JP2002012472A - Composite material, ceramic composition, oxygen separator, chemical reactor and method of manufacturing composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite material of a mixed conductor dense film and a porous body which has high oxygen permeability and is manufactured easily, and a ceramic composition for the above. SOLUTION: The composite material comprises the porous body of the mixed conductor oxide and a film containing a continuous dense layer of the mixed conductor oxide formed on the porous body. The oxide material consisting of the porous body is compacted at a temperature higher than that of the film. The ceramic composition which is an oxide ion mixed conductor with a perovskite structure is used for the porous body or the thin dense film. The composite material consisted of the above composition is useful for the application such as a permselective separator of oxygen and a diaphragm reactor of partial oxidation of a hydrocarbon for its excellent oxygen permeability, and is manufactured easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an industrial selective permeation / separation process of oxygen, or a dense mixed oxide ion conductor applied to a chemical reactor such as a membrane reactor for partial oxidation of hydrocarbons. The present invention relates to a composite material having a continuous film and a porous body as main components. The present invention also relates to a porcelain composition suitable for constituting the composite material.

[0002]

2. Description of the Related Art In recent years, a process of thinning an ion conductive material and industrially separating or purifying a specific component using the thin film has been remarkably advanced and developed. Above all, the process of separating and purifying oxygen by selectively permeating oxygen from air and other gas mixtures is expected to be applied from small-scale oxygen pumps for medical use to large-scale gas generation and purification plants. ing. In recent years, the use of a so-called diaphragm reactor, for example, in which an oxygen-mixed gas and a hydrocarbon gas are separated by a membrane made of an ion-conductive material and oxygen is selectively permeated to partially oxidize hydrocarbons, has been studied.

As an oxide ion conductive ceramic material that can be used for this purpose, an oxide ion conductor that transmits only oxygen ions and an oxide ion mixed conductor that simultaneously transmits oxygen ions and electrons or holes are known. ing. Among them, oxide ion mixed conductors can transmit electrons or holes by themselves, so that the charge necessary to maintain the movement of oxygen ions can be compensated without forming an external current circuit. As such, it is believed to be more suitable for oxygen separation and diaphragm reactor applications.

[0004] That is, in order to perform oxygen separation using an oxide ion mixed conductor, it is only necessary to make the oxygen potentials on both sides of the mixed conductor different, and from the higher oxygen partial pressure side to the lower oxygen partial pressure side. Only oxygen permeates the mixed conductor, other gas components cannot permeate the mixed conductor,
Selective permeation and separation of oxygen can be performed. The principle is the same in the case of the diaphragm reactor, and the oxygen component selectively permeates the mixed conductor because the oxygen potential on the hydrocarbon gas side is low. Since the permeated oxygen component is consumed by the oxidation reaction of the hydrocarbon gas, the oxygen potential on the hydrocarbon gas side is kept extremely low.

In order to put such a selective permeation / separation process of oxygen or a membrane reactor into practical use, a material having high oxygen ion conductivity is required.
Some ceramics having a perovskite type crystal structure, for example, a porcelain composition of the following formula (a) disclosed in JP-A-56-92103, or JP-A-61-21717.
The porcelain composition represented by the following formula (b) and the like disclosed in Japanese Patent Application Laid-Open Publication No. H10-163, are known as potential candidate materials. In addition, JP-A-6-206707 proposes an ion transport permeable membrane represented by the following formula (c) and having an extremely wide composition range. [La _x Sr _(1-x) ] CoO _3-α (x ranges from 0.1 to 0.9, α ranges from 0 to 0.5) ... (a) [La _(1-x) Sr _x ] [Co _(1-y) Fe _y ] O _(3-δ) (x is in the range of 0.1 to 1.0, y is in the range of 0.05 to 1.0, δ is in the range of 0.5 to 0) ... (b) A _x A '_x' A "_x" B _y B '_y' B "_y" O _3-z (A and A "are selected from the group consisting of groups 1, 2, and 3 according to the Periodic Table of the Elements adopted by IUPAC and lanthanides having f periods, where A 'is Sr, Ca and Mg is selected from the group consisting of Mg, and B, B 'and B "are selected from transition metals of d period, and further 0 <x <1, 0 <x'<1, 0 <x"<1, 0 < y <1, 0 <y '<1, 0 <y "<1, x + x' + x" = 1, y + y '+ y "= 1, and z indicates that the charge of the composition is neutral. Numerical value given at some time) ... (c)

On the other hand, the elementary process which becomes rate-determining when oxygen passes through the mixed conductor is based on the diffusion process in the mixed conductor (diffusion-determining) as the thickness of the mixed conductor is reduced.
It changes into a process of oxygen exchange reaction with the gas phase at the surface of the mixed conductor (surface reaction rate-limiting). Therefore, even when the mixed conductor materials having the same composition are used, as long as the surface reaction is controlled, the thinner the thickness, the larger the amount of permeation of oxygen can be increased.

For this reason, as a method of actually performing oxygen separation, an oxide ion mixed conductor is not formed as a single bulk, but is formed as a dense thin film on a porous support. (Teraoka et al., The Ceramics Society of Japan, vol.
97, No. 4, pp 467-72, 1989).

[0008] The mechanical strength of the composite material is ensured by the porous body portion, and the porous body functions as a support. The role of selectively permeating and separating oxygen from the source gas is played by the thin film portion. Note that in this specification, a thin film or a continuous phase is dense.
It indicates that no gas leaks through the film or layer or that it is practically negligible.

Regarding the conditions of the material for forming the porous body, the following three are mentioned in the above-mentioned paper. 1) Good adhesion to the oxide ion mixed conductor film. 2) Not reacting with the oxide ion mixed conductor membrane or, even if it reacts, the product does not decrease the oxygen permeability. 3) The thermal expansion coefficient is substantially equal to that of the oxide ion mixed conductor film.

