JP2014097443A - Hydrogen separation membrane, hydrogen separator, and organic hydride system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen separation membrane, which can be formed into a complicated shape by using a metal support easy to fabricate as a support for the hydrogen separation membrane and which is free from occurrence of damage due to hydrogen embrittlement even in the presence of a high-concentration organic solvent; a hydrogen separator; and an organic hydride system.SOLUTION: The hydrogen separation membrane comprises a stainless filter as a carrier, the surface of which is plated with palladium or a palladium-based palladium alloy. The membrane is constructed so that pores having an average diameter of 2 μm or smaller, preferably 0.4-0.6 μm in consideration of efficiency of Pd, are formed by compression-crushing meshes of the stainless filter made by weaving stainless wires.

Description

  The present invention relates to a hydrogen separation membrane, a hydrogen separator, and an organic hydride system for separating hydrogen gas.

  Various conventional hydrogen separation membranes using porous sintered metals such as ceramics as palladium or palladium alloy supports have been proposed (see, for example, Patent Documents 1 to 4).

Japanese Patent No. 4759664 JP 2006-346621 A JP 2010-119921 A JP 2011-206629 A

  However, since the hydrogen separation membranes of Patent Documents 1 to 4 described above use a porous sintered metal such as ceramics as a support (support) for the hydrogen separation membrane, it is difficult to process into a complicated shape. There was a problem of being. In particular, the application of hydrogen separation membranes to hydrogen automobiles and the like has been recently studied. However, when porous sintered metals such as ceramics are used as a support (support), the shape is complicated or small. There was a problem that it could not be processed.

  In addition, hydrogen separation membranes for plating palladium using a metallic filter such as a stainless steel filter as a support (support) in methane reforming have been widely studied, but simply incorporating a metallic wire such as stainless steel. The hydrogen separation membrane formed by electroless plating of palladium or palladium-based palladium alloy on the filter is hydrogenated by a liquid membrane formed in the vicinity of the hydrogen separation membrane against high-concentration organic solvents such as methylcyclohexane. It is easy to cause damage such as a decrease in permeation amount and so-called hydrogen embrittlement, and no reports of effective membranes have been found.

  Accordingly, the present invention has been made paying attention to such problems. First, a metal support (support) that is easy to process is used as a support (support) for the hydrogen separation membrane. The second object of the present invention is to provide a hydrogen separation membrane, a hydrogen separator, and an organic hydride system that can be processed into a complicated shape and do not cause damage due to hydrogen embrittlement even in the presence of a high concentration organic solvent.

In order to solve the above problems, the hydrogen separation membrane according to the present invention preferably has a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm as a carrier, considering the efficiency of Pd being 2 μm or less and Pd. The surface of the stainless steel filter is plated with palladium or a palladium alloy based on palladium.
Here, considering the efficiency of Pd of 2 μm or less, preferably a stainless steel filter having pores having an average diameter of 0.4 to 0.6 μm is compressed and crushed by a mesh of a stainless steel filter woven with a stainless steel wire. It is good to form by.
In addition, the hydrogen separator according to the present invention preferably has a porous portion in which a stainless filter having pores having an average diameter of 0.4 to 0.6 μm is formed in a pipe shape, in consideration of efficiency improvement of Pd of 2 μm or less and Pd, It is formed in the shape of a pipe so that hydrogen that has passed through the inside of the part passes, and it is composed of a non-porous part having no holes on its surface, and at least the surface of the porous part is plated with palladium or a palladium alloy based on palladium. A hydrogen separation membrane is formed by the above, hydrogen gas is separated by a hydrogen separation membrane on the surface of the porous portion in the reactor, passed through the porous portion and the nonporous portion, and hydrogen gas is passed from the other end where the nonporous portion is opened. It is characterized by discharging.
Here, the conditions in the reactor were such that the permeated hydrogen flux of the hydrogen separation membrane was 2.0 [m ³ / m ² · h · MPa] or less for a working pressure difference of 0.2 Mpa and a temperature range of 140 ° C. or higher. In the presence of a high concentration organic solvent such as methylcyclohexane, the hydrogen purity by the hydrogen separation membrane may be 99% or more.
In addition, the organic hydride system according to the present invention uses the above-described hydrogen separator to separate hydrogen gas from a mixed gas of hydrogen gas and an organic solvent gas such as high-concentration methylcyclohexane without causing hydrogen embrittlement. It is characterized by doing.

  According to the hydrogen separation membrane, the hydrogen separator, and the organic hydride system of the present invention, a stainless filter having pores with an average diameter of 0.4 to 0.6 μm is desirably used as the carrier, considering the efficiency of Pd of 2 μm or less and Pd. Since the surface of the stainless steel filter was plated with palladium or a palladium alloy based on palladium to form a hydrogen separation membrane, the hydrogen separation membrane could be a complex shape such as a straight pipe, a spiral pipe, or even a plate. It can be processed into a shape. In addition, considering the efficiency of Pd as a hydrogen separation membrane, 2 μm or less, preferably a palladium-copper alloy membrane is formed on the surface of a stainless steel filter having an average diameter of 0.4 to 0.6 μm. Damage due to hydrogen embrittlement can be prevented even in the presence of an organic solvent.

