JP5594017B2 - Hydrogen separation method and apparatus - Google Patents

Description

  The present invention relates to a hydrogen separation method and apparatus using a hydrogen separation membrane, and more particularly to a hydrogen separation method and apparatus using a hydrogen separation membrane made of a V (vanadium) alloy.

  There is a Pd-based alloy membrane as a hydrogen separation membrane that selectively permeates and separates hydrogen from a hydrogen-containing gas. However, in the case of a hydrogen separation membrane of a Pd-based alloy, even when rare earth elements having a large performance improvement effect such as Y and Gd are added, the hydrogen separation performance is improved only 2 to 3 times, and Pd itself is a noble metal. There is a disadvantage of high costs.

  As a substitute for the Pd-based alloy film, a film made of Nb, V or an alloy thereof is known. Group 5A metals such as Nb and V have high hydrogen permeability and are inexpensive compared to Pd-based hydrogen-permeable alloys. Since this Nb, V or an alloy thereof is susceptible to hydrogen embrittlement due to its high hydrogen solid solution amount, various studies have been made on hydrogen separation membranes capable of achieving both high hydrogen permeation rate and hydrogen embrittlement resistance. .

  Japanese Patent Application Laid-Open No. 2006-722 describes a hydrogen separation membrane composed of at least one of Nb, Ta and V and Cu of 40 to 60 at%. In Example 5, the hydrogen separation membrane is composed of V-54 at% Cu. A hydrogen separation membrane having a membrane body having a thickness of 2 μm and a Pd layer having a thickness of 0.05 μm formed on the surface of the membrane body and having a permeated hydrogen flow rate of 3.5 sccm is described (paragraph 0046). Table 1).

  In JP-A-2008-55295, Cr, Fe, Ni or Co is added to V, and if necessary, Al, Sc, Ti, Y, Zr, Nb, Mo, Ta, La, Ce, Pr, Nd , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or a hydrogen separation membrane made of a V alloy to which Lu is added is described. In FIG. 2 of the publication, it is described that 6 to 25 at% of Al, Sc, Ti, Cr, Fe, Co, Ni, Y, Zr, Nb, Mo, or Ta is added.

  However, this publication does not describe any hydrogen permeation characteristics of this alloy film.

  Japanese Patent Application Laid-Open No. 2006-35063 and Japanese Patent Application Laid-Open No. 2007-44593 describe a hydrogen separation membrane made of a V alloy, but do not describe a specific alloy composition.

JP 2006-722 JP 2008-55295 A JP 2006-35063 A JP2007-44593

  The present invention uses a hydrogen separation membrane having a high hydrogen permeation rate and excellent hydrogen embrittlement resistance, and a hydrogen separation method and apparatus capable of separating hydrogen from a hydrogen-containing gas having a hydrogen partial pressure of atmospheric pressure or higher The purpose is to provide.

The hydrogen separation membrane apparatus of the present invention (Claim 1) is a hydrogen separation apparatus that supplies a hydrogen-containing gas to a primary chamber and extracts hydrogen that has permeated through the hydrogen separation membrane from the secondary chamber. made of V alloys containing Mo, the V alloy W 0.1 to 15 mol%, Mo0.1～15 mol%, and is characterized in that it consists of the balance V.

The hydrogen separation method of the present invention (Claim 2 ) uses the hydrogen separator according to Claim 1 to separate hydrogen from a hydrogen-containing gas at a temperature of 400 to 550 ° C.

According to a third aspect of the present invention, the hydrogen separation method according to the second aspect is characterized in that a hydrogen-containing gas having a hydrogen partial pressure of 1 atm or more is supplied to the primary chamber.

According to a fourth aspect of the present invention, the hydrogen separation method according to the third aspect is characterized in that the secondary chamber is depressurized to less than 1 atm.

  The hydrogen separation membrane used in the hydrogen separation method and apparatus of the present invention has a high hydrogen permeation rate and excellent resistance to hydrogen embrittlement. In the method and apparatus of the present invention, hydrogen can be separated with high efficiency by supplying a hydrogen-containing gas having a hydrogen partial pressure of 1 atm or more to the primary chamber. The hydrogen separation membrane used in the present invention is made of a non-Pd-based alloy and has a low material cost, so that the hydrogen separation cost can be reduced.

