JPH049724B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-purity hydrogen purification device that can be used, for example, in the process of removing impurities in a nuclear fusion reactor fuel supply and exhaust system.

Conventional technology Conventionally, a method using a palladium alloy membrane has been known as a method for producing high-purity hydrogen.
This method takes advantage of the extremely high hydrogen permeability of palladium to separate impurities from hydrogen. In other words, by heating a palladium-based alloy membrane, only the hydrogen in hydrogen gas containing impurities permeates.
It purifies high-purity hydrogen, and it is said to be the method that can obtain the highest purity hydrogen today.

By the way, in a conventional hydrogen purification device using a palladium alloy membrane, as shown in Fig. 2, one end 1a of a Pd-Ag alloy membrane tube 1 is directly connected to a main body (usually made of stainless steel) 2.
The other end 1b of the Pd--Ag alloy membrane tube 1 is sealed with the same material. Although not shown in Fig. 2, a heater is usually provided on the outside (i.e., the primary side) of the Pd-Ag alloy membrane tube 1 to heat it, and stainless steel powder is used to make the heating temperature uniform. (cutting powder) etc. may be added. Hydrogen gas to be treated is supplied to the outside of the Pd--Ag alloy membrane tube 1, and the structure is such that only hydrogen permeates from the outside of the tube 1 to the inside and is drawn out to the secondary side.

However, in such conventional equipment, palladium alloy is extremely brittle, so Pd-
When an Ag alloy membrane tube is welded directly to a main body made of stainless steel, etc., cracks tend to form in the welded part, which causes leaks and impurities to flow into the secondary side (high-purity hydrogen side), resulting in extremely low reliability. . Furthermore, when manufacturing the above-mentioned Pd--Ag alloy membrane tube, a mechanical method is usually used, so that the inside and outside of the tube are considerably contaminated with oil and fat. Therefore, with a structure in which the tip is sealed, the inside of the tube cannot be sufficiently cleaned, and impurity gas is generated on the secondary side, causing a decrease in the purity of hydrogen. Furthermore, in the case where a large amount of powder of stainless steel or the like is filled on the primary side in order to make the heating temperature uniform, impurities are generated from the powder and may corrode the palladium alloy film and create holes.

By the way, as one of the conventional techniques, the Journal of the Atomic Energy Society of Japan, Vol. 24, No. 6, published in 1982, states that one end of a Pd-Ag membrane tube is sealed, the other end is silver-brazed to a nickel tube, and this is attached to a stainless steel outer tube. A welded hydrogen purifier is disclosed. With this structure, among the various problems mentioned above, the disadvantage associated with cracking at the welded portion can be solved, but the other problems cannot be substantially solved.

Problems to be Solved by the Invention Therefore, the present invention solves the problem of cracking in the welded part of palladium membrane tubes, the difficulty of cleaning palladium membrane tubes, the problem of impurity gas generation that corrodes palladium alloy membrane tubes, and The purpose of the present invention is to provide a high-purity hydrogen purification device that solves the problem of impurity contamination due to leakage.

Means for Solving the Problems In order to achieve the above object, the high purity hydrogen purification device according to the present invention has a tubular membrane made of palladium alloy with both ends open, and one end of which is welded or brazed. A sealing member made of the same material as the tubular member is fitted and fixed to the other end of the tubular membrane, and a heater for the tubular member is supported by pure metal. It is characterized in that it is supported by the body and further uses an ultra-vacuum flange as a sealing member.

Operation With the above configuration, in the high-purity hydrogen purification apparatus according to the present invention, the nickel tubular member inserted between the main body made of stainless steel and the tubular membrane made of palladium alloy is Since it has a coefficient of thermal expansion between the coefficient of thermal expansion and that of the tubular membrane, strain at each joint can be suppressed to a low level, and cracks or cracks can be prevented from forming at welded parts. The palladium-based alloy tubular membrane used is open at both ends, so it can be easily and thoroughly cleaned before assembly, which prevents impurity gases from entering the secondary side due to oil, fat, dust, etc. There is no fear that it will.