(A), (b) is the front view and perspective view which respectively show simple structures other than the reactor in the hydrogen separator of this Embodiment 1. FIG. It is a telegraph micrograph showing a mesh of a stainless steel filter woven with a stainless steel wire. It is a telegraph photomicrograph showing pores formed by crushing a mesh of a stainless steel filter woven with a stainless steel wire. It is a telegraph photomicrograph showing a state where the plating of the hydrogen separation membrane is peeled off at the welded portion between the porous portion and the nonporous portion. It is a figure which shows an example of the pre-processing performed prior to the hydrogen separation membrane to a stainless steel filter. It is a figure which shows the performance comparison result of the isolation | separation by the hydrogen separation membrane of the hydrogen separator of this embodiment, and another hydrogen separation method. It is a figure which shows the density | concentration of the hydrogen separated by the hydrogen separator of this embodiment, and the impurity contained in the hydrogen. It is a figure which shows the result of the nitrogen permeation test by the hydrogen separator of this embodiment. It is a figure which shows the result of the hydrogen permeation test by the hydrogen separator of this embodiment. (A), (b) is a figure which shows the result of the hydrogen embrittlement test by the hydrogen separator of this embodiment, respectively. It is a figure which shows the temperature which the palladium membrane in the presence of the high concentration organic solvent by the hydrogen separator of this embodiment damages (breaks). (A), (b) is a figure which shows the damage of the palladium-copper (Pd-Cu) alloy membrane formation in the presence of the high concentration organic solvent by the hydrogen separation membrane of the hydrogen separator 1 of this embodiment, respectively. It is a figure which shows the structure of the organic hydride system which concerns on this invention. (A), (b) is the top view and sectional drawing which show an example which provided four hydrogen separators in the reactor, respectively. (A), (b) is the expanded sectional view of A part in FIG.14 (b), respectively, and the expanded sectional view of B part. (A), (b) is the top view and sectional drawing which show an example of the hydrogen separator which accommodated the porous part comprised in the spiral in the reactor, respectively. (A)-(c) is the top view, front sectional drawing, and side view which show an example of the hydrogen separator which accommodated the porous part comprised in plate shape in the reactor, respectively.

  Hereinafter, embodiments of a hydrogen separation membrane, a hydrogen separator, and an organic hydride system according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1. FIG.
1A and 1B are diagrams showing a simplified structure other than the reactor in the hydrogen separator 1 of the first embodiment.

  As shown in FIGS. 1 (a) and 1 (b), this hydrogen separator 1 has a pipe-like shape in which a hydrogen separation membrane according to the present invention is formed on the outer peripheral surface by plating of palladium or palladium alloy based on palladium ( (Hollow) porous portion 11 and pipe-like (hollow) non-porous portion 12 similar to porous portion 11, and porous portion 11 is welded with a blind plug 13 at one end by Tig welding or the like, One end of the nonporous portion 12 is welded to the other end by Tig welding or the like, and the nonporous portion 12 is welded to the porous portion 11 by Tig welding or the like, while the other end is an open end. At least the porous part 11 and the blind plug 13 are accommodated in a reactor (not shown), and hydrogen gas and methylcyclohexane (MCH) are formed outside the porous part 11 on which the hydrogen separation membrane according to the present invention is formed. ) A mixed gas of organic solvent gas such as gas is injected, hydrogen gas is separated by a hydrogen separation membrane on the surface of the porous portion 11, passed through the porous portion 11 and the nonporous portion 12, and the nonporous portion 12 is opened. The other end is configured to discharge hydrogen gas.

  The porous part 11 is 2 μm or less, and considering the efficiency of Pd, preferably a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is used as a carrier, and the surface of the stainless steel filter is basically palladium or palladium. A palladium separation alloy is plated to form a hydrogen separation membrane.

  Here, considering the efficiency of Pd of 2 μm or less, preferably a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is, for example, a diameter of about 10 to 30 μm such as SUS304 as shown in FIG. By compressing and crushing the mesh of a stainless steel filter woven with a stainless steel wire, the pores with an average diameter of 0.4 to 0.6 μm are desirable considering the efficiency of Pd of 2 μm or less as shown in FIG. Is forming. This is because the porous portion 11 is woven with a stainless steel wire material such as US304 to give strength, but as shown in FIG. 2, the mesh is large at about 10 μm as shown in FIG. This is because even if a palladium alloy is plated, a hole is formed in the plating, and a hydrogen separation membrane cannot be formed.

  For this reason, the inventor repeatedly conducted experiments, applied pressure (external force) to the porous portion 11 made of a stainless steel filter woven with a stainless steel wire such as SUS304, and compressed and crushed so that the pore diameter was about 10 μm. In consideration of the efficiency of Pd, the mesh of the porous portion 11 is 2 μm or less, and preferably about 0.5 μm pores having an average diameter of 0.4 to 0.6 μm. The surface of the porous portion 11 is made of palladium or the like by electroless plating. It was confirmed that when a palladium alloy was plated, a hydrogen separation membrane having no pores was formed on the surface of the porous portion 11.

  Here, a stainless steel wire material such as SUS304 constituting a stainless steel filter which is a carrier (support) for the hydrogen separation membrane has characteristics that it has good corrosion resistance and is easy to process. Therefore, by processing a stainless steel filter woven with a stainless steel wire such as SUS304, not only the linear porous portion 11 (see FIG. 14) but also the spiral porous portion 11 (see FIG. 15), It can be easily processed into a complicated shape such as a plate-like porous portion 11 ′ (see FIG. 16). In consideration of the efficiency of Pd of 2 μm or less and Pd, it is desirable to make the hydrogen separation membrane uniform by electrolessly plating palladium or a palladium alloy on a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm. It is possible to plate the film thickness. In the present invention, the wire forming the stainless steel filter is not limited to the SUS304 wire, but may be other stainless steel such as SUS303 or SUS305.