It is a graph which shows the PCT curve of a VW-Mo type | system | group hydrogen separation membrane. It is a graph which shows the PCT curve of a VW type | system | group hydrogen separation membrane. It is sectional drawing of the module for hydrogen permeation tests. It is sectional drawing which shows the form which set the module for hydrogen permeation tests to the electric furnace. It is sectional drawing of a small punch test apparatus. FIG. 6 is an enlarged view of a part of FIG. 5. It is a graph which shows a small punch test result. It is a flowchart of a hydrogen separator.

  The hydrogen separation membrane used in the present invention is made of a V alloy containing W and Mo, preferably W 30 mol% or less, particularly 0.1 to 30 mol%, particularly 0.1 to 15 mol%, Mo 30 mol%. In particular, it is composed of 0.1 to 30 mol%, particularly 0.1 to 15 mol%, and the balance V.

  As described above, a hydrogen separation membrane made of V has a higher hydrogen permeation rate than a widely used hydrogen separation membrane made of Pd or a Pd alloy, but has a low hydrogen embrittlement resistance. By adding W and Mo to V, hydrogen embrittlement resistance is improved while maintaining a high hydrogen permeation rate.

  The hydrogen separation membrane used in the present invention is obtained by melting an alloy having the above composition, and can be produced by rolling it to a thickness of preferably 1 to 500 μm, particularly preferably 10 to 50 μm. In addition, you may employ | adopt means other than rolling. In addition, the hydrogen separation membrane of the present invention may be formed on the surface of the air-permeable support material by a film formation method such as sputtering, CVD, or plating to a thickness of 1 to 500 μm, particularly about 1 to 20 μm. .

  Since V and V alloy itself do not have catalytic activity for hydrogen molecule detachment and bonding reaction, a surface catalyst layer made of Pd or Pd alloy (both on the process side and on the permeate side) is made of Pd or Pd alloy. It is necessary to form a coating metal layer. As the covering metal layer, pure Pd or Pd alloy is suitable. As the Pd alloy, an alloy containing at least one of Ag, Cu, and Au in an amount of 50 wt% or less, for example, about 20 to 40 wt% is preferable. In particular, Pd—Ag having an Ag content of 30 wt% or less (particularly 10 to 30 wt%). An alloy or pure Pd is preferred. The thickness of the coating metal layer is preferably about 0.01 to 3 μm, particularly about 0.1 to 1 μm. This covering metal layer can be formed by sputtering, CVD, a cladding method, or the like.

  In the hydrogen separation membrane having such a coating metal layer, mutual diffusion between the base metal layer made of the V alloy and the coating metal layer, and alloy components of the base metal layer by oxygen permeating the coating metal layer ( Hereinafter, the oxidation of the parent alloy component)) reduces the hydrogen permeation performance and durability of the hydrogen separation membrane. It is also conceivable that the base alloy component or its oxide diffuses in the coated metal layer and reaches the surface, thereby inhibiting the dissociation of hydrogen molecules and the binding reaction. For this reason, an intermediate layer for preventing mutual diffusion of metals and preventing diffusion of oxygen may be provided between the base metal layer and the covering metal layer.

  As a hydrogen production apparatus equipped with a hydrogen separation membrane, the hydrogen separation membrane is installed in a container called a housing, casing, vessel or the like, and has a primary chamber and a secondary chamber separated by a hydrogen separation membrane. The structure is not particularly limited as long as it further has heating means as required. The form of the film may be any form such as a flat film type and a cylindrical type. The hydrogen separation membrane may be superimposed on a porous support or a support plate having a groove on the surface, or may be formed on the surface of the porous body. As a porous body, any of a metal material, a ceramic material, etc. may be sufficient.

  Examples of the configuration of a hydrogen production apparatus that can be employed in the present invention are shown in FIGS. 8 (a), (b), and (c), but the present invention apparatus is not limited to these.

  In FIG. 8A, a raw material gas such as hydrocarbon is compressed by the compressor 61 and supplied to the hydrogen separation reformer 62. The hydrogen separation type reformer 62 includes a hydrogen reforming catalyst and a hydrogen separation membrane. Steam is supplied from the boiler 64 to the hydrogen separation type reformer 62 and heat is given by the combustor 63 to perform reforming and hydrogen separation. Hydrogen from the hydrogen separation reformer 62 is taken out via a heat exchanger 65. The off-gas is recovered by the heat exchanger 66 and then supplied to the combustor 63 via the pressure regulating valve 69. Heat is also recovered by the heat exchangers 67 and 68 from the combustion exhaust gas of the combustor 63 and the boiler 64, respectively. Heat supplied to the boiler 64, combustion air, fuel, and the like is performed by the heat recovered by the heat exchangers 65-68.

