JP2006346608A - Hydrogen separating membrane and hydrogen separating membrane module - Google Patents

Hydrogen separating membrane and hydrogen separating membrane module Download PDF

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JP2006346608A
JP2006346608A JP2005177262A JP2005177262A JP2006346608A JP 2006346608 A JP2006346608 A JP 2006346608A JP 2005177262 A JP2005177262 A JP 2005177262A JP 2005177262 A JP2005177262 A JP 2005177262A JP 2006346608 A JP2006346608 A JP 2006346608A
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hydrogen
alloy
separation membrane
hydrogen separation
separating membrane
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Yuya Konno
勇哉 紺野
Makoto Ogawa
真 小川
Masaki Kawano
将樹 河野
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Mitsubishi Heavy Industries Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen separating membrane which has high hydrogen permeability performance, in which crystalline structure does not change by thermal treatment and thereby which is excellent in heat stability and to provide a hydrogen separating membrane module using the same. <P>SOLUTION: The hydrogen separating membrane contains Y or Gd and Ag within a range satisfying conditions: x≤15, 0.1≤y≤5 and 3x+y>36, wherein content of Y or Gd is xat% and content of Ag is yat% and the remainder contains an alloy comprising Pd and inevitable impurities. Further the hydrogen separating membrane module is constituted by sticking a metallic porous plate on one surface of the hydrogen separating membrane and sticking a supporting plate on an opposite side surface of the metallic porous plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、水素精製装置や水素製造装置などに用いられる優れた水素透過性能を有する水素分離膜および水素分離膜モジュールに関する。   The present invention relates to a hydrogen separation membrane and a hydrogen separation membrane module having excellent hydrogen permeation performance used in a hydrogen purification device, a hydrogen production device and the like.

水素を含む混合ガスから水素を選択的に透過する水素分離膜は、高純度水素の製造または精製装置への適用が考えられている。現在、水素分離膜としてPdが使用されている。Pdは貴金属でありかつ戦略物質である。そのため、Pdは既に高価である上、大量の消費が見込まれれば、更に高騰する可能性がある。そこで、Pdを他の元素で代替えしてPdの使用量を低減するとともに、水素透過性能を向上することを目的に、他の元素を添加したPd合金が提案されている。   A hydrogen separation membrane that selectively permeates hydrogen from a mixed gas containing hydrogen is considered to be applied to production or purification equipment of high-purity hydrogen. Currently, Pd is used as a hydrogen separation membrane. Pd is a noble metal and a strategic substance. Therefore, Pd is already expensive, and if a large amount of consumption is expected, it may further increase. Thus, Pd alloys with other elements added have been proposed for the purpose of reducing the amount of Pd used by substituting Pd with other elements and improving the hydrogen permeation performance.

例えば、特開平11−99323号公報には、PdにY、GdおよびLuからなる群から選択される1希土類元素とAgとを添加した3元合金であって、希土類元素の含有量をxat%、Agの含有量をyat%として、x≧3かつ36≧3x+y≧24の範囲の合金が提案されている。本公報には、上記添加元素の含有量がこの範囲内である場合は、優れた水素透過性能を発揮するものの、この範囲外、特に3x+y>36の場合は、希土類元素の含有量が多いため、金属間化合物からなる第二相が析出して二相分離状態を起こし、水素透過性能が低下することが記載されている。   For example, JP-A-11-99323 discloses a ternary alloy in which one rare earth element selected from the group consisting of Y, Gd, and Lu and Ag is added to Pd, and the content of the rare earth element is xat%. Alloys in the range of x ≧ 3 and 36 ≧ 3x + y ≧ 24 have been proposed, where the Ag content is yat%. In this publication, when the content of the additive element is within this range, excellent hydrogen permeation performance is exhibited, but when the content is outside this range, particularly 3x + y> 36, the content of rare earth elements is large. In addition, it is described that a second phase composed of an intermetallic compound is precipitated to cause a two-phase separation state, and the hydrogen permeation performance is lowered.

また、上記のような合金は、酸化しやすい希土類金属を含んでいるため、高温で使用すると酸化による脆化が起こり、長時間の使用における耐久性に問題があることが指摘されている。そこで、特開平11−104471号公報には、耐酸化性に優れるPdまたはPd−Ag合金で上記の合金の表面を被覆して、酸化による脆化を防止することが記載されている。
特開平11−99323号公報 特開平11−104471号公報
Further, it has been pointed out that such an alloy contains a rare earth metal that easily oxidizes, and therefore, when used at a high temperature, embrittlement occurs due to oxidation, and there is a problem in durability in use for a long time. Japanese Patent Application Laid-Open No. 11-104471 describes that the surface of the above alloy is coated with Pd or Pd—Ag alloy having excellent oxidation resistance to prevent embrittlement due to oxidation.
JP-A-11-99323 JP-A-11-104471

Pdに上記の範囲の量の希土類元素とAgとを添加することにより、水素透過性能を向上させることができる。水素透過係数が高いほど水素透過性能は高く、例えば、Pd−8at%Gd合金とすることで水素透過係数を5.5×10-8mol/m・s・Pa0.5と高くすることができる。しかしながら、上記のPd合金を水素分離膜として使用するためには、圧延による薄膜化が必要であり、それには焼鈍処理を行うが、例えば800℃の高温で熱処理を施すと、加熱により結晶構造が変化し、水素透過性能が劣化するという問題がある。また、添加元素の割合が多すぎると、このような加熱により膜が脆化して、差圧によって割れやすくなる等の機械的特性も劣化するという問題がある。 The hydrogen permeation performance can be improved by adding rare earth elements and Ag in the above ranges to Pd. The higher the hydrogen permeation coefficient, the higher the hydrogen permeation performance. For example, by using a Pd-8 at% Gd alloy, the hydrogen permeation coefficient can be increased to 5.5 × 10 −8 mol / m · s · Pa 0.5 . However, in order to use the above Pd alloy as a hydrogen separation membrane, it is necessary to reduce the thickness by rolling, and annealing is performed. For example, when heat treatment is performed at a high temperature of 800 ° C., the crystal structure is increased by heating. There is a problem that the hydrogen permeation performance deteriorates. Further, when the ratio of the additive element is too large, there is a problem that the film becomes brittle due to such heating, and mechanical properties such as easy cracking due to differential pressure are deteriorated.

