JP2003225567A - Ceramic composite material converted into catalyst, production method therefor, and ceramic film type reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a ceramic composite material converted into a catalyst which is applicable to a film type reactor for producing synthesis gas using an oxygen-containing gas and hydrocarbons as raw materials and can stably obtain a high oxygen transmission velocity. <P>SOLUTION: The ceramic composite material converted into the catalyst has a multi-layer structure in which a porous catalyst layer comprising a mixed conductive oxide adjoins the first surface of a selectively oxygen-permeable compact continuous layer comprising the mixed conductive oxide, a porous intermediate catalyst layer comprising the mixed conductive oxide and/or a catalytic oxide having a combustion catalyst function adjoins the second surface of the continuous layer, and a porous reaction catalyst layer comprising a metal catalyst and a carrier adjoins the porous intermediate catalyst layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to separation of oxygen components in an oxygen-containing mixed gas and hydrocarbon gas molecules in a hydrocarbon (methane, natural gas, ethane, gasoline, kerosene, etc.) gas or a hydrocarbon-containing mixed gas. And a method for producing the same, and a method for producing the same, which is used in a ceramic membrane reactor capable of performing the oxidation or partial oxidation reaction of a single device in a single apparatus. It relates to a membrane reactor.

[0002]

2. Description of the Related Art Separation of oxygen from oxygen-containing gas has conventionally been an industrially important process, but the oxygen production technology represented by the current cryogenic distillation system is a capital-intensive and energy-consuming type. However, although technological improvements such as the process form have progressed, it is difficult to significantly reduce the cost because it is a separation technique based on the boiling point difference between oxygen and nitrogen, which have an extremely small boiling point.

Under such circumstances, as a new innovation in oxygen production technology,
In recent years, especially in Europe and the United States, research and development is rapidly becoming active, and high temperature (~ 900
(° C) Oxygen separation technology has attracted a great deal of attention because it has the potential to lead to energy savings with compact equipment.

In the dense mixed conductive ceramics film, oxygen ions and electrons are selectively transported through the dense ceramics film material in which other species (nitrogen, water, carbon dioxide, etc.) are impermeable. On the surface of the dense ceramic film (cathode side), oxygen molecules combine with the electrons that have moved from the opposite side of the film (anode side) to generate oxygen ions. Oxygen ions diffuse and move in the dense film according to the difference in chemical potential of oxygen ions, emit electrons on the anode side, and become oxygen molecules again. At this time, the electrons maintain electrical neutrality by moving in the opposite direction to the oxygen ions.

The technology for reforming hydrogen or a synthetic gas (a mixed gas of carbon monoxide and hydrogen) from a gas containing a hydrocarbon as a raw material occupies an important position in petroleum and chemical processes. Technology for producing a synthetic liquid fuel using a gas containing hydrogen as a raw material (Gas-To-Liqu)
ids: GTL) and advances in fuel cell technology,
The former is "effective utilization of unused natural gas resources" and "supply of clean energy sources that are kind to the global environment", the latter is "installation in clean vehicles", "spreading of distributed power sources",
And "use of clean energy",
Research activities at home and abroad have been remarkably increasing in recent years.

Under the circumstances, researches for using the dense mixed conductive ceramics film as a reforming reactor as well as separating oxygen from oxygen-containing gas such as air have recently been accelerated. In this membrane reforming reactor, air is caused to flow on one side (cathode side) of the membrane and a catalyst is arranged on the opposite side (anode side) thereof to cause a hydrocarbon gas such as methane to flow to cause a partial oxidation reaction ( Oxygen is consumed), and the oxygen partial pressure on the methane side is minimized, and as a result, the oxygen partial pressure difference, that is, the driving force for oxygen selective permeation can be maximized. Have. Further, the partial oxidation reaction of methane or the like can be carried out at the same time as the air separation, that is, both the oxygen separation and the oxidation reaction can be carried out at the same time in a single unit.

