JP2010036123A - Carbon dioxide concentration membrane and carbon dioxide concentration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon dioxide concentration membrane and a carbon dioxide concentration method by which a user can concentrate CO<SB>2</SB>at a relatively high temperature from high-temperature and high-pressure gas containing CO<SB>2</SB>and H<SB>2</SB>without allowing a sweep gas to flow through the permeation side. <P>SOLUTION: The carbon dioxide concentration membrane has a multilayer structure comprising: a liquid membrane including an ionic liquid of which the 5% thermal weight loss temperature is ≥250°C, or a polymer gel made by polymerizing the ionic liquid in an inorganic porous substrate; and a sealing membrane which is not permeated by the ionic liquid and is a membrane of which the 5% thermal weight loss temperature is ≥250°C, wherein the liquid membrane is sandwiched between two layers of sealing membranes. The carbon dioxide concentration method uses the carbon dioxide concentration membrane. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a membrane and method for concentrating carbon dioxide in a gas containing carbon dioxide, particularly in a high-temperature high-pressure gas containing carbon dioxide and hydrogen.

In recent years, technology for concentrating carbon dioxide has attracted attention from the viewpoint of preventing global warming. Conventionally known CO ₂ separation methods include a chemical absorption method or a physical adsorption method, or a CO ₂ membrane separation technique.

  Generally, separation techniques such as chemical absorption and physical adsorption require enormous amounts of energy for separation. On the other hand, in the membrane separation method, if the partial pressure of carbon dioxide in the gas mixture to be separated is sufficiently high, the energy required for separation / concentration can be extremely reduced. For this reason, development of carbon dioxide membrane separation technology is underway.

  Regarding such carbon dioxide membrane separation technology, Patent Document 1 and Non-Patent Documents 1 and 2 describe polymer membranes, and Non-Patent Document 3 describes inorganic membranes.

On the other hand, in refinery hydrogen production equipment (naphtha, liquefied petroleum gas or methane steam reforming) and gasification combined power generation equipment (IGCC. Gasification of coal, asphalt, and other heavy oils), CO ₂ In addition, a high-pressure and high-temperature mixed gas mainly composed of hydrogen is generated.
JP 2008-36463 A Journal of Membrane Science 291 (2007) 157-164 Journal of Membrane Science 314 (2008) 1-4 Adv. Mater. 2008, 20, 729-732

Patent Document 1 and Non-Patent Document 1 describe a technique using a polymer membrane (PVA-PAA) having a high CO ₂ / H ₂ separation factor. In this technique, a sweep gas is allowed to flow on the permeate side. Gas is permeated under the condition of equal pressure difference. For example, there are many cases where it is difficult to flow the sweep gas to the permeate side, such as a refinery. The polymer film (PVA-PAA) has a heat resistant temperature as low as about 160 ° C.

  The film described in Non-Patent Document 2 has an even lower heat resistance temperature of approximately 70 ° C.

The inorganic membrane described in Non-Patent Document 3 can be used at high temperatures and high pressures, but there is a limit to the separation between CO ₂ , which has a close molecular size, and H ₂ and H ₂ O.

An object of the present invention is to concentrate CO ₂ at a relatively high temperature without requiring a sweep gas to flow to the permeate side from a high-temperature and high-pressure gas containing CO ₂ and H ₂ such as a hydrogen production apparatus in a refinery. And providing a carbon dioxide concentration membrane and a carbon dioxide concentration method.

According to the present invention, a liquid membrane comprising an ionic liquid or a polymer gel obtained by polymerizing an ionic liquid having a 5% thermal weight loss temperature of 250 ° C. or higher in an inorganic porous support;
A carbon dioxide-enriched membrane having a multilayer structure in which a liquid film is sandwiched between two layers of sealing films, the sealing film being a film having a 5% thermal weight loss temperature of 250 ° C. or higher that does not transmit ionic liquid Is provided.

  The liquid membrane preferably has a carbon dioxide / hydrogen separation factor of 10 or more.

