JPH11300182A - Production of hydrogen separation membrane and its producing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the film forming range to form a Pd film in a reactor in the process of sublimating a Pd film source material and forming the Pd film on a film carrier body through pyrolysis in the film forming range, by using a carrier gas flowing the film forming range and supplying the sublimated Pd film source material to the film forming range. SOLUTION: As the film carrier body, a porous ceramic hollow plate is used. When a hydrogen separation membrane is to be produced, a porous ceramic hollow fiber 2 is fixed in a reactor tube 1 and the inside of the hollow fiber 2 is continuously evacuated by a vacuum pump 3. When the inner pressure of the reaction tube 1 and the hollow fiber 2 reaches a specified vacuum degree, a carrier gas is supplied from a gas supplying device 9 to the reactor tube 1 through a gas inlet 7 and a flow controller 8. After a Pd film source material 12 in the reactor tube 1 is heated to the sublimation temp. in the source part 10 of a heater, the temp. of the film forming part 11 of the heater is increased to the film forming temp. While the Pd film source material 12 is supplied by the carrier gas to the film forming range 4 of the hollow fiber 2 to form a Pd film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a hydrogen separation membrane and an apparatus for producing the same. More specifically, the present invention relates to a technique for manufacturing a large-area hydrogen separation membrane by expanding a film formation range in which a Pd film or a Pd-based alloy film can be formed in a reactor.

[0002]

2. Description of the Related Art Pd-A is used as a membrane for purifying hydrogen with high purity.
g alloy films are known (Sep. Sci. Techn.
ol. Vol. 22, pages 873-887, 1987).

[0003] Such a Pd-based alloy membrane for hydrogen separation is conventionally made of a single alloy in a hollow shape, and therefore has an outer diameter of 1.6 mm and a thickness of about 1.6 mm due to limitations in workability and strength. The limit is about 80 μm, and the hydrogen permeation rate is inversely proportional to the film thickness.

As a countermeasure, a method of forming a Pd-based alloy film on the surface of a porous alumina tube by a chemical plating method has been proposed (J. Memb. Sci. Vol. 56, No. 3).
03-315, 1991), and the film thickness is 4.5.
Although it is improved to about 6.4 μm, it is still thick, and the film forming process is complicated and has many drawbacks.

[0005] Accordingly, Japanese Patent Application No. Hei.
In Japanese Patent Application Laid-Open No. 5004 (JP-A-7-136577), a low-temperature metal organic chemical vapor deposition (MOCVD) method is used to form a Pd-based thin film in the pores of a porous body.

In this MOCVD method, a pressure difference is provided on both sides of a porous ceramic film, and a sublimated / diffused Pd film source or a Pd-based alloy film source is sucked into the pores of the porous ceramic film while being drawn into the pores. The hydrogen separation film is formed by forming a Pd film or a Pd-based alloy film in the above.

[0007]

However, the Pd film or Pd-based alloy film formed by the conventional MOCVD method described above is subjected to a film-forming process mainly at a film-forming position by diffusion of a Pd film source or a Pd-based alloy film source. Therefore, the transfer of the Pd film source to the film forming position in the reactor may be insufficient.

Further, since sublimation / diffusion of the Pd film source or Pd-based alloy film source and thermal decomposition at the film forming position are performed by the same heat source, it is difficult to optimize the respective temperature control, and the effect at the film forming position is difficult. Thermal decomposition may not be performed.

Therefore, due to the above-mentioned phenomena, as a result, a satisfactory film forming process can be obtained only in a very narrow region in the reactor, and there is a problem that the film forming range is as small as about 10 mm.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to expand a film forming range in which a Pd film can be formed in a reactor and to increase the area. It is an object of the present invention to provide a method for producing a hydrogen separation membrane and an apparatus therefor.

[0011]

Means for Solving the Problems In order to achieve the above object, in a method for producing a hydrogen separation membrane according to the present invention, a Pd membrane source material and a membrane carrier are arranged inside a reactor, Pd
In the method for producing a hydrogen separation membrane in which a Pd film is formed on the film carrier by sublimating the film source material and thermally decomposing in the film forming range, the film carrier is disposed from the position where the Pd film source material is disposed. The sublimated Pd film source material is supplied to the film formation region by a carrier gas flowing toward the film formation region.