そこで、本発明は、上記の問題に鑑み、高い水素透過性能を有するとともに、熱処理による結晶構造の変化がない熱安定性に優れた水素分離膜および水素分離膜モジュールを提供することを目的とする。   In view of the above problems, an object of the present invention is to provide a hydrogen separation membrane and a hydrogen separation membrane module that have high hydrogen permeation performance and excellent thermal stability with no change in crystal structure due to heat treatment. .

上記の目的を達成するために、本発明に係る水素分離膜は、YまたはGdの含有量をxat%、Agの含有量をyat%として、x≦15、0.1≦y≦5、かつ3x+y>36の条件を満たす範囲でYまたはGdとAgとを含有し、残部がPdおよび不可避不純物からなる合金を含むことを特徴とする。   In order to achieve the above object, the hydrogen separation membrane according to the present invention is configured such that x ≦ 15, 0.1 ≦ y ≦ 5, and the content of Y or Gd is xat% and the content of Ag is yat%. The alloy contains Y or Gd and Ag within a range satisfying the condition of 3x + y> 36, and the balance includes an alloy made of Pd and inevitable impurities.

YまたはGdとAgの含有量を増大させるに従い、Pd合金の水素透過性能は向上する。しかしながら、3x+y=36の関係を超えてYまたはGdとAgとを添加すると、添加量が多くなり過ぎ、Pdが固溶できる限界を超え、Pd3YまたはPd3Gd等の金属間化合物が析出して水素透過性能が低下し、機械的特性が劣化するという問題があった。ところが、本発明によれば、3x+y>36の範囲でも、x≦15かつ0.1≦y≦5という更に限定された範囲では、驚くべきことに、このように添加量を多くしても材料が固溶体を形成し、それが熱的に安定であり、水素透過性能及び機械的特性にも優れていることがわかった。 As the content of Y or Gd and Ag is increased, the hydrogen permeation performance of the Pd alloy is improved. However, when Y or Gd and Ag are added beyond the relationship of 3x + y = 36, the amount of addition becomes too large, exceeding the limit where Pd can be dissolved, and intermetallic compounds such as Pd 3 Y or Pd 3 Gd are precipitated. As a result, the hydrogen permeation performance deteriorates and the mechanical properties deteriorate. However, according to the present invention, even in the range of 3x + y> 36, and in the further limited range of x ≦ 15 and 0.1 ≦ y ≦ 5, surprisingly, even if the addition amount is increased, the material Formed a solid solution, which was found to be thermally stable and excellent in hydrogen permeation performance and mechanical properties.

YまたはGdの含有量(x)は12〜14at%がより好ましく、Agの含有量(y)は0.3〜4at%がより好ましい。含有量を更にこの範囲に限定することで、より高い水素透過性能が得られるとともに、熱処理後もその性能を高く維持することができる。   The content (x) of Y or Gd is more preferably 12 to 14 at%, and the content (y) of Ag is more preferably 0.3 to 4 at%. By further limiting the content to this range, higher hydrogen permeation performance can be obtained and the performance can be kept high even after heat treatment.

上記合金を芯材として、この少なくとも一方の表面に、表層材としてPdまたはPd−Ag合金を被覆することが好ましい。上記合金(芯材)の表面に、耐酸化性に優れた表層材を被覆して、複数層構造とすることにより、酸化を防止でき、長時間使用においても水素透過性、熱安定性、耐酸化性の全てに優れた水素分離膜を得ることができる。   It is preferable to cover at least one surface of the alloy as a core material with a Pd or Pd—Ag alloy as a surface layer material. The surface of the above alloy (core material) is coated with a surface layer material excellent in oxidation resistance to form a multi-layer structure, so that oxidation can be prevented and hydrogen permeability, thermal stability, acid resistance can be maintained even after long-term use It is possible to obtain a hydrogen separation membrane excellent in all of the chemical conversion properties.

本発明は、別の態様として、水素分離膜モジュールであって、このモジュールは、上記の水素分離膜の一方の表面に、金属多孔板が貼り付けられており、この金属多孔板の反対側の表面に、支持板が貼り付けられていることを特徴とする。   Another aspect of the present invention is a hydrogen separation membrane module, in which a metal porous plate is attached to one surface of the hydrogen separation membrane, and the opposite side of the metal porous plate is provided. A support plate is affixed to the surface.

このように、本発明によれば、高い水素透過性能を有するとともに、熱処理による結晶構造の変化がない熱安定性に優れた水素分離膜および水素分離膜モジュールを提供することができる。   Thus, according to the present invention, it is possible to provide a hydrogen separation membrane and a hydrogen separation membrane module that have high hydrogen permeation performance and excellent thermal stability with no change in crystal structure due to heat treatment.