The support made of pure metal, such as light oxygen copper, that supports the heater can be made cylindrical and the heater can be wrapped around the outside of the support, so the tubular membrane of palladium alloy can be inscribed in the cylindrical support of the heater. Alternatively, even if there are some gaps, the heating temperature can be made uniform, and since it contains almost no material that generates impurities, the tubular membrane will not corrode. Furthermore, by using an ultra-high vacuum flange, there is no risk of contamination with impurities due to leakage. In fact, impurities in hydrogen purified using this device
As measured by MSQ, the content was
It was below 0.1ppm.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 of the accompanying drawings.

Fig. 1 schematically shows an embodiment of a high-purity hydrogen purification device, where 3 is a stainless steel body, 4 is a Pd.
-Ag tubular membrane, one open end 4a of this tubular membrane 4;
is brazed to one end of a nickel tubular member 5 using palladium brazing material, and the other end of the tubular member is welded to the end wall 6 of the main body 3. On the other hand, a nickel sealing member 7 is fitted and brazed to the other open end 4b of the tubular membrane 4. Although two tubular membrane assemblies constructed in this manner are illustrated, the number can be designed arbitrarily (for example, one, three or more). A cylinder 8 made of oxygen-free copper is inserted around the outer periphery of the tubular membrane assembly and extends along its entire length, and this cylinder 8 is fixed at one end to the end wall 9 of the main body 3, and this cylinder A heater 10 is wound around the outer peripheral surface of the body 8. The heater 10 is connected to an external power source via a conductive wire (not shown), and the inside of the main body 3 is naturally connected to an exhaust system (not shown).

Further, in FIG. 1, reference numeral 11 is an introduction pipe for introducing hydrogen gas to be purified, and the tip thereof is open into the main body 3. The inside of the tubular membrane assembly communicates with a purified hydrogen take-off pipe 13 provided in the lid member 12 via a cavity 14 . Flanges 3a and 3b at both ends of main body 3
The seals between the assembled end walls 6 and 9 and between the end wall 6 and the lid member 12 are designed so that the inside of the device can be made into an ultra-high vacuum in order to purify hydrogen with a high purity of 99.99999% or more. Moreover, in order to withstand high temperatures of 200°C or higher, metal gaskets 15, 16, and 17 are used, respectively, to form an ultra-high vacuum flange.

Effects As explained above, the following effects can be obtained in the high purity hydrogen purification apparatus according to the present invention.

(1) There is no risk of cracking in welded parts, etc., and the reliability of the device can be improved.

(2) All parts containing palladium-based alloys can be easily and thoroughly cleaned, preventing the generation of impurity gases and improving the purification purity of hydrogen.

(3) There is almost no impurity gas generated on the primary side, preventing corrosion of the palladium alloy, and as a result, ensuring stable operation of the device.

(4) The use of an ultra-high vacuum flange prevents impurities from leaking.

(5) By using an intermediate connecting member such as nickel, welding or brazing during assembly becomes easier, and manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
FIG. 2 is a partial sectional view showing the structure of a conventional device. In the figure, 3: main body, 3a, 3b: flange, 4:
palladium-based alloy tubular membrane, 5: nickel tubular member, 6, 9: end wall, 7: nickel sealing member, 8:
Heater support, 12: Lid member, 15, 16, 1
7: Metal gasket.

Claims (1)

[Claims] 1 High-purity hydrogen produced by welding a palladium-based alloy tubular membrane to a stainless steel body and heating this tubular membrane to allow only the hydrogen in the hydrogen gas containing impurities to pass through to purify high-purity hydrogen. In the refining equipment, a palladium-based alloy tubular membrane has both ends open, one end of which is fixed via a nickel tubular member that is easy to weld or braze, and the other end of the tubular membrane is attached to the tubular member. A sealing member made of the same material as the tubular member is fitted and fixed, a heater for the tubular member is supported by a support made of pure metal, and an ultra-high vacuum flange is used for each sealing member. Purity hydrogen purification equipment.