JPH0929045A - Gas separation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas separation device of such a structure that uses a metal porous form, obtained by treatment including a hot hydrostatic pressure treatment and equipped with an electrode so that a voltage is applicable, formed on a gas separation part, and which has such advantages that the heat resistance strength and the gas permeability are superb and no separate heating device is required. SOLUTION: A gas separation part 2 is composed of a metal porous form which is obtained through a molding treatment process including a hot hydrostatic pressure treatment for sintering a metal powder material under a hydrostatic pressure in a heated condition, and has numerous pores, generated in the molding treatment process, penetrating through the rear surface from the front surface. Therefore, the gas separation part 2 can store a perovskite compound 4. In addition, the metal porous form making up the gas separation part 2 is equipped with a pair of electrodes 3, so that the metal porous form can be heated by itself. For this purpose, this gas separation device is equipped with a voltage application device 7 and, at the same time, a temperature control device 8 for switching an applied voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a gas separation section for accommodating perovskite compounds having different adsorption capacities for gases to be separated in different temperature ranges, and the temperature of the gas separation section is set to a predetermined temperature range. The present invention relates to a gas separation device that includes a settable heating means and that includes a raw material gas supply passage that supplies a raw material gas to the gas separation portion and a product gas passage through which the separated gas sent from the gas separation portion flows.

[0002]

2. Description of the Related Art The structure of such a gas separator is shown in FIG. The apparatus is provided with a gas separation part 2 containing a perovskite compound 4 as a gas flow passage specific portion partitioned by a pair of ceramic porous bodies 15, and further, the gas flow passage specific portion is provided in at least two different temperature ranges. The heating device 16 is provided as a heating unit that can be set to. On the upstream side of the gas separation section 2, first, a source gas supply path 5 capable of selectively supplying a source gas or a carrier gas to the gas separation section 2 is provided, and on the downstream side thereof, the gas separation section 2 is provided. It was equipped with a product gas path 6 through which the separated gas delivered from Explaining the operating conditions of this device, first, the temperature range of the perovskite compound contained in the gas separation section is set to a high temperature state (for example, about 1000 ° C.), and the perovskite compound is made into a state where the valence of oxygen is low. . For example, when the perovskite compound is strontium ferrate (SrFeO _x ), this x
Is reduced to about 2.5. When the compound temperature range is set to a low temperature state (for example, about 300 ° C.) from this state and, for example, air is supplied from the raw material gas supply passage, oxygen in the air is adsorbed by the perovskite compound, and the product gas passage is rich in nitrogen. Gas can be obtained. That is, in such a low temperature range, for example, when the perovskite compound is strontium ferrate (SrFeO _x ), this x increases to about 2.8. Next, from this low temperature state, the supply of air from the raw material gas supply path is stopped, and, for example, an oxygen-rich gas as a carrier gas is supplied, and when the gas separation section is brought to the high temperature state, the compound is formed. The adsorbed oxygen is desorbed and sent out together with the carrier gas, so that an oxygen-rich gas can be obtained on the product gas path side. In such an apparatus, the temperature of the gas separation section is alternately set to different predetermined temperature ranges required for the perovskite compound contained therein. Therefore, this portion is subjected to a large thermal shock. Conventionally, such a gas separation unit has been formed of a heat-resistant metal member forming a pipe and a porous ceramic filter 15.

[0003]

However, when such a ceramic filter is used, there is a problem that cracks and chips are likely to occur because the ceramic cannot withstand thermal shock. Further, it is difficult to get familiar with the metal pipe forming the pipe line, and the heating device 16 needs to be provided as a separate body from the member forming the gas separation unit 2. Therefore, it is an object of the present invention to obtain a gas separation device having a gas separation portion which is excellent in both heat resistance and air permeability.

[0004]

To achieve the above object, the gas separator according to claim 1 is characterized in that hot isostatic pressure is used for sintering metal powder under hydrostatic pressure in a heated state. The gas separation part is constituted by a metal porous body obtained through a molding process including a pressure sintering process and provided with a large number of holes penetrating between the front and back surfaces generated in the process. The body is provided with a pair of electrodes so that the metal porous body can be applied with a voltage. The operation and effect are as follows.