以下、添付図面を参照して、本発明に係る水素分離膜の一実施の形態を説明する。図1は、本発明に係るPd−Ag−YまたはPd−Ag−Gd合金の組成範囲を示すグラフである。図2は、本発明に係る水素分離膜の一例を示す断面図であり、芯材の両面に表層材を被覆した場合である。図3は、本発明に係る水素分離膜の別の一例を示す断面図であり、芯材の片面に表層材を被覆した場合である。   Hereinafter, an embodiment of a hydrogen separation membrane according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a graph showing a composition range of a Pd—Ag—Y or Pd—Ag—Gd alloy according to the present invention. FIG. 2 is a cross-sectional view showing an example of the hydrogen separation membrane according to the present invention, in which the surface layer material is coated on both surfaces of the core material. FIG. 3 is a cross-sectional view showing another example of the hydrogen separation membrane according to the present invention, in which one surface of the core material is covered with a surface layer material.

図2および図3に示すように、水素分離膜20は、芯材22の両面または片面に表層材24が被覆されている。芯材22としては、YまたはGdの含有量をxat%、Agの含有量をyat%として、x≦15、0.1≦y≦5、かつ3x+y>36の条件を満たす範囲でYまたはGdとAgとを含有し、残部がPdおよび不可避不純物からなる合金が用いられる。この条件を満たす範囲が、図1の斜線部分である(なお、3x+y=36の線上はこの範囲に含まれない)。   As shown in FIGS. 2 and 3, in the hydrogen separation membrane 20, the surface material 24 is coated on both surfaces or one surface of the core material 22. The core material 22 has a Y or Gd content of xat%, an Ag content of yat%, and Y or Gd within a range satisfying the conditions of x ≦ 15, 0.1 ≦ y ≦ 5, and 3x + y> 36. And an alloy containing Pd and inevitable impurities are used. The range satisfying this condition is the hatched portion in FIG. 1 (note that the 3x + y = 36 line is not included in this range).

図1に斜線部分で示された範囲の組成を有するPd合金は、YまたはGdとAgの含有量が3x+y=36の関係よりも多く添加されても、従来の知見に反して、良好な水素透過性能を示し、第二相の析出も観察されない。さらに、Pd合金を水素分離膜として使用するためには、圧延による薄膜化が必要であり、それには焼鈍処理を行う必要がある。この範囲の組成を有する合金は、例えば焼鈍処理として800℃で10時間の加熱を行っても、熱安定性に優れていることから、結晶構造が固溶体のまま変化せず、水素透過性能、機械的特性は劣化しない。   In the Pd alloy having the composition in the range indicated by the hatched portion in FIG. 1, even if the content of Y or Gd and Ag is larger than the relationship of 3x + y = 36, the hydrogen content is good, contrary to the conventional knowledge Shows permeation performance and no second phase precipitation is observed. Further, in order to use the Pd alloy as a hydrogen separation membrane, it is necessary to reduce the thickness by rolling, and it is necessary to perform an annealing treatment. An alloy having a composition in this range is excellent in thermal stability even when heated at 800 ° C. for 10 hours as an annealing treatment, for example, so that the crystal structure remains a solid solution and the hydrogen permeation performance, machine The characteristics are not degraded.

一方、Agの含有量が0.1at%未満かつGdまたはYの含有量が10at%以上の場合は、初期には水素透過性能が十分に高くても、製作時あるいは運転中の加熱によってPd3YまたはPd3Gdが析出し、結晶構造が変化して、水素透過性能、機械的特性が劣化してしまう。 On the other hand, when the content of Ag is less than 0.1 at% and the content of Gd or Y is 10 at% or more, even if the hydrogen permeation performance is sufficiently high at the initial stage, Pd 3 may be heated by heating during production or operation. Y or Pd 3 Gd is precipitated, the crystal structure is changed, and the hydrogen permeation performance and mechanical properties are deteriorated.

また、YもしくはGdの含有量が15at%を超える場合は、Agの含有量にかかわらずPd3YまたはPd3Gd等の金属間化合物が第二相として析出するため、高い水素透過性能を得ることはできない。なお、YまたはGdの含有量が15at%より多い場合は、熱安定性も低く、加熱により結晶構造が変化する。 Further, when the Y or Gd content exceeds 15 at%, an intermetallic compound such as Pd 3 Y or Pd 3 Gd precipitates as the second phase regardless of the Ag content, so that high hydrogen permeation performance is obtained. It is not possible. When the content of Y or Gd is more than 15 at%, the thermal stability is low, and the crystal structure is changed by heating.

また、Agの含有量が5at%を超える場合は、水素透過性能が低下する。   On the other hand, when the Ag content exceeds 5 at%, the hydrogen permeation performance decreases.

芯材22であるPd−Ag−YまたはPd−Ag−Gd合金は、酸化しやすい希土類金属を含んでいるため、高温で使用すると酸化による脆化が起こるとともに、表面に酸化層が形成され、水素透過性能も低下するおそれがある。そこで、耐酸化性に優れるPdまたはPd−Ag合金を表層材24として用いて、これで芯材22の少なくとも一方の表面を被覆して、酸化による脆化および水素透過性能の低下を防止する。Pd−Ag合金としては、Agを0〜30at%含有するものが好ましい。なお、このように芯材22の表面を表層材24で被覆すると、膜20全体の水素透過性能は芯材のみよりも低下するが、表層材24によって酸化層の形成が防止されるので、長時間使用しても水素透過性能の低下は小さい。すなわち、長時間使用した場合の水素透過性能を比較すると、芯材のみよりも表層材24で表面を被覆した方が水素透過性能が良好となる。また、このような複数層構造の膜20の水素透過係数は、芯材22の水素透過係数が大きく関与しており、芯材22の水素透過係数が大きいほど、膜20全体の水素透過係数は大きくなる。   The Pd—Ag—Y or Pd—Ag—Gd alloy that is the core material 22 contains a rare earth metal that easily oxidizes, so that when used at a high temperature, embrittlement occurs due to oxidation, and an oxide layer is formed on the surface. Hydrogen permeation performance may also be reduced. Therefore, Pd or Pd—Ag alloy having excellent oxidation resistance is used as the surface layer material 24, thereby covering at least one surface of the core material 22 to prevent embrittlement and deterioration of hydrogen permeation performance due to oxidation. As the Pd—Ag alloy, an alloy containing 0 to 30 at% of Ag is preferable. If the surface of the core material 22 is coated with the surface layer material 24 in this way, the hydrogen permeation performance of the entire membrane 20 is lower than that of the core material alone, but the surface layer material 24 prevents the formation of an oxide layer. Even when used for a long time, the decrease in hydrogen permeation performance is small. That is, when the hydrogen permeation performance when used for a long time is compared, the hydrogen permeation performance is better when the surface is coated with the surface material 24 than with the core material alone. Further, the hydrogen permeation coefficient of the membrane 20 having such a multi-layer structure is greatly related to the hydrogen permeation coefficient of the core material 22. growing.