The effective surface area for plating the porous part 11 with a hydrogen separation membrane of palladium or a palladium alloy has an outer diameter of 1/2 inch (1.27 cm) and a length of the porous part 11 of 100 mm (10 cm). ) If the length of the non-porous portion is 150 mm (15 cm),
Effective surface area = 2πr × length = 2 × 3.14 × 0.635 × 10 = 39 cm ²
It becomes.

  The non-porous portion 12 is made of a stainless pipe having no hole formed on the surface thereof, such as a pipe-shaped (hollow) SUS304 having both ends open, having the same diameter as the porous portion 11. The blind plug 13 is made of a solid stainless steel rod such as SUS304 having the same diameter as the porous portion 11.

  Here, the welded portion between the porous portion 11 that forms a hydrogen separation membrane by plating palladium or palladium alloy on the surface and the nonporous portion 12 or the blind plug 13 is a convex portion and is not a smooth surface. When the hydrogen separation membrane is formed later by plating, as shown in the electron micrograph of FIG. 4, the plating in the vicinity of the welded portion, that is, the hydrogen separation membrane peels off and floats, from which hydrogen gas, hydrogen gas, and organic solvent gas In some cases, leakage of mixed gas may occur. Therefore, in order to prevent the hydrogen separation membrane in the vicinity of the weld from floating and prevent gas leakage, the inventor tried clogging such as high-temperature adhesive, soldering, and vapor deposition on the leaked portion of the weld. However, good results were not obtained.

  Therefore, in the present invention, in the vicinity of the welded portion between the porous portion 11 and the non-porous portion 12 or the blind plug 13, not only the surface of the porous portion 11 but also the non-porous portion 12 and the blind plug 13 side has a length of about 1 cm. Then, palladium or a palladium alloy is plated on the surface, and further, as shown in FIG. 1, by fitting O-rings 14 on both sides of the porous portion 11 in the vicinity of the welded portion and forming the hydrogen separation membrane, Plating, that is, lifting of the hydrogen separation membrane was prevented to prevent mixed gas leakage.

  Next, considering the efficiency of Pd of 2 μm or less, preferably a hydrogen separation membrane by plating palladium or palladium alloy on the surface of the porous part 11 made of a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm The forming method will be described.

  First, prior to the hydrogen separation membrane on the stainless steel filter, the stainless steel filter that has been thoroughly cleaned is subjected to pretreatment by procedures (1) to (7) as shown in FIG. 5 at room temperature, for example. Note that (2) to (7) are repeated a total of three times.

  Next, a hydrogen separation membrane of palladium or palladium alloy is formed on the surface of the porous part 11 made of a stainless steel filter subjected to the above pretreatment process by a generally known palladium-electroless plating method. Here, as the palladium alloy, for example, a palladium-copper (Pd-Cu) alloy is used.

  In the production method of the palladium-copper (Pd-Cu) alloy film, first, a palladium film is produced by a palladium-electroless plating method, and then a copper film is produced thereon. For example, the copper film is composed of 10 g / L of a metal salt / copper (II) sulfate pentahydrate and 30 g / L of a complexing agent ethylenediaminetetraacetic acid disodium dihydrogen dihydrate 30 g / L, and the pH is adjusted to 10 with sodium hydroxide. The electroless copper plating bath was adjusted to -12. The plating temperature can be 40 to 60 ° C., but 65 ° C. or higher is desirable in order to reduce dissolved oxygen in the plating bath. Formaldehyde is added as a reducing agent at 3.3 g / L to form a copper film. Here, a stabilizer and a surfactant can be used in the copper plating bath. 2,2'-bipyridine was used as the stabilizer and polyethylene glycol was used as the surfactant. Since there is little peeling with a tape, both addition amount is desirable 5 mg / L. Further, the material of the copper film plating bath was glass which is difficult to be plated on the surface. The optimum V / A ratio, which is the ratio of the plating solution amount (V) to the plating area (A), is 4 to 6. This is because when the V / A ratio is small, the plating film thickness is small, and when the V / A ratio is large, the metal salt is saturated and many metal salts that are not consumed remain.

  As described above, in the hydrogen separator 1 of this embodiment, the surface of the porous portion 11 made of a stainless steel filter having pores having an average diameter of 0.4 to 0.6 μm is desirable in consideration of efficiency of 2 μm or less and Pd. On the other hand, palladium-copper film | membrane was performed alternately and laminated | stacked, and after making it the copper weight ratio 40%, alloying was performed. However, since cracks occur during alloying, the copper film is preferably formed by adjusting the plating time per time to 60 to 90 minutes so that the film thickness of copper does not exceed 7 μm at a time. Alloying is performed in a hydrogen atmosphere at 675 ° C. for 16 hours. Thereby, the structure of the palladium film formed on the surface of the porous portion 11 is changed from fcc (face centered cubic lattice structure) to bcc (body centered cubic lattice structure). Note that the total film thickness of the palladium membrane formed on the surface of the porous portion 11 or the palladium-copper alloy membrane hydrogen separation membrane is 30 μm or less.

  Next, the experimental result about the performance of the hydrogen separator 1 of this invention comprised as mentioned above is shown.

  FIG. 6 shows performance comparison results between the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment and other hydrogen separation methods.