[0010]

However, the above conditions are indispensable for a mixed conductor film to be formed on a porous body in a sound manner, but materials satisfying these conditions 1) to 3) at the same time. Is not easy to find. First, in connection with the above condition 3), Co and / or Fe-containing perovskite, which is a promising candidate for an oxide ion mixed conductor membrane,
The oxide has a problem that it has an unusually large coefficient of linear thermal expansion. For example, the average linear thermal expansion coefficient of the oxide of the following formula (d) and the oxide of the following formula (e) disclosed in JP-A-9-235121 from room temperature to 800 ° C. is about 26 ppm / ° C., respectively. And about 20 ppm / ° C, whereas even oxide magnesia, which is known to have a large coefficient of linear thermal expansion, is 13.4 ppm / ° C (YS Touloukian et al., Th
ermophysical Properties of Matter vol. 13, IFI / Plen
um), which are greatly different values. (La _0.2 Sr _0.8 ) (Co _0.8 Fe _0.2 ) O _(3-δ) ... (d) (La _0.2 Sr _0.8 ) (Co _0.4 Fe _0.4 Cu _0.2 ) O _(3-δ) ... (e) (La _{1- x} Sr _x ) CoO _(3-δ) ... (f) (La _0.6 Sr _0.4 ) CoO _(3-δ) ... (g)

In addition, the perovskite-type oxide has low coexistence with other oxide materials, and the condition 2) also greatly restricts the choice of material. For example, when a typical oxide material such as alumina or zirconia is used as a support and an oxide of the above formula (f) is sintered as a thin film thereon, the alkaline earth element in the perovskite is extracted. This causes a problem that the membrane is decomposed, and cations form a solid solution from the support in the perovskite, and the oxygen permeation rate is greatly reduced.

In order to avoid such a problem, Teraoka et al. Proposed in the above-mentioned paper to produce a porous body with the same porcelain composition as the ion-mixed conductor film, and another literature ( Teraoka et al., The Ceramic Society of Japan
vol. 97, No. 5, pp. 533-38, 1989), a composite in which the porous body and the mixed conductor film are both oxides of the above formula (g) is being experimentally manufactured.

In other published patents and papers relating to oxygen separation, the material of the porous body is determined based on the above conditions 1) to 1).
In many cases, anything that satisfies 3) may be used. However, there are few examples in which a composite conductor is formed by forming a dense film of a mixed conductor on a porous body, and as disclosed in Japanese Patent Application Laid-Open No. 8-276112, a trial production of a composite material is performed. Even in such a case, the porous body still has the same composition as the dense film of the mixed conductor. As described above, the porous body in the prior art had to be practically forced to have the same composition as the mixed conductor film in order to satisfy the required severe conditions.

On the other hand, when the porous body and the mixed conductor film have the same composition, the sinterability of the porous body and the film is the same. Under this condition, a mixed conductor film without gas leakage, that is,
If a dense and dense film is to be formed on a porous body by sintering or the like, the porous body will be densified at the same time during the film formation process, and the porosity of the porous body will decrease. I will. When the porosity of the porous body is reduced, the gas permeation rate in the porous body is reduced, which causes a problem that the oxygen separation performance of the composite is reduced.

On the other hand, if the firing temperature of the film is lowered or the firing time is shortened in order to avoid a decrease in the porosity of the porous body, the mixed conductor film cannot be sufficiently densified. In this case, during the oxygen separation process, the supply gas component leaks through the membrane portion, and the raw material gas is mixed with the separated oxygen, resulting in a problem such as a decrease in the purity of the obtained oxygen.

In the method of forming the porous body and the mixed conductor film from the same material as described above, it is difficult to manufacture a composite material having a high oxygen separation rate. The range is extremely narrow. In the production of a composite material for oxygen separation and a diaphragm reactor combining a dense membrane of a mixed conductive material and a porous body, examples disclosed prior to the filing of the present invention show that there is such a technical problem. There is nothing in the scope of the inventors' investigation, and therefore no solution is known.

The above is a technical problem common to materials for a selective permeation / separation process of oxygen and a material for a membrane reactor such as partial oxidation of hydrocarbons utilizing a mixed conductor membrane. With regard to these, in addition to these, the hydrocarbon gas side atmosphere becomes a low oxygen partial pressure,
In some cases, the mixed conductor material constituting the diaphragm and / or the porous support is reduced to cause a volume change, which causes a problem that a crack is generated and, in an extreme case, destroyed. Therefore, a mixed conductor material for a chemical reaction device (diaphragm reactor) utilizing a diaphragm process needs to have excellent fracture resistance (reduction resistance) under a low oxygen partial pressure. Such problems are well known in the field of solid oxide fuel cells utilizing ionic conductor membranes, but have not yet been fully explored in this field utilizing mixed conductors. For example, U. Balachandran et al., La _0.2 Sr _0.8 Fe _0.2 Co _0.8 O _x material having a perovskite type crystal structure breaks under the partial oxidation condition of methane, but the crystal structure is non-perovskite type and SrCo _0.5 FeO _x It is reported that the material of the composition had excellent resistance to reduction and could be used for a long time without breaking as a diaphragm for partial oxidation of methane (U. Balachandran et a.
l., Applied Catalysis A: General, vol.133 (1995) 19-
29). However, there was no example disclosed before the filing of the present invention regarding a measure for improving the reduction resistance of a mixed conductor having a perovskite type crystal structure without changing the crystal structure, within the scope of the present inventors' investigation. .

An object of the present invention is to provide a porous body in the fields of oxygen separation and membrane reactors, which is required for the above-mentioned 1) to 3).
In order to satisfy the condition, the porous body must be formed of the same material as the dense continuous film. In the prior art, it is inevitable in the prior art that the production of a composite material having a high oxygen permeation rate is difficult. An object of the present invention is to provide a solution and a new porcelain composition suitable for solving the problem. Another object of the present invention is to provide a material which exhibits a particularly excellent range of reduction resistance among the porcelain compositions and is particularly suitable for diaphragm reactor applications.

[0019]

According to the present invention, there is provided a composite material comprising a porous body having a mixed conductive porous oxide, and a mixed conductive oxide formed on the porous body. Wherein the densification temperature of the oxide material constituting the porous body portion is higher than the densification temperature of the material of the film portion.

In one embodiment of the composite material of the present invention,
The porosity of the porous body is in the range of 20% to 80%, and the thickness of the dense continuous layer is 10 μm to 1 mm.