Therefore, the sublimated Pd film source material can be forcibly supplied to the film forming range, and the film forming range can be expanded.

Further, a Pd film source material and a film carrier are disposed inside the reactor, and the Pd film source material is sublimated and a Pd film is formed on the film carrier by thermal decomposition in a film forming range. In the method for producing a hydrogen separation membrane, the temperature of the position where the Pd film source material is arranged and the temperature of the film formation range are independently controlled, so that sublimation and film formation at the position where the Pd film source material is arranged are performed. And simultaneously performing pyrolysis in the range.

Therefore, the sublimation / diffusion of the Pd film source material and the temperature control of the thermal decomposition at the film forming position can be more optimally performed, and the effective thermal decomposition at the film forming position is performed, and the film forming range is reduced. Can be expanded.

Further, a Pd film source material and a film carrier are disposed inside the reactor, and the Pd film source material is sublimated and a Pd film is formed on the film carrier by thermal decomposition in a film forming range. In the method for producing a hydrogen separation membrane, the sublimated Pd film source material is supplied to the film formation region by a carrier gas flowing from the position of the Pd film source material toward the film formation region where the membrane support is disposed. At the same time, by independently controlling the temperature at the position where the Pd film source material is arranged and the temperature of the film formation range, sublimation at the position where the Pd film source material is arranged and thermal decomposition in the film formation range are simultaneously performed. It is characterized by performing.

The film carrier is a film-like porous material, and a pressure difference is provided on both sides of the film, and the sublimated Pd film source is sucked into the pores of the porous material while the Pd film is formed in the pores. It is also preferable to make it.

In the apparatus for producing a hydrogen separation membrane, the Pd membrane source material and the membrane support can be arranged inside, and the temperature can be controlled independently from the reactor connected to the vacuum exhaust device. First heating means for heating the arrangement position of the Pd film source material to sublimate the Pd film source material;
d. a second heating means for heating a film forming area in which the film carrier is disposed in order to thermally decompose the film source material;
d to feed the membrane source material to the deposition zone
d. gas supply means for supplying a carrier gas flowing from the position where the film source material is disposed to the film forming area where the film carrier is disposed.

As the Pd film source, one that generates Pd by thermal decomposition is used. For example, metal salts such as palladium acetate, palladium chloride and palladium nitrate, and organic metals such as palladium acetonate other than metal salts are also used. be able to.

Further, Ag, Au, Pt, Rh, Ru,
It may be alloyed with Ir, Ta, Nb, V, Zr, Ni, or the like. In such a case, a metal salt or the like that generates each metal by thermal decomposition is used as a metal source. At that time, it is preferable to use a material having a thermal decomposition temperature close to that of the Pd source.

Although there is no limitation on the form of the film carrier used for the film formation, it is preferably a film-like porous body, and is preferably made of a porous ceramic such as alumina, silica, zirconia, or a composite or mixture thereof. Examples of the formed porous body, porous glass, and metal porous body can be given.

The average pore diameter of the porous body is 5 to 5000 nm.
Preferably, those having a thickness of 50 to 500 nm are used.

The shape of the film carrier may be a film, a sheet or the like in addition to a hollow shape.

As a hydrogen separation membrane manufacturing apparatus, a gas-tight reactor connected to at least an evacuation unit,
Independently controllable first and second heating means and gas supply means for supplying a carrier gas are provided.

The shape of the reactor is not particularly limited, and for example, a tubular shape, a spherical shape, a square shape, and a combination thereof can be used. The inside of the reactor is provided with two regions, a region where a Pd film source material is arranged, and a film formation range where a film carrier is arranged. These two regions are preferably arranged adjacent to each other.

The first and second heating means are each composed of Pd
It is sufficient that the two regions, that is, the region where the film source material is arranged and the film forming region where the film carrier is arranged, are configured to enable heating with temperature control independently. The form may be either a separated type or an integrated type.

As the heating means, besides electric resistance heating, lamp heating, induction heating, or a combination thereof can be used.

The gas supply means may be any as long as it can supply gas into the reactor at a fixed, predetermined flow rate.
Usually, a gas cylinder equipped with a flow controller is used.