このように、水素分離膜20の芯材22に、優れた水素透過性能の合金を用い、図2または図3に示すように、この芯材22の両面もしくは一方の表面を、耐酸化性に優れた表層材24で被覆することにより、高い水素透過性能を維持しつつ、耐酸化性を得ることができる。   As described above, an alloy having excellent hydrogen permeation performance is used for the core material 22 of the hydrogen separation membrane 20, and both or one surface of the core material 22 is made oxidation resistant as shown in FIG. 2 or FIG. By covering with the excellent surface layer material 24, oxidation resistance can be obtained while maintaining high hydrogen permeation performance.

なお、芯材22の表面に表層材24を被覆する方法としては、芯材22の合金と表層材24の合金の各インゴットを作製し、これらインゴットを重ねて加熱することでクラッド接合した後、さらにこれを圧延する方法が好ましい。インゴットは重ねる前に予め圧延して薄膜化しておくことが好ましい。   In addition, as a method of coating the surface material 24 on the surface of the core material 22, after making each ingot of the alloy of the core material 22 and the alloy of the surface material 24, and laminating and heating these ingots, Furthermore, the method of rolling this is preferable. The ingot is preferably rolled into a thin film before being stacked.

クラッド接合の際の加熱処理は、500〜900℃の範囲が好ましい。圧延は冷間または熱間で行うのが好ましい。また、接合後の圧延により水素分離膜20の厚さを2〜50μmにすることが好ましい。芯材22と表層材24の厚さの比は、芯材:表層材=4:1またはこれより表層材を薄くすることが好ましい。   The heat treatment during clad bonding is preferably in the range of 500 to 900 ° C. Rolling is preferably performed cold or hot. Moreover, it is preferable that the thickness of the hydrogen separation membrane 20 be 2 to 50 μm by rolling after bonding. The ratio of the thicknesses of the core material 22 and the surface layer material 24 is preferably as follows: core material: surface layer material = 4: 1 or thinner than this.

次に、本発明に係る水素分離膜モジュールの一実施の形態について説明する。図4は、水素分離膜モジュールの一例を模式的に示す組立図である。図4に示すように、上記により作製した水素分離膜20は、金属多孔板30上に配置される。金属多孔板30は、多数の開口を形成したもので、総合的に強度を増すべく、複数枚で用いることが多い。図4では、3枚の金属多孔板30が使用されている。   Next, an embodiment of the hydrogen separation membrane module according to the present invention will be described. FIG. 4 is an assembly diagram schematically showing an example of the hydrogen separation membrane module. As shown in FIG. 4, the hydrogen separation membrane 20 produced as described above is disposed on a metal porous plate 30. The metal porous plate 30 is formed with a large number of openings, and is often used as a plurality of sheets in order to increase the overall strength. In FIG. 4, three metal porous plates 30 are used.

金属多孔板30は、更に支持板40上に配置される。支持板40は、その一方の面に、水素分離膜20および金属多孔板30を通過してくる水素を集めるための溝42が形成されており、この溝42が形成されている面に金属多孔板30が設置される。そして、水素分離膜20、金属多孔板30および支持板40の周囲にシール溶接を施し、全体を一体化して水素分離膜モジュールとする。このような構成によれば、水素透過に有利な高温で、膜の表裏に高い圧力差をかけることができるため、高性能な水素分離膜モジュールとなる。また、この形状は容易に作成でき、更に安価であるという利点もある。   The metal porous plate 30 is further disposed on the support plate 40. The support plate 40 has a groove 42 for collecting hydrogen passing through the hydrogen separation membrane 20 and the metal porous plate 30 formed on one surface thereof, and a metal porous surface is formed on the surface where the groove 42 is formed. A plate 30 is installed. Then, seal welding is performed around the hydrogen separation membrane 20, the metal porous plate 30, and the support plate 40, and the whole is integrated into a hydrogen separation membrane module. According to such a configuration, since a high pressure difference can be applied to the front and back of the membrane at a high temperature advantageous for hydrogen permeation, a high-performance hydrogen separation membrane module is obtained. In addition, this shape can be easily created and has the advantage of being inexpensive.

(Pd−Ag−Gd合金膜の作製)
Pd−3at%Ag−14at%Gd合金、Pd−0.3at%Ag−12at%Gd合金およびPd−4at%Ag−12at%Gd合金の各インゴットをアーク溶解で作製した。その後、各インゴットから厚さ1mm程度の薄膜を切り出し、これを冷間で0.5mmまで圧延して各組成の合金膜を作製した(試料番号1〜4)。
(Preparation of Pd—Ag—Gd alloy film)
Ingots of Pd-3 at% Ag-14 at% Gd alloy, Pd-0.3 at% Ag-12 at% Gd alloy, and Pd-4 at% Ag-12 at% Gd alloy were prepared by arc melting. Thereafter, a thin film having a thickness of about 1 mm was cut out from each ingot, and this was cold-rolled to 0.5 mm to prepare alloy films having respective compositions (sample numbers 1 to 4).

