JP7079708B2 - Thermal synthetic crystal film manufacturing equipment and thermal synthetic crystal film manufacturing method - Google Patents

Description

The present invention relates to a thermosynthetic crystal membrane manufacturing apparatus and a thermosynthetic crystal membrane manufacturing method capable of efficiently producing a thermosynthetic crystal membrane formed by inducing crystallization by heat, for example, a zeolite membrane.

In the current field of separation technology, there is a need to develop a technique for separating a required substance from a liquid or gaseous fluid containing various substances at the molecular level.

As one of them, a technique for separating various mixed fluids using a crystalline separation membrane having molecular-sized pores is already known.

Porous ceramic substrates are generally known as objects on which a crystalline separation membrane is formed. A crystalline separation film refers to a finely thinned film obtained by precipitating crystals from any organic or inorganic crystallization material and growing the film on such a substrate.

Such a crystalline separation membrane may be referred to as a hydrothermally synthesized crystal membrane which is a heat-promoted crystallization membrane, and the most common such hydrothermally synthesized crystal membrane is Zeolite membranes formed by hydrothermal synthesis are known.

In order to produce a zeolite membrane, a silicon source material in zeolite, for example silica, and an aluminum source material, for example, alumina are added in a predetermined ratio to a liquid medium such as water to form a slurry. A predetermined organic compound that serves as a channel template for zeolite is appropriately added to a reaction solution for film formation, and the above substrate is dipped in the reaction solution, and the reaction vessel is heated and aged to obtain a desired zeolite film on the substrate. Form to. The substrate after film formation is appropriately washed with water, dried, and fired to obtain a zeolite membrane capable of separating a required substance from a liquid or gaseous fluid containing various substances at the molecular level.

The structure of such a crystal membrane such as a zeolite membrane can be arbitrarily selected depending on the composition of the reaction solution, the heating temperature, the heating time, the type of the organic compound, etc., and as a manufacturing apparatus used for hydrothermal synthesis, for example, a patent. Those described in Documents 1 and 2 are known.

The manufacturing apparatus described in Patent Document 1 includes a fixing jig for fixing a tubular support (tubular base material) in a synthetic container in which a synthetic liquid for forming a membrane is housed. The fixing jig has a plurality of supports for supporting the tubular substrate from the inside. In this device, the side wall portion of the synthetic container has a cylindrical shape, and a plurality of base materials are arranged on a virtual circle at equal intervals.

The manufacturing apparatus described in Patent Document 2 has the same basic configuration as that described in Patent Document 1, but has a plurality of supports (bases) in a reaction vessel having two flat surfaces parallel to each other. Since the material) is arranged parallel to the flat surface, the overall shape of the device is long in one direction when viewed from above.

However, in the apparatus described in Patent Document 1, the synthetic container is housed in a thermostat, and the synthetic liquid in the synthetic container is heated via the synthetic container. Therefore, it is considered that heat transfer to the base material placed near the center of the synthetic container becomes poor, and it becomes difficult to form a homogeneous crystalline separation film on the outer peripheral surface of the base material.

In Patent Document 2, the device shape is long in one direction, and a heat transfer area can be obtained, but there are problems such as the device being complicated and the base material shape being restricted. There is.

Further, in the conventional manufacturing apparatus including the above-mentioned Patent Documents 1 and 2, since the base material is heated from the outer peripheral side of the reaction vessel via the synthetic liquid, the wall surface of the vessel becomes the highest temperature. For this reason, heat-induced formation of the crystal film becomes a competition between the inner wall of the reaction vessel and the substrate, and as a result, nutrients for film formation on the substrate are insufficient and the yield is lowered. There are also problems such as the need for a large excess of synthetic solution.

Japanese Unexamined Patent Publication No. 2015-85238 International Publication No. 2006/132237

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat-synthesizing crystal film manufacturing apparatus and a heat-synthesizing crystal film manufacturing method capable of efficiently manufacturing a homogeneous heat-synthesizing crystal film. do.

As a result of diligent studies to solve the above problems, the present inventors can obtain a homogeneous thermosynthetic crystal film with a simple structure if heat for inducing crystallization preferentially can be supplied on the substrate. It has been found that it can be efficiently produced, and the present invention has been completed.