  In FIG. 8B, a hydrogen-containing gas containing hydrogen gas is supplied to the hydrogen separator 71, and the hydrogen separator 71 is heated by the combustor 72. The separated hydrogen is taken out via the heat exchanger 73. The off-gas is taken out through the heat exchanger 74, and a part or all of the off-gas is supplied to the combustor 72 through the pressure regulating valve 76 as necessary. The heat of the combustion exhaust gas is recovered by the heat exchanger 75. The fuel gas and air to the combustor 72 are heated by the recovered heat.

  Although the combustor 72 is used in FIG. 8 (b), when there is a heat source that generates high-temperature waste heat, this high-temperature waste heat is guided to the heater 77 as shown in FIG. 8 (c). The hydrogen separator 71 may be heated.

  The source gas (hydrogen-containing gas) supplied to the primary chamber of the hydrogen production apparatus of the present invention may be any gas that contains hydrogen, including hydrocarbon steam reformed gas, fuel cell fuel off-gas, and hydrogen. Examples include biogas and gas generated from a biomass gasification furnace, but are not limited thereto.

  The operating temperature of the device (specifically, the gas temperature on the primary side) is usually about 300 to 600 ° C., particularly about 400 to 550 ° C., although it depends on the composition of the film.

  In the present invention, as confirmed in the examples described later, the raw material gas is 1 so that the hydrogen partial pressure in the primary chamber is 1 atm or more, for example, 1 to 6 atm at 500 ° C. and 1 to 3 atm at 450 ° C. Hydrogen can be separated with high efficiency by supplying it to the next chamber. The pressure in the secondary chamber is preferably 1 atm or less, particularly 0.1 atm or less.

  Hereinafter, examples and comparative examples will be described.

[Example 1]
An ingot was obtained from a molten alloy having a composition of V90 mol%, W5 mol% and Mo5 mol%, and this was rolled to produce a V-5W-5Mo hydrogen separation membrane having a thickness of 500 μm and a diameter of 12 mm.
Subsequently, a coating metal layer made of Pd and having a thickness of 200 nm was formed on both surfaces by sputtering to form a hydrogen separation membrane. This hydrogen separation membrane was set in the test module 41 shown in FIG. 3, and the hydrogen permeation rate was measured.

  In this hydrogen permeation test module 41, a hydrogen separation membrane 44 is disposed between the rear end face of the gas introduction pipe 42 and the front end face of the gas extraction pipe 46 via gaskets 43 and 45. A nut 47 is fitted on the introduction pipe 42, and a cap nut 48 is engaged with a flange portion 46 a at the tip of the extraction pipe 46.

  The cap nut 48 is extended to the introduction tube 42 side, and the male screw on the outer peripheral surface of the nut 47 is screwed into the female screw on the inner peripheral surface. The leading end of the nut 47 abuts on the flange portion 42 a at the rear end of the introduction pipe 42, whereby the extraction pipe 46 is attracted to the introduction pipe 42 via the cap nut 48, and the rear end surface of the introduction pipe 42 and the extraction pipe 46 are connected. A hydrogen separation membrane 44 is sandwiched between the front end surface via gaskets 43 and 45.

  The gaskets 43 and 45 have an annular shape of the same size, and the area of the inner hole is the membrane permeation area A of the hydrogen separation membrane 44. The cap nut 48 is provided with a small hole 48a for a gas leak test.

Although the inner hole of the gasket is 5.6 mm, the diameter of the contact portion between the gasket and the membrane sample when tightened with a VCR is 7.1 mm, and the effective membrane permeation area A is 39.6 mm ² (3.96). × 10 ⁻⁵ m ² ).

  This hydrogen permeation test module 41 is installed in the electric furnace 50 as shown in FIG. 4, the raw material gas is supplied to the introduction pipe 42, and the hydrogen gas is taken out from the extraction pipe 46.

The gas pressure _{P 1} of the introduction tube 42 and 0.6MPa or 0.3 MPa, the gas pressure _{P 2} of the take-out pipe 46 was 0.01MPa or 0.1 MPa.

