KR100352449B1 - Gas separation membrane and method for producing the same - Google Patents

Abstract

The present invention relates to a gas separation membrane and a method for producing the same, which has a very good selectivity of oxygen to nitrogen and generates a high concentration of oxygen. The gas separation membrane of the present invention dissolves a polymer selected from the group consisting of silicone, polyimide, polyamide, cellulose acetate, polysulfone, polyvinyl alcohol, polyphenyloxide, polybutyl acrylate and a mixture of two or more thereof in a solvent, To the resulting melt is added carbonates, nitrates, acetates, halides or acetylacetonates of nickel, cobalt, ruthenium, rhodium, palladium, titanium, iron, copper or chromium, and the resulting mixture is cast or spun through a nozzle It is prepared by forming a film, solidifying, washing and drying the formed film in sequence, and optionally heat treating or coating the dried film.

Description

GAS SEPARATION MEMBRANE AND METHOD FOR PRODUCING THE SAME}

The present invention relates to a functional membrane for separating gases. More particularly, the present invention relates to a gas separation membrane composed of a metal compound mixed with a polymer and a method of manufacturing the same.

Membrane separation is a method of separating a gas of one component from a gas of another component in a gaseous stream. The gas separation membrane used in the membrane separation method separates gas using the difference in permeation rate between gases in the gas flow to be contacted, and its performance is determined by permeability and selectivity. In general, membranes derived from acetate esters and olefins are used as gas separation membranes, which are useful for separating oxygen for nitrogen or carbon dioxide for methane.

U.S. Patent No. 4542010 describes a membrane that separates oxygen and nitrogen. This membrane is a liquid membrane containing a solvent, a hexabase (e.g., Lewis base containing nitrogen atom) and an oxygen carrier (e.g. metal-containing complex) in a liquid state between two membrane supports which are solid films.

Korean Patent Registration No. 10-198198 discloses a polymer selected from polysulfone, polyisosulfone, polycarbonate, polyimide, polyamide, polyaramid and mixtures thereof, N-methylpyrrolidone, N, N-dimethylformamide, Tetrahydrofuran, methylethylketone, ethyl acetate, trichloroethane, 2-methyl-1-butanol, 2-methyl-butanol, and a solvent selected from N, N-dimethylacetamide, N-dimethylsulfoxide and mixtures thereof Gas separation membranes prepared by solidifying a mixture of additions selected from 2-pentanol are described.

Gas separation membranes are constantly being researched and developed for new membranes having high selectivity, high permeability and economic advantages for improved gas separation performance.

The present inventors found that the membrane containing the polymer and the organometallic compound was prepared, and the gas permeability and selectivity of the prepared membrane showed very good oxygen generation ability.

1 is a manufacturing process of the gas separation membrane according to the present invention.

2 is a scanning electron microscope (Scanning Electron Microscopy) photograph of the gas separation membrane prepared according to the method of the present invention.

In one aspect, the invention provides a polymer selected from the group consisting of silicone, polyimide, polyamide, cellulose acetate, polysulfone, polyvinyl alcohol, polyphenyloxide, polybutyl acrylate and mixtures of two or more thereof and nickel, cobalt It provides a gas separation membrane comprising a carbonate, nitrate, acetate, halide or acetylacetonate of ruthenium, rhodium, palladium, titanium, iron, copper or chromium.

In another aspect, the present invention is a polymer selected from the group consisting of silicone, polyimide, polyamide, cellulose acetate, polysulfone, polyvinyl alcohol, polyphenyloxide, polybutyl acrylate and mixtures of two or more thereof, To the resulting melt, add carbonates, nitrates, acetates, halides or acetylacetonates of nickel, cobalt, ruthenium, rhodium, palladium, titanium, iron, copper or chromium, and cast the formed mixture or spin through a nozzle To form a membrane, to solidify the formed membrane, to wash and dry the solidified membrane, and optionally to heat or coat the dried membrane.

The novel gas separation membrane according to the invention can be in any form. That is, the separation membrane of the present invention can be prepared as a single membrane (homogeneous membrane), a composite membrane or an asymmetric membrane. These membranes can be in the form of flat plates, hollow tubes, hollow fibers and the like. It is well known to produce membranes in this form (see FIG. 1).

Membranes prepared according to the method of the present invention can be very useful for separating various gases such as oxygen, nitrogen, hydrogen, carbon monoxide, carbon dioxide, NO, NOx.

In the present invention, the polymer may be used in an amount of 10 to 40% by weight, preferably 15 to 25% by weight, based on the solvent.