That is, the heat synthetic crystal film manufacturing apparatus of the present invention contains a reaction liquid containing a film precursor and serves as a reaction field for forming a heat-induced heat synthetic crystal film, and the inside of the reaction container. A heating means for heating the reaction solution of the above from the periphery of the reaction vessel, and a support arranged in the reaction vessel and supporting a base material on which a film is formed on the surface thereof are provided, and inside the support. It is characterized in that a heat transfer path is formed so that the support can be heated from the outside of the reaction vessel via the heat transfer path.

In such a heat-synthesized crystal film manufacturing apparatus, it is preferable that a heater that functions as a heat transfer path is embedded in the support.

Further, in such a heat synthetic crystal film manufacturing apparatus, it is preferable that the support has a hollow structure that functions as a heat transfer path so that a heat medium can penetrate into the hollow structure. Examples of such a heat medium include silicone oil, low temperature molten salt, air, and an inert gas.

Further, in each of the above-mentioned thermosynthetic crystal film manufacturing apparatus, a reaction liquid temperature measuring means for measuring the temperature of the reaction liquid in the reaction vessel and a support temperature measuring means for measuring the temperature of the support are provided. It is preferable to have.

Further, in this thermosynthetic crystal film manufacturing apparatus, the temperature measurement value of the reaction solution is input from the reaction liquid temperature measuring means, and the temperature measurement value of the support is input from the support temperature measuring means, and these temperatures are input. Based on the measured values, it is preferable to provide the heating means and / or the control means for controlling the temperature of the support so that the temperature of the support is + 2 to 10 ° C. higher than the temperature of the reaction solution.

Further, in the method for producing a thermally synthetic crystal film of the present invention, a reaction solution containing a precursor of a crystal film and a substrate on which the crystal film is to be formed are in contact with each other, the crystals are crystallized. It is a method for producing a thermally synthetic crystal film in which crystallization proceeds by supplying heat for inducing crystallization to a base material, and the heat for inducing crystallization is applied to the base material via a support supporting the base material. It is supplied on the material.

In the heat-synthesizing crystal film manufacturing apparatus of the present invention, a heat transfer path is formed inside the support, and the support can be heated from the outside of the reaction vessel via the heat transfer path. Further, in the method for producing a thermally synthetic crystal film of the present invention, heat for inducing crystallization is supplied to the substrate via a support supporting the substrate.

Therefore, according to the heat-synthesizing crystal film manufacturing apparatus and the heat-synthesizing crystal film manufacturing method of the present invention, preferential rapid heating on the surface of the base material can be realized, and a homogeneous synthetic film on the surface of the base material can be manufactured. Can be done efficiently. Such a configuration possessed by the present invention can easily cope with an increase in length / size of a base material.

Further, in the heat-synthesizing crystal film manufacturing apparatus and the heat-synthesizing crystal film manufacturing method of the present invention as described above, the crystalline separation film is "improved in yield", "shortened in synthesis time", and "reduced in the amount of film-forming solution used". , It is possible to realize all of "significant reduction of manufacturing cost".

It is a schematic block diagram which shows the heat synthetic crystal film manufacturing apparatus (1) which concerns on this invention. It is an enlarged view which shows the support (3) arranged in the reaction vessel (2), and the base material (4) supported by this support (3) in an enlarged manner. It is the schematic which illustrates the arrangement of each support (3). It is a schematic diagram which shows the case where the support is arranged on the upper side of a reaction vessel. It is a schematic diagram which shows the thermosynthetic crystal film manufacturing apparatus used in an Example. It is a graph which shows the temperature change of the reaction solution in the thermosynthetic crystal membrane manufacturing apparatus in the Example which manufactures an LTA type zeolite membrane. It is a graph which shows the temperature change of the reaction solution in the thermosynthetic crystal membrane manufacturing apparatus in the Example which manufactures a CHA type zeolite membrane.

1 Thermal synthetic crystal film manufacturing equipment 2 Reaction vessel 3 Support 4 Base material 5 Heat transfer path 6 Inhibition layer

Hereinafter, the heat-synthesized crystal film manufacturing apparatus and the heat-synthesized crystal film manufacturing method of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a heat-synthesized crystal film manufacturing apparatus (1) according to the present invention.