  As the source gas, high purity hydrogen having a purity of 99.99999% or more was used. The hydrogen gas that permeated the hydrogen separation membrane 44 was recovered in a recovery container (not shown).

The electric furnace 50 was operated at a temperature of 500 ° C. Table 1 shows the product J · d of the hydrogen permeation rate J and the thickness d. Here, the J · d value is the number of moles of hydrogen atoms that permeate the film of 1 m ² (unit area) × 1 m (unit thickness) in 1 second (unit time).

  As will be described later, when a strength test for hydrogen embrittlement evaluation was performed on a pure V film which is a base material of this VW-Mo alloy, the amount of dissolved hydrogen H / M (metal atom 1 of the alloy element) It was confirmed that the number of hydrogen atoms dissolved per unit) was ductile (or tough) up to 0.22.

[Comparative Example 1]
The hydrogen permeation rate was measured in the same manner as in Example 1 except that the hydrogen separation membrane was a V-5W alloy membrane having the composition shown in Table 1. The results (J · d value) are shown in Table 1.

[Comparative Example 2]
The hydrogen permeation rate was measured in the same manner as in Example 1 except that the hydrogen separation membrane was a Pd-26Ag membrane, and P ₁ = 0.26 MPa and P ₂ = 0.06 MPa. As a result, the J · d value was 11 × 10 ⁻⁶ molH · m ⁻¹ · s ⁻¹ .

[Measurement of PCT characteristics]
PCT curves were obtained for a hydrogen separation membrane made of a V-5W-5Mo alloy, a hydrogen separation membrane made of a V-5W alloy membrane, and a hydrogen separation membrane made of pure V metal.

That is, when the temperature T is 673 K (400 ° C.), 723 K (450 ° C.) or 773 K (500 ° C.) and the hydrogen gas pressure is variously changed between 10 ⁻³ MPa to 6 MPa, the above alloy or pure V metal The hydrogen solid solution amount (hydrogen storage amount) C was measured with a PCT measuring device. Note that pure V was measured only at T = 673K. The results are shown in FIGS.

  Here, the PCT measurement device is in accordance with JIS H 7201 (2007), and measures characteristics (pressure P, hydrogen storage amount C) when a substance absorbs and releases hydrogen at a certain temperature T. It is. The solid solution hydrogen amount C in FIGS. 1 and 2 corresponds to the hydrogen storage amount C.

  The unit H / M of the hydrogen solid solution amount indicates the number of solid solution (occlusion) hydrogen atoms per metal atom.

[Measurement of hydrogen embrittlement resistance]
In order to ascertain the hydrogen embrittlement resistance of the hydrogen separation membrane, the premise is that in the operating temperature range of the hydrogen separation membrane, in a hydrogen atmosphere where the primary and secondary sides have the same hydrogen pressure, It is necessary to have a test device that can measure and evaluate the mechanical properties such as hydrogen embrittlement of the hydrogen separation membrane quantitatively on the spot during permeation, that is, in a hydrogen atmosphere where the primary hydrogen pressure is greater than the secondary hydrogen pressure. is there.

  Accordingly, the present inventors have developed a small punch test apparatus shown in FIGS. 5 and 6 that can measure the mechanical properties such as hydrogen embrittlement of the hydrogen permeable alloy film on the spot, and use the small punch test apparatus. The hydrogen embrittlement and other characteristics of the hydrogen separation membrane were quantitatively measured and evaluated.

  By using this small punch test apparatus, a material such as pure V, which is the base material of the VW-Mo alloy, has a corresponding PCT (pressure-solid hydrogen content-temperature) curve in its operating temperature range. Based on the relationship between the amount of dissolved hydrogen based on the deformation and the form of fracture, the critical amount of dissolved hydrogen can be evaluated for hydrogen embrittlement resistance.

  The structure of the small punch test apparatus and its operating method will be described with reference to FIGS. FIGS. 5 and 6 are views for explaining the structure of the small punch test apparatus, FIG. 5 is a longitudinal sectional view, and FIG. 6 is an enlarged view of the core portion in FIG. The small punch test apparatus is generally cylindrical.