In order to industrialize the reactor, it is a major premise that a sufficient oxygen permeation rate can be obtained by the combination of the dense mixed conductive ceramics membrane and the hydrocarbon partial oxidation catalyst, which are the basic constituent materials. In the process of oxygen permeation through the ceramic film, the reaction in which oxygen molecules are decomposed into oxygen ions (cathode side reaction), the diffusion transfer depending on the chemical potential difference of oxygen ions, the oxygen ions become oxygen atoms / oxygen molecules, and further hydrocarbons It can be evaluated by dividing it into three processes of oxidation reaction (reaction on the anode side). In order to improve the oxygen permeation rate per unit area, it is necessary to increase the rate of these three processes in a well-balanced manner, otherwise, one of the processes will be rate-determining, and a high oxygen permeation rate cannot be obtained as a whole. For example, thinning a dense mixed conductive ceramics material is an effective measure in order to increase the diffusion and migration rate of oxygen ions in the film, but on the other hand, the reaction on the cathode side and / or the anode is performed at a certain thickness or less. The rate of side reaction becomes to control the whole oxygen permeation process, and the effect of increasing the oxygen permeation rate due to the decrease in film thickness cannot be obtained. Therefore, in order to obtain a high oxygen permeation rate, not only thinning the dense portion but also improving the reaction rates on the cathode side and the anode side are important issues.

In the case of a reactor which obtains a synthesis gas from an oxygen-containing gas such as air and a hydrocarbon gas as a raw material by a combination of a dense mixed conductive ceramics film and a hydrocarbon partial oxidation catalyst, the anode on the hydrocarbon gas side of the ceramic film is used. The reactions occur, the oxygen atom / molecularization reaction of oxygen ions and the partial oxidation reaction of them with hydrocarbons. In such a case, the hydrocarbon gas side of the ceramic film is exposed to a high-level reducing atmosphere, and it is an object to have a function of withstanding the reducing atmosphere while promoting the anode reaction.

For these problems, WO98 / 4139
In Fig. 4, a dense mixed conductive ceramics film used for producing a synthetic gas by a partial oxidation reaction of a hydrocarbon gas such as methane is used to promote the cathode reaction by increasing the surface area on the oxygen-containing gas side of the film such as air. The intended porous layer was formed using a material similar to the dense ceramic material, and a partial oxidation catalyst was adjacent to the surface on the opposite side.
Although a technique related to a layer-structured catalyzed ceramics composite material is disclosed, there is no specific description regarding the structure and material composition of the layer forming the partial oxidation catalyst.

The present inventor has tried, as a partial oxidation catalyst layer, a catalyst layer in which a metal catalyst is supported on an oxide carrier (same as the porous reaction catalyst layer described in claim 5 of the present specification). , A mixed conductive oxide (mixed conductive oxide having a composition described in claim 4 of the present specification) is used as the dense film and the porous layer, and methane gas is added to the catalyst layer side and the mixed conductive oxide is added to the porous layer side. The oxygen permeation rate (calculated from the partial oxidation reaction rate) of the three-layer structure material described in WO98 / 41394 was measured by flowing air, but the oxygen permeation rate was not large, and a high oxygen permeation rate was obtained in the material structure. We found that there is room for further improvement.

In Japanese Unexamined Patent Publication No. 7-240115, a first surface of a film composed of a dense (dense) multi-component metal oxide layer is coated with a single-layer oxygen dissociation catalyst for promoting a cathode reaction, and a second layer is formed. The surface has a single-layer or multi-layered porous structure made of a mixed conductive multi-component metal oxide or a substance that does not show mixed conductivity under the operating conditions of the process for the purpose of accelerating the anodic reaction and imparting mechanical strength to the dense film. An ion transport membrane having a three-layer or four-layer structure in which a quality layer is adjacent is disclosed. Japanese Unexamined Patent Publication No. 7-240115 is an invention mainly aimed at a technique of separating oxygen from an oxygen-containing gas such as air. However, in paragraph 0015 and claim 46 of the specification,
"Oxidation of organic compounds containing hydrocarbons" is described as a use for the ion transport membrane.