The heat-synthesized crystal film manufacturing apparatus (1) of the present invention includes a reaction vessel (2) for synthesizing a heat-synthesized crystal film.

The reaction vessel (2) contains a reaction solution containing a precursor of a heat-synthesized crystal film. Further, although not shown in FIG. 1, a heating means for heating the reaction solution filled in the reaction vessel from the periphery of the reaction vessel (2) is provided.

Further, a support (3) is arranged inside the reaction vessel (2), and the support (3) supports and fixes the base material (4). The base material (4) supported and fixed to the support (3) is in direct contact with the reaction solution filled in the reaction vessel (2), and is formed from the membrane precursor contained in the reaction solution by heat. When the film forming reaction occurs, a film is formed on the surface of the substrate.

FIG. 2 is an enlarged view showing an enlarged support (3) arranged in the reaction vessel (2) and a base material (4) supported by the support (3).

Inside the support (3), a heat transfer path (5) capable of transferring heat toward the surface of the support (3) is formed. As shown in FIG. 2, heat is supplied to the heat transfer path (5) from the outside of the reaction vessel (2). Therefore, the heat supplied from the reaction vessel (2) is supplied to the surface of the support (3) via the heat transfer path (5).

As shown in FIG. 2, heat that induces crystallization in the reaction vessel (2) in a state where the reaction solution containing the precursor of the crystal film and the substrate (4) are in direct contact with each other. Is supplied from the surface of the support (3) via the heat transfer path (5), and this heat supply causes the desired crystallization to proceed on the surface of the substrate (4) (in FIG. 2). , (Displayed in (7)).

According to the present invention schematically described above, heat is supplied from the support (3) itself supporting the base material (4) toward the base material (4), and the vicinity of the surface of the base material (4) is provided. Is the hottest in the reaction vessel, and preferential crystal film formation occurs on the surface of the substrate (4).

As a result, since the inner wall of the reaction vessel (2) has the highest temperature in the reaction vessel, nutrients are taken up for the formation of the crystal film on the inner wall, and the nutrient shortage for the membrane formation on the hepato-renal substrate (4). The problem that the conventional technique of becoming becomes is solved.

Here, the heat-synthesized crystal film referred to in the present invention is generally based on a seed crystal in which crystals are precipitated on a substrate by thermal synthesis and grown or adhered on the substrate. It means a crystal film obtained by growing, and a dense film is formed on the substrate.

In the present invention, a crystal film is formed on a substrate by heat synthesis induced by heat, and a typical example of such a method is hydrothermal synthesis of zeolite.

However, it is considered that it can be applied to any film as long as it is based on the principle that film formation is induced by heat. Therefore, the present invention is a zeolite or metal-organic framework synthesized by a hydrothermal method. It can also be applied to crystal films such as porous coordination polymers) and metal oxides, and can also be applied to hydrothermal synthesis methods under conditions that do not lead to harsh conditions such as the hydrothermal method. For example, a crystal film of a metal organic structure can generally be prepared at room temperature using a solvent such as alcohol, but by using this manufacturing apparatus and heating a support that supports a base material, the crystal film can be prepared. The formation reaction is promoted, and preferential crystal film formation can be caused on the surface of the substrate.

The base material used for forming the thermosynthetic crystal film may be any material as long as it can withstand thermal synthesis conditions such as high temperature and high pressure, but is typical, for example. Examples include ceramics such as silica, alumina, mulite, zirconia (including stabilized zirconia such as yttria-stabilized zirconia (YSZ)), corderite, titania, and metals such as stainless steel, copper, aluminum, and titanium. Examples thereof include a sintered body, and nitrides and carbides such as silicon nitride and silicon carbide.

According to the present invention, the heat transfer path (5) is formed in the support (3) as described above. In short, such a heat transfer path (5) may be any as long as it supplies heat radiated to the surface of the support (3).

As such a heat transfer path (5), for example, a heater is embedded in the support (3), and a form in which such a heater functions as the heat transfer path (5) can be assumed.

Alternatively, it is conceivable that a hollow structure is formed in the support (3), and a predetermined heat medium penetrates into the hollow structure.