  In FIG. 6, the horizontal axis indicates the catalyst temperature [° C.] and the vertical axis indicates the hydrogen purity [%]. The hydrogen purity separated by the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment, the gas cooling, and the high The hydrogen purity separated by the molecular membrane separation and the hydrogen purity separated by the gas cooling separation are indicated by a circle mark, a triangle mark, and a square mark, respectively. As is clear from FIG. 6, the hydrogen separated by the hydrogen separator 1 of the present embodiment has a purity of 99% or more without deteriorating the fuel cell performance, gas cooling separation (square mark), gas cooling separation + high It was found that hydrogen having a higher purity than that of the molecular film (triangle mark) can be obtained. In the case of the hydrogen separation membrane of the hydrogen separator 1 indicated by circles, the ratio of hydrogen gas (inlet hydrogen) in the mixed gas before separation is 8.9%, while the gas cooling indicated by squares In the case of separation or the like, the ratio of hydrogen gas in the mixed gas (inlet hydrogen) was 7.4%.

  FIG. 7 is a diagram showing the concentration of hydrogen separated by the hydrogen separator 1 of the present embodiment and impurities contained in the hydrogen.

  FIG. 7 shows the maximum concentration, the minimum concentration, and the average concentration after 14 tests. The separated hydrogen has a maximum concentration of 99.71%, a minimum concentration of 98.44%, and an average concentration. 99.28%. As impurities contained in the separated hydrogen, methane, which is a by-product gas decomposed from methylcyclohexane (MCH), which is a hydrogen storage raw material, has an average concentration of 0.72%, and methylcyclohexane (MCH), cyclohexane (CYH) ), Toluene (TOL), which is an organic gas obtained by extracting hydrogen from methylcyclohexane (MCH), and carcinogenic benzene (BEN) were not contained in hydrogen. Since it has been confirmed that even if 5% of methane is contained, it is not a poisoning component of the fuel cell, the hydrogen separator 1 of this embodiment can be used for a fuel cell.

  FIG. 8 is a diagram showing the results of a nitrogen permeation test using the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment.

In FIG. 8, the horizontal axis represents the plating film thickness [μm], the vertical axis represents the nitrogen permeation flux [m ³ / m ² · h · MPa], and the curve L81 represents a porous stainless steel filter having a maximum diameter of 3 μm. Shows the nitrogen permeation flux [m ³ / m ² · h · MPa] when a palladium film is formed. A curve L82 indicates a nitrogen permeation flux [m ³ / m ² · h · MPa] by the hydrogen separator 1 in which a stainless steel filter having an average diameter of 4 μm to 0.6 μm is plated with a palladium membrane. When a palladium film is formed on a porous stainless steel filter having a maximum diameter of 3 μm, as shown by a curve L81, the nitrogen permeation flux [m ³ / m ² · h · MPa] is higher than that of the curve L82, It can be seen that even if the plating film thickness of the palladium film is increased to about 30 [μm], nitrogen gas cannot be blocked.

  On the other hand, in the case of the hydrogen separator 1 of this embodiment in which a palladium film is plated on a stainless filter having an average diameter of 0.4 μm to 0.6 μm, as shown by a curve L82, the plating film thickness of the palladium film. Is 25 μm or less, it can be seen that nitrogen gas can be blocked.

FIG. 9 is a diagram showing the results of the hydrogen permeation test using the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment. In FIG. 9, the horizontal axis indicates time [h], while the vertical axis indicates hydrogen permeation flux [m ³ / m ² · h · MPa] or temperature [° C.]. A hydrogen gas cylinder (99.5%) atmosphere was used. In FIG. 9, the nitrogen permeation flux is indicated by square marks, the hydrogen permeation flux is indicated by circles, and the temperature change is indicated by cross marks. Between 4 hours and 6 hours, nitrogen gas and The test was performed by switching to hydrogen gas.

From the experimental results shown in FIG. 9 as well, the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment does not allow nitrogen to pass through at most temperatures, and hydrogen is about 45 [m ³ / m ² · h · MPa]. It turned out to be permeated. As a result, from the experimental results shown in FIG. 8 and FIG. 9, the hydrogen separation membrane of the hydrogen separator 1 of this embodiment is a porous stainless steel filter having pores with an average diameter of 0.4 μm to 0.6 μm. When the thickness of the plating film of the separation membrane is 25 μm or less, the hydrogen permeation flux is 45 [m ³ / m ² · h · MPa] and the nitrogen permeation flux is 0.0 [m ³ / m ² · h · MPa]. The following (detection limit value) was found.

FIG. 10 is a diagram showing the results of a hydrogen embrittlement test using the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment. FIG. 10A shows time [h] on the horizontal axis and the hydrogen permeation flow on the vertical axis. The figure shows the bundle [m ³ / m ² · h · MPa] and the temperature [° C.] of the palladium film, while (b) shows the temperature [° C.] of the palladium film on the horizontal axis, It is the figure which took the permeation flux [m < ³ > / m < ² > * h * MPa] of hydrogen. As test conditions, the surface of the porous part 11 made of a stainless steel filter is made of palladium, and the supplied hydrogen is a hydrogen gas cylinder with a hydrogen concentration of 99.5% and a hydrogen gas pressure of 0.2 MPa. . In FIG. 10A, a curve L91 indicates a temperature change [° C.] of the palladium film, while a curve L92 indicates a change in hydrogen permeation flux [m ³ / m ² · h · MPa]. Is shown. As is clear from FIGS. 10A and 10B, hydrogen embrittlement due to hydrogen gas occurs in the palladium film when the film temperature of the palladium film is approximately 120 ° C.

  FIG. 11 is a diagram illustrating a temperature at which a palladium membrane is damaged (broken) in the presence of a high concentration organic solvent by the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment.