The ion transport membrane contains no reaction catalyst comprising a metal catalyst and a carrier in the porous layer or MC porous layer (porous layer of mixed conductive multi-component metal oxide). . More specifically, the materials listed in the claims as forming the porous layer are multi-component metal oxides, metal alloys compatible with oxygen at high temperatures, metal oxide stabilized zirconia, ceria, electrons. Alternatively, it is a substance that does not conduct oxygen, such as alumina or magnesia, and does not include a reaction catalyst having a metal catalyst and a carrier. Also, M
The material forming the C porous layer is a multi-component metal oxide,
A reaction catalyst comprising a metal catalyst and a carrier is also not included. The invention of Japanese Patent Application Laid-Open No. 7-240115 should be considered as an invention that basically defines the structure of the ion transport film that promotes the reaction on the cathode side and / or the anode side, and constitutes the ion transport film. Although a very wide range of materials are claimed, the explanation of the reason is insufficient, and therefore, even a person skilled in the art will be able to request a specific material based on the same specification and a simple test. The choice is virtually impossible except in the cases described in the examples.

The present inventor has tried to make a dense film and a second film.
Adjacent to the first surface of the membrane is a mixed conductive multi-component metal oxide (same as the mixed conductive oxide of the composition set forth in claim 4 herein) as the porous layer adjacent to the surface. As the catalyst layer to be used, an oxide carrier-supported metal catalyst layer (the same as the porous reaction catalyst layer described in claim 5 of the present specification)
As described in paragraph 0015, methane gas is flowed on the second surface side and air is flowed on the first surface side so that the ion transport membrane "contacts the oxygenated feed gas with the catalyzed surface of the membrane". After flowing, the oxygen permeation rate (calculated from the oxidation reaction rate) was measured. As a result, they found that the oxygen permeation rate was not large and there was room for significant improvement in the material structure.
In addition, when the methane gas is flown on the first surface side and the air is flown on the second surface side by changing the gas flow, the above-mentioned WO98 / 4
It is the same as the measurement performed by the present inventor regarding 1394, and there is room for improvement in the material structure in this case as described above.

As described above, the membrane-type synthetic gas production technique for producing a synthetic gas or the like from a hydrocarbon gas and an oxygen-containing gas using a catalyzed ceramics composite material,
Although a general membrane structure that promotes the reaction on the cathode side and / or the anode side has been disclosed, they have been proposed for practical application by promoting both reactions and stably causing a partial hydrocarbon oxidation reaction. However, no specific technique regarding a catalyzed ceramic composite material for stably obtaining a sufficiently high oxygen permeation rate has been disclosed, and there is room for improvement.

[0015]

[Patent Document 1] International Publication WO98 / 41394 Pamphlet

[Patent Document 2] Japanese Patent Laid-Open No. 7-240115

[0016]

DISCLOSURE OF THE INVENTION The present invention is used in a membrane reactor for producing a synthesis gas using an oxygen-containing gas and a hydrocarbon gas as raw materials, and accelerates the cathode and anode reactions while partially oxidizing the hydrocarbon. It is an object of the present invention to provide a specific composition of a structure and a constituent material of a catalyzed ceramic composite material which can stably generate a reaction and can obtain a higher oxygen permeation rate than in the prior art.

[0017]

In order to solve the above-mentioned problems, the present invention forms a multilayer structure by combining a porous catalyst layer, a dense continuous layer, a porous intermediate catalyst layer, and a porous reaction catalyst layer. The following is the summary of this work.