[0005]

In the gas separation device according to the first aspect, the metal separation body obtained by a process including a so-called HIP sintering method (hot isostatic pressing under pressure) is used in the gas separation section. It
Since such a porous metal body is superior in strength to, for example, a conventional ceramic porous body, it is excellent in shape retention and durability. In addition, such a porous metal body has a high heat resistance temperature, and even when it is subjected to a severe thermal shock by being alternately set to different temperatures as in the gas separation device of the present application, the conventional ceramics can be used. As described above, there is no possibility of causing an accident such as cracking, chipping, or the like, resulting in the device not functioning. Furthermore, such a HIP
In the porous metal body obtained through the sintering treatment, pores communicating between the front and back surfaces of the molded body are more likely to be formed than in the conventional general sintered body. The reason for this is that, for example, in the conventional sintering process, in order to obtain a predetermined strength along with the sintering, it is necessary to use a metal powder having a nonuniform particle shape and a shape far from a spherical shape. On the other hand, HIP
Since the sintering is effective in the sintering process, it is possible to sinter particles having a relatively constant particle shape and a nearly spherical shape to obtain a predetermined strength, and the pores formed between the particles. However, it is formed continuously between the front and back of the material. Therefore, it is possible to easily obtain such a metal porous body having a high open porosity (a high proportion of pores which are communicated with the outer surface of the material and can be used as, for example, pores for gas flow). At the same time, the diameters of the holes formed can be made uniform, so that it is possible to obtain a gas separation part that is uniform and has excellent gas permeability, and to separate the gas with a small driving pressure. Furthermore, since this gas separation portion is a porous metal body obtained through the HIP sintering process, it can be set in a complicated shape. In addition, since the metal porous body is provided with an electrode and has a structure capable of applying a voltage, it becomes possible to function as a conventional heating means by heating the metal porous body in an energized state to generate heat. There is no need to equip them.

[0006]

The gas separation device according to the first aspect of the present invention is provided with a gas separation portion which is excellent in strength, thermal shock resistance, and air permeability, has high reliability, and does not require a separate heating device. A gas separation device can be obtained.

[0007]

Embodiments of the present application will be described with reference to the drawings. FIG. 1 shows the structure of a gas separation device 1 of the present application.
The structure of the apparatus is almost the same as that of the conventional one, but the above-described gas separation unit 2 is a metal porous body obtained through a forming process including a hot isostatic pressing process which is a characteristic configuration of the present application. And that the metal porous body is provided with an electrode 3 capable of applying a voltage, and the gas separation portion 2 itself made of the metal porous body is formed in a self-heating type. It's different.

The apparatus 1 comprises a gas separation section 2 containing a perovskite compound 4 in a gas flow path. A raw material gas supply path 5 capable of selectively supplying a raw material gas or a carrier gas to the gas separation portion 2 is provided on the upstream side of the gas separation portion 2, and is delivered from the gas separation portion 2 on the downstream side thereof. It is provided with a product gas passage 6 through which the separated separated gas comes.

The gas separating section 2 is obtained through a molding process including a hot isostatic pressing process (HIP sintering process) in which a metal powder material is sintered under a hydrostatic pressure in a heated state. ,
In addition, the perovskite compound 4 can be accommodated in a porous metal body having a large number of holes which are generated in the process of treatment and penetrate between the front and back surfaces.

The metal porous body which constitutes the gas separation part 2 is provided with a pair of electrodes 3, and a voltage is applied between the electrodes 3 so that the metal porous body itself can be heated. There is. For this purpose, a voltage applying device 7 is provided, and the applied voltage is adjusted so that the perovskite compound 4 has a high temperature (for example, 1000 ° C.) at which oxygen is easily separated and a temperature at which oxygen is easily absorbed. A temperature control device 8 for switching the applied voltage is provided so that the gas separation unit 2 is set to a certain low temperature (for example, 300 ° C.). The temperature control device 8 is connected to the raw material gas supply passage 5
It is also configured to interlock with a switching mechanism 10 that switches the type of gas supplied from the storage unit 9 and switches the storage unit 9 depending on the type of gas delivered from the product gas passage 6.

Explaining the operating conditions of the gas separation device 1,
When the apparatus 1 is started, the temperature range of the perovskite compound 4 stored in the gas separation unit 2 is set to a high temperature state (for example, about 1000 ° C.), and the perovskite compound 4 is made to have a low oxygen valence. . From this state, the compound temperature range is set to a low temperature state (for example, about 300 ° C.), and, for example, air is supplied from the raw material gas supply passage 5. By this operation, oxygen in the air is adsorbed by the perovskite compound 4, and a nitrogen-rich gas can be obtained in the product gas passage 6. Next, from this low temperature state, the supply of air from the raw material gas supply path 5 is stopped, and, for example, an oxygen-rich gas as a carrier gas is supplied, and further the gas separation unit 2 is set to the high temperature state, Compound 4
Oxygen adsorbed on is desorbed and sent out together with the carrier gas, and an oxygen-rich gas can be obtained on the product gas passage 6 side. Through the above steps, the temperature control device 8,
The switching mechanism 10 works together.

As described above, since the gas separation section 2 is manufactured by so-called hot isostatic pressing sintering (HIP sintering), the gas separating section 2 is stronger and has the same strength as the conventional metal sintering method. The one having the strength of (1) has a large number of open pores communicating between the surfaces of the material, and has excellent characteristics of air permeability, heat resistance, and thermal shock resistance.