In FIG. 11, the horizontal axis represents the heating temperature [° C.] of the reactor of the hydrogen separator 1 of the present embodiment, while the vertical axis represents hydrogen purity [%] and permeation flux [m ³ / m ² · h · [MPa], and the hydrogen purity, hydrogen permeation flux, and nitrogen permeation flux are indicated by square marks, circle marks, and triangle marks, respectively. From FIG. 11, it can be seen that when the heating temperature [° C.] of the reactor falls below 250 ° C., the hydrogen purity becomes smaller than 99%, and thus the palladium film is damaged at 250 ° C.

FIG. 12 shows the damage of the palladium-copper (Pd—Cu) alloy membrane in the presence of the high concentration organic solvent by the hydrogen separation membrane of the hydrogen separator 1 of the present embodiment. In FIG. While taking the heating temperature [° C.] of the reactor, the hydrogen purity [%] and the permeation flux [m ³ / m ² · h · MPa] are taken on the vertical axis, , Square marks and circle marks. In (b), the horizontal axis represents the reactor heating temperature [° C.] while the vertical axis represents the reactor power [Wh].

By removing hydrogen in the same reactor as the catalyst, the palladium-copper (Pd—Cu) alloy film-forming temperature was raised to 140 ° C. at the residual heat gas temperature of 350 ° C. in the previous step, and FIG. As shown in FIG. 4, the power consumption of heating of the palladium-copper (Pd—Cu) alloy film became zero. Even when the palladium-copper (Pd—Cu) alloy film-forming temperature, that is, the heating temperature of the reactor was 140 ° C., the hydrogen purity was slightly over 98% as shown in FIG. It can be judged that the hydrogen permeation flux is almost 2.0 [m ³ / m ² · h · MPa] and there is no change, and the palladium-copper (Pd—Cu) alloy film is not damaged. This is because the hydrogen permeation flux of the palladium-copper (Pd-Cu) alloy film sample is 2.0 [m ³ / m ² · h · MPa] (reference) as shown in FIG. This is considered to be an effect using

  Therefore, according to the hydrogen separation membrane and the hydrogen separator of the present embodiment, the stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is desirably used as the carrier in consideration of efficiency of 2 μm or less and Pd, Since the surface of the stainless steel filter is plated with palladium or palladium-copper (Pd-Cu) alloy based on palladium to form a hydrogen separation membrane, the hydrogen separator 1 can be processed into a complicated shape. it can.

  In particular, welding between the porous portion 11 and the non-porous portion 12 made of a stainless steel filter plated with palladium or a palladium-copper (Pd—Cu) alloy based on palladium, or between the porous portion 11 and the blind plug 13. As shown in FIG. 1, since the O-ring 14 is fitted to the part, the hydrogen separation membrane in the welded part can be prevented from peeling off, and the mixed gas can be prevented from leaking from the porous part 11.

  Also, considering the efficiency of Pd of 2 μm or less, preferably when a palladium film is plated on the surface of a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm, hydrogen embrittlement as shown in FIG. The film temperature at which the generation of hydrogen was 120 ° C. However, in an organic hydride system using a high-concentration organic solvent, as shown in FIG. 11, damage to the palladium film occurs even when the heating temperature of the reactor is 250 ° C. . However, when a palladium-copper (Pd-Cu) alloy is plated on the surface of the stainless steel filter, the palladium-copper (Pd-Cu) alloy film is damaged even when the heating temperature of the reactor is 140 ° C., as shown in FIG. Even in an organic hydride system using a high concentration organic solvent, damage due to hydrogen embrittlement can be prevented.

Embodiment 2. FIG.
Next, an organic hydride system according to the present invention using the hydrogen separator 1 of Embodiment 1 will be described as Embodiment 2.

  FIG. 13 is a diagram showing a configuration of the organic hydride system 2 according to the present invention.

  As shown in FIG. 13, the organic hydride system 2 includes an MCH (methylcyclohexane) tank 21, a metering pump 22, a hydrogen cylinder 23, the hydrogen separator 1 of the first embodiment, a cooling separator 25, A recovery tank 26 and a fuel cell 27 are provided.

  The hydrogen separator 1 according to the first embodiment accommodates a porous portion 11 in which a hydrogen separation membrane is formed in a reactor 24 and a catalyst such as platinum (platinum). A hydrogen cylinder 23 is contained in the reactor 24. The hydrogen gas from the MCH (methylcyclohexane) tank 21 and the MCH (methylcyclohexane) gas mixture gas from the MCH (methylcyclohexane) tank 21 are allowed to flow into the hydrogen separation membrane on the surface of the porous portion 11 to separate only the hydrogen gas and Pass through the porous portion 12. The hydrogen gas that has passed through the porous portion 11 and the non-porous portion 12 is supplied to the fuel cell 27 from the open end (see FIG. 1) of the non-porous portion 12, while passing through the hydrogen separation membrane. An organic gas such as methylcyclohexane (MCH) gas or toluene (TOL), which is a hydrogen storage raw material (organic solvent) that has not been supplied, is supplied to the cooling separator 25.

  The cooling separator 25 cools methylcyclohexane (MCH) gas that has not passed through the hydrogen separation membrane, toluene (TOL), etc. to about 5 ° C., and further, hydrogen gas, methylcyclohexane (MCH) gas, The hydrogen gas is separated into organic gas such as toluene (TOL) and supplied to the fuel cell 27, while the organic gas such as methylcyclohexane (MCH) gas and toluene (TOL) is supplied to the recovery tank 26. To collect and reuse.

  Next, the installation form of the porous part 11 in which the hydrogen separation membrane is formed in the reactor 24 will be specifically described.