同様に比較例として、Pd−3at%Ag−6at%Gd合金膜、Pd−3at%Ag−16at%Gd合金膜、Pd−7at%Ag−12at%Gd合金膜、Pd−12at%Gd合金膜およびPd−24at%Ag合金膜を作製した(試料番号5〜9)。   Similarly, as comparative examples, a Pd-3 at% Ag-6 at% Gd alloy film, a Pd-3 at% Ag-16 at% Gd alloy film, a Pd-7 at% Ag-12 at% Gd alloy film, a Pd-12 at% Gd alloy film, and Pd-24 at% Ag alloy films were prepared (sample numbers 5 to 9).

(水素透過性能評価)
上記により得られた各合金膜について水素透過性能評価を行った。合金膜を試験セルにセットして500℃に加熱し、その片側に水素ガスを流通させる時に、反対側に透過した水素のガス流量を測定し、表裏の水素分圧、試料評価面積および試料厚さを考慮して、水素透過係数(mol/m・s・Pa0.5)を算出した。その結果を表1に示す。
(Hydrogen permeation performance evaluation)
Each alloy film obtained as described above was evaluated for hydrogen permeation performance. When the alloy film is set in a test cell and heated to 500 ° C. and hydrogen gas is circulated on one side, the hydrogen gas permeate on the opposite side is measured, the hydrogen partial pressure on the front and back, the sample evaluation area, and the sample thickness Taking this into consideration, the hydrogen permeation coefficient (mol / m · s · Pa 0.5 ) was calculated. The results are shown in Table 1.

(結晶構造の熱安定性評価)
また、上記により得られた各合金膜について、結晶構造の熱安定性評価を行った。合金膜を800℃で10時間の熱処理を施した後、X線回折パターンを解析し、結晶構造の変化を調査するとともに、熱処理後の水素透過係数を上記の評価法にて算出した。その結果を表1に示す。
(Evaluation of thermal stability of crystal structure)
Moreover, thermal stability evaluation of crystal structure was performed about each alloy film obtained by the above. The alloy film was subjected to a heat treatment at 800 ° C. for 10 hours, and then the X-ray diffraction pattern was analyzed to investigate the change in crystal structure, and the hydrogen permeability coefficient after the heat treatment was calculated by the above evaluation method. The results are shown in Table 1.

Figure 2006346608
Figure 2006346608

表1に示すように、実施例である試料番号1〜3のPd−Ag−Gd合金膜は、熱処理前の水素透過係数がいずれも6.0×10-8mol/m・s・Pa0.5以上と非常に高かった。そして、800℃で10時間の熱処理を施しても、結晶構造に変化がなく、第二相は観察されなかった。また、熱処理後の水素透過係数も5.6×10-8mol/m・s・Pa0.5以上と高く維持されていた。 As shown in Table 1, the Pd—Ag—Gd alloy films of Sample Nos. 1 to 3 as examples have a hydrogen permeability coefficient before heat treatment of 6.0 × 10 −8 mol / m · s · Pa 0.5. It was very high with the above. And even if it heat-processed at 800 degreeC for 10 hours, there was no change in a crystal structure and the 2nd phase was not observed. Further, the hydrogen permeability coefficient after the heat treatment was also maintained as high as 5.6 × 10 −8 mol / m · s · Pa 0.5 or more.

一方、比較例であるPd−12at%Gd合金膜(試料番号5)は、熱処理前の水素透過係数が6.8×10-8mol/m・s・Pa0.5以上と非常に高かったものの、800℃で10時間の熱処理を施すと、結晶構造に変化があり、第二相の析出が観察された。熱処理後の水素透過係数も5.0×10-8mol/m・s・Pa0.5と著しく低下していた。 On the other hand, the Pd-12 at% Gd alloy film (sample No. 5), which is a comparative example, had a very high hydrogen permeability coefficient before heat treatment of 6.8 × 10 −8 mol / m · s · Pa 0.5 or more, When heat treatment was performed at 800 ° C. for 10 hours, the crystal structure was changed, and precipitation of the second phase was observed. The hydrogen permeation coefficient after the heat treatment was also significantly reduced to 5.0 × 10 −8 mol / m · s · Pa 0.5 .

また、比較例であるPd−3at%Ag−6at%Gd合金膜(試料番号6)とPd−7at%Ag−12at%Gd合金膜(試料番号7)は、熱処理前の水素透過係数が5.3×10-8mol/m・s・Pa0.5、5.4×10-8mol/m・s・Pa0.5と当初から低かった。800℃で10時間の熱処理を施しても、結晶構造に変化がなく、第二相は観察されなかったものの、熱処理後の水素透過係数は5.0×10-8mol/m・s・Pa0.5と低いものであった。 Further, the Pd-3 at% Ag-6 at% Gd alloy film (sample number 6) and the Pd-7 at% Ag-12 at% Gd alloy film (sample number 7), which are comparative examples, have a hydrogen permeation coefficient of 5. 3 × 10 −8 mol / m · s · Pa 0.5 and 5.4 × 10 −8 mol / m · s · Pa 0.5 were low from the beginning. Even when heat treatment was performed at 800 ° C. for 10 hours, the crystal structure was not changed and the second phase was not observed, but the hydrogen permeability coefficient after the heat treatment was 5.0 × 10 −8 mol / m · s · Pa. It was as low as 0.5 .