  The sealing film preferably has a carbon dioxide / methane separation factor of 1.5 or more.

It is preferable that the sealing film has a carbon dioxide permeability of 1.5 × 10 ⁻⁶ mol-CO ₂ / m ² / s / kPa or more.

  According to the present invention, carbon dioxide is concentrated from a mixed gas containing at least carbon dioxide and hydrogen at a pressure of 0.6 MPa to 3.5 MPa and a temperature of 200 ° C. to 600 ° C. using the carbon dioxide concentration membrane. A method for concentrating carbon dioxide to obtain a gas is provided.

According to the present invention, it is possible to concentrate CO ₂ at a relatively high temperature without requiring a sweep gas to flow to the permeate side from a high-temperature and high-pressure gas containing CO ₂ and H ₂ such as a hydrogen production device at a refinery. A carbon dioxide concentration membrane and a carbon dioxide concentration method are provided.

  Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 is a schematic view showing an embodiment of the carbon dioxide enrichment membrane of the present invention. The carbon dioxide enriched film has a multilayer structure having at least the liquid film 1 and the sealing film, and is a two-layer sealing film 2-1 (non-permeation side sealing film) and 2-2 (permeation side sealing film). Has a multilayer structure in which the liquid film 1 is sandwiched. Due to the presence of the two sealing films 2-1 and 2-2 with the liquid film 1 in between, the disappearance of the ionic liquid (or polymer gel obtained by polymerizing the ionic liquid) 1c can be prevented.

  In order to increase the solubility of carbon dioxide, an additive 1b such as a basic compound or a carbon dioxide adsorbent can be added to the liquid film.

  For example, when a mixed gas containing carbon dioxide, hydrogen, carbon monoxide, methane, water vapor, hydrocarbon (other than methane) and sulfur oxide is supplied to the carbon dioxide enriched membrane, the non-permeate side sealing membrane 2-1 Carbon oxide, methane, hydrocarbons and sulfur oxides are separated from carbon dioxide, hydrogen and water vapor, then hydrogen, carbon dioxide and water vapor are separated by liquid membrane 1, and water vapor and carbon dioxide are separated by hydrophobic membrane 3. A gas in which carbon is separated and carbon dioxide is concentrated on the permeate side is obtained.

[Liquid film]
The liquid film has an inorganic porous support 1a.

  The inorganic porous support includes an ionic liquid or a polymer gel 1c obtained by polymerizing the ionic liquid.

  The liquid film is a film that allows more carbon dioxide to pass through between hydrogen and carbon dioxide. That is, carbon dioxide is concentrated by barriering hydrogen.

  5% thermogravimetric decrease temperature is when the sample is dried at 120 ° C. for 12 hours and then heated from 50 ° C. at 5 ° C./min with a thermogravimetry device, the mass decreases by 5 mass% of the initial mass. Temperature. In the present specification, the expression “heat resistance” or “having heat resistance” means that the 5% thermal weight loss temperature is 250 ° C. or higher.

  From the viewpoint of more efficient carbon dioxide concentration, the liquid membrane preferably has a carbon dioxide / hydrogen separation factor of 10 or more.

  The carbon dioxide / hydrogen separation coefficient here is represented by carbon dioxide permeability coefficient / hydrogen permeability coefficient at 80 ° C. The carbon dioxide / hydrogen separation factor of the liquid membrane can be measured by the following method. For example, when the multi-layered carbon dioxide concentration film is a film having a structure in which the liquid film 1 is sandwiched between the sealing films 2-1 and 2-2, first, a test method (K7126-1 or K7126 specified by JIS) is used. -2), the carbon dioxide permeation coefficient and hydrogen permeation coefficient of the multi-layer structure carbon dioxide-enriched membrane at an evaluation temperature of 80 ° C., and the carbon dioxide permeation coefficients of the sealing membranes 2-1 and 2-2, respectively, Obtain hydrogen permeability coefficient. As the test apparatus, for example, a flow type gas permeability measuring apparatus (RGP-3000 type) manufactured by Round Science Co., Ltd. can be used. Since the permeability coefficient is constant regardless of the shape, area, and film thickness of the film, it always shows the same value if the film uses the same material.