  As shown in FIG. 13, one porous portion 11 having a hydrogen separation membrane formed therein may be provided in the reactor 24, but in this case, the efficiency of hydrogen separation is not so good. Therefore, it is preferable to provide a plurality of porous portions 11 formed with hydrogen separation membranes in the reactor 24.

  FIG. 14 shows an example in which four porous portions 11 in which a hydrogen separation membrane is formed are provided in the reactor 24. The reactor 24 has a length and width of 100 mm and a length of 200 mm, and accommodates four porous portions 11 therein. In FIG. 14, 24a is an inlet of a mixed gas of hydrogen gas and methylcyclohexane, and 24b is an outlet of a residual gas obtained by separating the hydrogen gas from the mixed gas. In addition, the inlet and outlet of the mixed gas can be reversed. The nonporous portion 12 is provided outside the reactor 24. Here, as described above, in the hydrogen separator 1, in the welded portion between the porous portion 11 and the non-porous portion 12 or between the porous portion 11 and the blind plug 13, poor plating of the hydrogen separation membrane occurs and gas leakage occurs. For this purpose, an O-ring 14 is provided as shown in FIG.

Here, the conditions in the reactor 24 are as follows, for example.
Hydrogen permeation flux: 20 [m ³ / m ² · h · MPa].
Nitrogen permeation flux: 2 [m ³ / m ² · h · MPa] or less.
Hydrogen permeation amount: 1.5 L / min (equivalent to 100 W of fuel cell).
Pressure difference: 0.2 MPa
Operating temperature range: 140 ° C. or higher Pd membrane permeation hydrogen purity: 99% or higher Pd alloy film plating effective area: 225 cm ²

This is because the theoretical amount of hydrogen required for 1 kWh output is 13.88 L / min (832 L / H), but since there is unused hydrogen that passes through the fuel cell 27 unreacted, in general, 1 It is said [m ³ / kWh]. The amount of hydrogen required for the 100 W fuel cell 27 is 100 [L / h] ÷ 60 [min] ≈1.5 [L / min] (1.5 × 60 = 90 [L / h]) · 0 .09 [m ³ / h].

The performance of the hydrogen separation membrane is indicated by hydrogen permeance [m ³ / m ² · h · MPa]. A hydrogen separation membrane having 20 [m ³ / m ² · h · MPa] has a surface area of 0.05 [m ² ] (500 [cm ² ]) in order to extract 1 [m ³ / h] of hydrogen. If it is corrected at 0.2 [MPa], 500 × 1 / 0.2 = 2500 [cm ² ] is obtained. Therefore, since the hydrogen permeation amount of the fuel cell 27 equivalent to 100 W needs to be 1.5 [L / min] (0.09 [m ³ / h], 2500 [cm ² ] × 0.09 = 225 [ cm ² ].

Therefore, if four stainless steel pipes having a diameter of 1/2 inch are provided as the porous portion 11 provided with the hydrogen separation membrane, 225 [cm ² ] ÷ (2 × 3.14 × 2.54 / 4) × 4≈14 [cm], and a length of about 14 cm is sufficient, and it falls within the outer diameter of the reactor 24 having a size of 10 cm × 10 cm × 20 cm. However, in this embodiment, since a stainless steel tube having a diameter of 1/2 inch and a length of 20 cm is used, the surface area is 2πr × length = 2 × 3.14 × 2.54 / 4 per tube. × 20 cm = 80 [cm ² ], and since four stainless steel tubes are used, 80 × 4 = 320 [cm ² ]. This is larger than 225 [cm ² ], which is the effective plating area of the palladium (Pd) alloy film.

Therefore, in this organic hydride system 2, the surface area of the hydrogen separation membrane formed on the surface of porous portions 11 and 11 ′, which will be described later, accommodated in the reactor 24 is set to 225 [cm ² ] or more, which is equivalent to 100 W. The hydrogen permeation amount of the fuel cell 27 of 1.5 [L / min] can be achieved.

  FIG. 15 is a view showing a method of attaching the O-ring 14 to the hydrogen separator 1 in the organic hydride system 2 of Embodiment 2, and (a) is a welded portion between the porous portion 11 and the nonporous portion 12. 14B is an enlarged cross-sectional view of a portion A in FIG. 14B, and FIG. 14B is an enlarged cross-sectional view of a portion B in FIG. 14B, which is a welded portion between the porous portion 11 and the blind plug 13.

  As shown in FIG. 15 (a), an upper support 24c that supports the vicinity of the welded portion between the porous portion 11 and the nonporous portion 12 is provided at the top of the reactor 24. A cut groove 24c1 is provided on the peripheral surface, and in order to prevent gas leakage in the cut groove 24c1, a porous portion 11 and a non-porous portion 12 having an outer diameter of 12.7 mm can be inserted, and the porous portion 11 In order to suppress the floating of the hydrogen separation membrane on the surface, an O-ring 14 having an inner diameter of about 12.0 to 12.5 mm is fitted. If the O-ring 14 is fixed to the kerf 24c1 with an adhesive or the like, it can be further prevented from passing between the O-ring 14 and the kerf 24c1, thereby further preventing gas leakage. Further, a screw portion 24c2 is provided on the outer peripheral surface of the upper support portion 24c, and a cap nut 15 having a screw groove 15a on the inner peripheral surface is fitted into the screw portion 24c2 by screw connection. However, in the case of the cap nut 15 shown in FIG. 15 (a), it is necessary to pass through the porous portion 11 and the nonporous portion 12 of the hydrogen separator 1, so that the outer diameters of the porous portion 11 and the nonporous portion 12 are at the center. A 12.7 mm hole is formed. In the case of FIG. 15A, the tip of the cap nut 15 does not reach the O-ring 14 fitted in the kerf 24c1, but the tip of the cap nut 15 is extended so as to reach the O-ring 14, and the cap nut The tightening effect of the O-ring 14 by 15 may be increased.