さらに、比較例であるPd−3at%Ag−16at%Gd合金膜(試料番号8)は、熱処理前の水素透過係数が5.2×10-8mol/m・s・Pa0.5と当初から低かった上、800℃で10時間の熱処理を施すと、結晶構造に変化があり、第二相の析出が観察された。熱処理後の水素透過係数は4.8×10-8mol/m・s・Pa0.5と更に低下した。 Furthermore, the Pd-3at% Ag-16at% Gd alloy film (sample number 8), which is a comparative example, has a hydrogen permeability coefficient before heat treatment of 5.2 × 10 −8 mol / m · s · Pa 0.5, which is low from the beginning. In addition, when heat treatment was performed at 800 ° C. for 10 hours, the crystal structure was changed, and precipitation of the second phase was observed. The hydrogen permeation coefficient after the heat treatment further decreased to 4.8 × 10 −8 mol / m · s · Pa 0.5 .

また、比較例であるPd−24at%Ag合金膜(試料番号9)は、熱処理前の水素透過係数が2.6×10-8mol/m・s・Pa0.5と著しく低かった。800℃で10時間の熱処理を施しても、結晶構造に変化がなく、第二相は観察されなかったものの、熱処理後の水素透過係数は2.4×10-8mol/m・s・Pa0.5と著しく低いものであった。 Further, the Pd-24 at% Ag alloy film (Sample No. 9), which is a comparative example, had a remarkably low hydrogen permeation coefficient before heat treatment of 2.6 × 10 −8 mol / m · s · Pa 0.5 . Even when heat treatment was performed at 800 ° C. for 10 hours, the crystal structure was not changed and the second phase was not observed, but the hydrogen permeability coefficient after the heat treatment was 2.4 × 10 −8 mol / m · s · Pa. It was extremely low at 0.5 .

このように、比較例である試料番号5〜9のPd合金は、熱処理後の水素透過係数が最高でも5.0×10-8mol/m・s・Pa0.5であったのに対し、実施例の試料番号1〜3のPd合金は、熱安定性に優れ、熱処理後の水素透過係数は最低でも5.6×10-8mol/m・s・Pa0.5あった。よって、実施例のPd合金は、比較例のPd合金に比べ、水素透過係数を12%以上も飛躍的に向上させることができた。 Thus, the Pd alloys of Sample Nos. 5 to 9, which are comparative examples, had a hydrogen permeation coefficient after heat treatment of 5.0 × 10 −8 mol / m · s · Pa 0.5 at most, while The Pd alloys of sample numbers 1 to 3 in the example were excellent in thermal stability, and the hydrogen permeability coefficient after heat treatment was at least 5.6 × 10 −8 mol / m · s · Pa 0.5 . Therefore, the Pd alloy of the example was able to dramatically improve the hydrogen permeation coefficient by 12% or more compared to the Pd alloy of the comparative example.

(Pd−Ag−Y合金膜の作製および評価)
実施例1と同様の手順にて、Pd−3at%Ag−14at%Y合金膜を作製し(試料番号4)、水素透過性能評価および結晶構造の熱安定性評価を行った。また、比較例として同様にPd−3at%Ag−6at%Y合金膜(試料番号10)およびPd−3at%Ag−16at%Y合金膜(試料番号11)を作製し、各評価を行った。これらの結果を表1に併記した。
(Preparation and evaluation of Pd—Ag—Y alloy film)
A Pd-3 at% Ag-14 at% Y alloy film was prepared in the same procedure as in Example 1 (Sample No. 4), and the hydrogen permeation performance evaluation and the thermal stability evaluation of the crystal structure were performed. Further, as a comparative example, a Pd-3at% Ag-6at% Y alloy film (sample number 10) and a Pd-3at% Ag-16at% Y alloy film (sample number 11) were similarly produced and evaluated. These results are also shown in Table 1.

表1に示すように、添加元素としてGdに代えてYを用いても、Gdと同様の結果を示した。具体的には、実施例であるPd−3at%Ag−14at%Y合金膜(試料番号4)は、水素透過係数が熱処理前で5.7×10-8mol/m・s・Pa0.5、800℃10時間の熱処理後で5.4×10-8mol/m・s・Pa0.5あり、熱処理による結晶構造の変化はみられず、熱処理後も高い水素透過係数を維持した。 As shown in Table 1, even when Y was used instead of Gd as an additive element, the same results as Gd were obtained. Specifically, the Pd-3at% Ag-14at% Y alloy film (sample number 4) as an example has a hydrogen permeability coefficient of 5.7 × 10 −8 mol / m · s · Pa 0.5 before heat treatment, After the heat treatment at 800 ° C. for 10 hours, there was 5.4 × 10 −8 mol / m · s · Pa 0.5 , the crystal structure was not changed by the heat treatment, and a high hydrogen permeability coefficient was maintained even after the heat treatment.

一方、比較例であるPd−3at%Ag−6at%Y合金膜(試料番号10)は、熱処理前の水素透過係数が5.1×10-8mol/m・s・Pa0.5と当初から低く、熱処理による結晶構造の変化はなかったものの、熱処理後の水素透過係数は4.8×10-8mol/m・s・Pa0.5と低いものであった。また、比較例であるPd−3at%Ag−16at%Y合金膜(試料番号11)は、熱処理前の水素透過係数が5.4×10-8mol/m・s・Pa0.5と当初から低かった上、熱処理を施すと結晶構造に変化があり、熱処理後の水素透過係数は5.1×10-8mol/m・s・Pa0.5に低下した。 On the other hand, the Pd-3 at% Ag-6 at% Y alloy film (sample number 10), which is a comparative example, has a hydrogen permeability coefficient before heat treatment of 5.1 × 10 −8 mol / m · s · Pa 0.5, which is low from the beginning. Although the crystal structure was not changed by the heat treatment, the hydrogen permeation coefficient after the heat treatment was as low as 4.8 × 10 −8 mol / m · s · Pa 0.5 . In addition, the Pd-3 at% Ag-16 at% Y alloy film (sample No. 11), which is a comparative example, has a hydrogen permeability coefficient before heat treatment of 5.4 × 10 −8 mol / m · s · Pa 0.5, which is low from the beginning. Moreover, when the heat treatment was performed, the crystal structure was changed, and the hydrogen permeation coefficient after the heat treatment was reduced to 5.1 × 10 −8 mol / m · s · Pa 0.5 .