In the present invention, the organometallic compound may be used in an amount of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the solvent.

Solvents used in the present invention include tetrahydrofuran, alcohols (eg 1,2-butanol, 1,2-pentanol, 1,3-pentanol) or derivatives thereof, alkyl acetates (eg ethyl acetate, methyl acetate). ) Or derivatives thereof, trichloroethyl acetate and the like.

In preparing the membranes of the present invention, surfactants may additionally be used as additives to improve the resolution of the membranes. Surfactants include, for example, copolymers of polyoxyethylene and polyoxypropylene, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, and the like. Its use amount is about 0.1 to 10% by weight.

The present invention will be described in more detail with reference to the following Examples. However, these examples should not be understood as limiting the present invention.

Example

Example 1

In a 500 ml reactor, 25 g of polysulfone (PS, S6010 from BASF) was dissolved in 78.7 ml of tetrahydrofuran (THF, Aldrich) as a solvent. Rhodium acetate [Rh (CH ₃ COO) ₃ , Aldrich as a metal compound was dissolved in the melt. ) 5 g was added. The mixture was cast using an automatic membrane making machine (IMOTO 301) under conditions of driving stroke 150 mm, application speed 30 mm / sec, 55 bar (125.7 μm). The film was evaporated and dried slowly in a dryer and then dried in a vacuum oven (80 ° C.) for at least 24 hours to remove residual solvent. The dried membrane was coated with a 5 wt% silicone solution using the above automatic membrane manufacturing apparatus (3 bar (6.86 μm)), and then dried under the same conditions as the above drying process. The film thus obtained had a thickness of about 88 μm.

Example 2

In a 500 ml reactor, 25 g of polysulfone (PS, S6010 from BASF) was dissolved in 76.5 ml of N-methylpyrrolidone (NMP, Aldrich) as a solvent, and cobalt acetate (Co (CH ₃ COO)) as a metal compound was dissolved in the solution. ₃ , 5 g of Aldrich) was added. The mixture was cast using an automatic membrane making machine (IMOTO 301) under the conditions of driving stroke 150 mm, application speed 30 mm / sec, bar 55 (125.7 ?? m). The film was evaporated and dried slowly in a dryer and then dried in a vacuum oven (80 ° C.) for at least 24 hours to remove residual solvent. The dried membrane was coated with a 5 wt% polyethyleneimine (PEI) solution using the above automatic membrane manufacturing apparatus (3 bar (6.86 μm)), and then dried under the same conditions as the above drying process.

Example 3

The membrane was prepared under the same conditions as described in Example 1 except that 25 g of polyacrylonitrile (PAN, Aldrich) was used as the spinning stock solution.

Example 4

The membrane was prepared under the same conditions as described in Example 2 except that 25 g of polyacrylonitrile (PAN, Aldrich) was used as the spinning stock solution.

Example 5

Membranes were prepared under the same conditions as described in Example 1 except that 25 g of polyimide (PI, MW = 86000 from Aldrich) was used as the spinning stock solution.

Example 6

Membranes were prepared under the same conditions as described in Example 2 except that 25 g of polyimide (PI, MW = 86000 from Aldrich) was used as the spinning stock solution.

Comparative Example 1

Membranes were prepared under the same conditions as described in Example 1 except that no metal compound was added to the solution of the spinning stock solution and the solvent.

Comparative Example 2

Membranes were prepared under the same conditions as described in Example 2 except that no metal compound was added to the solution of the spinning stock solution and the solvent.

Comparative Example 3

Membranes were prepared under the same conditions as described in Example 3 except that no metal compound was added to the lysate of the spinning stock solution and the solvent.

Comparative Example 4

Membranes were prepared under the same conditions as described in Example 4 except that no metal compound was added to the solution of the spinning stock solution and the solvent.

Comparative Example 5

The membrane was prepared under the same conditions as described in Example 5 except that no metal compound was added to the lysate of the spinning stock solution and the solvent.

Comparative Example 6

Membranes were prepared under the same conditions as described in Example 6 except that no metal compound was added to the solution of the spinning stock solution and the solvent.

Laboratory Example 1

Membrane Permeability and Selectivity of Oxygen to Nitrogen

The permeability and selectivity of the membranes prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were measured using a gas permeation apparatus (Millipoa film holder 90mm, YY3009000), a gas permeation measuring apparatus (Dwyer, RMA-23SSV) and gas chromatography ( GC-17A, Shimadzu). The results are listed in Tables 1 and 2 below.