  Therefore, by providing the O-ring 14 on the porous portion 11 side of the welded portion between the porous portion 11 and the nonporous portion 12, the hydrogen separation membrane plated near the welded portion between the porous portion 11 and the nonporous portion 12 can be obtained. It is possible to suppress floating, and to prevent the mixed gas filled in the reactor 24 from reaching the welded portion between the porous portion 11 and the nonporous portion 12 through the outer peripheral surface of the porous portion 11. It can prevent entering into the porous part 11 from the welding part of the part 11 and the non-porous part 12. FIG. In particular, the O-ring 14 is fitted in a kerf 24c1 of the upper support 24c of the reactor 24, and the upper support 24c is tightened by screw connection with a cap nut 15, so that a cap nut 15 is provided. The expansion of the O-ring 14 can be suppressed as compared with the case where there is no gas leakage, and gas leakage can be further prevented.

  Further, as shown in FIG. 15 (b), a lower support portion 24d for supporting the vicinity of the welded portion between the porous portion 11 and the blind plug 13 is provided at the lower portion of the reactor 24. A cut groove 24d1 is provided on the inner peripheral surface of 24d, and in order to prevent gas leakage into the cut groove 24d1, the porous portion 11 and the blind plug 13 can be inserted, and the hydrogen separation membrane on the surface of the porous portion 11 can be inserted. An O-ring 14 that holds the float is fitted. Similarly to the upper support portion 24c, if the O-ring 14 is fixed to the kerf 24d1 with an adhesive or the like, gas leakage can be more effectively prevented. In addition, a screw portion 24d2 is provided on the outer peripheral surface of the lower support portion 24d, and a cap nut 15 'having a screw groove 15a' on the inner peripheral surface is fitted into the screw portion 24d2 by screw connection. However, in the case of the cap nut 15 'shown in FIG. Also, in the case of FIG. 15B, the tip of the cap nut 15 ′ does not reach the O-ring 14 fitted in the cut groove 24d1, but in order to increase the tightening effect of the O-ring 14 by the cap nut 15 ′, The tip of the cap nut 15 ′ may be extended to the O-ring 14.

  Therefore, by providing the O-ring 14 on the porous portion 11 side of the welded portion between the porous portion 11 and the blind plug 13, the hydrogen separation membrane plated near the welded portion between the porous portion 11 and the blind plug 13 is floated. The mixed gas filled in the reactor 24 can be prevented from reaching the welded portion between the porous portion 11 and the blind plug 13 through the outer peripheral surface of the porous portion 11 and the porous portion 11. It can prevent entering into the porous part 11 from the welding part with the blind plug 13. In particular, the O-ring 14 is fitted in a kerf 24d1 of the lower support portion 24d of the reactor 24, and the lower support portion 24d is tightened by screw connection with a cap nut 15 '. The expansion of the O-ring 14 can be suppressed as compared with the case where 15 ′ is not provided, and gas leakage can be further prevented.

And in the organic hydride system 2 as shown in FIG. 13, when the porous part 11 in which the hydrogen separation membrane having the effective surface area of 39 [cm ² ] of the first embodiment is used, the temperature is changed from 350 ° C. to 250 ° C. for a while. It was confirmed that there was no hydrogen embrittlement even if the operation was carried out for 5 hours each. Hydrogen purity 99.48% at 350 ° C., hydrogen permeation flux 5.7 [m] ³ / m ² · h · MPa], nitrogen permeation flux 0.3 [m ³ / m ² · h · MPa], 250 The hydrogen purity at 98 ° C. was a hydrogen permeation flux of 6.8 [m ³ / m ² · h · MPa] and a nitrogen permeation flux of 3.0 [m ³ / m ² · h · MPa]. In addition, since the hydrogen separation membrane was damaged at less than 250 ° C., the hydrogen separation membrane needs to be heated, and the power consumption cannot be significantly reduced.

Further, in the organic hydride system 2 as shown in FIG. 13, when the hydrogen separation membrane is continuously operated at 280 ° C., after 100 hours, the hydrogen purity is 99.24% and the hydrogen permeation flux is 7.1 [m ³ / m ^2. h · MPa] and nitrogen permeation flux 1.1 [m ³ / m ² · h · MPa], and there was no damage to the membrane.

Further, a palladium-copper alloy film having an effective surface area of 39 [cm ² ] was used, and the temperature was temporarily lowered from 260 ° C. to 140 ° C. for 5 hours, and it was confirmed that there was no hydrogen embrittlement. Hydrogen purity 99.36% at 260 ° C., hydrogen permeation flux 1.9 [m ³ / m ² · h · MPa], nitrogen permeation flux 2.3 [m ³ / m ² · h · MPa], 140 ° C. The hydrogen purity was 98.10%, the hydrogen permeation flux was 2.0 [m ³ / m ² · h · MPa], and the nitrogen permeation flux was 2.3 [m ³ / m ² · h · MPa].

  Further, in the organic hydride system 2 as shown in FIG. 13, the exhaust heat of the catalyst heating can be used at 140 ° C., so that the power consumption required for heating the hydrogen separation membrane is zero. Therefore, the power consumption can be significantly reduced by using a palladium-copper (Pd-Cu) alloy film.