When the transmission coefficient is represented by P and the film thickness is represented by L, the following equations hold for each of carbon dioxide and hydrogen. Where L (multilayer): film thickness of carbon dioxide enriched membrane (multilayer structure),
P (multilayer): Permeability coefficient of carbon dioxide enriched membrane (multilayer structure),
L (1): film thickness of the liquid film 1,
P (1): Permeability coefficient of the liquid film 1
L (2-1): film thickness of the sealing film 2-1,
P (2-1): Permeability coefficient of sealing film 2-1.
L (2-2): Film thickness of the sealing film 2-2,
P (2-2): Permeability coefficient of the sealing film 2-2.

  Since other than P (1) is clear, the carbon dioxide permeability coefficient and hydrogen permeability coefficient of the liquid film can be known from this equation, respectively, and the carbon dioxide permeability of the liquid film can be obtained by dividing the carbon dioxide permeability coefficient by the hydrogen permeability coefficient. / Hydrogen separation factor can be determined.

-Inorganic porous support The liquid porous inorganic porous support preferably has an aperture ratio of 30% to 70%.

  The inorganic porous support preferably has a pore diameter of 5 μm or less, particularly 0.5 μm or less. As a method for measuring the pore diameter of the inorganic porous support, from the measurement method such as bubble point method, glass bead method, measurement by mercury porosimeter, measurement by scanning electron microscope, etc., to the shape of the inorganic porous support, etc. Depending on the situation, it can be appropriately selected. For example, measurement by a glass bead method is suitable if the inorganic porous support is a disc shape, and measurement by a mercury porosimeter if it is a tube shape.

  Alumina, silica, titania, zirconia or a composite material thereof, a stainless fiber or glass fiber filter, or a silver membrane filter can be used as the material for the inorganic porous support of the liquid membrane.

-Ionic liquid The ionic liquid impregnated in the inorganic porous support is an ionic liquid having a 5% thermal weight loss temperature of 250 ° C or higher. The ionic liquid here is a liquid composed of ions that do not use a solvent and have a melting point of 300 ° C. or lower, preferably 100 ° C. or lower, more preferably 50 ° C. or lower. If the melting point is low, the inorganic porous support can be impregnated without heating. However, a gel made of a polyionic liquid obtained by polymerizing an ionic liquid may not have a melting point of 300 ° C. or lower as long as the melting point of the original ionic liquid is 300 ° C. or lower. These gels can be prepared, for example, by the technique described in Macromolecules 2005, 38, 2037-2039.

  The upper limit value of the 5% thermal weight loss temperature of the ionic liquid is, for example, 600 ° C. or lower, and about 400 ° C. or lower for many ionic liquids, although there is no particular limitation.

  The thickness of the inorganic porous support containing the ionic liquid or gel thereof is preferably 10 μm or more and 500 μm or less, more preferably 30 μm or more and 150 μm or less. This thickness is preferable in order to prevent defects in the liquid film part and to easily maintain gas permeability.

  As the ionic liquid, a compound comprising a combination of the following cation and anion can be used.

  The cation is an imidazolium having the following substituents at the 1 and 3 positions, and has an alkyl group, a hydroxyalkyl group, an allyl group, or an aminoalkyl group as a substituent, particularly an amino group and a hydroxyl group in one side chain. Those having an aminohydroxyalkyl group are preferable, and those having a 1-amino-2-hydroxyalkyl group in which the carbon atom adjacent to the carbon atom bonded to the amino group is bonded to the hydroxyl group are preferable. .

  Anions include boron tetrafluoride ion, bis (trifluoromethanesulfonyl) imide ion, hexafluorophosphate ion, trifluoromethanesulfonate ion, lactate ion, acetate ion, methylcarboxylate ion, bicarbonate ion, amino acid ion, especially bis (Trifluoromethanesulfonyl) imide ion is preferred.