The porcelain composition of the present invention is a mixed oxide ion conductor having a perovskite crystal structure, and has a composition represented by the following general formula (Formula 1). [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (1) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. )

In one embodiment of the porcelain composition of the present invention, in the above (Formula 1), B is at least one selected from Co, Fe, Cr and Ga, which always contains Fe. In the combination of elements, the mole number of Co is 0% or more 1
0% or less, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or less based on the number of moles x of all B elements, and B ″ is one or more kinds selected from Zn, Li, and Mg. It is a combination of elements.

In one embodiment of the composite material of the present invention,
The porous body is a mixed oxide ion conductor having a perovskite crystal structure, and has a porcelain composition represented by the following general formula (Formula 1). [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (1) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. )

In one embodiment of the composite material of the present invention,
In the above (Equation 1), B is F among Co, Fe, Cr, and Ga.
e is one or a combination of two or more elements always selected, and the mole number of Co is 0% or more and 10% or more of the mole number of Fe.
Below, and the sum of the number of moles of Cr and Ga is the number of moles x of all B elements
0% or more and 20% or less, B ″ is selected from Zn, Li, Mg 1
A species or a combination of two or more elements.

In one embodiment of the composite material of the present invention,
The dense continuous layer is a mixed conductive oxide ceramic having a composition represented by the following general formula (Formula 2). [Ln _1-a A _a ] [B _x B ' _y ] O _(3-δ) (2) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of one or two elements selected from Fe and Co. B 'is 1 selected from Cu, Ni, Zn, Li, and Mg
A species or a combination of two or more elements. Where 0.8 ≦ a ≦
1, 0 <x, 0 ≦ y ≦ 0.2, 0.98 ≦ x + y ≦ 1.02, and δ are values determined to satisfy the charge neutrality condition. )

In one embodiment of the composite material of the present invention,
The dense continuous layer is a mixed oxide ion conductor having a perovskite-type crystal structure, and is a porcelain composition represented by the following general formula (Formula 1). [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (1) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. )

In one embodiment of the composite material of the present invention,
In the above (Equation 1), B is F among Co, Fe, Cr, and Ga.
e is one or a combination of two or more elements always selected, and the mole number of Co is 0% or more and 10% or more of the mole number of Fe.
Below, and the sum of the number of moles of Cr and Ga is the number of moles x of all B elements
0% or more and 20% or less, B ″ is selected from Zn, Li, Mg 1
A species or a combination of two or more elements.

In one embodiment of the composite material of the present invention,
The dense continuous layer is a mixed oxide ion conductor having a perovskite-type crystal structure, and is a porcelain composition represented by the following general formula (Formula 1), wherein the sum of the contents of Nb and Ta is Is less than the sum of the contents of Nb and Ta in the porous body. [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (1) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. )

In one embodiment of the composite material of the present invention,
In the above (Equation 1), B is F among Co, Fe, Cr, and Ga.
e is one or a combination of two or more elements always selected, and the mole number of Co is 0% or more and 10% or more of the mole number of Fe.
Below, and the sum of the number of moles of Cr and Ga is the number of moles x of all B elements
0% or more and 20% or less, B ″ is selected from Zn, Li, Mg 1
A species or a combination of two or more elements.

The oxygen separation apparatus of the present invention has the above-mentioned composite material. Further, an oxygen separation device of the present invention has the above-described porcelain composition.

The chemical reaction device of the present invention has the above-mentioned composite material. Further, a chemical reaction device of the present invention has the above-described porcelain composition.

In the method for producing a composite material according to the present invention, the porous body portion having the mixed conductive porous oxide is formed by forming the mixed conductive oxide layer on the porous body portion in a dense continuous state. Baking at a temperature higher than the baking temperature of the layer to form a film portion including a dense continuous layer on the porous body portion.

[0033]

DETAILED DESCRIPTION OF THE INVENTION The inventors of the present invention have studied the problem that it is difficult to produce a composite material having a high oxygen permeation rate when the porous body is formed of the same material as the dense membrane. Attention was paid to the temperature required for densification of each material constituting the composite material, which has not been performed. Then, when the densification temperature of the oxide material constituting the porous body is sufficiently higher than the densification temperature of the film part material, the porosity of the porous body hardly decreases even in the process of forming the film part, It has been found that a composite material having a high oxygen transmission rate can be easily produced.

In producing such a composite material, a porcelain composition satisfying the following conditions is effective as a material for the porous body. 1) High densification temperature. 2) Good adhesion to the oxide ion mixed conductor film. 3) It does not react with the oxide ion mixed conductor membrane, or even if it reacts, the product does not decrease the oxygen permeability. 4) The thermal expansion coefficient is almost equal to that of the oxide ion mixed conductor film. 5) High oxygen permeation rate. Among these conditions, the oxygen permeation rate 5) is also important for the porous body. This is for the following reason.

That is, a mixed conductor having a high oxygen permeation rate is
It has a high surface exchange reaction rate with high oxygen ion conductivity, and the exchange reaction between oxygen in the gas phase and oxygen ions in the solid phase is fast. When such a material is in contact with a mixed conductive dense membrane as a porous body, the effect of promoting the exchange reaction of oxygen on the surface of the dense membrane is expected due to the large surface area of the porous body. . As a result, even when the same mixed conductor material is used for the dense membrane, a composite material having higher oxygen separation characteristics can be obtained if the porous material has a high oxygen permeation rate.

Among the conditions of the above-mentioned porcelain composition, the inventor paid attention next to the fact that the linear thermal expansion coefficient of the oxide ion mixed conductor film must be substantially equal to that of the oxide ion mixed conductor film.
As described above, the linear thermal expansion coefficients of the candidate materials for the mixed conductor film are all 20 to 25 ppm / ° C., which is unusually large as an oxide material. As a result of investigation, it has been found that a perovskite oxide containing Co and / or Fe at the B site is suitable as an oxide material having a thermal expansion coefficient as large as this.

However, Co and / or Fe is added to the B site.
Depending on the temperature and oxygen atmosphere, even perovskite-type oxides can change the crystal structure from cubic to JCPDS No. 40-10.
It may change to hexagonal as shown in 18,
When this structural change occurs, the coefficient of thermal expansion drops significantly,
It has also been found that it becomes unsuitable as a porous material.