(1) A porous catalyst layer containing a mixed conductive oxide is adjacent to a first surface of a selective oxygen-permeable dense continuous layer containing a mixed conductive oxide, A porous intermediate catalyst layer comprising a mixed conductive oxide and / or a catalyst oxide having a combustion catalyst function is adjacent to the second surface of the dense continuous layer, and the porous intermediate catalyst layer further comprises ,
A catalyzed ceramics composite material having a multi-layer structure in which porous reaction catalyst layers comprising a metal catalyst and a carrier are adjacent to each other.

(2) The catalyzed ceramic composite material according to the above (1), wherein the multilayer structure is formed as a coating layer on a porous support.

(3) At least one of the dense continuous layer, the porous catalyst layer and the porous intermediate catalyst layer has a mixed conductive oxide represented by the composition formula (1). 5. The catalyzed ceramics composite material according to the above (1) or (2). [Ln _1-ab A _a Ba _b ] [B _{x B'y} B " _z ] O _3-δ Composition formula (1) (where Ln is one or more elements selected from lanthanoid elements) Combination, A is Sr, C
a, or a combination of these elements, B is Co, F
e, Cr, and a combination of two or more elements selected from Ga, the sum of the number of moles of Cr and Ga is 0% or more and 20% or less with respect to the number of moles of all B elements, and B ′ is Nb. ,
Nb, Ta, In, a combination of one or more elements selected from Ta, Ti, Zr, In, and Y.
B ″ containing at least one of Y is Zn, Li, Mg
A combination of one or more elements selected from
0.8 ≦ a + b ≦ 1, b is 0.4 ≦ b ≦ 1.0 when B ′ is composed only of In, and 0.5 ≦ b when B ′ is composed of only Y. ≦ 1.0, B ′ is In and Y
0.2 ≦ b ≦ 1.0 when it is composed only, and 0 ≦ b ≦ 1.0, 0 when B ′ contains an element other than In and Y
<X, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x
+ Y + z ≦ 1.02, δ is a value determined so as to satisfy the charge neutral condition. )

(4) The catalyst oxide having a combustion catalyst function contains one or more selected from Co, Fe, Mn, and Pd. (1) to (3)
The catalyzed ceramics composite material according to item 1.

(5) The main component of the carrier of the porous reaction catalyst layer is MgO, and the metal catalyst of the porous reaction catalyst layer is Ni, Co, Ru, Rh, Pt, Pd, Ir, Re.
(1) to (4), which is a supported metal catalyst containing one or more active metal species selected from
2. The catalyzed ceramic composite material according to any one of 1.

(6) The catalyzed ceramics composite material according to (5) above, wherein the mass per unit membrane area of the metal catalyst is 20 to 50 mg / cm ² .

(7) On the first surface and the second surface of the dense continuous layer having the mixed conductive oxide represented by the composition formula (1), the composition formula (1) is used with a particle size of 10 μm or less. Fine powder of the mixed conductive oxide represented is mixed with an organic solvent to form a slurry, which is applied and dried to 950 ° C or higher and 1500 ° C.
Baking is performed below to form a porous catalyst layer and a porous intermediate catalyst layer, respectively, and Ni, Co, Ru and R are further formed on the support containing MgO as a main component on the porous intermediate catalyst layer.
1 or 2 selected from h, Pt, Pd, Ir and Re
The fine powder of the metal-supported catalyst supporting at least one active metal species is added with the fine powder of the material of the porous intermediate catalyst layer, mixed with an organic solvent to form a slurry, which is applied and dried.
A method for producing a catalyzed ceramic composite material, which comprises performing baking at 0 ° C or higher and 1500 ° C or lower.

(8) A ceramic membrane reactor comprising the catalyzed ceramic composite material according to any one of (1) to (6).

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyzed ceramic composite material of the present invention will be described below.

As described above, in order to improve the oxygen permeation rate (synthesis gas production rate) per unit area, it is necessary to improve the three steps of the reaction on the cathode side, the diffusion transfer of oxygen ions, and the reaction on the anode side in a well-balanced manner. is there.