Further, in a 99.5% industrial level hydrogen gas atmosphere, the porous part 11 having a hydrogen separation membrane having an effective surface area of 39 [cm ² ] was used, and the temperature was temporarily lowered from 328 ° C. to 140 ° C. It was confirmed that there was no hydrogen embrittlement even when operated for more than an hour. The hydrogen permeation flux was 63.5 [m ³ / m ² · h · MPa] at 328 ° C. and 46.9 [m ³ / m ² · h · MPa] at 140 degrees. When the temperature was lower than 140 ° C., the hydrogen permeation flux increased significantly, and damage to the hydrogen separation membrane was observed.

  The heating heat amount of the hydrogen separation membrane attached to the front stage of the fuel cell 27 is 175.6 [J / g · min (42.5 caL / g · min)] at 140 ° C., and the fuel cell 27 is heated at 60 to 80 ° C. The amount of heat for humidifying can be supplemented.

  In addition, the porous part 11 of the hydrogen separator 1 is 2 μm or less in consideration of the efficiency of Pd by weaving a stainless steel wire that can be easily processed as described in the first embodiment, and compressing and crushing the mesh. Desirably, since it is constituted by a stainless steel filter having pores having an average diameter of 0.4 to 0.6 μm, for example, as shown in FIG. In addition, as shown in FIG. 17, it is not a pipe-shaped stainless steel filter, and it is preferably 2 μm or less, and pores having an average diameter of 0.4 to 0.6 μm, considering the efficiency of Pd A flat plate-like porous portion 11 ′ in which a hydrogen separation membrane is provided by plating palladium or a palladium alloy on a plate-like stainless steel filter having (mesh) is provided in the reactor 24. And it may be.

However, in the case of the flat porous portion 11 ′ shown in FIG. 17, a plurality of plates are arranged stepwise between the mixed gas inlet 24a and the outlet 24b so that hydrogen gas can be efficiently separated. A zigzag mixed gas flow path is provided, and the hydrogen gas separated by the hydrogen separation membrane provided on the surface of the flat porous portion 11 ′ is discharged from an outlet 24 e provided in the reactor 24. In this case, for example, the reactor 24 has a length of about 50 mm × 120 mm × 200 mm, and the operating conditions are the same as those shown in FIG. 14, and the hydrogen permeation flux 20 [m ³ / m ² · h · MPa ], Nitrogen permeation flux 2 [m ³ / m ² · h · MPa] or less, hydrogen permeation amount 1.5 [L / min] (equivalent to 100 W of fuel cell), pressure difference 0.2 [MPa], hydrogen separation The membrane permeation hydrogen purity is 99% or more, and the effective plating surface area of the hydrogen separation membrane is 225 [cm ² ].

  In the case of the linear tube shape shown in FIG. 14 and the spiral tube shape shown in FIG. 16, the porous portion 11 is welded between the porous portion 11 and the non-porous portion 12 of the stainless steel filter, or the porous portion. Since the gas leaks from the welded portion between the plug 11 and the blind plug 13, the O-ring 14 and the cap nuts 15 and 15 ′ are used as shown in FIG. 15. However, in the case of the flat plate shape shown in FIG. Gas leakage may be prevented between the portion 11 ′ and a gasket.

DESCRIPTION OF SYMBOLS 1 Hydrogen separator 11 Porous part 12 Non-porous part 13 Blind plug 14 O-ring 15,15 'Cap nut 2 Organic hydride system 21 MCH (methylcyclohexane) tank 22 Metering pump 23 Hydrogen cylinder 24 Reactor 24c1, 24d1 Cut groove 25 Cooling separator 26 Recovery tank 27 Fuel cell

Claims (5)

  Considering efficiency improvement of Pd of 2 μm or less, preferably a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is used as a support, and the surface of the stainless steel filter is plated with palladium or a palladium alloy based on palladium. A hydrogen separation membrane characterized by that. The hydrogen separation membrane according to claim 1,
In consideration of efficiency improvement of Pd of 2 μm or less, desirably a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is
A hydrogen separation membrane formed by compressing and crushing a mesh of a stainless steel filter woven with a stainless steel wire. 2 μm or less, and considering the efficiency of Pd, a porous part in which a stainless steel filter having pores with an average diameter of 0.4 to 0.6 μm is preferably formed in a pipe shape;
It is formed in a pipe shape so that hydrogen that has passed through the inside of the porous portion passes through and a non-porous portion that does not have holes on the surface thereof,
A hydrogen separation membrane is formed by plating at least the surface of the porous portion with palladium or a palladium alloy based on palladium, and the hydrogen gas is separated in the reactor by the hydrogen separation membrane on the porous portion surface to thereby remove the porous portion and the non-porous portion. A hydrogen separator, characterized in that hydrogen gas is discharged from the other open end of the non-porous part through the porous part. The hydrogen separator according to claim 3, wherein
The conditions in the reactor were such that the permeated hydrogen flux of the hydrogen separation membrane was 2.0 [m ³ / m ² · h · MPa] or less for a working pressure difference of 0.2 Mpa and a temperature range of 140 ° C. or higher. A hydrogen separator characterized in that the hydrogen purity of the hydrogen separation membrane is 99% or more in the presence of an organic solvent such as methylcyclohexane at a concentration.   Using the hydrogen separator according to claim 3 or 4, the hydrogen gas is separated from a mixed gas of hydrogen gas and a high concentration organic solvent gas such as methylcyclohexane without causing hydrogen embrittlement. Organic hydride system.

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