Based on these findings, a perovskite-type oxide containing Co and / or Fe at the B site has a high densification temperature, and the perovskite-type structure has a wide temperature range from the temperature at which a thin film is formed to room temperature. We have sought to find a material that is stable over a wide range of oxygen partial pressures when composite materials are used.

As a result, (1) by adding Nb and / or Ta in addition to Co and Fe to the B site of perovskite, the perovskite structure can be further stabilized, and the firing temperature can be greatly reduced. To obtain a porous body that can be heated to a high temperature and that does not easily cause a decrease in porosity even after heat treatment.
(2) A part of Co and / or Fe is converted to Nb by Cr and / or Ga.
Even if a part of Ta and / or Ta is replaced by Ti and / or Zr, the material properties such as crystal structure, coefficient of thermal expansion, firing temperature and the like are not significantly changed if the total replacement amount is below a limit value. No, (3) Co, Fe, Nb, and part of Ta are Cu, Ni, Z
If the total substitution amount is equal to or less than the limit value even if n, Li, and Mg are substituted, the same as above, the crystal structure, the coefficient of thermal expansion, the material properties such as high firing temperature are not significantly changed. It was also found that (4) a composition range that does not contain Cu and Ni and has a Co content below a certain limit value is particularly excellent in reduction resistance, in which oxygen permeability is improved.

When a dense film of an oxygen-permeable mixed conductor is formed on the porous body, the thermal expansion coefficient is well matched, the adhesion of the film is good, and the ionic conductivity of the film is reduced. No such reaction occurred, and it was confirmed that the porous body was extremely excellent.

Further, the porcelain composition developed for the porous body is a mixed conductor, and a dense bulk is manufactured using the mixed conductor to evaluate the oxygen permeation rate. It was confirmed that the material has a high oxygen permeation rate equal to or higher than that of a typical material, for example, the oxide of the formula (f). This result indicates that the porcelain composition of the present invention is useful not only as a porous material but also as a dense film material. Therefore, the present inventors have studied a material for a dense membrane capable of obtaining a composite material having high oxygen separation performance in combination with the porous body made of the above-described porcelain composition, and have completed the present invention.

In the composite material provided by the present invention, the porous body portion is composed of a mixed conductive oxide and has a porosity of preferably 20% or more and 80% or less, more preferably 40% or more and 60% or less. % Or less. The range of the porosity of the porous body is determined by the conditions under which the porous body does not become a gas permeation resistance during the oxygen separation process and the conditions under which the mechanical strength of the composite material is kept healthy. The porosity of the porous body is
Calculated by {100-relative bulk density (%)}, which is the bulk density of the porous body divided by the theoretical density. The bulk density of the porous body
Alternatively, in the case of a porous body having a simple shape such as a plate, it can be easily obtained by measuring the outer size of the support, obtaining the volume, and dividing the weight.

The porosity of the porous body can be changed by the composition of the porous body material, the amount and type of the resin to be mixed, the molding conditions, and the firing temperature. The porosity of the porous body can be increased by increasing the amount of resin to be mixed, lowering the pressure during molding, or lowering the firing temperature of the porous body.

The thickness of the dense continuous film of the mixed conductor of the film portion formed on the porous body may be any thickness as long as the separation rate of oxygen and the selectivity of gas are not reduced. A range of 10 μm or more and 1 mm or less is preferable. If the thickness of the dense membrane is larger than this, the amount of oxygen that can be separated by the composite material may decrease. If the thickness is reduced outside this range, it is difficult to form a dense film without gas leak, and the strength of the film is reduced and the film is easily broken. In some cases, problems such as a decrease in gas selectivity may occur.

In order to determine the combination of the materials of the porous body and the dense continuous film, it is important to pay attention to the relationship of the densification temperature of the material, which is the point of the present invention. Specifically, the densification temperature of the porous body needs to be at least 20 ° C. or higher, preferably 50 ° C. or higher, higher than that of the dense film. The densification temperature of a material referred to here is a firing temperature required to make the relative density of the material, for example, 94% or more.

However, the relative density as a measure of the densification does not necessarily need to be 94%, but can be determined in the range of 90% or more and 100% or less. It is important that the firing temperature at which the relative density becomes equal to or higher than the determined value is determined for each material, and this is compared to determine the combination of the porous body and the dense continuous film.

In the film portion, in addition to the dense film, the surface of the film,
Alternatively, it may include a porous catalyst layer of metal or oxide formed at the interface between the membrane and the porous body. This porous catalyst layer increases the rate of oxygen / oxygen ion exchange reaction between the gas phase and the solid phase or the rate of oxidation reaction of hydrocarbons or the like on or near the surface of the dense membrane, and in some cases, progresses the specific reaction. This is effective for suppressing the reaction and expressing the reaction selectivity. Note that the type, number, and arrangement position of the catalyst layers may be selected as needed. For example, the inside or surface of any porous layer provided on the membrane, and the inside or surface of a porous body as a support. May be arranged.

The porcelain composition provided by the present invention is represented by the following (formula 1) and has a perovskite crystal structure. The A site of the perovskite structure (the site where 12 anions are coordinated) is represented by [Ln _1-a A _a ] in Formula 1,
Is a combination of one or more elements selected from Y or lanthanoid elements, and A is a combination of one or more elements selected from Ba, Sr, and Ca;
≦ a ≦ 1. Regardless of the choice of Ba, Sr, or Ca, or the selection and combination of two or more of these elements, properties such as crystal structure stability and oxygen permeability do not change significantly. Can also be used as the porcelain composition of the present invention. Ln introduced on site A
Produces an effect of stabilizing the perovskite-type crystal structure by introduction, but when Ln is introduced beyond the above range,
Because the oxygen permeability as a porcelain composition is reduced,
This leads to a decrease in oxygen permeation performance when made into a composite material. [Ln _1-a A _a ] [B _x B ' _y B " _z ] O _(3-δ) ... (Equation 1)