As such a heat medium, a liquid or gas fluid medium is assumed, and specifically, a silicone oil or a low-temperature molten salt (ionic liquid or the like) is assumed.

The support (3) should be formed of a material having heat transferability by itself and having heat resistance and mechanical strength to withstand the conditions of a heat synthesis reaction, and examples thereof include SUS.

The shape of the support (3) itself depends on the shape of the base material (4) as long as heat can be supplied from the support (3) to the surface of the base material (4). It may be arbitrarily selected.

For example, as the form of the base material, a tubular or disc-shaped one may be used.

FIGS. 1 and 2 show a case where the base material (4) is tubular, and in this case, the support (3) also has a tubular shape so as to support the tubular base material (4) from the inside. is doing.

Alternatively, if a thermosynthetic crystal film is formed on a disk-shaped substrate, the support also has a structure having a flat surface for mounting the disk-shaped substrate, and a heat transfer path is provided inside the flat surface. What is formed will be selected.

Regarding the installation and mounting of the base material (4) on the support (3), as shown in FIGS. 1 and 2, when the base material (4) has a tubular shape, the reaction solution is contained in the base material. It is envisioned that the support will be covered with a base material that has been sealed at one end in advance so that it will not easily penetrate. If it is not sealed, it can be sealed with molten glass, a heat-shrinkable tube, or the like.

When the support (3) has a tubular shape as shown in FIGS. 1 and 2, the length thereof may be arbitrarily selected depending on the dimensions of the base material (4), and is, for example, 0.01 to. The one of about 1.2m is assumed. If the support (3) has a tubular shape, its wall thickness may be arbitrarily selected, but is preferably 1 to 2 mm, for example. If it is less than 1 mm, there may be a problem of bending / breaking due to insufficient strength, and if it is more than 2 mm, there may be a problem that the size of the base material is restricted.

Here, the gap between the support (3) and the base material (4) needs to be made as small as possible in consideration of the heat transfer property to the base material (4), but conversely, if it is made too small, it will be taken in and out. Further, it becomes difficult, and it is assumed that the base material (4) is damaged due to the thermal expansion of the support (3). Therefore, it is considered desirable that the gap between the two is 0.5 to 1 mm.

As described above, crystallization proceeds by supplying heat for inducing crystal film formation onto the surface of the substrate (4) via the support (3), but the reaction solution in the reaction vessel (2) The whole of is also needed to be heated.

Therefore, the reaction vessel (2) itself is housed in a constant temperature bath, a jacket (heating means) provided with a heater, or the like.

Further, it is assumed that a plurality of supports and a base material supported by the supports are installed in the reaction vessel (2) so as to be parallel to each other.

Regarding the arrangement of each support (3), it is considered preferable to arrange them as shown in FIGS. 3 (a) and 3 (b) in consideration of the uniformity of external heating.

However, the shape of the reaction vessel (2) is not particularly limited as long as it can make the thermal state of the reaction solution in the reaction vessel (2) uniform.

Further, when the support (3) has a hollow structure and a heat medium such as silicone oil or a low-temperature molten salt is supplied into the hollow structure to transfer heat through the support (3). In order to heat efficiently, the air remaining in the hollow structure should be removed as much as possible by degassing. Alternatively, when the heat medium as described above is used as described above, as shown in FIG. 4, the reaction vessel is provided so that the heat medium can penetrate into the hollow structure of the support without entraining air. The support may be arranged on the upper side.

Further, since the reaction vessel (2) is heated from the outer peripheral side thereof by the heating means, crystallization may occur from the inner wall of the reaction vessel (2) as in the conventional problem. In order to prevent such crystal precipitation, a heat transfer inhibitory layer (6) such as PTFE may be formed on the inner wall side of the reaction vessel (2).

The reaction solution filled in the reaction vessel (2) contains a precursor that is a source of crystallization.

For example, in the case of forming a zeolite membrane as a typical example, the reaction solution filled in the reaction vessel (2) is an aqueous slurry containing alumina and a precursor (sodium aluminate, colloidal silica, etc.) as a raw material for silica. Therefore, the content of each precursor may be appropriately selected according to the target zeolite membrane. The amount of water is also selected as appropriate.

