JP3305484B2 - Joint of metal-coated ceramic and metal and hydrogen gas separation device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joined body of a metal-coated ceramic and a metal and a hydrogen gas separation apparatus using such a joined body.

[0002]

2. Description of the Related Art Hydrogen gas is used in large quantities as a basic material gas for petrochemicals, and is expected to have a great potential as a clean energy source. High-purity hydrogen gas is obtained by converting a natural gas, naphtha or the like as a raw material into a hydrogen-containing gas using a catalyst and further separating the hydrogen gas from the hydrogen-containing gas.

[0003] Hydrogen gas can be separated by utilizing its property of dissolving in palladium or an alloy containing palladium. Since only hydrogen gas is dissolved in these metals, hydrogen gas can be selectively separated. Palladium is usually used in the form of a film coated on a porous substrate such as ceramics. In order to efficiently separate a gas using a gas separation membrane, in order to increase the speed of gas diffusion in the gas separation membrane, at 5 to 10 atmospheres, 300 ° C. or more, preferably 50 ° C. or more.
It is advantageous to separate at a high temperature of 0 ° C. or higher and a high pressure. Then, what is problematic is the airtightness and durability of the joint between the gas separator and the support. That is, it is necessary that the support portion of the hydrogen gas separation membrane has durability even under high temperature and high pressure conditions, and that the gas to be treated and the separated hydrogen gas do not leak from the support portion. .

When the processing temperature is in the range of 200 ° C. or less, o
There are devices for joining the gas separator to the support using a ring. However, at 200 ° C. or higher, it is not easy to make the joint between the gas separator and the support airtight, and a joint that can be used at 500 ° C. or higher has not yet been developed.
For example, before forming a gas separation membrane, a substrate made of ceramics and a support are bonded with glass, and then the surface of the gas separation body and the surface of the joint are chemically plated to form a gas separation membrane. In some cases, the glass and the gas separation membrane do not sufficiently adhere to each other, and the gas separation membrane peels off at the glass joint, and the gas to be treated may leak to the purified gas side.

Further, after a gas separator is formed on the surface of a substrate made of ceramics to prepare a gas separator, the gas separator and the support are separated by glass having an appropriate coefficient of thermal expansion and a contact angle with the gas separator. In the case of bonding, there is a problem in airtightness and strength after repeating the thermal cycle.

Further, when the gas separator and the metal support are brazed with Ag brazing or the like, the palladium alloy layer dissolves in the brazing material and the porous ceramic tube used as the base is exposed. There's a problem.

[0007]

Therefore, in the present invention,
Even when the gas to be treated is separated at a temperature of 200 ° C. or more, the joint between the gas separator and the support is airtight, and the joint between the metal-coated ceramic and the metal such that the gas to be treated hardly leaks to the purified gas side, And a hydrogen gas separation device using the same.

[0008]

That is, according to the present invention, there is provided a joined body of a metal member and a metal-coated ceramic in which a metal having a gas separating ability is coated on a porous ceramic, wherein the gas separating ability is improved. Metal covering made of metal
The thickness of the cover layer is 50 μm or less, and the surface of the metal-coated ceramics that is involved in bonding with the metal member is further
A joined body of a metal-coated ceramic and a metal, wherein a metal layer having a thickness of 1 μm to 50 μm is provided, and the metal layer and the metal member are joined by brazing. In the present invention, the metal having gas separation ability is preferably palladium or an alloy containing palladium, and the thickness thereof is preferably 50 μm or less, more preferably 20 μm or less. The metal layer provided on the surface of the metal-coated ceramic is formed of a compound having a higher melting point than a brazing material such as nickel.
Tei Rukoto is preferable.

Further, according to the present invention, in the high-pressure vessel, a cylindrical hydrogen gas separator is provided at the upper end thereof.
Fixed to a metal support through a through hole having a diameter slightly larger than the outer diameter of the hydrogen gas separator so that the inside communicates with the upper space of the high-pressure vessel defined by the metal support. At the lower end, on a metal support,
A hydrogen gas separation device in which an end portion is sealed and fixed by a hole that does not penetrate, wherein the hydrogen gas separator is coated with a base made of porous ceramics and the base is coated. A gas separation membrane made of a metal that selectively allows hydrogen gas to pass therethrough and having a thickness of 50 μm or less, and further having a thickness of 1 μm to 50 μm on the surface of the gas separation membrane involved in bonding with the metal member. Wherein the metal layer is provided, and the metal layer and the metal member are brazed to each other.

[0010]

The present inventor has studied from various angles a structure in which a porous ceramic tube coated with a gas separation membrane is penetrated through a metal support, and is adhered and fixed to support.