In the porcelain composition of the present invention, a B site having a perovskite structure (a site to which six anions are coordinated, and B represented by [B _x B ′ _y B ″ _z ] in the formula 1) B ', and
The B '' element group) must contain at least one of Co and Fe as a B element, and always contain at least one of Nb and Ta as a B 'element. That is, in Expression 1, x and y are always larger than 0. Even if a part of Co and / or Fe is replaced with Cr and / or Ga of 0% or more and 20% or less with respect to the total number of moles of the B element (that is, x in the formula 1), the material properties are not significantly changed. Absent. Nb and Ta may be used alone or in combination, but the total amount is 0 <y
≦ 0.5. When the amount of Nb and Ta is increased, the densification temperature rises, but when the amount of Nb and Ta is out of this range, the second phase is generated and the linear thermal expansion coefficient changes,
Problems such as a decrease in the oxygen permeability of the composite material occur. Part of Nb and / or Ta is the number of moles of all B 'elements.
Substituting 0% or more and 20% or less of Ti and / or Zr with respect to (i.e., y in Formula 1) does not significantly change the material properties. The B site also contains Cu and N as B '' elements
It may include one or a combination of two or more elements selected from i, Zn, Li, and Mg. Since these B ″ elements have a valence smaller than 3, the introduction of these elements causes oxygen deficiency in the oxide, and as a result, has the effect of increasing oxygen permeability. However, if too much B '' element is introduced, the perovskite crystal structure becomes unstable, so that the range is limited to 0 ≦ z ≦ 0.2. A
The ratio between the site and the B site can be changed in the range of 0.98 ≦ x + y + z ≦ 1.02, but this can also control the sinterability of the material to some extent. However, when the ratio of the A site and the B site is out of this range, a second phase is generated, which is not preferable.

When it is necessary to particularly improve the fracture resistance, that is, the reduction resistance of the above-mentioned porcelain composition under a low oxygen partial pressure as in the case of a diaphragm reactor, it is an element which is easily reduced among the B elements. The content of Co is set to 10% or less with respect to the number of moles of Fe, and Cu and Ni which are easily reduced among the B ″ elements are not included. In addition, among the B elements, Cr and G
a, B 'element Nb, Ta, Ti, and Zr, B''element Zn, L
Since i and Mg are elements that are harder to be reduced than Fe, which is one of the B elements, the restriction on the content does not change.

The porcelain composition having the above composition range has not been studied or reported for the purpose of oxygen separation or diaphragm reactor, etc., and is a novel material which has been found useful by the present invention for the first time.

In the composite material provided by the present invention, a preferred material for the porous body is the porcelain composition of the above formula (1). In the perovskite B site, in addition to Co and Fe,
By containing Nb or Ta, the perovskite structure can be stabilized, and the firing temperature can be significantly increased, so that the porous body is not easily reduced in porosity even when heat-treated. is there.

On the other hand, one of the preferable mixed conductive materials to be formed as a dense continuous film on the porous body prepared from the porcelain composition of the above (formula 1) has a composition represented by the following general formula ( Expression 2) [Ln _1-a A _a ] [B _x B ' _y ] O _(3-δ) (Equation 2)

The A site is represented by [Ln _1-a A _a ], where Ln is one or a combination of two or more elements selected from Y or lanthanoid elements, and A is one of Ba, Sr and Ca. 0.8 ≦ a ≦ 1 in combination of one or more elements selected from
Range. Regardless of the choice of Ba, Sr, or Ca, or the selection and combination of two or more of these elements, properties such as crystal structure stability and oxygen permeability do not change significantly. Can also be used as the dense continuous film of the present invention. Ln introduced into the A site has an effect of stabilizing the perovskite-type crystal structure by the introduction, but if Ln is introduced beyond the above range, the oxygen permeability decreases.

The B site is represented by [B _x B ' _y ] and contains at least one of Co and Fe as a B element. B 'is Cu, N
It is a range of 0 ≦ y ≦ 0.2 in one or a combination of two or more elements selected from i, Zn, Li, and Mg. Since the B site does not contain Nb and Ta, it has a densification temperature lower than the densification temperature of the porous body, and contains at least one of Co and Fe. Has the advantage of having a linear thermal expansion coefficient of Further, by having an element group having a smaller valence at the B site, oxygen vacancies are generated, and as a result, there is an advantage that a high oxygen permeability is realized. However, if too much element is introduced, the perovskite-type crystal structure becomes unstable, so that the amount of B ′ element introduced is limited to a range of 0.2 or less. That is,
In Expression 2, 0 ≦ y ≦ 0.2.

The value of x + y defining the ratio between the A site and the B site is 0.98 ≦ x + y ≦ 1.02. This is because, if it is out of this range, the second phase is generated or the oxygen permeation rate is decreased, which is not preferable.

A more preferred mixed conductive material for the dense continuous film is a porcelain composition represented by the following formula (1). this is,
This is because the inclusion of Nb and / or Ta has a great advantage in that a more stabilized crystal structure can be formed without impairing the oxygen permeability, but rather while enhancing the ability. However, the composition needs to be selected so that the densification temperature of the film material is lower than the densification temperature of the porous body. The densification temperature of the dense continuous film can be made lower than the densification temperature of the porous body by making the Nb and Ta contents of the film smaller than the Nb and Ta contents of the porous body. Also, Cu, Li,
The densification temperature can be controlled to some extent by increasing or decreasing the content of other elements such as Ba.
It is easier to control the Ta content.

In the present invention, a reinforcing body may be provided in addition to the porous body and the membrane for the purpose of reinforcing the strength of the composite.

For the production of the porous body according to the present invention, a method usually used for producing a porous ceramic body can be used. As one of the methods, there is a method in which an oxide containing a necessary element is used as a raw material and is fired. In addition, as a raw material, in addition to oxides, salts, for example, carbonate,
Use inorganic acid salts such as nitrates and sulfates, organic acid salts such as acetates and oxalates, halides such as chlorides and bromide iodides, or hydroxides and oxyhalides, and use them in a predetermined ratio. And firing.

A method of dissolving a water-soluble salt in water at a predetermined ratio and evaporating and drying the salt, or
Co-precipitation method of drying by freeze-drying or spray-drying and then firing, dissolving water-soluble salts in water, adding an alkaline solution such as aqueous ammonia to precipitate hydroxides and firing. Alternatively, a sol-gel method of using a metal alkoxide as a raw material, hydrolyzing the metal alkoxide, obtaining a gel, and calcining the gel is also applicable.