Additive In order to increase the affinity of the liquid film portion with carbon dioxide, a basic compound can be added to the ionic liquid as an additive. The basic compound is preferably a compound having a melting point of 150 ° C. or higher. If the melting point is high, a decrease in the solubility of carbon dioxide due to the vaporization of the additive can be easily prevented. P-aminobenzoic acid etc. are mentioned as a preferable basic compound.

  When the basic compound is dissolved in the ionic liquid, it is preferable to dissolve the ionic liquid while measuring the pH so that the pH of the ionic liquid after the addition is 7 to 10 from the viewpoint of preventing the decomposition of the ionic liquid. It is because it can suppress that an ionic liquid decomposes | disassembles under the influence of a basic compound.

  When adding an inorganic basic compound, it is preferable to carry | support a basic compound on a support body instead of dissolving directly in an ionic liquid. As the supporting method, an impregnation method such as an Incipient Wetness method can be used. By doing so, decomposition of the ionic liquid can be easily suppressed.

  Basicity may be increased by introducing an amino group into the cation or anion constituting the ionic liquid, and this method is more preferred. Examples of the ionic liquid having an amino group include N-aminopropyl-3-butylimidazolium tetrafluoroborate. This ionic liquid is, for example, J. Am. Chem. Soc. 124 (2002) 926-927.

  Among the ionic liquids having an amino group, a compound having a hydroxyl group is particularly preferred, and the structure of the amino group and the hydroxyl group is that the terminal is an amino group and the carbon atom adjacent to the carbon atom bonded to the amino group is a hydroxyl group. Those having a linked 1-amino-2-hydroxyalkyl group are preferred.

An inorganic adsorbent that adsorbs CO ₂ may be added to the ionic liquid. As an adsorbent, J.A. Am. Chem. Soc. 2005, 127, 17998-17999, called MO ₃ (Metal-Organic frameworks) called Cu ₃ (Btc) ₂ (Btc = benzeneticboxylate), [Cu (PF ₆ ) ₂ (bpetha) ₂ ] n (bpetha = 1, Metal complexes such as 2-bis (4-pyridyl) ethane) and Zn ₄ O (1,3,5-benzotribenzoate) ₂ are preferred.

The metal complex preferably has a CO ₂ adsorption amount of 7 mmol / g or more at room temperature (25 ° C.) and 2 MPa as measured by a CO ₂ adsorption amount measuring apparatus using a constant volume method. When the metal complex does not dissolve in the ionic liquid, it is preferable to pulverize the complex with a mill so that the particle size is less than 0.5 μm and add and disperse it in the ionic liquid. The addition amount of the complex is preferably 0.01% by mass or more and 1.0% by mass or less with respect to the ionic liquid. This is to facilitate impregnation of the ionic liquid into the inorganic porous support while increasing the solubility of carbon dioxide.

The higher the solubility of carbon dioxide in the liquid membrane and the higher the hydrogen barrier property, the better the separation between CO ₂ and H ₂ having a close molecular size.

[Sealing film]
The sealing film 2 is a film having a 5% thermal weight loss temperature of 250 ° C. or higher that does not allow the ionic liquid to permeate. Whether or not the sealing film permeates the ionic liquid can be easily estimated by measuring the pore volume with a nitrogen gas adsorption device. If it is a non-porous film in which nitrogen adsorption into the pores is not observed, the ionic liquid is not permeated. Zeolite is a porous film, but when an X-ray diffractometer is used and the crystal structure does not contain amorphous and the oxygen atom contained in the pore ring structure has a skeleton structure of 10-membered ring or less, it does not penetrate the ionic liquid. .