As for the vacuum evacuation device, the inside of the reactor is 1000 Pa, preferably 100 Pa
What is necessary is as follows, and two or more units may be connected. Usually, the inside of the reactor is controlled to a constant pressure by a pressure regulating valve or the like.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method and an apparatus for producing a hydrogen separation membrane according to the present invention will be described with reference to the illustrated embodiments. FIG. 1 is a schematic configuration diagram of a manufacturing apparatus for manufacturing a hydrogen separation membrane when a porous ceramic hollow fiber is used as a membrane support.

The porous ceramic hollow fiber 2 is hermetically fixed inside the reaction tube 1 as an reactor with an O-ring or the like, and the inside of the porous ceramic hollow fiber 2 is continuously evacuated by the vacuum pump 3.

Here, the portion of the porous ceramic hollow fiber 2 other than the film forming range 4 is made of glass (for example, Na ₂ O—B
It is hermetically sealed with ₂ O ₃ -SiO ₂ based glass). Also,
The inside of the reaction tube 1 is also evacuated by the vacuum pump 3, and the internal pressure of the reaction tube 1 and the porous ceramic hollow fiber 2 becomes
Each is measured by a vacuum gauge 5 and controlled by a pressure regulating valve 6.

Into the reaction tube 1, a carrier gas is supplied from a gas supply 9 through a gas inlet 7 through a flow controller 8. The internal pressure of the reaction tube 1 and the porous ceramic hollow fiber 2 cannot be specified unconditionally because it varies depending on the flow rate of the carrier gas, the displacement of the vacuum pump 3, and the like. Is 20-2000
Pa, the internal pressure of the porous ceramic hollow fiber 2 is 1 to 5
00Pa is maintained. The carrier gas forms a flow from the Pd film source material 12 toward the film forming area 4 of the porous ceramic hollow fiber 2 in FIG.

The temperature of the reaction tube 1 is independently controlled by a heater divided into at least two or more of a raw material section 10 and a film forming section 11.

The range 4 for forming the porous ceramic hollow fiber 2
Is disposed in the film forming unit 11 of the heater, and the Pd film source material 12
The Pd film source material 12 placed in the reaction tube 1 kept at or below the thermal decomposition temperature of the (or Pd alloy film source material) is heated to the sublimation temperature by the raw material section 10 of the heater.

When an increase in the pressure inside the reaction tube 1 is observed with the sublimation of the Pd film source material 12, the film forming part 11 of the heater is rapidly heated to a film forming temperature of 200 to 500 ° C. The inside of the tube 1 is set to a film forming temperature.

The sublimated Pd film source material 12 is forcibly supplied to the film forming area 4 by the flow of the carrier gas, and when the film forming temperature is maintained for 1 to 3 hours, Pd generated by the thermal decomposition
Alternatively, the Pd alloy is supported on the outer surface of the porous ceramic hollow fiber 2 and in the pores on the outer surface, and a Pd film or Pd film is formed.
An alloy film is formed.

[0037]

EXAMPLES The production apparatus of the above embodiment was set as described below in detail to produce a hydrogen separation membrane.

As the porous ceramic hollow fiber 2, a porous alumina hollow fiber having a length of 100 mm, an outer diameter of 2.0 mm, an inner diameter of 1.7 mm, an average pore diameter of 150 nm, and a porosity of 38% is used. As palladium acetate 12, was used.

The reaction tube 1 has a length of 400 mm and an inner diameter of 85 m.
m stainless steel tube, heater is 350mm long
The electric furnace of the resistance heating method is used for the raw material part 10 and the film forming part 11
The temperature was controlled independently.

First, an argon gas was flowed at 18 cm / s as a carrier gas while the reaction tube was evacuated, and the inside of the porous alumina hollow fiber was simultaneously evacuated. The pressure in the alumina hollow fiber was controlled to about 100 to 200 Pa, respectively.

The raw material section 10 is kept at 200 ° C. and the porous alumina hollow fiber serving as a membrane support is slowly heated to 205 ° C. and held, and when an increase in the pressure inside the reaction tube starts to be observed, the film forming section 11 is formed. The temperature was rapidly raised to a film temperature of 300 ° C. at a rate of 10 ° C./min or more, and kept at the film forming temperature for 2 hours.