The sintering of the porous body is generally divided into two steps, that is, calcination and main sintering (sintering). The calcination temperature is usually in the range of 400 to 1000 ° C. for several hours to several tens of hours. The calcined powder may be molded as it is and then subjected to main firing, or the calcined powder may be mixed with a resin such as polyvinyl alcohol (PVA) and then formed and subjected to main firing. The firing temperature varies depending on the composition, etc.
It is in the range of 0 to 1400C, preferably 1000 to 1350C.

For the main firing, a temperature higher than the temperature at which the film is fired on the porous body later is selected. The time for the main firing varies depending on the composition and the firing temperature, but usually requires several hours or more. The atmosphere for the main firing is generally sufficient in the air, but may be fired under a controlled atmosphere if necessary. As a method of forming the porous body, similarly to the production of ordinary bulk ceramics, calcined powder or mixed powder may be filled in a die, and then pressed and molded, or a slurry casting method or an extrusion method. A molding method or the like may be used.

On the other hand, the dense continuous film can be produced by a method usually used for producing a ceramic film.
The film may be formed by a so-called thin film forming method such as PVD or CVD such as a vacuum evaporation method, but more economically, a raw material powder or a calcined powder in a slurry state is applied on a porous body and fired. Is preferred. The firing temperature of the dense film is
While densifying the film so that gas leak does not occur,
It is necessary to select conditions under which the porosity of the porous support does not significantly decrease during the firing process. If the combination of the material of the dense membrane and the material of the porous support is determined according to the requirements of the present invention, the firing temperature of the dense membrane is sufficient to be about the densification temperature of the material constituting the membrane. In the firing time,
Usually takes several hours.

In order to selectively permeate and separate oxygen from an oxygen-containing gas mixture by the composite material formed by the above process, the oxygen potential on both surfaces of the composite material may be made different. For example, in order to separate oxygen from the atmosphere, it is only necessary to pressurize the raw material air side or reduce the pressure on the oxygen extraction side. The operating temperature of this oxygen separation is in the range of 500-1000C, preferably 650-950C. In the case of a diaphragm reactor, an oxygen-containing gas such as air may flow through one of the diaphragms, and a hydrocarbon gas may flow through the other. The operating temperature is the same as in the case of oxygen separation.

As described above, the composite material and the porcelain composition of the present invention can be applied to an apparatus for producing pure oxygen or oxygen-enriched air. Further, the present invention can be used for applications other than oxygen separation, particularly for a chemical reaction device involving an oxidation reaction. For example, it can be used for a reactor for the partial oxidation reaction of methane, which produces a synthesis gas composed of carbon monoxide and hydrogen from methane.

Conventionally, a reactor has been used which obtains a synthesis gas by a catalytic partial oxidation reaction (catalytic reaction) using a mixed gas of methane and oxygen as a starting material. In the membrane reactor using the mixed conductive ceramics of the present invention, for example, air (or a mixed gas containing oxygen) and methane are separately flowed through the mixed conductive ceramics, and Rh is applied to the ceramic surface on the side where the methane is flowing. For example, a conventional catalyst for syngas production is arranged. By heating the ceramic, only oxygen permeates according to the same principle as oxygen separation, and then reacts with methane on the methane-side ceramic surface to generate synthesis gas.

Therefore, unlike the conventional method, it is not necessary to separate oxygen from the oxygen-containing source gas (oxygen source such as air) in advance, and components other than oxygen in the oxygen-containing source gas (for example, oxygen-containing source gas). When air is used as the gas, there is a great effect that a synthesis gas can be obtained without mixing nitrogen or other components other than oxygen), a reaction occurs continuously, and the production apparatus is simplified. In addition to the partial oxidation of methane, the present invention can be used in any reaction apparatus involving an oxidation reaction, such as partial oxidation of hydrocarbons to form olefins, partial oxidation of ethane, and substitution of aromatic compounds.

[0068]

EXAMPLES The present invention will now be described in detail with reference to Examples, which are for the purpose of illustration only, and the scope of the present invention is not limited to these contents.

(First Example) In this example, the densification temperature, crystal structure, and linear thermal expansion were determined to confirm that the porcelain composition provided by the present invention was suitable for a porous body or a dense film. The coefficient and the oxygen transmission rate were evaluated. The raw materials of the sample include La ₂ O ₃ , CaCO ₃ , SrCO ₃ , BaCO ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , Nb ₂ O ₅ ,
Ta ₂ O ₅ , CuO, ZnO, NiO, Li ₂ CO ₃ , MgO, Cr ₂ O ₃ , Ga ₂ O ₃ ,
Using TiO ₂ and ZrO ₂ , a required amount was weighed, and then ball mill mixing was performed together with zirconia balls for 24 hours using isopropyl alcohol as a dispersion medium. The resulting slurry is dried, crushed, and packed into MgO square pods, 850 in air.
Calcination was performed at 12 ° C. for 12 hours. Grind the calcined powder obtained, 12mm
It was packed in a φ die, uniaxially formed into a tablet shape, and further packed in an ice bag to perform CIP molding. The obtained molded body was fired for 5 hours at each sintering temperature in a square pod made of MgO, and about 10 mmφ
Was obtained.

This sintered body was polished to a thickness of 1 mm, bonded to the end of an Al ₂ O ₃ tube, exposed to air on the outside, and depressurized on the inside. The oxygen partial pressure on the reduced pressure side was measured, and the oxygen permeation rate was determined based on the difference from the partial pressure value when there was no oxygen permeation through the sintered body. The sample temperature was 750 ° C. The measured value is expressed in terms of the volume of permeated oxygen per unit area per unit surface area of the mixed conductor in a standard state, and the unit is cc / cm ² · min. The presence or absence of gas leakage through the sample was examined using a helium leak detector, changing the outside to a mixed gas of air and helium. As a result, no gas leak was observed in the samples within the scope of the present invention.