Table 1. Permeability and Selectivity of Gas Separation Membranes According to the Present Invention

Example Polymer menstruum Introduction metal compound 2nd polymer Oxygen Gas Permeability Oxygen / nitrogen selectivity One PS THF Rh (CH ₃ COO) ₂ silicon 2.10 3.8 2 PS NMP Co (CH ₃ COO) ₃ PEI 1.85 4.24 3 PAN THF Rh (CH ₃ COO) ₂ silicon 2.43 4.30 4 PAN NMP Co (CH ₃ COO) ₃ PEI 2.67 4.10 5 PI THF Rh (CH ₃ COO) ₂ silicon 3.25 3.90 6 PI NMP Co (CH ₃ COO) ₃ PEI 2.98 4.51

Transmittance Unit: GPU, x10 ^-4 cm ³ / cm ² .s.cmHg

Selectivity = oxygen permeability / nitrogen permeability

Table 2. Permeability and Selectivity of Gas Separators without Metal Compounds in Comparative Group

Comparative example Polymer menstruum 2nd polymer Oxygen Gas Permeability Oxygen / nitrogen selectivity One PS THF silicon 2.12 2.42 2 PS NMP PEI 2.01 2.32 3 PAN THF silicon 2.45 2.50 4 PAN NMP PEI 2.67 2.31 5 PAN THF silicon 3.30 3.5 6 PI NMP PEI 3.21 3.4

Transmittance Unit: GPU, × 10 ^-4 cm ³ / cm ² .sec.cmHg

Selectivity = oxygen permeability / nitrogen permeability

From the results of Table 1 and Table 2, the novel gas separation membrane according to the present invention can be seen that the oxygen / nitrogen selectivity is significantly improved compared to the gas separation membrane containing no metal compound.

Laboratory Example 2

In order to evaluate the oxygen generating performance of the gas separation membrane according to the present invention, the oxygen concentration by the module prepared with the membrane of Example 1 was measured. A Japanese Ubesa product (UBE, NM-CO5A) was used as a control. The oxygen concentration was measured with a gas flow meter MFM Mass Flowmeter (manufactured by Brookes) under an operating pressure of 4 kgf / cm ² . The results are shown in Table 3 below.

Table 3. Measurement result of oxygen concentration change caused by the gas separation membrane module and Ubesa products of the present invention

Hour Invention module Ubesa Products 0.5 38.0 37.0 One 38.2 37.4 2 38.5 38.2 3 38.5 38.0 4 38.5 38.0 5 38.6 37.4 8 38.4 37.6 10 38.4 36.6 12 38.4 36.6

From the above results, it can be seen that the gas separation membrane according to the present invention has an excellent oxygen generating ability compared to the known gas separation membrane.

The gas separation membrane according to the present invention has excellent oxygen / nitrogen selectivity, and the module manufactured with the gas separation membrane of the present invention generates high concentration of oxygen as compared to the conventional gas separation membrane module, and thus is expected to be useful in various industrial fields. .

Claims (9)

Nickel, cobalt, ruthenium, rhodium, palladium, titanium and polymers selected from the group consisting of silicones, polyimides, polyamides, cellulose acetates, polysulfones, polyvinyl alcohols, polyphenyloxides, polybutylacrylates and mixtures of two or more thereof Gas separation membrane comprising a carbonate, nitrate, acetate, halide or acetylacetonate of iron, copper or chromium. The gas separation membrane according to claim 1, wherein the polymer is polyacrylonitrile or polyimide. A polymer selected from the group consisting of silicone, polyimide, polyamide, cellulose acetate, polysulfone, polyvinyl alcohol, polyphenyloxide, polybutyl acrylate and mixtures of two or more thereof is dissolved in a solvent, and nickel is dissolved in the resulting melt. , Add carbonates, nitrates, acetates, halides or acetylacetonates of cobalt, ruthenium, rhodium, palladium, titanium, iron, copper or chromium, cast the formed mixture or spun through a nozzle to form a film, and form a film Coagulating, washing and drying the coagulated membrane to prepare a gas separation membrane. The method of claim 3 wherein the polymer is polyacrylonitrile or polyimide. 4. The process of claim 3 wherein said solvent is selected from the group consisting of tetrahydrofuran, alcohols, alkyl acetates and trichloroethyl acetate. 4. The method of claim 3, wherein a copolymer of polyoxyethylene and polyoxypropylene, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether is further added to the mixture. The method of claim 5, wherein the alcohol is 1,2-butanol, 1,2-pentanol or 1,3-pentanol. The method of claim 5 wherein the alkyl acetate is ethyl acetate or methyl acetate. The method of claim 3, further comprising heat treating or coating the dried film.