Hereinafter, a sample suitable as a porous metal body constituting the gas separation section 2 will be described. Specimens can be divided into two groups according to their manufacturing method. Hereinafter, the first group and the second group will be separately described. 1 First group Specimens belonging to this group are manufactured through two steps. In manufacturing, the first step, which is a step typified by a so-called CIP method, for pressure-molding a metal powder material to obtain a powder preform, and the powder preform obtained in the first step It is manufactured through a second step in which hot isostatic pressing is performed. Then, in this second step, the powder preform is left naked and placed in the hydrostatic medium for treatment. Therefore, in this step, the hydrostatic medium is allowed to enter the holes existing in the powder preform and penetrating the front and back of the powder preform, and the process proceeds. Such a hole can maintain its open state, and as a result, a metal sintered body having a high open porosity can be obtained. Table 1 shows the production conditions and physical properties of the specimens belonging to this group. less than,
Each sample will be described. Using the following metal powder as a raw material, it is enclosed in a rubber mold and CIP-molded to form a powder preform (first step). Then, the powder preform was placed in a HIP device and subjected to a sintering treatment (second step) to obtain porous metal bodies Nos. 1 to 5. Stainless steel powder: SUS 310S equivalent, atomized powder (C:
0.02, Si: 1.0, Mn: 0.1, Cr: 18.3, Ni: 10.8.%) Alloy tool steel powder: SKD 61 equivalent, atomized powder (C: 0.3
8, Si: 0.9, Mn: 0.01, Cr: 5.25, Ni: 1.20, V: 1.0.%) Specimen Nos. 1 to 5 are invention examples, and No. 11 is a powder preform in a vacuum atmosphere. It is a comparative example obtained by heating and sintering. In the table, the value in the "Pore size distribution" column is the maximum pore size (μm), the value in the "Degassing property" column is the pressure (Kgf / cm ² ) required for air permeation, and the "Bending strength" column is , JIS B
The measurement results of three-point bending strength (Kgf / mm ² ) by the bending test method of 1601 (span distance: 30 mm) are shown. The metal porous body obtained by HIPing the powder preform is No. 1
As shown in Nos. 3 to 3, as compared with the porous metal body No. 11 of the comparative example, the porous body has high degassing property and, at the same time, has a strength far exceeding that of No. 11. In particular, No. 2 has achieved extremely high strength. No. 4 has a large pore size, a high open porosity, and higher gas permeability while maintaining the same strength as Comparative Example No. 11, and No. 5 is a metal material type. Although different, it has a high open porosity, degassing properties, and improved strength. The difference from 11 is obvious.

[0014]

[Table 1] In Samples 1 to 5, it is clear from the fact that the ratio of open porosity / porosity is higher than that in Comparative Examples, that there are many through holes between the front and back surfaces of the material.

2 Second Group Specimens belonging to this group are also manufactured through two steps. In the production, a hot isostatic pressing sintering process corresponding to the above-mentioned second step is first performed, and the product obtained by this process is heat-treated to obtain a desired product. In the hot isostatic pressing sintering process belonging to this group, the metal powder is deaerated and hermetically sealed in a mild steel capsule. The feature of the hot isostatic pressing sintering process in this method is that the process time is selected to be shorter than that in the case where the above-mentioned one belonging to the first group is obtained, and the process is performed only for this process. There is something happening. Table 2 shows the production conditions and physical properties of the specimens belonging to this group. Below, each sample is demonstrated. The following metal powder is used as a raw material, filled in a mild steel capsule, and degassed and sealed (1 × 10 ^-2
rr), and then put in a HIP device for preforming. Then, the capsules, as they are, are placed in a heating furnace and heat-treated.
After the treatment, the capsule is removed by machining to obtain a porous metal body. Stainless steel powder: SUS 310S equivalent, atomized powder (C:
0.02, Si: 1.0, Mn: 0.1, Cr: 18.3, Ni: 10.8.%) Alloy tool steel powder: SKD 61 equivalent, atomized powder (C: 0.3
8, Si: 0.9, Mn: 0.01, Cr: 5.25, Mo: 1.20, V: 1.0.%)

Specimen Nos. 6 to 10 are inventive examples, and No.
12 is a comparative example obtained by heating and sintering a powder compact in a vacuum atmosphere. In the table, the value in the "Pore size distribution" column is the maximum pore size (μm), the value in the "Degassing property" column is the pressure (Kgf / cm ² ) required for air permeation, and the "Bending strength" column is ,
The measurement results of three-point bending strength (Kgf / mm ² ) by the bending test method of JIS B 1601 (span distance: 30 mm) are shown. As shown in Nos. 6 to 8, the metal porous body of the invention example has a high open porosity and a high gas permeability, although the average pore diameter and the like of the metal porous body No. 12 of the comparative example are almost the same. In addition to being excellent in strength, it possesses high strength that greatly exceeds that of Comparative Example No. 12, and as in No. 9 and No.
While maintaining the mechanical strength equivalent to No. 12, it is possible to make the pore size large and the pore distribution with high open porosity, and the difference from the conventional material is obvious.