  In FIG. 5, reference numeral 1 denotes a support member. Although it can be said that the support member 1 is a support base, it is referred to as a support member in this specification. The support member 1 is configured to have a two-stage convex shape (having two flanges) in the longitudinal section, and has a cylindrical gap at the center thereof. 2 is an introduction hydrogen storage section provided in the support member 1, 3 is a conduit communicating from the introduction hydrogen storage section 2 to a primary hydrogen atmosphere Y described later, 5 is a lead hydrogen storage section provided in the support member 1, and 4 is a secondary storage described later. This is a conduit communicating from the side hydrogen atmosphere Z to the derived hydrogen reservoir 5.

Introducing hydrogen reservoir 2 communicates with the conduit for supplying hydrogen to the introduction of hydrogen reservoir 2 comprises a valve V _1, deriving hydrogen reservoir 5 is hydrogen discharged from the outlet hydrogen reservoir 5 having the valve V ₂ Communicating with a conduit for use.

  The flange which fixes the lower end part of bellows 9 to the convex outer periphery of the 1st step (lower side in a figure) among the 2 steps | paragraphs of convex shape (it has two flanges) in the supporting member 1 A member (hereinafter abbreviated as a fixed member) 6 is disposed. The fixing member 6 is fixed to the flange of the support member 1 with bolts 7, and the gasket (copper) 8 is hermetically sealed between the fixing member 6 and the flange.

  Reference numeral 12 denotes an upper lid member which is placed at an upper position facing the support member 1 and can be moved up and down. The upper lid member 12 is configured to have an inverted convex shape (having two flanges) having a vertical section of two steps. A flange member 10 for fixing the upper end portion of the bellows 9 is disposed on the outer periphery of the first step (upward in the drawing) of the two steps of the reverse convex shape of the upper lid member 12. The fixing member 10 is fixed to the flange of the upper lid member 12 by bolts (not shown), and the gasket (copper) 11 is hermetically sealed between the fixing member 10 and the flange of the upper lid member 12.

  Reference numeral 13 denotes a sliding shaft (sliding shaft) for moving the upper lid member 12 up and down, and its lower end is fixed to the support member 1. A compression rod 16 is connected to the load cell and applies pressure from above. After setting the membrane sample 20 to be described later, the upper lid member 12 is moved downward via the sliding shaft 13 so that the puncher 24 is also moved downward to apply a predetermined load (pressing force) to the membrane sample 20 to be described later. Can do. Reference numeral 14 denotes a lock nut (cap nut) for preventing the upper lid member 12 from dropping off when the pressure in the closed space Y rises. The upper lid member 12 is moved downward along the sliding shaft 13 via the 15 slide bushes. I can move.

  A closed space Y surrounded by the support member 1, the fixing member 6, the gasket 8, the bellows 9, the fixing member 10, the upper lid member 12, the gasket 11, the introduction hydrogen reservoir 5, the upper surface of the membrane sample 20 described later, and the fixing member 21 described later. The hydrogen atmosphere Y on the primary side with respect to the membrane sample 20 described later becomes a secondary hydrogen atmosphere Z in the space surrounded by the lower surface of the membrane sample 20 described later, the conduit 4 and the derived hydrogen storage part 5.

<Hydrogen pressure load on membrane sample>
The amount of hydrogen supplied via the inlet hydrogen reservoir 2 and the conduit 3 is adjusted by the valve V ₁ to adjust the primary hydrogen pressure, and the amount of hydrogen derived via the conduit 4 and the outlet hydrogen reservoir 5 is controlled by the valve V _2. To adjust the hydrogen pressure in the secondary hydrogen atmosphere. Thereby, the hydrogen atmosphere of the primary side and the secondary side which will be described later can be controlled to the same hydrogen pressure or different hydrogen pressures.

<Applying load to membrane sample and measuring>
20 is a membrane sample, and 19 is a gasket (made of stainless steel) for supporting the membrane sample 20. 21 is a fixing member for the film sample 20, 24 is a puncher, 25 is a steel ball or a silicon nitride (Si ₃ N ₄ ) ball. The lower part of the fixing member 21 is formed in a reverse concave shape, and has four through-holes 22 extending from the lower end surface to the upper end surface. The reverse concave bottom surface maintains a space with the top surface of the membrane sample, and the through-hole 22 communicates with the hydrogen atmosphere Y.