(表層材を被覆した水素分離膜の作製)
芯材として、Pd−4at%Ag−12at%Y合金およびPd−4at%Ag−12at%Gd合金の各インゴットをアーク溶解で作製し、冷間で厚さを1.8mmまで圧延して合金膜を作製した。また、表層材として、Pd−24at%Ag合金を同様に溶解し、冷間で厚さを0.2mmまで圧延して合金膜を作製した。芯材の合金膜の一方の表面に、表層材の合金膜を重ねて、これを500℃、1時間の加熱処理で接合した。そして、全厚20μmになるように冷間で圧延を行い、2層構造の水素分離膜を得た(試料番号21、22)。
(Production of hydrogen separation membrane covered with surface material)
As the core material, each ingot of Pd-4 at% Ag-12 at% Y alloy and Pd-4 at% Ag-12 at% Gd alloy is produced by arc melting, and the alloy film is rolled by cold to 1.8 mm. Was made. Further, as a surface layer material, a Pd-24 at% Ag alloy was similarly melted and rolled to a thickness of 0.2 mm in a cold state to produce an alloy film. The alloy film of the surface layer material was stacked on one surface of the alloy film of the core material, and this was joined by heat treatment at 500 ° C. for 1 hour. And it cold-rolled so that it might become the total thickness of 20 micrometers, and obtained the hydrogen separation membrane of 2 layer structure (sample number 21, 22).

芯材の厚さを1.6mmにした点と、表層材の厚さを0.2mmにした点と、芯材の両方の表面に表層材を重ねた点を除き、上記と同様の手順で3層構造の水素分離膜を得た(試料番号23、24)。また、この積層膜の効果を比較するために、Pd−4at%Ag−12at%Y合金、Pd−4at%Ag−12at%Gd合金およびPd−24at%Ag合金を溶解し、冷間で厚さを20μmまで圧延して、1層構造の水素分離膜を得た(試料番号25〜27)。   Except for the point where the thickness of the core material was 1.6 mm, the point where the thickness of the surface layer material was 0.2 mm, and the point where the surface layer material was overlapped on both surfaces of the core material, the same procedure as above was used. A hydrogen separation membrane having a three-layer structure was obtained (sample numbers 23 and 24). In addition, in order to compare the effects of this laminated film, a Pd-4 at% Ag-12 at% Y alloy, a Pd-4 at% Ag-12 at% Gd alloy, and a Pd-24 at% Ag alloy were melted, and the thickness was reduced. Was rolled to 20 μm to obtain a hydrogen separation membrane having a single layer structure (sample numbers 25 to 27).

(水素透過性能評価)
上記の各水素分離膜について、実施例1と同様の手順により水素透過性能評価を行った。その結果を表2に示す。
(Hydrogen permeation performance evaluation)
Each hydrogen separation membrane was evaluated for hydrogen permeation performance by the same procedure as in Example 1. The results are shown in Table 2.

(耐酸化性評価)
また、上記の各水素分離膜について耐酸化性評価を行った。0.1%の酸素を含有する窒素ガス雰囲気中で、水素分離膜を500℃、100時間にわたり加熱処理した後、180°曲げ試験を行って、脆化の有無を判定した。その結果を表2に示す。なお、表中、脆化がなかった場合は耐酸化性が良好として○印を記し、脆化が認められた場合は耐酸化性が劣るとして△印を記した。
(Oxidation resistance evaluation)
Moreover, oxidation resistance evaluation was performed about each said hydrogen separation membrane. The hydrogen separation membrane was heated at 500 ° C. for 100 hours in a nitrogen gas atmosphere containing 0.1% oxygen and then subjected to a 180 ° bending test to determine the presence or absence of embrittlement. The results are shown in Table 2. In the table, when there was no embrittlement, the symbol “◯” was marked as good oxidation resistance, and when embrittlement was observed, the symbol “と し て” was marked as inferior oxidation resistance.

Figure 2006346608
Figure 2006346608

表2に示すように、1層構造であるPd−4at%Ag−12at%Y合金膜またはPd−4at%Ag−12at%Gd合金膜からなる水素分離膜(試料番号25、26)は、水素透過係数が6.0×10-8mol/m・s・Pa0.5以上あり、優れた水素透過性能を示したが、脆化が生じた。また、1層構造であるPd−24at%Ag合金膜からなる水素分離膜(試料番号27)は、脆化がなく耐酸化性に優れていたが、水素透過係数は2.6×10-8mol/m・s・Pa0.5と非常に低かった。 As shown in Table 2, a hydrogen separation membrane (sample numbers 25 and 26) made of a Pd-4at% Ag-12at% Y alloy film or a Pd-4at% Ag-12at% Gd alloy film having a single layer structure is hydrogen. The permeability coefficient was 6.0 × 10 −8 mol / m · s · Pa 0.5 or more, indicating excellent hydrogen permeation performance, but embrittlement occurred. In addition, the hydrogen separation membrane (sample No. 27) made of a Pd-24 at% Ag alloy membrane having a single layer structure was not brittle and excellent in oxidation resistance, but the hydrogen permeability coefficient was 2.6 × 10 −8. mol / m · s · Pa 0.5 was very low.