As the sealing film 2, a film that allows molecules having a molecular size of 3.5 Å (3.5 × 10 ⁻¹⁰ m) or less to permeate preferentially over molecules larger than 3.5 Å can be used. Specifically, a membrane that allows permeation of carbon dioxide, hydrogen, and water vapor more preferentially than carbon monoxide and methane can be used. Here, preferentially transmitting means that the transmission coefficient is larger. That is, as the sealing film 2, a film having a barrier property against carbon monoxide and methane can be used.

  From the viewpoint of more efficient carbon dioxide concentration, it is preferable that the sealing membrane has a carbon dioxide / methane separation factor of 1.5 or more.

From the viewpoint of more efficiently concentrating carbon dioxide, the sealing film preferably has a carbon dioxide permeability of 1.5 × 10 ⁻⁶ mol-CO ₂ / m ² / s / kPa or more.

  The carbon dioxide / methane separation coefficient here is represented by carbon dioxide permeability coefficient / methane permeability coefficient at 80 ° C. The permeation coefficient of each gas can be determined by a test method (K7126-1 or K7126-2) defined in JIS, and the carbon dioxide permeability can also be determined by the same test method. As the test apparatus, for example, a flow type gas permeability measuring apparatus (RGP-3000 type) manufactured by Round Science Co., Ltd. can be used.

  For the sealing film, organic materials such as polyimide, polydiphenylacetylene, polytrimethylsilylpropyne; zeolites such as MFI type, CHA type (especially SAPO34), DDR type, T type; rubbers such as polydimethylsiloxane; or these Composite materials can be used.

  Since the aromatic or SOx can be barriered by the sealing film, the deterioration of the liquid film can be excellently suppressed.

[Hydrophobic membrane]
In order to suppress the permeation of water as required, the multilayer structure is a membrane for separating carbon dioxide and water (a membrane that selectively permeates carbon dioxide and carbon dioxide in water), and 5% It is possible to have a hydrophobic film 3 which is a film having a thermogravimetric temperature reduction temperature of 250 ° C. or higher.

  The hydrophobic film can be provided outside the sealing film 2-2 on the carbon dioxide permeation side (the side opposite to the liquid film 1).

  From the viewpoint of more efficiently concentrating carbon dioxide, it is preferable that the hydrophobic membrane can separate carbon dioxide and hydrogen (can selectively permeate carbon dioxide of carbon dioxide and hydrogen).

As the hydrophobic membrane, a heat-resistant membrane having a CO ₂ / H ₂ O separation coefficient of 1.2 or more expressed by the ratio of the CO ₂ permeability coefficient and the H ₂ O permeability coefficient is preferable. The CO ₂ / H ₂ O separation coefficient here is expressed as CO ₂ permeability coefficient / water vapor permeability coefficient at 80 ° C. The permeability coefficient of CO ₂ and water vapor can be determined by a test method (K7129) defined in JIS. As the test apparatus, for example, a flow type gas permeability measuring apparatus (RGP-3000 type) manufactured by Round Science Co., Ltd. can be used.

  For example, silsesquioxane gel as described in 3D105 (2006) of the 86th Annual Meeting of the Chemical Society of Japan, having a thickness of 50 μm and containing Ti can be used as the material of the hydrophobic film.

[CO2 enrichment method]
Using the carbon dioxide concentrating membrane of the present invention, CO ₂ can be separated and concentrated with low energy by using the pressure at the time of production of the mixed gas produced by the refinery hydrogen production apparatus or IGCC.

The main components in the refinery hydrogen production apparatus and the mixed gas produced by IGCC are CO ₂ and hydrogen, and since these apparatuses are high-pressure apparatuses, the CO ₂ partial pressure in the mixed gas is very high. By effectively using this pressure, there is a possibility that CO ₂ can be separated with low energy without increasing the pressure of the gas with a compressor. For this reason, a carbon dioxide enriched membrane that can be used at high temperatures is desired, but the carbon dioxide enriched membrane of the present invention is particularly useful in such cases.

  Specifically, from a mixed gas containing at least carbon dioxide and hydrogen having a pressure of 0.6 MPa or more and 3.5 MPa or less and a temperature of 200 ° C. or more and 600 ° C. or less, using the carbon dioxide enriched membrane of the present invention, A gas enriched with carbon can be obtained.