Sample composition, densification temperature, powder X at room temperature
Table 1 shows the results of the identification of the constituent phases by the line diffraction method, the linear thermal expansion coefficient in the range from room temperature to 800 ° C., and the measured value of the oxygen transmission rate. Here, the densification temperature is a temperature required to make the relative density 94% or more. In the column of constituent phases, C indicates that a cubic perovskite phase was included, and H indicates that a BaNiO ₃ type hexagonal phase was included.

[0072]

[Table 1]

From Examples 1, 2 and 5 to 8 in Table 1, it can be seen that the densification temperature increases as the Nb content increases.
Comparison between Example 5 and 25 to 28, and Example 18
And 29, the material properties greatly changed within the scope of the present invention even if part of Co or Fe was replaced by Cr or Ga, or part of Nb or Ta was replaced by Ti or Zr. It turns out not to be.

The materials within the scope of the present invention have a high densification temperature, a cubic perovskite structure is stable even at room temperature, have a linear thermal expansion coefficient of 20 ppm / ° C. or more, and are close to mixed conductors for dense films. It was confirmed that the porous material was suitable for use. In addition, this material has a high oxygen permeation rate and can be sufficiently used as a material for a dense membrane.

(Second Embodiment) In this embodiment, after the porous body was manufactured, it was confirmed that the characteristics of the porous body of the porcelain composition provided by the present invention did not deteriorate even after film formation. The heat treatment was further performed at the same temperature as that for forming the dense film, and the porosity before and after the treatment was compared. 30% by weight of PVA was added to the calcined powder produced in the same manner as in the first example, and the mixture was mixed and pulverized for 2 hours by a ball mill. The obtained mixed powder was packed in a 12 mmφ die, uniaxially formed into a tablet shape, and further packed in an ice bag to perform CIP molding. The obtained molded body was degreased at 450 ° C. for 5 hours in a square pod made of MgO, and further fired at each firing temperature for 5 hours. A disk-shaped porous body having a thickness of 1 mm was cut out from the obtained sintered body, and the porosity was measured. In addition, 1200 ° C for this substrate
Heat treatment was performed for 5 hours, and the porosity was evaluated again. This heat treatment is performed under substantially the same conditions as the formation of the dense film, and changes in the porous body during the thin film formation process can be confirmed.

Table 2 shows the composition of the sample, the densification temperature of the composition, the firing temperature at the time of producing the porous body, and the porosity after firing and after the heat treatment. After firing and after heat treatment,
If the porosity does not become a value larger than 20%, it is determined that the porous body is not suitable. However, it is confirmed that the materials within the scope of the present invention satisfy this condition. Was.

[0077]

[Table 2]

(Third Embodiment) In this embodiment, a composite material was actually manufactured and its characteristics were confirmed. First, a disc-shaped porous body having a thickness of 1 mm was produced in the same manner as in the second embodiment. On the other hand, a calcined powder was prepared in the same manner as in the first embodiment, dispersed in water to form a slurry, applied and dried on one side of the porous body, and sintered for 5 hours in the air. Was done. This coating and baking process was repeated three times or more to form a dense mixed conductive ceramics thin film, thereby obtaining a composite material. The thickness of the formed thin film, assuming that the thin film is dense to the theoretical density, the weight change of the sample before and after the thin film formation, the thin film area obtained from the sample shape, further,
It was calculated by theoretical density. The oxygen transmission rate of the obtained composite material was measured by the same method as in the first example.
Further, for some of the composite materials, the porosity of the porous body after the formation of the film portion by removing the thin film portion was evaluated. Was also maintained within the range of 20% to 80%.

Table 3 shows the compositions of the porous body and the dense thin film, the sintering temperature of the porous body, the sintering temperature of the thin film, the thickness of the thin film, and the measured values of the oxygen transmission rate. Example 4 in Table 3
Comparing Comparative Examples 6 and 30, and Comparative Examples 30 and 31, the composite material according to the present invention maintains a high value of the oxygen permeation rate even when the calcination temperature of the film is changed.
It is wider than the conventional material of the comparative example. Comparing Examples 13 and 14, it can be seen that a higher oxygen permeation rate is more preferable when Nb is contained in the dense thin film than when Nb is not contained in the dense thin film. In Examples 25 and 26, since the thickness of the thin film was not within the preferable range of the present invention, the oxygen permeation rate was low and some leaks occurred. Example 1
3 to 23 and 24, the composition of the thin film was not within the preferred composition range of the present invention, so that the oxygen permeation rate was slightly lower than that of Examples 4 to 22 and 27 to 29, which were within the preferred composition range. Low.

[0080]

[Table 3]

The composite material within the scope of the present invention was prepared according to Comparative Example 30
Compared with Comparative Examples No. to No. 33, it was confirmed that a composite material showing excellent oxygen permeation characteristics and having a high oxygen permeation rate, which was difficult with the conventional technique, can be easily produced by the present invention.

(Fourth Embodiment) Embodiments 22 and 2 in Table 3
Disc-shaped samples of the composite materials shown in Nos. 8 and 29 were prepared by the method of the third embodiment, and the film side was an air atmosphere of 850 ° C, and the porous side was a 850 ° C 50% CH ₄ -Ar mixture. The resistance to reduction destruction under a low oxygen partial pressure was examined by exposure to a gas atmosphere. These are compositions in which the composition of both the porous support and the membrane is in a range particularly excellent in reduction resistance. The composite material of the present invention did not show any leakage of the Ar component even after holding for 10 hours or more under the above conditions. Next, the film side is 850 ° C.
50% CH ₄ -Ar mixed gas atmosphere, 850 ° C on the porous body surface side
, And the reduction destruction resistance was examined in the same manner as above. Also in this case, no leak of the Ar component was observed. 5
The 0% CH ₄ -Ar mixed gas side atmosphere has a low oxygen partial pressure, and if cracks occur in the film due to reduction of the film material and / or porous material, the Ar component should leak, Since it was not recognized, it was found that the porcelain composition and the composite material of the present invention had excellent resistance to reduction destruction. From this, it was confirmed that the porcelain composition and the composite material within the scope of the present invention are suitable for diaphragm reactor applications.

