JPS62136225A - Composite membrane for separating gas - Google Patents

Abstract

PURPOSE:To judge the flaw or breakage of a gas separation membrane without measuring the capacity thereof by visually detecting the state of said membrane, by laminating the colored gas permeable membrane prepared by forming a gas separable polymer having a dye added thereto into a membrane to a porous support. CONSTITUTION:A colored gas separation membrane prepared by forming a gas separable polymer having a dye added thereto into a membrane is laminated to a white porous support. By this constitution, light absorbing intensity in a visible light region becomes large and it can be visually detected that the gas separation membrane is laminated onto the porous support. As the material of the gas separation membrane, polyhydroxystyrene/polysulfone/ polydimethylsiloxane copolymer is used. A red or green dye is added to a solution of said copolymer and the colored solution is formed into the membrane by the water surface developing method and said membrane is used as the gas separation membrane. By this coloration, the flaw or breakage such as a pinhole of the membrane can be detected without measuring the capacity of the membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a composite membrane for gas separation that separates mixed gases.

BACKGROUND OF THE INVENTION In recent years, many gas separation membranes using organic polymers have been proposed. If oxygen in the air can be separated and concentrated at low cost using this method, it is expected to greatly contribute to combustion, iron manufacturing, ceramics, waste treatment, medical care, etc. For example, in a combustion system, if combustion is performed using oxygen-enriched air instead of normal air, it is expected that the combustion temperature will increase, the amount of available heat will increase, and the amount of combustion exhaust gas will decrease, making it possible to construct an energy-saving combustion system. A gas separation membrane for obtaining such oxygen-enriched air separates oxygen-containing gases such as air from
The ability to selectively separate oxygen is large, that is,
It is required that the oxygen selectivity coefficient and oxygen permeability coefficient be large. As such a gas separation membrane, Japanese Patent Application Laid-Open No. 51-1214
No. 845 discloses an organopolysiloxane-polycarbonate copolymer. Also, JP-A-56-
26506 and JP-A-156-26507 disclose copolymers of polyorganosiloxane and hydrocarbon polymers having unsaturated bonds. These organic polymers are coated on a porous support. Composite membranes for gaseous gold release are created by coating or spreading on the surface of water to form a thin film and laminating it on a porous support. In order to obtain a large permeation flow rate, the gas separation membrane must be very thin and have no pinholes.

Problems to be Solved by the Invention However, when polyorganosiloxane copolymers such as those described above are thinly laminated on a porous support, a large amount of light is generated due to the low absorption intensity of the polyorganosiloxane polymer in the visible light region. Even if there are holes, they cannot be visually detected, and it is also impossible to visually detect whether they are properly laminated.

Furthermore, damage to the gas separation membrane due to operator carelessness in the step of modularizing the composite membrane for gas separation that has been produced, or damage to the gas separation membrane due to various other causes cannot be visually detected. Therefore, even a completely defective product has the disadvantage that it cannot be concluded that it is defective unless the membrane performance and module performance are measured. In view of the above disadvantages, the present invention has developed a gas separator layered on a porous support. The present invention provides a composite membrane for gas separation in which defects in the membrane can be visually detected.

Means for Solving the Problems To achieve this objective, the composite membrane for gas separation of the present invention comprises:
It is constructed by laminating a dye-added gas separation membrane on a porous support.

Function: This structure increases the absorption intensity of light in the visible light region, making it possible to visually detect that the gas separation membrane is laminated on the porous support. Dyes selectively absorb visible light. The color corresponding to the complementary color of this absorbed light is perceived as the hue. Therefore, polymers such as polyorganosiloxane copolymers themselves have very low absorption intensity in thin films, but by adding dyes that selectively absorb in the visible light region to polymers, visible light can be absorbed even in thin films. It is possible to create a gas separation membrane that has a large absorption intensity in this region, and it becomes possible to detect the complementary color of the light absorbed by the dye.

Example Examples of the present invention will be described below.

Example 1 As a gas separation membrane, a copolymer of polyhydroxystyrene, polysulfone, and polydimethylsiloxane was dissolved in benzene at a concentration of 2% (wt%), and about 5% of tetrahydrofuran was added to the solution to obtain O, S%. (wt%) of red dye,
A solution containing the product name "Zudan ■" (manufactured by Kanto Kagaku ■) is spread on the water surface, and the solvent is evaporated to form a thin film. A gas separation membrane made of polypropylene is used as a porous support.
A composite membrane for gas separation was prepared by moving and laminating (two layers) on Duraguard (Grade 2400) J (manufactured by Polyplastic ■).

Example 2 As a gas separation membrane, a copolymer of polyhydroxystyrene/polysulfone and polydimethylsiloxane was dissolved in benzene at a concentration of 2% (wt%), and approximately 5% tetrahydrofuran was added to the solution. % (wt%) green dye,
A solution containing the product name "Automate (liquid dye)" (Mort/manufactured by Kagaku Co., Ltd.) is spread on the water surface, and the solvent is evaporated to form a thin film.The gas separation membrane is then placed on the same porous support as in Example 1. We created a composite membrane for gas separation that was transferred onto the body and laminated (two layers).

As described above, according to this example, by layering a gas separation membrane containing a dye on a white porous support, gas separation was colored pale red in Example 1 and pale green in Example 2. I was able to obtain a membrane.

Note that the porous support, gas-separating polymer, and dye are not limited to those in the examples.

Effects of the Invention As described above, the present invention creates a colored composite membrane for gas separation by adding a dye to a gas separation polymer and laminating the thinned and colored gas separation membrane on a porous support. The state of the gas separation membrane can be visually detected. Therefore, defects such as pinholes, which are obvious defects in gas separation membranes, and damage can be detected, and defects can be determined without measuring membrane performance, which has a great practical effect.

Claims (2)

[Claims] (1) A composite membrane for gas separation, characterized in that a gas separation polymer added with a dye is laminated on a porous support membrane. (2) The composite membrane for gas separation according to claim 1, wherein the gas separation polymer contains a siloxane structure.