This mixed gas can contain CO, methane, and H ₂ O in addition to carbon dioxide and hydrogen, and can further contain hydrocarbons other than methane, NOx, and SOx. The concentration of carbon dioxide is preferably 50 vol% or more, and the concentration of gases other than carbon dioxide, hydrogen, CO, methane, and H ₂ O is preferably 1 vol% or less.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by this.

[5% thermal weight loss temperature]
A sample was taken from the material constituting the carbon dioxide concentrated liquid film used for evaluation, dried at 120 ° C. for 12 hours, and then heated from 50 ° C. to 5 ° C./5° C. using a thermogravimetric apparatus (manufactured by Shimadzu Corporation, TGA-50). When the temperature is raised in minutes, the temperature when the mass is reduced by 5% by mass of the initial mass is the 5% thermal weight reduction temperature.

〔Evaluation methods〕
In Example 1, Example 2, Comparative Example 1 and Comparative Example 2, the film was evaluated by the following method. In these examples, a disk-shaped carbon dioxide enriched membrane was used.

  An outline of the evaluation apparatus used is shown in FIG. The carbon dioxide enriched membrane 14 was attached to the cell 13 for evaluation. This cell is configured such that a mixed gas is supplied from the sampling line 12, the non-permeate gas 19 is discharged from the non-permeate gas line 17, and the permeate gas 20 is discharged from the permeate gas line 18. A non-permeate gas pressure indicator 15 is connected to the non-permeate gas line, and a permeate gas pressure indicator 16 is connected to the permeate gas line. By switching the sampling valve 21, the permeated gas can be guided to the gas composition analyzer 23 via the sampling line 22.

A mixed gas of hydrogen / CO ₂ / CO / methane = 70/20/5/5 (molar ratio) was supplied to the sampling line 12 as the evaluation gas 11 at a gas flow rate of 100 ml / min. At this time, the pressure (P1) of the non-permeating gas is set to 0.98 MPa-G, the pressure (P2) of the permeating gas 20 is set to 0.20 MPa-G, and the temperature of the carbon dioxide enriched membrane is set to 80 ° C. or 300 ° C. Set. The temperature of the evaluation gas was the same as the temperature of the carbon dioxide enriched membrane. The CO ₂ concentration of the permeated gas was analyzed with a gas composition analyzer.

  Note that “G” in the pressure unit means a gauge pressure.

  In Examples 3 and 4, the film was evaluated by the following method. In these examples, a tubular (hollow cylindrical) carbon dioxide enriched membrane was used.

  An outline of the evaluation apparatus used is shown in FIG. The tube-shaped carbon dioxide concentration membrane 24 was passed through a cylindrical evaluation case 26 and the space between the evaluation case and the carbon dioxide concentration membrane was sealed with a glass seal 25. A non-permeating gas pressure indicator 15 is connected to the inside of the tubular carbon dioxide concentrating membrane, and a non-permeating gas 19 is discharged from the carbon dioxide concentrating membrane. The permeated gas 20 that has permeated the carbon dioxide enriched membrane is discharged from the inside of the evaluation case. A permeate gas pressure indicator 16 is connected to the outlet of the permeate gas. The permeated gas can be led to the gas composition analyzer 23 through the sampling valve 21 and the sampling line 22.

As an evaluation gas, a mixed gas of hydrogen / CO ₂ / CO / methane = 70/20/5/5 (molar ratio) was supplied to the inside of the tubular carbon dioxide enriched membrane at a gas flow rate of 100 ml / min. At this time, the non-permeate gas pressure (P1) was set to 0.98 MPa-G, the permeate gas pressure (P2) was set to 0.20 MPa-G, and the temperature of the carbon dioxide enriched membrane was set to 80 ° C. or 300 ° C. The temperature of the evaluation gas was the same as the temperature of the carbon dioxide enriched membrane. The CO ₂ concentration of the permeated gas was analyzed with a gas composition analyzer.