The thermosynthetic crystal film manufacturing apparatus (1) having the above configuration further includes a thermocouple (reaction liquid temperature measuring means) for measuring the temperature inside the reaction vessel (2) and a thermocouple (support) for measuring the temperature of the support. It is preferable to have (body temperature measuring means) and (not shown).

By providing each of such thermocouples, the temperatures of the reaction solution and the portion of the support (3) can be grasped, and the temperature of each place can be controlled by these.

Further, in the thermosynthetic crystal film manufacturing apparatus (1) of the present invention, a temperature measurement value from a thermocouple for measuring the temperature of the reaction solution is input, and the temperature is measured from the thermocouple for measuring the temperature of the support (3). It is more likely that a control means (not shown) for inputting temperature measurement values and controlling the temperature of the reaction vessel (2) and / or the temperature of the support (3) based on these temperature measurement values is provided. preferable. By doing so, the temperature of the reaction solution and the temperature of the support can be automatically controlled and controlled.

Specifically, in order to promote crystal growth on the substrate (4) and obtain a thin film having a uniform and dense structure, the temperature of the support (3) is +2 to 10 higher than the temperature of the reaction solution. It is considered necessary to set the temperature higher by about ° C., but if the configuration has the above-mentioned control means, the control and management can be performed more reliably within the above-mentioned temperature range.

By the heat-synthesizing crystal film manufacturing apparatus and the heat-synthesizing crystal film manufacturing method of the present invention described above, preferential rapid heating on the surface of the base material can be realized, and a homogeneous synthetic film on the surface of the base material can be manufactured. Can be done efficiently.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

(Example)
A cylindrical thermosynthetic crystal film manufacturing apparatus as shown in FIG. 5 was prepared, and the effect of the present invention was confirmed. The material of the synthesizer was SUS316, and the dimensions of the cylindrical container were 100 mm in diameter, 350 mm in length, and 3 mm in wall thickness. Inside the cylindrical container, five hollow metal columns (an example of a support) were placed at points A to E, one in the center, and four more were evenly arranged so as to surround it. The dimensions of the hollow metal column were 11 mm in diameter, 1.5 mm in wall thickness, and 300 mm in length. A hollow porous alumina tube having an outer diameter of 16 mm, an inner diameter of 12 mm, and a length of 300 mm was used as the base material for thermally synthesizing the crystal film. Porous alumina tubes coated with seed crystals in advance were placed on the hollow metal columns A to E, and a reaction solution containing a precursor of a crystal film was added and sealed. A heat-synthesized crystal film was obtained by heat synthesis for a predetermined time in a forced convection type air constant temperature bath set to a predetermined temperature.

Hereinafter, as an example, a preparation method and a detailed evaluation method when the LTA zeolite membrane and the CHA-type zeolite membrane are thermally synthesized will be shown.

The LTA-type zeolite membrane was prepared by heat synthesis at 100 ° C. (6 h) according to the method described in Non-Patent Document 1 (JOURNAL OF MATERIALS SCIENCE LETTERS 14 (1995) 206-208). The evaluation of the separation performance was carried out by osmotic vaporization separation (perversion) using a mixed solution of 10% water-90% ethanol at 75 ° C. Permeation flux (permeation amount per unit time / unit area), which means processing capacity, and separation coefficient (water concentration of permeate / alcohol concentration of permeate) / (water concentration of supply liquid / supply), which means selectivity. The alcohol concentration of the liquid)) was determined. A gas chromatograph (Shimadzu Corporation) was used to measure the water concentration.

The CHA-type zeolite membrane was prepared by heat synthesis at 160 ° C. (24 hours) according to the method described in Patent Document 3 (Patent No. 6373381). The separation performance was evaluated by allowing a 50% carbon dioxide-50% methane mixed gas to permeate the membrane at 40 ° C and a pressure difference of 3 atm, and the permeability of each component at that time (per unit area, unit time, unit pressure difference). Permeation amount) and transmittance ratio were calculated. A gas chromatograph (Shimadzu Corporation) was used to measure the concentrations of carbon dioxide and methane.

(Manufacturing of LTA type zeolite membrane)
Table 1 below shows the separation performance of the LTA-type zeolite membrane prepared at each position A to E of the heat-synthesized crystal membrane manufacturing apparatus of the present invention.