A cylindrical gap vertically passing through the center of the fixing member 21 and four fine pores on the concentric circles. A puncher 24 is inserted into the cylindrical gap in the center of the fixing member 21 along the inner wall 23, and a sphere 25 made of steel or silicon nitride (Si ₃ N ₄ ) is placed in contact with the upper surface of the film sample 20. . By pressing down the sphere 25 with the puncher 24 and pressing the sphere 25 against the membrane sample 20, it is possible to observe the presence or absence of the shape change of the membrane sample corresponding to a predetermined load and the degree of the change when the shape change is present. it can. The predetermined load value is measured by the compression rod 16 connected to the load cell.

  A ceramic heater 17 is built in the vicinity of the cylindrical gap at the center of the support member 1, and a thermocouple 18 is inserted to the vicinity of the membrane sample 20. The temperature of the film sample is measured and controlled by the ceramic heater 17 and the thermocouple 18.

  This small punch test device can apply a hydrogen pressure of vacuum to 0.3 MPa to the sample, and can control the temperature in the range of room temperature to 600 ° C., and can perform a ductile-brittle transition under these conditions. It is possible to evaluate.

Using this small punch test apparatus, a pure V film was tested. The test piece was manufactured by melting a metal lump by the arc melting method, and then subjecting the metal lump to cutting and polishing, and the length and width were 10 mm and the thickness was 0.5 mm (volume: 10 mm × 10 mm × 0.00 mm). 5 mm = 50 mm ³ ).

About this test piece, at a temperature of 400 ° C., 450 ° C., or 500 ° C., 0.001 to 0.30 (1 × 10 ^{−3 to} 3 × 10 ^{− 1} ) After grasping the relationship between each hydrogen pressure P and solid solution hydrogen amount C [H / M (atomic ratio of hydrogen atom to metal atom, hereinafter the same kind of description is the same)] up to a range exceeding MPa. A small punch test was conducted and the "load-displacement" was measured and evaluated.

  The primary hydrogen atmosphere Y and the secondary hydrogen atmosphere Z were set to the same hydrogen pressure.

  Quantitative evaluation of hydrogen embrittlement by the small punch test was performed as in the following i) to iii).

i) About the test piece of this pure V film, the temperature and the hydrogen pressure were set to 500 ° C. and 0.01 MPa, and kept in this atmosphere for 1 hour, and then the test piece was made of steel balls or silicon nitride (Si ₃ N ₄ ). The test piece is deformed while applying a pressing force by the load of the sphere 25, and recording is continued until the test piece breaks the load at that time and the amount of movement of the crosshead (or the steel ball 25). create.

  ii) The amount of dissolved hydrogen in the test piece [H / M (H / M is the atomic ratio of hydrogen atom to metal atom)] is determined based on the PCT curve at the test temperature of 500 ° C. (≈773 K). Estimated from the hydrogen pressure applied in

iii) From the “load-displacement” curve, the small punch absorbed energy until the film sample was broken was determined. Here, the small punch absorbed energy corresponds (corresponds) to the amount of work required from the start of deformation of the test piece to destruction. The pressure by which the steel ball or the silicon nitride (Si ₃ N ₄ ) sphere 25 is pushed down by the puncher 24, that is, the load (MPa) is integrated with respect to the displacement (= the area under the load-displacement curve is calculated). Thus, the small punch absorbed energy is calculated.

  FIG. 7 shows the relationship between the SP absorbed energy at a temperature of 400 to 500 ° C. and the amount of dissolved hydrogen. The horizontal axis represents the amount of solid solution hydrogen C [H / M] in the pure V film, and the vertical axis represents the absorbed energy at the time of ductility or brittle fracture with respect to the solid solution hydrogen content of the pure V film sample.

  The solid solution amount of hydrogen with respect to a metal is represented by the number of hydrogen atoms in solid solution with respect to the number of metal atoms at a predetermined temperature. For example, the amount of dissolved hydrogen C (H / M) = 0.22 indicates that the number of hydrogen atoms in solid solution is 22 with respect to 100 atoms of metal.

  As shown in FIG. 7, the absorption energy of pure V greatly decreases as the amount of dissolved hydrogen increases with H / M = 0.22. That is, as the amount of dissolved hydrogen increases with H / M = 0.22 as a boundary, the fracture mode of the film shifts (transitions) from ductility to brittleness. From this, it was found that a pure V membrane can be used as a hydrogen separation membrane under the condition of H / M ≦ 0.22. Since it became clear that the ductile-brittle transition of V which is a base material is H / M ≦ 0.22, it is considered that V alloy can be used as a hydrogen separation membrane under the condition of H / M ≦ 0.22.