As a result, the present inventor does not directly braze a porous ceramic tube coated with a gas separation membrane with a metal member, but further provides a metal layer on the gas separation membrane on the ceramic surface, It has been found that the above-mentioned problems can be solved by brazing the layer and the metal member.

The joined body of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an example of the joined body of the present invention. In the figure, reference numeral 1 denotes a porous ceramic tube, the surface of which is covered with a gas separation membrane 2. Further, a metal layer 3 is provided on a part of the surface of the gas separation membrane, and a metal member 4 is joined to the metal layer 3 via a solder 5.

Usually, palladium or a palladium alloy is used as the gas separation membrane 2. However, by providing the metal layer 3 on the gas separation membrane 2, the palladium or palladium alloy layer dissolves in the brazing material and the porous ceramic tube 1
To prevent exposure. For the metal layer 3 provided on the gas separation membrane 2, a metal such as nickel having a higher melting point than the brazing material is used. As a method of providing the metal layer 3,
A conventionally known method can be used, and for example, a chemical plating method, a vacuum evaporation method, a sputtering method, or the like can be used.
The thickness of the metal layer is 1 m to 50 m, and more preferably 5 m to 50 m. As the brazing material, for example, A
g wax is used.

As the metal member 4, a metal such as SUS, Inconel, and Kovar is used. Further, as described above, palladium or an alloy containing palladium is preferably used as the gas separation membrane 2, but the coating method is the same as that of the metal layer provided on the gas separation membrane.
A chemical plating method, a vacuum evaporation method, a sputtering method, or the like can be used. The film thickness of the gas separation membrane Ah at 50μm or less
And more preferably 20 μm or less. If the film thickness is too large, the time required for hydrogen gas to diffuse through the gas separation membrane during hydrogen gas separation becomes longer, which is undesirable because the processing time becomes longer.

The porous ceramic tube 1 is made of alumina,
It is made of a material such as silica-alumina, mullite, cordierite, zirconia, or the like. For example, it is manufactured by kneading a ceramic powder material, extruding it into a pipe shape, and firing. When the joined body of the present invention is used for a hydrogen gas separation device, a multi-tube type hydrogen gas separation device may be formed by joining a plurality of metal-coated ceramic tubes to the same metal support.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. First, a metal-coated ceramic tube was prepared as follows. As the porous ceramics tube, a porous α-alumina tube having a cylindrical shape with an outer diameter of 10 mm, an inner diameter of 7 mm and a length of 300 mm and a fine pore diameter of 0.1 μm was used. To activate this porous ceramic tube, the outer surface is immersed in a 0.1% hydrochloric acid aqueous solution containing 0.1% by weight of SnCl ₂ .2H ₂ O for 1 minute, and then PdC
l ₂ in a 0.1% hydrochloric acid aqueous solution containing 0.01% by weight
Immerse for a minute. This immersion treatment was alternately performed 10 times with each hydrochloric acid aqueous solution.

Next, palladium was chemically plated. [Pd (NH ₃ ) ₄ ] Cl ₂ .H ₂ O in 1 liter of deionized water
(5.4 g), 2Na.EDTA (67.2 g), 28
% Ammonia water (651.3 ml), H ₂ NNH ₂ .H
An aqueous solution to which ₂ O (0.46 ml) was added was prepared, and the outer surface of the activated porous alumina tube was heated to 50 ° C.
Immersed in this aqueous solution of which temperature was controlled to be. By changing the immersion time, the thickness of the metal to be coated and the depth of penetration into the porous ceramic tube were adjusted. Next, silver was chemically plated. In 1 liter of deionized water, [Pd (NH ₃ )
₄ ] Cl ₂ H ₂ O (0.54 g), AgNO ₃ (4.8
6g), 2Na.EDTA (33.6 g), 28% aqueous ammonia (651.3 ml), H ₂ NNH ₂ .H ₂ O
(0.46 ml) was prepared, and the outer surface of the porous alumina tube subjected to the activation treatment was immersed in the aqueous solution whose temperature was controlled at 50 ° C. By changing the immersion time, the weight ratio of palladium to silver is 80:20.
It was adjusted to be. Finally, under an argon atmosphere, 9
Heat treatment was carried out by holding at 00 ° C. for 12 hours, and palladium and silver were mutually diffused and alloyed to obtain a gas separator.

The gas separator was joined to a Kovar support. FIG. 2 is a cross-sectional view of the joined body of the gas separator and the Kovar support. First, nickel was plated on the side surface of the gas separator 6 with the Kovar supports 7 and 8 at a width of 25 mm to provide a nickel layer 9. Next, one end of the gas separator 6 is attached to a support 7 made of Kovar via a through hole 7 a having a diameter slightly larger than the outer diameter of the hydrogen gas separator 6. Was attached to the Kovar support 8 through a hole 8a that did not penetrate. The gap 10 between the gas separator 6 and the Kovar supports 7 and 8 was filled with a brazing material Ag-28Cu (BAg-8) and brazed at 820 ° C. in a vacuum.