The zeolite membrane synthesized by installing the hollow metal support as in the first embodiment has uniform separation performance regardless of the position (see “separation coefficient” in the rightmost column in Table 1), and is synthesized. It turned out that the yield was good.

Table 1 also shows, as Comparative Example 1, a solid Teflon (registered trademark) having no heat transfer path installed in place of the hollow metal support. It was found that the separation performance was non-uniform, and in particular, the separation performance at the center of the container (position C) was significantly reduced.

FIG. 6 shows the temperature change of the reaction solution in the thermosynthetic crystal film manufacturing apparatus. The internal temperature of the reaction solution rises as the synthesis starts, but when a solid Teflon (registered trademark) that does not have a heat transfer path is installed (marked with a circle in FIG. 6), the central and peripheral parts of the container are installed. Then, it can be seen that the temperature difference is large. It is considered that the reason why the homogeneous zeolite membrane could not be obtained in Comparative Example 1 is this temperature unevenness. On the other hand, it was found that when the hollow metal support column was installed according to the present invention (marked with □ in FIG. 6), the temperature unevenness was small and the time to reach the set temperature was short. As a result of rapid heating without uneven temperature in the container, it is considered that the formation of impurities and insufficient growth of the membrane are less likely to occur, and a high-quality zeolite membrane is obtained.

(Manufacturing of CHA type zeolite membrane)
Table 2 below shows the separation performance of the CHA-type zeolite membrane prepared at each position A to E of the heat-synthesized crystal membrane manufacturing apparatus of the present invention.

Similar to the case of the above-mentioned LTA-type zeolite membrane, when the hollow metal strut was installed (Example 2), the separation performance of the generated CHA-type zeolite membrane was homogeneous, and the yield of synthesis was also good. .. On the contrary, in Comparative Example 2 in which the solid Teflon (registered trademark) strut was installed, the CHA-type zeolite membrane was inhomogeneous because the separation performance was different between the prepared positions A to E.

FIG. 7 shows the temperature change of the reaction solution in the thermosynthetic crystal film manufacturing apparatus. Similarly, when solid Teflon (registered trademark) was installed (marked with a circle in FIG. 7), it was found that the temperature unevenness inside the device was large and the time to reach the set temperature was long.

Claims (4)

A reaction vessel that contains a reaction solution containing a membrane precursor and serves as a reaction field for forming a heat-induced heat-induced crystalline crystal film.
A heating means for heating the reaction solution in the reaction vessel from around the reaction vessel, and
A thermosynthetic crystal film manufacturing apparatus provided with a support arranged in the reaction vessel and supporting a hollow base material on the surface of which a film is formed from the inside .
The support has a hollow structure that functions as a heat transfer path, and the support can be heated from the outside of the reaction vessel via the heat transfer path by invading the hollow structure. It has become
A heat synthetic crystal film manufacturing apparatus characterized in that a heat transfer inhibitory layer is formed on the inner wall side of the reaction vessel . The thermosynthetic crystal film manufacturing apparatus according to claim 1 , further comprising a reaction liquid temperature measuring means for measuring the temperature of the reaction liquid in the reaction vessel and a support temperature measuring means for measuring the temperature of the support. .. The temperature measurement value of the reaction solution is input from the reaction liquid temperature measuring means, and the temperature measurement value of the support is input from the support temperature measuring means, and the temperature of the support reacts based on these temperature measurement values. The thermosynthetic crystal film manufacturing apparatus according to claim 2 , further comprising a control means for controlling the temperature of the heating means and / or the support so as to be higher than the temperature of the liquid by +2 to 10 ° C. In a state where the reaction solution containing the precursor of the crystal film and the hollow base material on which the crystal film is to be formed are in contact with each other, heat for inducing crystallization is supplied to the base material. This is a method for producing a hydrothermally synthesized crystal film in which crystallization progresses.
The reaction solution is housed in a reaction vessel in which a heat transfer inhibitory layer is formed on the inner wall side, and is heated from the periphery of the reaction vessel.
A method for producing a hydrothermal synthetic crystal film, wherein heat for inducing crystallization is supplied onto the substrate through a hollow support that supports the substrate.

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