JP4608657B2 - Hydrogen separation and permeation membrane that exhibits excellent hydrogen separation and permeation function over a long period of time by high pressure operation of high purity hydrogen purifier - Google Patents

Description

  The present invention relates to a hydrogen separation / permeation membrane that exhibits an excellent hydrogen separation / permeation function over a long period of time in a high-pressure operation of a high-purity hydrogen purifier.

  In recent years, high-purity hydrogen gas has attracted attention as a fuel gas for energy systems such as hydrogen fuel cells and hydrogen gas turbines, and this high-purity hydrogen gas is a mixed gas or liquefied natural gas obtained by electrolyzing water. As shown in the schematic explanatory diagram of FIG. 1, for example, the outer peripheral portion is reinforced with a frame made of, for example, Ni, and is made of a material such as a mixed gas obtained by steam reforming (LNG). Film thickness that allows only hydrogen to pass through: 20-50 μm hydrogen separation and permeation membrane partitioned into left and right side chambers, hydrogen-containing source gas introduction pipe and exhaust gas extraction pipe in the left chamber, and high in the right chamber Using a high-purity hydrogen purifier having a structure in which a reaction chamber made of, for example, stainless steel, provided with a purity hydrogen gas extraction tube is provided in the center, the reaction chamber is heated to 200 to 300 ° C., and from the introduction tube An internal pressure of the right side chamber in which the high-purity hydrogen gas present through the hydrogen separation and permeable membrane is introduced is maintained at 0.1 MPa, while an internal pressure of the left side chamber in which the hydrogen-containing source gas exists is introduced. It is also known that it is produced by separating and refining high-purity hydrogen gas through the hydrogen separation / permeation membrane under the condition that is maintained at 0.2 to 0.5 MPa.

Further, as the hydrogen separation / permeation membrane, an amorphous Ni-Zr alloy is known, which sprays a molten alloy having a predetermined composition on the surface of a copper roll mold that rotates at a high speed, for example. It is also known that it is produced by a liquid quenching method for solidifying with a film thickness of ˜50 μm.
JP 2000-256002 A JP 2004-42017 A JP 2004-167379 A JP 2004-169116 A

  On the other hand, there is a strong demand for large-scale and high-efficiency hydrogen high-purity purification equipment, and as a result, high-pressure operation, that is, operation under the condition that the internal pressure of the left chamber of the equipment is increased to 0.6 MPa or more. However, in the conventional high-purity hydrogen purifier using the above-mentioned amorphous Ni-Zr alloy as the hydrogen separation and permeable membrane, the internal pressure of the left chamber is set to 0.6 MPa during the operation. In this way, in addition to an increase in the load on the hydrogen separation / permeation membrane due to an increase in the pressure difference between the two chambers, a decrease in strength due to an increase in the amount of hydrogen dissolved in the membrane, corrosion due to water vapor in the source gas, etc. At present, defects occur and the service life is reached.

In view of the above, the present inventors have made the above-described conventional hydrogen high-purity purification device made of an amorphous Ni-Zr alloy in order to enable high-pressure operation of the hydrogen high-purity purification device. As a result of conducting research by paying attention to the hydrogen separation / permeation membrane, the hydrogen separation / permeation membrane is expressed in atomic% (hereinafter,% indicates atomic%)
Zr: 15 to 37 atomic%, Ti: 20 to 37 atomic%,
And the remainder is made of an amorphous Ni—Zr—Ti alloy having a composition consisting of Ni and inevitable impurities (Ni: containing 37 to 57 atomic%). The Ti contained as a component not only significantly improves the resistance to steam corrosion, but also suppresses a decrease in membrane strength during hydrogen permeation, which greatly affects the service life during high-pressure operation, and thus further improved by high-pressure operation. The research result that it became possible to exhibit the hydrogen separation permeation function for a long time was obtained.

This invention was made based on the above research results,
Zr: 15 to 37 atomic%, Ti: 20 to 37 atomic%,
High-pressure operation of a high-purity hydrogen purifier comprising an amorphous Ni-Zr-Ti alloy having a composition comprising Ni and the remainder consisting of Ni and inevitable impurities (however, Ni: 37-57 atomic percent) It is characterized by a hydrogen separation / permeation membrane that exhibits a hydrogen separation / permeation function for a long time.

  Next, the reason why the composition of the amorphous Ni—Zr—Ti alloy constituting the hydrogen separation / permeable membrane of the present invention is limited as described above will be described.

(A) Zr
The Zr component has an action of forming an amorphous structure that exhibits a hydrogen separation and permeation function by rapid solidification in the state of coexisting with the Ni and Ti components, but if the content is less than 15%, the amorphous structure However, when the amount exceeds 37%, the film strength tends to decrease in the usage environment, and mechanical damage is likely to occur in the high pressure operation described above. Since the service life is reached in a relatively short time, the content is determined to be 15 to 35%, desirably 18 to 32%.

(B) Ti
The Ti component, together with the Ni and Zr components, forms an amorphous structure that exhibits a hydrogen separation and permeation function, and as described above, improves the water vapor corrosion resistance and strength of the membrane. However, if the content is less than 20%, a desired improvement effect cannot be obtained in the above-described operation. On the other hand, if the content exceeds 37%, an amorphous structure is formed. Since it becomes unstable and a decreasing tendency appears in the service life, the content is set to 20 to 37%, preferably 24 to 35%.

(B) Ni
As described above, the Ni component forms an amorphous structure that exhibits a hydrogen separation and permeation function in the coexistence of the Zr and Ti components, and has an effect of improving the film strength, but its content is less than 37%. Then, even if the Ti component is contained, the high strength necessary for high-pressure operation cannot be ensured over a long period of time. On the other hand, if its content exceeds 55%, the hydrogen separation and permeation function tends to decrease. Therefore, the content is determined to be 37 to 55%, desirably 39 to 52%.