[Example 1]
A hydrophilic silver membrane filter (made by Sterlitech) having a film thickness of 50 μm, a diameter of 47 mm, and a pore diameter of 5 μm is used as an inorganic porous support (disc shape), and this is an ionic liquid in which 1 mol% of p-aminobenzoic acid is dissolved (Kanto). A porous membrane was impregnated with an ionic liquid by immersion in allylethylimidazolium bis (trifluoromethylsulfonyl) imide (manufactured by Chemical Co., Ltd.) to obtain a liquid film.

  A polyparatrimethylsilyldiphenylacetylene (manufactured by the method described in Macromolecules 2005, 38, 4096-4102) having a film thickness of 20 μm and a diameter of 50 mm was provided on both sides of the liquid film as a sealing film, respectively, Obtained.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1.

[Example 2]
A hydrophilic silver membrane filter (made by Sterlitech) having a film thickness of 50 μm, a diameter of 47 mm, and a pore diameter of 5 μm is used as an inorganic porous support (disc-shaped), and an ionic liquid (N-aminopropyl-3-butylimidazo) having an amino group thereon. A liquid film was obtained by impregnating with lithium tetrafluoroborate (produced by the method described in J. Am. Chem. Soc. 124 (2002) 926-92).

  A polyparatrimethylsilyldiphenylacetylene having a thickness of 20 μm and a diameter of 50 mm (manufactured by the method described in Macromolecules 2005, 38, 4096-4102) was provided on both sides of the liquid film as a sealing film to obtain a carbon dioxide concentrated film It was.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1.

Example 3
Incipient wetness method using 1N potassium hydroxide aqueous solution on cylindrical alumina tube (SPG Techno Co., Ltd., trade name: SPG membrane) having an outer diameter of 10 mm, inner diameter of 7 mm, length of 50 mm, and pore diameter of 0.1 μm. (Or may be the Pore Filling method) and impregnated with potassium. This was fired at 400 ° C. for 1 hour to obtain a porous support.

  Adv. As a sealing film on the inner wall and outer wall of the central part (length 40 mm) of the tubular porous support, respectively. Mater. A SAPO34 zeolite membrane was formed by the method described in 2008, 20, 729-732. The thickness of the zeolite membrane was 10 μm as measured with a scanning electron microscope.

  Thereafter, an ionic liquid having an amino group (N-aminopropyl-3-butylimidazolium tetrafluoroborate (J. Am. Chem. Soc. 124 (2002) 926-92) is formed from the end of the tubular porous support. Impregnated by the method described))).

  Both ends 10 mm of the tubular porous support were glass sealed to obtain a carbon dioxide concentrated membrane.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1.

Example 4
A cylindrical alumina tube (manufactured by SPG Techno Co., Ltd., trade name: SPG membrane) having an outer diameter of 10 mm, an inner diameter of 7 mm, a length of 50 mm, and a pore diameter of 0.1 μm was used as the porous support.

  Adv. As a sealing film on the inner wall and the outer wall of the central part (length 40 mm) of this tubular support, respectively. Mater. A SAPO34 zeolite membrane was formed by the method described in 2008, 20, 729-732. The thickness of the zeolite membrane was 10 μm as measured with a scanning electron microscope.

Next, an ionic liquid (Kanto Chemical Co., Ltd.) added with 0.1% by mass of Cu ₃ (Btc) ₂ (Btc = benzenetic boxylate) (produced by the method described in JP-A-2002-204953) as a CO ₂ adsorbent. ), Allylethylimidazolium bis (trifluoromethylsulfonyl) imide was impregnated into a tubular porous support, and then gelled (gelled according to the method described in Macromolecules 2005, 38, 2037-2039). ), 10 mm at both ends were glass-sealed to obtain a carbon dioxide concentrated membrane.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1.