The performance of the membrane was evaluated by hydrogen permeation rate and hydrogen selectivity, which is the ratio of hydrogen permeation rate to nitrogen.
A gas chromatograph was used to determine the permeation rate. The permeation performance at 300 ° C. of the obtained Pd film was as shown in Table 1.

Comparative Example 1 As Comparative Example 1, Table 2 shows the permeation performance at 300 ° C. of a Pd film obtained by forming a film in the same manner as in the example except that argon gas was not supplied. Was.

Comparative Example 2 As Comparative Example 2, the heater was 1
Then, the temperature of the raw material part and the film forming part are controlled together, and other than that, the Pd film obtained by forming a film in the same manner as in the example is used.
Table 3 shows the transmission performance at 00 ° C.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3] From the results of Tables 1 to 3, in the film forming method to which the present invention is applied,
It is possible to increase the area of the membrane while maintaining the performance of the membrane (high hydrogen selectivity).

[0048]

As described above, according to the present invention,
A method for producing a hydrogen separation membrane and a device for producing a hydrogen separation membrane capable of enlarging a film formation range capable of forming a Pd film or a Pd-based alloy film in a reactor and increasing the area can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a manufacturing apparatus according to an embodiment of the present invention.

[Description of Signs] 1 Reaction tube 2 Porous alumina hollow fiber (membrane carrier) 3 Vacuum pump 4 Film forming range 5 Vacuum gauge 6 Pressure control valve 7 Gas introduction hole 8 Flow controller 9 Gas supply device 10 Raw material for heater Part 11 Film forming part of heater 12 Pd film source material

Claims (5)

[Claims] 1. A Pd film source material and a film carrier are disposed inside a reactor, and a Pd film is formed on the film carrier by sublimation of the Pd film source material and thermal decomposition in a film forming range. In the method for producing a hydrogen separation membrane, the sublimated Pd film source material is supplied to the film formation region by a carrier gas flowing from the position where the Pd film source material is arranged to the film formation region where the membrane support is arranged. A method for producing a hydrogen separation membrane, comprising: 2. A Pd film source material and a film carrier are disposed inside a reactor, and a Pd film is formed on the film carrier by sublimation of the Pd film source material and thermal decomposition in a film forming range. In the method for producing a hydrogen separation membrane, the temperature of the position where the Pd film source material is disposed and the temperature of the film formation range are controlled independently of each other.
d. A method for producing a hydrogen separation membrane, comprising simultaneously performing sublimation at an arrangement position of a membrane source material and thermal decomposition in a film formation range. 3. A Pd film source material and a film carrier are disposed inside a reactor, and a Pd film is formed on the film carrier by sublimation of the Pd film source material and thermal decomposition in a film forming range. In the method for producing a hydrogen separation membrane, the sublimated Pd film source material is supplied to the film formation region by a carrier gas flowing from the position where the Pd film source material is arranged to the film formation region where the membrane support is disposed. In addition, by independently controlling the temperature at the position where the Pd film source material is disposed and the temperature within the film formation range,
d. A method for producing a hydrogen separation membrane, comprising simultaneously performing sublimation at an arrangement position of a membrane source material and thermal decomposition in a film formation range. 4. The membrane support is a membrane-like porous body, and a pressure difference is provided on both sides of the membrane to suck the sublimated Pd film source into the pores of the porous body. The method for producing a hydrogen separation membrane according to any one of claims 1 to 3, wherein the method is formed into a Pd film. 5. A reactor in which a Pd film source material and a film carrier can be arranged inside, and a temperature of each of the reactors connected to a vacuum exhaust device can be controlled independently, so that the Pd film source material can be sublimated. A first heating means for heating the arrangement position of the Pd film source material, and a second heating means for heating the film formation area where the film carrier is arranged to thermally decompose the sublimated Pd film source material.
Heating means, and a carrier gas flowing from the position where the Pd film source material is disposed in the reactor toward the film forming region where the film carrier is disposed in order to supply the sublimated Pd film source material to the film forming region. An apparatus for producing a hydrogen separation membrane, comprising: gas supply means for supplying gas.