[0017]

[Table 2] It is clear from Samples 6 to 10 that there are many through-holes extending between the front and back surfaces of the material because the ratio of open porosity / porosity is higher than that of the comparative example. As a result, the gas separation device 1 which employs the metal porous body produced in this way as the gas separation part 2 is excellent in thermal shock resistance and strength, and has excellent air permeability and is very easy to use. there were.

[Other Embodiment] In the above embodiment, a single gas separation unit 2 is provided, and a raw material gas supply passage 5 for selectively supplying a raw material gas or a carrier gas to the separation unit 2. In addition to the above, the product gas passage 6 that can selectively collect the gas coming out of the gas separation unit 2 into the storage unit 4 according to its state is provided. When taking, another kind of gas can be continuously separated. This device configuration will be described. In this device 100, the perovskite compound 4 is circulated in a constant circulation path 101 while being maintained in a predetermined temperature range. The circulation path 101 includes the low temperature section 101a.
And the high temperature part 101b are separated, and the compound 4 is circulated between the parts 101a and 101b to separate the gas. The apparatus 100 includes a pair of gas separation units 20 each including a raw material gas supply passage 50 for supplying a raw material gas or a carrier gas, a product gas passage 60 for collecting the delivered gas, and these gas separation portions. It is composed of a pair of connecting passages 30 that connect 20 and 20 in a circulating form of the compound. And these connection paths 30
Are configured to be maintained at the temperature of the gas separation unit 20 on the starting side, respectively. These gas separation parts 20 are made of a metal porous body peculiar to the present invention, as in the previous embodiment. The case where the perovskite compound is strontium iron oxide (SrFeO _x ) will be described below. In the drawing, the gas separation section 20 provided on the left side is the low temperature side gas separation section 20a, and in this section 20a, adsorption of oxygen from the air supplied via the raw material gas supply passage 50a to the compound 4 is prevented. Then, the nitrogen-rich product gas is discharged to the product gas passage 60a. The perovskite compound 4 in the state of adsorbing oxygen is moved to the high temperature side gas separation section 20b on the right side of the drawing while maintaining this temperature, and is heated at this site 20b. Therefore, oxygen is desorbed in the high temperature side gas separation unit 20b and is supplied to the oxygen-rich gas as the carrier gas supplied through the raw material gas supply passage 50b, and as the product gas, the oxygen-rich gas is supplied to the product gas passage 60b. Can be obtained. In the examples described so far, an example of strontium iron oxide (SrFeO _x ) was shown as the perovskite compound, but in addition to this, BaFeO _x , SrNiO _x , SrCoO 3
A compound having any chemical composition, such as _x , can be used as long as it exhibits oxygen nonstoichiometry depending on temperature and oxygen concentration. In the above examples, as the metal porous body of the present application, examples of stainless steel, alloy tool steel, and atomized powder are shown, but as a material that can obtain heat resistance and thermal shock resistance,
It is preferable to obtain a metal porous body by using a metal material containing Inconel, titanium, chromium or the like.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a gas separation device of the present application.

FIG. 2 is a diagram showing another embodiment of the gas separation device of the present application.

FIG. 3 is a diagram showing a configuration of a conventional gas separation device.

[Explanation of symbols] 2 gas separation part 3 electrode 4 perovskite compound 6 product gas path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Nishi Nishi 1-1-1, Nakamiya Oike, Hirakata-shi, Osaka Prefecture Kubota Hirakata Manufacturing Company (72) Inventor Akira Kosaka 1-1-1, Nakamiya Oike, Hirakata-shi, Osaka No. 1 stock company Kubota Hirakata Factory

Claims (1)

[Claims] 1. A perovskite compound (4) having different adsorption capacities for gases to be separated in different temperature regions.
A raw material for supplying a raw material gas to the gas separation part (2), the gas separation part (2) for accommodating the gas, the heating means capable of setting the temperature of the gas separation part (2) in a predetermined temperature range, A gas separation device comprising a gas supply path (5) and a product gas path (6) through which a separated gas sent from the gas separation section (2) flows, which is heated and under hydrostatic pressure. A metal porous body having a large number of pores penetrating between the front and back surfaces, which is obtained through a molding treatment process including a hot isostatic pressing sintering process for sintering a metal powder, and which is generated in the treatment process. A gas separation device, which constitutes the gas separation part (2), is provided with a pair of electrodes (3) on the porous metal body, and is capable of applying a voltage to the porous metal body.