一方、複数層構造である試料番号21〜24の各水素分離膜は、耐酸化性に優れたPd−24at%Ag合金膜を表層材として被覆したので、脆化の発生を防ぐことができた。また、水素分離膜の水素透過係数は、2層構造で5.2×10-8〜5.4×10-8mol/m・s・Pa0.5、3層構造で4.9×10-8〜5.1×10-8mol/m・s・Pa0.5と、表層材のみからなる1層構造の水素分離膜(試料番号27)と比べて約2倍も高かった。なお、芯材のみからなる1層構造の水素分離膜(試料番号25、26)と比べると10〜20%程度低いが、長時間使用しても表層材のために酸化層の形成が防止され、水素透過係数の低下は抑えられる。よって、長時間使用する場合は、芯材のみの試料番号25、26よりも表層材を被覆した試料番号21〜24の方が水素透過性能に優れている。 On the other hand, each of the hydrogen separation membranes of Sample Nos. 21 to 24 having a multi-layer structure was covered with a Pd-24 at% Ag alloy membrane excellent in oxidation resistance as a surface layer material, and thus it was possible to prevent the occurrence of embrittlement. . The hydrogen permeation coefficient of the hydrogen separation membrane is 5.2 × 10 −8 to 5.4 × 10 −8 mol / m · s · Pa 0.5 in the two-layer structure, and 4.9 × 10 −8 in the three-layer structure. ˜5.1 × 10 −8 mol / m · s · Pa 0.5 , which is about twice as high as that of the hydrogen separation membrane (sample number 27) having a single-layer structure made of only the surface layer material. Although it is about 10 to 20% lower than the hydrogen separation membrane (sample numbers 25 and 26) having a single layer structure consisting only of the core material, the formation of an oxide layer is prevented due to the surface layer material even when used for a long time. In addition, a decrease in the hydrogen permeability coefficient can be suppressed. Therefore, when using for a long time, the sample numbers 21-24 which coat | covered the surface layer material are more excellent in the hydrogen permeation performance than the sample numbers 25 and 26 of only a core material.

本発明に係るPd−Ag−YまたはPd−Ag−Gd合金の組成範囲を示すグラフである。It is a graph which shows the composition range of the Pd-Ag-Y or Pd-Ag-Gd alloy which concerns on this invention. 本発明に係る水素分離膜の一例を模式的に示す断面図である。It is sectional drawing which shows typically an example of the hydrogen separation membrane which concerns on this invention. 本発明に係る水素分離膜の別の一例を模式的に示す断面図である。It is sectional drawing which shows typically another example of the hydrogen separation membrane which concerns on this invention. 本発明に係る水素分離膜モジュールの一例を模式的に示す組立図である。It is an assembly figure showing typically an example of a hydrogen separation membrane module concerning the present invention.

符号の説明Explanation of symbols

20 水素分離膜
22 芯材
24 表層材
30 金属多孔板
40 支持板
42 溝
20 Hydrogen separation membrane 22 Core material 24 Surface layer material 30 Metal porous plate 40 Support plate 42 Groove

Claims (4)

YまたはGdの含有量をxat%、Agの含有量をyat%として、x≦15、0.1≦y≦5、かつ3x+y>36の条件を満たす範囲でYまたはGdとAgとを含有し、残部がPdおよび不可避不純物からなる合金を含む水素分離膜。   Y or Gd and Ag are contained within a range satisfying the conditions of x ≦ 15, 0.1 ≦ y ≦ 5, and 3x + y> 36, where the content of Y or Gd is xat% and the content of Ag is yat%. A hydrogen separation membrane containing an alloy whose balance is made of Pd and inevitable impurities. 12〜14at%のYまたはGdと、0.3〜4at%のAgとを含有し、残部がPdおよび不可避不純物からなる合金を含む水素分離膜。   A hydrogen separation membrane comprising an alloy containing 12 to 14 at% Y or Gd and 0.3 to 4 at% Ag, the balance being Pd and inevitable impurities. 前記Pd−Ag−YまたはPd−Ag−Gd合金を芯材として、この少なくとも一方の表面に、表層材としてPdまたはPd−Ag合金が被覆されている請求項1または2に記載の水素分離膜。   The hydrogen separation membrane according to claim 1 or 2, wherein the Pd-Ag-Y or Pd-Ag-Gd alloy is used as a core material, and at least one surface thereof is coated with Pd or Pd-Ag alloy as a surface layer material. . 請求項1〜3のいずれか一項に記載の水素分離膜の一方の表面に、金属多孔板が貼り付けられており、この金属多孔板の反対側の表面に、支持板が貼り付けられている水素分離膜モジュール。   A metal porous plate is attached to one surface of the hydrogen separation membrane according to any one of claims 1 to 3, and a support plate is attached to the opposite surface of the metal porous plate. Hydrogen separation membrane module.
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Cited By (2)

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KR101772171B1 (en) * 2015-01-29 2017-09-12 한국교통대학교 산학협력단 MANUFACTURING METHOD OF Bzy-Pd-Ag COMPOSITES MEMBRANE
CN112281016A (en) * 2020-09-30 2021-01-29 武汉船用电力推进装置研究所(中国船舶重工集团公司第七一二研究所) Palladium alloy for hydrogen permeation and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101772171B1 (en) * 2015-01-29 2017-09-12 한국교통대학교 산학협력단 MANUFACTURING METHOD OF Bzy-Pd-Ag COMPOSITES MEMBRANE
CN112281016A (en) * 2020-09-30 2021-01-29 武汉船用电力推进装置研究所(中国船舶重工集团公司第七一二研究所) Palladium alloy for hydrogen permeation and preparation method thereof

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