nozzle.

  Then, the four zeolite membrane bodies were moved up and down at a speed of 1.6 cm / s so that the washing water was sprayed on the entire zeolite membrane. Thereafter, the zeolite membrane was dried. A separation membrane having a zeolite membrane formed on the surface of the support was thus obtained. Of the four zeolite membranes arranged in a straight line, the one at the extreme end is referred to as zeolite membrane A, and hereinafter referred to as zeolite membrane B, zeolite membrane C, and zeolite membrane D in this order. Moreover, the distance from the spray nozzle to the zeolite membranes A to D was 10.12 cm for the zeolite membranes A and D, and 10.1 cm for the zeolite membranes B and C.

(Comparative Example 1)
A zeolite membrane was obtained in the same manner as in Example 1 except that the washing step was not performed. Hereinafter, this zeolite membrane is referred to as a zeolite membrane E.

(Reference Example 1)
A zeolite membrane was obtained in the same manner as in Example 1 except that the washing process was manually washed by a skilled worker. Hereinafter, this zeolite membrane is referred to as a zeolite membrane F.

(Evaluation methods)
[Separation performance and permeation flux ]
In order to evaluate the separation performance of the zeolite membranes obtained in Examples 1 to 3, Comparative Example 1 and Reference Example 1, a pervaporation (PV) test apparatus shown in FIG. 3 was assembled. This PV test apparatus has a supply tank 11 to which a supply liquid A is supplied. A pipe 21 for supplying the supply liquid A to the supply tank 11 is connected to the supply tank 11, and a separator 12 is installed in the supply tank 11 and a stirring device 22 for stirring the supply liquid A is provided. ing. As the separator 12, the zeolite membranes of Examples 1 to 3, Comparative Example 1, and Reference Example 1 were used. A tube 16 is connected to the open end of the separator 12, and a vacuum pump 14 is connected to the end of the tube 16 via a liquid nitrogen trap 13. A vacuum gauge 15 is attached in the middle of the tube 16.

A 75 ° C. supply liquid A (mass ratio of ethanol / water = 90/10) was supplied to the supply liquid container 11 of this PV test apparatus through a tube 21 and the inside of the separator 12 was sucked by a vacuum pump 14 (vacuum gauge) 15 degree of vacuum: 10 to 1000 Pa). The liquid B that passed through the separator 12 was collected by a liquid nitrogen trap 13. The composition of the supply liquid A and the permeate B was measured using a gas chromatograph (trade name: GC-14B, manufactured by Shimadzu Corporation) to determine the separation performance α. Further, the weight of the collected liquid was measured, and the permeation flux Q was determined based on the weight, membrane area, and collection time. The obtained results are shown in Tables 2 and 3. In Table 3, “No separation performance” refers to a case where the separation factor is 1000 or less under the above measurement conditions.

From the results of Examples 1 to 3 and Comparative Example 1 described above, it was found that the permeation flux and the separation performance were greatly improved by the method for producing a zeolite membrane according to the present invention. Moreover, from the results of Examples 1 to 3 and Reference Example 1, it was found that according to the method for producing a zeolite membrane according to the present invention, a zeolite membrane having high characteristics was obtained as in the case of manual washing. From this, it is considered that according to the method for producing a zeolite membrane of the present invention, a homogeneous zeolite membrane can be produced and a zeolite membrane having sufficient permeation flux and separation performance can be provided.

FIG. 1 is a schematic view showing a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies in the cleaning step of the first embodiment. In the cleaning process of the first embodiment, a schematic view of a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies, as viewed from the extending direction side of the support, ) Is a schematic view seen from the direction of arrow C in (a). FIG. 2 is a schematic view showing a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies in the cleaning step of the second embodiment. FIG. 5 is a schematic view of a state in which cleaning water having a constant injection pressure is sprayed from a spray nozzle to a plurality of zeolite membrane bodies, as viewed from the extending direction side of the support, in the cleaning process of the second embodiment; ) Is a schematic view seen from the direction of arrow D in (a). FIG. 3 is a schematic view showing the pervaporation (PV) test apparatus used in Examples 1 to 3, Comparative Example 1 and Reference Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Spray nozzle, 1a ... Tip part, 2 ... Zeolite membrane body, 3 ... Washing water, 5 ... Center axis along the extending direction of zeolite membrane body, 6 ... Center axis along the extending direction of nozzle, 11 DESCRIPTION OF SYMBOLS ... Supply tank, 12 ... Separator, 13 ... Liquid nitrogen trap, 14 ... Vacuum pump, 15 ... Vacuum gauge, 16, 21 ... Tube, 22 ... Stirrer, A ... Feed liquid, B ... Permeate.

Claims (5)

A membrane element forming step of reacting a support and a reaction solution containing a raw material of the zeolite membrane to form a zeolite membrane element on the surface of the support;
A separation step of separating the zeolite membrane and the reaction solution;
With respect to the zeolite membrane element, cleaning water having an injection pressure of 1 MPa to 10 MPa from a spray nozzle spreads in the plane perpendicular to the extending direction of the zeolite membrane element as the washing water moves toward the zeolite membrane element. The zeolite membrane element is moved relative to the support while the distance between the zeolite membrane element and the tip of the spray nozzle is maintained at 100 cm or less. A washing process for washing the body to remove the deposits on the surface of the zeolite membrane and obtaining a zeolite membrane with improved permeation flux and separation performance ;
A method for producing a zeolite membrane, comprising: In the washing step, washing water having an injection pressure of 1 MPa to 10 MPa from the spray nozzle is applied to the plurality of zeolite membrane bodies separated in the separation step within a plane orthogonal to the extending direction of the zeolite membrane elementary body. The washing water is sprayed so as to spread toward the zeolite membrane body, and the spray is applied to the support while maintaining the distance between each zeolite membrane body and the tip of the spray nozzle at 100 cm or less. By moving a nozzle relatively, a plurality of zeolite membrane bodies are washed to remove deposits on the surface of the zeolite membrane, thereby obtaining a zeolite membrane with improved permeation flux and separation performance. The method for producing a zeolite membrane according to claim 1. The method for producing a zeolite membrane according to claim 1 or 2, wherein a relative moving speed of the zeolite membrane body with respect to the spray nozzle is 5 cm / s or less. A membrane element forming step of reacting a support and a reaction solution containing a raw material of the zeolite membrane to form a zeolite membrane element on the surface of the support;
A separation step of separating the zeolite membrane and the reaction solution;
While maintaining the distance between the zeolite membrane element and the tip of the spray nozzle to 100 cm or less, wash water having a spray pressure of 1 MPa to 10 MPa from the spray nozzle is applied to the zeolite membrane element. The zeolite membrane element is washed by spraying the washing water so as to spread toward the zeolite membrane element in a plane parallel to the extension direction of the element body and parallel to the extension direction of the spray nozzle. A cleaning step for obtaining a zeolite membrane with improved permeation flux and separation performance by removing deposits on the surface of the zeolite membrane;
A method for producing a zeolite membrane, comprising: The method for producing a zeolite membrane according to any one of claims 1 to 4 , further comprising a cooling step of cooling the zeolite membrane body after the separation step.

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