Using the joined body of the gas separator 6 and the supports 7 and 8 made of Kovar, a hydrogen gas separator was prepared. FIG. 3 shows a sectional view of one embodiment. High pressure vessel 11
Inside, a plurality of tubular hydrogen gas separators 6 are housed. Each hydrogen gas separator 6 is attached to a support 7 made of Kovar.
The inside of the hydrogen gas separator 6 is supported so as to communicate with the upper space of the Kovar support 7, and the end of the Kovar support 8 is sealed by a hole 8a that does not penetrate. Supported.

The flanges 12 and 13 support the support plate 1
4, the Kovar support 7 is fixed by a support plate 14, and the hydrogen gas separator 6 and the Kovar support 8 are suspended. In FIG. 3, the gas to be purified is supplied into the high-pressure vessel 11 from the first pipe 15. The purified hydrogen gas passes through the cylindrical hydrogen gas separator 6 and moves into the cylinder, and the purified hydrogen gas is led to the third pipe 16. On the other hand, the gas that was not purified
It flows out of the second pipe 17.

Examples 1 to 4 By changing the thickness of a nickel layer provided on a gas separation membrane,
An airtightness test was performed using the hydrogen gas separator configured as described above. First, as an airtight test, 8 kg / cm ² of argon gas was introduced into the non-treatment gas side, and the flow rate of argon gas leaking to the permeated gas side was measured. Table 1 shows the results.

(Comparative Examples 1 and 2 ) The hydrogen gas separator prepared by the above-mentioned method was directly brazed to a Kovar support without providing a nickel layer.
After producing the hydrogen gas separation device shown in FIG.
An airtightness test was performed in the same manner as in Example 4 . Table 1 shows the results. As a result of the above test, it was found that the thickness of the nickel layer is preferably 1 μm or more.

[0023]

[Table 1]

[0024]

Effect of the Invention The joined body of metal-coated ceramics and metal of the present invention, and a hydrogen gas separation device using the same,
Under high temperature and high pressure to separate hydrogen gas, it has excellent airtightness at the joint.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a joined body of the present invention.

FIG. 2 is a cross-sectional view of the joined body of the present invention comprising a gas separator and a Kovar support.

FIG. 3 is a cross-sectional view of an example of a hydrogen separation device using the joined body of the present invention.

[Explanation of symbols]

1 ... porous ceramic tube, 2 ... gas separation membrane, 2α ...
-Hydrogen separation membrane, 3-metal layer, 4-metal member, 5-wax, 6-gas separator, 7-support plate, 8-support made of Kovar, 9 ... nickel layer, 10 ... gap, 11 ...
・ High pressure vessel, 12 ・ ・ ・ Flange, 13 ・ ・ ・ Flange, 14 ・
..Support plate, 15 ... first pipe, 16 ... third pipe, 17 ... second pipe

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 53/22 B01D 61/00-71/82 B32B 1/00-35/00 C04B 37/00-37/04

Claims (4)

(57) [Claims] 1. A joined body of a metal member and a metal member in which a metal having a gas separating ability is coated on a porous ceramic, wherein the metal has a gas separating ability.
A metal coating layer having a thickness of 50 μm or less, and a metal layer having a thickness of 1 μm to 50 μm is further provided on a surface of the metal-coated ceramics involved in bonding with the metal member;
A joined body of a metal-coated ceramic and a metal, wherein the metal layer and the metal member are joined by brazing. 2. The joined body according to claim 1, wherein the metal having a gas separating ability is palladium or an alloy containing palladium. 3. The metal layer provided on the surface of the metal-coated ceramic is made of a metal having a melting point higher than that of a brazing material.
The conjugate of the above. 4. In a high-pressure vessel, a cylindrical hydrogen gas separator is provided at its upper end with a metal support through a through hole having a diameter slightly larger than the outer diameter of the hydrogen gas separator. , The inside of which is fixed so as to communicate with the upper space of the high-pressure vessel defined by the metal support, and at the lower end, the end is closed by a hole that does not penetrate the metal support. A hydrogen gas separator, wherein the hydrogen gas separator is made of porous ceramics, and a thickness of a metal which selectively permeates hydrogen gas is coated on the substrate. Is 50μ
m or less of a gas separation membrane, and the surface of the gas separation membrane involved in bonding with the metal member has a further thickness.
A hydrogen gas separation device, wherein a metal layer having a thickness of 1 μm to 50 μm is provided, and the metal layer and the metal member are joined by brazing.