JPS614519A - Manufacture of inorganic gas separating membrane - Google Patents

Abstract

PURPOSE:To obtain an inorganic gas separating membrane remarkably high in separatability by immersing an inorganic porous body into a soln. consisting essentially of organic metallic compds. and thereafter drying and calcining it. CONSTITUTION:Glass for raw material is formed into hollow fibrous shape having 2mm. outer diamter and 1mm. inner diameter and heat-treated at 580 deg.C for 24hr and furthermore treated with sulfuric acid soln. at 90 deg.C for 24hr to make an inorganic porous body consisting of a silicate skeleton. It is preferable that the narrow pore diameter obtained with gaseous nitrogen adsorption method is 10- 300Angstrom . The inorganic porous body is immersed into a soln. consisting essentially of organic metallic compds. such as Si(OC2H5)4 and drawn up, dried and calcined to form an extremely compact inorganic membrane layer having thickness of several mu or below on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a novel inorganic gas separation membrane.

Relationship with conventional technology Porous or non-porous membranes mainly made of organic polymer materials have traditionally been widely used as gas separation membranes, but membranes that satisfy heat resistance, corrosion resistance, chemical resistance, etc. However, inorganic porous membranes have been mainly used in these required fields of application.In particular, alkali borosilicate glass is formed into a hollow fiber shape and then heat-treated to form an alkali borate. Hollow fibrous porous glass obtained by separating into a silicate-rich phase and a silicate-rich phase and eluting the alkali borate-rich phase by acid treatment is easy to manufacture and has a pore diameter of 300A or less. It is advantageous for gas separation due to the principle of controllable molecular flow.

However, the separation performance of conventional hollow fiber porous glass is still not satisfactory in chair separation.For example, when separating hydrogen gas and nitrogen gas, the maximum value of the separation coefficient is about 3.74. In addition, when separating helium gas and nitrogen gas, the maximum value of the separation coefficient was 2.65.

OBJECTS OF THE INVENTION The present inventors have discovered the present invention as a result of intensive study on a method for manufacturing an inorganic gas separation membrane that can improve separation performance.

Structure of the Invention: The gist of the present invention is to immerse an inorganic porous body in a solution containing an organic metal compound as a main component, and then dry and sinter it.

First, the inorganic porous body according to the present invention is produced as described above. For example, 810□ 62.6%, B20327.
3%, NtL207.2%, A12o, 0.3% (%
is weight%) of raw material glass with outer diameter Q, Owxs, and inner diameter 1.
The sample was formed into a hollow fiber having a thickness of 0 m and heat treated at 580°C for 24 hours. This heat treatment separates the soda borate-rich phase and the silicate-rich phase. Furthermore, the separated state is treated with a sulfuric acid solution at 90° C. for 24 hours to produce an inorganic porous body having a silica@salt skeleton. There is no control over the conditions of the heat treatment, acid treatment, etc. mentioned above.
The conventional method can be adopted, and J is 1, preferably the pore size determined by the nitrogen gas adsorption method -Z lo o X or less, more preferably 10 to 100λ is produced. . That is, if the pore diameter is less than 101, the gas permeability will be significantly worse, and if the pore diameter is more than 30 OA, the inorganic membrane layer described by him will easily peel off, which is not preferable.

The inorganic porous body produced in this manner is then immersed in a solution containing an organometallic compound as a main component. Preferred examples of this solution include organic solutions containing Si (002Ha )4 as a main component. After being immersed in this solution, it is pulled up, dried and fired to form an inorganic film layer. In other words, by dry firing, S
i (002Fk)4 is gelled and dehydrated to form a very dense inorganic film layer with a thickness of several μ or less on the surface of the porous body. An inorganic gas separation membrane formed with an inorganic membrane layer containing alcoholate as a main component has significantly improved separation performance compared to conventional porous glass membranes.

EXAMPLES Examples will be described below, but the present invention includes such examples,
, l does not limit the number of ships.

In addition, the "separation coefficient" in the examples is a value measured as follows. In other words, it is the ratio of the gas permeation flow rate measured in one run using pure gas (purity of 99.9% or more), supply gas pressure of 3 to G - permeation gas + dimension, atmospheric pressure, and operating temperature of 100°C. (Defined as 0IL) The values of hydrogen gas, helium gas, and nitrogen gas are respectively QHz r QHer
When QNl, the separability of hydrogen gas and nitrogen gas is QH
The separation coefficient of 2/QNi is determined, and the separability of helium gas and nitrogen gas is determined by the separation coefficient of Q, He/QN2.

Example L Pore diameter is 40A1, separation coefficient between hydrogen gas and nitrogen gas is 3.
After washing the hollow fibrous porous glass (3) to clean the surface, drying is performed to reduce the moisture content of the hollow fibrous porous glass. The above hollow fibrous porous glass is 81 (O
The material was immersed in an organic solution containing C2Hs)4 as a main component, pulled up and dried to obtain a material for an inorganic gas separation membrane. 5 of the above materials
After firing at 00°C for 30 minutes, the film was further fired at 500°C for 24 hours. This membrane is soaked, dried,
The firing process was repeated to obtain an inorganic gas separation membrane. The separation coefficient of the above inorganic gas separation membrane is 3. for hydrogen gas and nitrogen gas.
7, and 3.2 for helium gas and nitrogen gas.

Example 2 The inorganic gas separation membrane material described in Example 1 was heated at 500°C for 3
After baking for 0 minutes, the film was further baked at 600° C. for 24 hours to obtain a film. The inorganic gas separation membrane was obtained by repeating the above-mentioned dipping, drying, and firing treatments for this membrane: 6 The separation coefficient of the above inorganic gas separation membrane was 1 for hydrogen gas, and 4.7 for 1 chamber elemental gas.
In the case of helium gas and nitrogen gas, it was 5.8.

Example & Example 1 The inorganic gas separation membrane material described in Example 1 was heated at 500°C.
After baking for 0 minutes, the film was further baked at 700° C. for 24 hours to obtain a film. This membrane was subjected to the above-described dipping, drying, and baking treatments to obtain an inorganic gas separation membrane. The separation coefficient of the above inorganic gas separation membrane is 3.6 for hydrogen gas and nitrogen gas,
In the case of helium gas and nitrogen gas, it was 2.9〇

Claims (3)

[Claims] (1) A method for producing an inorganic gas separation membrane, which comprises immersing an inorganic porous body in a solution containing an organometallic compound as a main component, and then drying and firing it. (2) Claim No. 1 in which the inorganic porous body is hollow fibrous porous glass having a pore diameter of 300A or less.
) The manufacturing method described in section 2. (3) The manufacturing method according to claim (1), wherein the bath liquid is an organic liquid containing Si(OC_2H_5)_4 as a main component.