  The hydrogen separation permeable membrane of the present invention is composed of an amorphous Ni-Zr-Ti alloy containing 20 to 37% of Ti as an alloy component, and has excellent steam corrosion resistance and high resistance due to the action of the Ti component. Since it has strength, it can be used for various high-purity hydrogen purifiers, allowing not only high-pressure operation of the high-purity hydrogen purifier, but also excellent hydrogen separation and permeation function for a long time. It comes to show over.

  Next, the hydrogen separation / permeation membrane of the present invention will be specifically described with reference to examples.

  Purity: 99.5% Zr sponge material, 99.9% Ni shot material, and 99.5% Ti sponge material were used, and these materials were blended in the proportions shown in Table 1, respectively. A water-cooled copper roll in which 300 g of ingot is melted by arc melting in a high purity Ar atmosphere, this ingot is remelted in an Ar atmosphere by a high frequency induction heating furnace, and the molten metal is rotated at a roll speed of 20 m / sec. Amorphous Ni—Zr—Ti alloy foil material having a width of 30 mm × thickness: 35 μm was formed on each surface by spraying at 0.05 MPa, and the width: 30 mm × length from these foil materials. : The hydrogen separation permeation membranes of the present invention (hereinafter referred to as permeation membranes of the present invention) 1 to 24 were produced by cutting them into a plane size of 100 mm.

  Further, for comparison purposes, as shown in Table 2, except that the content ratio of any one of the three components Ni, Ti, and Zr as alloy components is not included in the content range of the present invention. Comparative hydrogen separation permeable membranes (hereinafter referred to as comparative alloy permeable membranes) 1 to 6 were produced under the same conditions.

  Further, in addition to the above raw materials, the purity: 99.6% pure Al material, Ni-51% V mother alloy material, and Ni-60% Nb mother alloy material were used, and these raw materials are shown in Table 2. Conventional hydrogen separation permeable membranes (hereinafter referred to as conventional alloy permeable membranes) 1 to 7 were produced under the same conditions except that they were blended in the proportions described above.

  When these various permeable membranes were observed by X-ray diffractometry, a broad peak derived from an amorphous structure was observed, and quantitative analysis was performed. The composition was substantially the same as the composition shown.

Next, each of the above-described permeable membranes 1 to 24 of the present invention, the permeable membranes 1 to 6 of the comparative alloy, and the permeable membranes 1 to 7 of the conventional alloy is formed by vapor deposition of a Pd thin film having a thickness of 100 nm on both surfaces. And each lateral outer dimension: 35 mm × vertical outer dimension: 105 mm × frame width: 5 mm × frame thickness: sandwiched from both sides by two copper reinforcing frames having dimensions of 0.5 mm, the various permeable membranes are 1 is installed in a reaction chamber of a high-purity hydrogen purifier having the structure shown in FIG. 1 while being fixed to a reinforcing frame, the reaction chamber is heated to 300 ° C., and LNG steam reforming is performed in the left chamber of the reaction chamber. Hydrogen-containing source gas simulated by gas, that is, hydrogen containing H ₂ : 71 vol%, CO ₂ : 17 vol%, CO: 1.5 vol%, H ₂ O (water vapor): 10.5 vol% First, the internal pressure of the left and right chambers of the reaction chamber is introduced. When the internal pressure of the right side chamber was maintained at 0.1 MPa, the internal pressure of the left side chamber was increased to 0.9 MPa at a rate of 5 minutes per 0.1 MPa, and maintained for 1 hour under this condition. Then, the flow rate of the separated and purified high-purity hydrogen gas was measured with a gas flow meter, and further under these conditions, that is, the internal pressure of the right side chamber was maintained at 0.1 MPa and the internal pressure of the left side chamber was maintained at 0.9 MPa. The treatment was continued, and the hydrogen purification treatment time until the time when the internal pressure of the left chamber decreased to 0.85 MPa due to the occurrence of a defect was measured, and this treatment time was defined as the lifetime. These measurement results are shown in Tables 1 and 2.

  As shown in Tables 1 and 2, each of the permeable membranes 1 to 24 made of the present invention exhibits an excellent hydrogen separation and permeation function over a long period of time despite the high pressure operation in which the internal pressure of the left chamber is 0.9 MPa. In contrast, the comparative alloy permeable membranes 1 to 6 and the conventional alloy permeable membranes 1 to 7 exhibit at least one of the hydrogen separation permeation function and the service life, while exhibiting excellent durability (service life). It is clear that the properties are inferior and are not suitable for high pressure operation.

  As described above, the hydrogen separation / permeation membrane of the present invention is used not only in a high-purity hydrogen purifier operated under normal conditions, but also in a high-pressure operation where the internal pressure of the hydrogen high-purity purifier is 0.6 MPa or more. Even when used for the above, since it exhibits an excellent hydrogen separation and permeation function over a long period of time, it can satisfactorily meet the demand for larger size and higher efficiency of the high-purity hydrogen purifier.

It is a schematic explanatory drawing which illustrates a hydrogen high purity refiner.

Claims (1)

Zr: 15-37 atomic%, Ti: 20-37 atomic%,
Of high-purity hydrogen purifier characterized by comprising an amorphous Ni—Zr—Ti alloy having a composition comprising Ni and the remainder consisting of Ni and inevitable impurities (however, Ni: 37 to 57 atomic% contained) Hydrogen separation / permeation membrane that exhibits excellent hydrogen separation / permeation function over a long period of time under high pressure operation.

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