[Comparative Example 1]
A hydrophilic membrane filter (manufactured by Nihon Millipore Co., Ltd.) made of polyvinylidene fluoride having a film thickness of 100 μm, a diameter of 47 mm, and a pore diameter of 0.1 μm was used as a porous support (disc shape).

  On this porous support, Ind. Eng. Chem. Res. As described in 2007, 46, 2272-2279, a gel composed of polyvinyl alcohol / potassium hydroxide / 2-aminobutyric acid potassium salt / polyallylamine = 40/20/20/20 (% by weight) was cast (this) The gel soaked into the porous support) and dried at 120 ° C. for 6 hours to obtain a carbon dioxide concentrated membrane.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1. In this example, there is no sealing film.

[Comparative Example 2]
A hydrophilic membrane filter (manufactured by Nihon Millipore Co., Ltd.) made of polyvinylidene fluoride having a film thickness of 100 μm, a diameter of 47 mm, and a pore diameter of 0.1 μm was used as a porous support (disc shape).

  This porous support was prepared by an ionic liquid having an amino group (N-aminopropyl-3-butylimidazolium tetrafluoroborate (J. Am. Chem. Soc. 124 (2002) 926-92). ))) Was impregnated to obtain a liquid film.

  An ethyl cellulose membrane (J. Mem. Sci., Vol. 312 (2008), 207-216) was provided on both sides of the liquid membrane as a sealing membrane to obtain a carbon dioxide concentrated membrane.

  This carbon dioxide enriched membrane was evaluated according to the evaluation method described above. The results are shown in Table 1.

  The present invention is suitably used, for example, when concentrating carbon dioxide in a mixed gas containing carbon dioxide and hydrogen obtained by a refinery hydrogen production apparatus or IGCC. It is conceivable that the concentrated carbon dioxide is, for example, compressed into a liquid and sequestered in the ground.

It is a schematic diagram which shows an example of a carbon dioxide concentration membrane. It is a schematic diagram which shows a carbon dioxide concentration film | membrane evaluation apparatus. It is a schematic diagram which shows another carbon dioxide concentration film | membrane evaluation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid membrane 1a Inorganic porous support 1b Additive 1c Ionic liquid 2 Sealing membrane 3 Hydrophobic membrane 11 Evaluation gas 12 Evaluation gas line 13 Cell 14 Carbon dioxide concentration membrane (disc shape)
DESCRIPTION OF SYMBOLS 15 Non-permeate gas pressure indicator 16 Permeate gas pressure indicator 17 Non-permeate gas line 18 Permeate gas line 19 Non-permeate gas 20 Permeate gas 21 Sampling valve 22 Sampling line 23 Gas composition analyzer 24 Carbon dioxide concentration membrane (tube shape)
25 Glass seal 26 Evaluation case

Claims (5)

A liquid film comprising an ionic liquid or a polymer gel obtained by polymerizing an ionic liquid having a 5% thermal weight loss temperature of 250 ° C. or higher in an inorganic porous support;
A carbon dioxide enriched membrane having a multilayer structure in which a liquid film is sandwiched between two layers of sealing films, the sealing film being a film having a 5% thermal weight loss temperature of 250 ° C. or higher that does not transmit ionic liquid .   The carbon dioxide-enriched membrane according to claim 1, wherein the liquid membrane has a carbon dioxide / hydrogen separation factor of 10 or more.   The carbon dioxide concentration membrane according to claim 1 or 2, wherein the sealing membrane has a carbon dioxide / methane separation factor of 1.5 or more. The sealing film ^{is, 1.5 × 10 -6 mol-CO} 2 / m 2 / s / kPa or more according to one of the carbon dioxide concentration membrane of claim 1 having a carbon dioxide permeability.   The carbon dioxide-enriched membrane according to any one of claims 1 to 4 is used from a mixed gas containing at least carbon dioxide and hydrogen at a pressure of 0.6 MPa to 3.5 MPa and a temperature of 200 ° C to 600 ° C. A carbon dioxide enrichment method for obtaining a gas enriched with carbon dioxide.

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