[0083]

According to the present invention, excellent oxygen permeation characteristics are exhibited in a technical field such as a selective permeation / separation process of oxygen by a mixed oxide ion conductor or a membrane reactor for partial oxidation of hydrocarbons. At the same time, it is possible to obtain a composite material of a dense continuous film of a mixed ion conductor and a porous material, which is easy to produce. Further, the porcelain composition disclosed by the present invention is excellent as a material for this porous body or dense thin film. These technologies provided by the present invention,
This greatly contributes to high performance and low cost of an oxygen separation device from air or a membrane reactor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 19/24 B01J 19/24 Z C04B 35/495 C04B 35/00 J (72) Inventor Donomae etc. Futtsu 20-1 Shintomi Nippon Steel Corporation Technology Development Headquarters (72) Inventor Noriko Yamada 20-1 Shintomi Futtsu-shi Nippon Steel Corporation Technology Development Headquarters (72) Inventor Tadashi Sakai 20 Futtsu City Shintomi -1 F-term in the Technology Development Division of Nippon Steel Corporation (Reference) 4D006 GA41 KA31 KB30 MA09 MB06 MB15 MB16 MC03X NA05 NA31 NA62 PB62 PC80 4G030 AA02 AA08 AA09 AA10 AA12 AA13 AA16 AA20 AA21 AA22 AA27 AA31 AA29 CA01 4G075 AA05 BA01 BA06 BD12 CA54 EE12 EE21 FA14 FB04 FC02

Claims (16)

[Claims] 1. A porous body portion having a mixed conductive porous oxide, and a film portion including a dense continuous layer of the mixed conductive oxide formed on the porous body portion. A composite material, wherein the densification temperature of the oxide material forming the porous body portion is higher than the densification temperature of the material of the film portion. 2. The porosity of the porous body is 20% or more and 80% or more.
2. The composite material according to claim 1, wherein the thickness is in the following range, and the thickness of the dense continuous layer is 10 μm or more and 1 mm or less. 3. An oxide-ion mixed conductor having a perovskite-type crystal structure, which has a composition represented by a general formula [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (I) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. A porcelain composition represented by the formula: 4. In the formula (I), B is a combination of at least one element selected from the group consisting of Co, Fe, Cr and Ga. 0% or more and 10% or less based on the number of moles, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or less based on the number x of moles of all B elements, B ''
The porcelain composition according to claim 3, wherein is a combination of one or more elements selected from Zn, Li, and Mg. 5. The porous body part is a mixed oxide ion conductor having a perovskite type crystal structure, and has a composition represented by a general formula [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ]. O _(3-δ) (I) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. 3. The composite material according to claim 1, comprising a porcelain composition represented by the formula: 6. In the formula (I), B is a combination of one or more elements necessarily including Fe from Co, Fe, Cr, and Ga, and the mole number of Co is Fe. 0% or more and 10% or less based on the number of moles, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or less based on the number x of moles of all B elements, B ''
The composite material according to claim 5, wherein is a combination of one or more elements selected from Zn, Li, and Mg. 7. The method according to claim 1, wherein the dense continuous layer has a general formula [Ln _1-a A _a ] [B _x B ' _y ] O _(3-δ) (II) (where Ln is selected from Y or a lanthanoid element) 1
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of one or two elements selected from Fe and Co. B 'is 1 selected from Cu, Ni, Zn, Li, and Mg
A species or a combination of two or more elements. Where 0.8 ≦ a ≦
1, 0 <x, 0 ≦ y ≦ 0.2, 0.98 ≦ x + y ≦ 1.02, and δ are values determined to satisfy the charge neutrality condition. 7. The composite material according to claim 5, which is a mixed conductive oxide ceramic having a composition represented by the formula: 8. The dense continuous layer is a mixed oxide ion conductor having a perovskite crystal structure, and has a composition represented by the following general formula [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (I) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. 2. The porcelain composition represented by the formula:
7. The composite material according to any one of 2, 5, and 6. 9. In the formula (I), B is one or a combination of two or more elements necessarily including Fe from Co, Fe, Cr and Ga, and the number of moles of Co is Fe 0% or more and 10% or less based on the number of moles, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or less based on the number x of moles of all B elements, B ''
The composite material according to claim 8, wherein is a combination of one or more elements selected from Zn, Li, and Mg. 10. The dense continuous layer is a mixed oxide ion conductor having a perovskite type crystal structure, and has a composition represented by a general formula [Ln _1-a A _a ] [B _x B ′ _y B ″ _z ] O _(3-δ) (I) (where Ln is 1 selected from Y or a lanthanoid element)
A species or a combination of two or more elements. A is one or a combination of two or more elements selected from Ba, Sr, and Ca.
B is a combination of at least one element selected from Co, Fe, Cr, and Ga, which always contains Fe or Co.
The sum of the number of moles of Ga is 0% or more and 20% of the number of moles x of all B elements
Less than. B ′ is one or a combination of two or more elements necessarily including Nb or Ta from among Nb, Ta, Ti, and Zr, and the sum of the number of moles of Ti and Zr is the mole of all B ′ elements. 0% for number y
More than 20%. B ″ is one or a combination of two or more elements selected from Cu, Ni, Zn, Li, and Mg. However, 0.
8 ≦ a ≦ 1, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.
02 and δ are values determined to satisfy the charge neutral condition. ), Wherein the sum of the contents of Nb and Ta is smaller than the sum of the contents of Nb and Ta in the porous body. Composite material. 11. In the formula (I), B is a combination of at least one element selected from the group consisting of Co, Fe, Cr and Ga, and the mole number of Co is Fe. 0% or more and 10% or less based on the number of moles, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or less based on the number x of moles of all B elements, B ''
The composite material according to claim 10, wherein is a combination of one or more elements selected from Zn, Li, and Mg. 12. An apparatus for separating oxygen, comprising the composite material according to any one of claims 1, 2 and 5 to 11. 13. An oxygen separator comprising the porcelain composition according to claim 3 or 4. 14. A chemical reaction apparatus comprising the composite material according to claim 1, 2, or 5. 15. A chemical reaction device comprising the porcelain composition according to claim 3 or 4. 16. A porous body portion having a mixed conductive porous oxide is fired at a temperature higher than a firing temperature of a dense continuous layer of the mixed conductive oxide formed on the porous body. Forming a film portion including a dense continuous layer on the porous body portion.