[Discussion]
A hydrogen separation membrane made of a V—W—Mo alloy has a higher hydrogen permeation rate than a Pd—Ag alloy membrane, a V—W membrane, and a pure V membrane.

As shown in Table 1 and FIG. 1, the hydrogen separation membrane made of the V—W—Mo alloy of the present invention has a performance higher than that of the V—W alloy alloy, and is a practical condition at 500 ° C. In gas, hydrogen partial pressure = 0.6 MPa (about 6 atm), 450 ° C. hydrogen partial pressure = 0.3 MPa (about 3 atm), 400 ° C. hydrogen partial pressure = 0.1 MPa (about 1 atm), Highly efficient hydrogen separation becomes possible. Further, the apparent hydrogen permeability φ at 500 ° C. is 2.3 × 10 ⁻⁸ [mol ⁻¹ m ⁻¹ s ^{− of} Pg-26Ag alloy when P ₁ / P ₂ = 0.6 MPa / 0.01 MPa. ¹ Pa ^−1/2 ], whereas the V—W—Mo alloy is 4.3 × 10 × 10 ⁻⁷ [mol ⁻¹ m ⁻¹ s ⁻¹ Pa ^−1/2 ]. If the separation membrane has the same area and the same thickness, the hydrogen permeation amount is 4.3 times higher under the same pressure condition.

  The hydrogen separation membrane of the present invention is an epoch-making separation membrane in which hydrogen embrittlement does not occur up to 0.6 MPa (about 6 atmospheres) at 500 ° C., and it is not necessary to depressurize the permeate side by power, and a sufficient hydrogen permeation amount Therefore, more efficient hydrogen production becomes possible.

  The hydrogen separation membrane comprising the V—W—Mo alloy of the present invention can be used at 0.1 to 0.3 MPa (about 1 to 3 atm) even at 400 to 450 ° C., and the hydrogen partial pressure is higher than atmospheric pressure. Hydrogen can be separated from a hydrogen-containing gas having hydrogen.

  Since the hydrogen separation membrane of the present invention is non-Pd-based, the material cost is extremely low.

DESCRIPTION OF SYMBOLS 1 Support member 2 Introduction hydrogen storage part provided in support member 1 3 Conduit communicating from hydrogen storage part 2 to primary side hydrogen atmosphere Y 4 Conduit communicating from secondary side hydrogen atmosphere Z to hydrogen storage part 5 5 Support member 1 Derived hydrogen storage portion 6 provided in 6 A flange member for fixing the lower end portion of the bellows 9 7 Bolt 8 Gasket 9 A bellows 10 A flange member for fixing the upper end portion of the bellows 9 11 Gasket 12 Placed at an upper position opposite to the support member 1 Upper lid member capable of moving up and down 13 Sliding shaft 14 Cap nut 15 Slide bush 16 Compression rod connected to load cell 17 Ceramic heater 18 Thermocouple 19 Support gasket for membrane sample 20 20 Membrane sample 21 Fixing member for membrane sample 20 22 Through-hole 23 Inner wall of the cylindrical gap in the center of the fixing member 21 24 Puncher 25 Steel or S i ₃ N ₄ sphere 26 convex portion of support member 1 module 41 for hydrogen permeation test 42 gas introduction pipe 43, 45 gasket 44 hydrogen separation membrane 46 gas extraction pipe 47 nut 48 cap nut 50 electric furnace 61 compressor 62 hydrogen separation Mold reformer 65-68, 73-75 heat exchanger

Claims (4)

In a hydrogen separation apparatus that supplies a hydrogen-containing gas to a primary chamber and extracts hydrogen that has permeated through the hydrogen separation membrane from the secondary chamber, the hydrogen separation membrane is made of a V alloy containing W and Mo, and the V alloy is A hydrogen separation membrane device comprising 0.1 to 15 mol %, Mo 0.1 to 15 mol %, and the balance V.   The hydrogen separation method which isolate | separates hydrogen from hydrogen containing gas at the temperature of 400-550 degreeC using the hydrogen separator of Claim 1.   3. The hydrogen separation method according to claim 2, wherein a hydrogen-containing gas having a hydrogen partial pressure of 1 atm or more is supplied to the primary chamber.   4. The hydrogen separation method according to claim 3, wherein the pressure in the secondary chamber is reduced to less than 1 atmosphere.

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