The inventor of the present invention firstly proposes, as a cathode side reaction promoting method for converting oxygen molecules in an oxygen-containing gas into oxygen ions,
Attention was paid to the generally known increase in the reaction field, that is, the increase in the surface area obtained by adding the porous catalyst layer. By adjoining the porous catalyst layer comprising the mixed conductive oxide to the first surface of the dense continuous layer, a significant promotion of the cathode reaction is achieved. As a material for the porous catalyst layer of the present invention, a mixed conductive perovskite oxide having high oxygen permeability is suitable. The present inventors have, for the material of the porous catalyst layer, eagerly searched result those having a high oxygen permeability, composition, the following formula _{(1) [Ln 1-ab} A a Ba b] [B x B 'y B ″ _z ] O _3-δ (1) (where Ln is one or a combination of two or more elements selected from lanthanoid elements. A is S
r, Ca, or a combination of these elements. B
Is a combination of one or more elements selected from Co, Fe, Cr, and Ga, and the sum of the number of moles of Cr and Ga is 0% or more and 20% or more with respect to the number of moles of all B elements. %
It is the following. B'is Nb, Ta, Ti, Zr, In,
And a combination of two or more elements selected from Y and at least one of Nb, Ta, In and Y. B ″ is one or a combination of two or more elements selected from Zn, Li and Mg. 0.8 ≦ a + b ≦
It is 1. b is 0.4 ≦ b ≦ 1.0 when B ′ is composed only of In, and 0.5 ≦ b ≦ 1.0 when B ′ is composed of only Y, and B ′ is When it is composed only of In and Y, 0.2 ≦ b ≦ 1.0. 0.98 ≦
When x + y + z ≦ 1.02, 0 <x, 0 <y ≦ 0.5, 0
≦ z ≦ 0.2. δ is a value determined so as to satisfy the charge neutral condition. ), A material composed of a perovskite type oxide is found.

To increase the oxygen ion diffusion rate in the dense continuous layer, it is appropriate to use a perovskite type oxide having high ion conductivity as a material, as is generally known. The present inventor, as a specific material, has high ionic conductivity and has compatibility with the porous catalyst layer material and the porous intermediate catalyst layer material (eg, peeling does not occur during baking of the porous layer). As a result of an intensive search, it was found that a material similar to the porous catalyst layer, that is, a material made of the perovskite type oxide represented by the above formula (1) is suitable.

On the other hand, regarding the method of accelerating the anode side reaction in which hydrocarbon gas such as methane is oxidized, the present inventor has not mixed the conventionally known porous reaction catalyst layer with the dense continuous layer but mixed it. A structure in which a porous intermediate catalyst layer made of a conductive oxide and / or a catalyst oxide having a combustion catalyst function is adjacent to a dense continuous layer, and the porous reaction catalyst layer is adjacent to the porous intermediate catalyst layer via the porous intermediate catalyst layer , Was newly found to be extremely effective in promoting the reaction on the anode side.

The material of the porous intermediate catalyst layer of the present invention has high reduction resistance so that the anode side reaction can be stably promoted even in a reducing atmosphere due to hydrocarbon or the like.
Highly oxygen permeable mixed conductive oxides are suitable. The present inventor, as a result of diligent search for a mixed conductivity, high oxygen permeability, and reduction-resistant perovskite-type oxide for use in a porous intermediate catalyst layer, the porous catalyst layer, or a dense continuous It was found that a composition material similar to that of the layer, that is, a perovskite type oxide represented by the above formula (1) satisfies these conditions. Furthermore, in the porous intermediate catalyst layer of the present invention, a catalyst oxide that does not have mixed conductivity but has a combustion catalyst function, that is, Co, Fe, Mn, Pd.
Oxides containing one or more of the above are also effective.
In the porous intermediate catalyst layer of the present invention, both of these mixed conductive oxides and catalyst oxides may be used at the same time, or only one of them may be used.

Regarding the material forming the porous reaction catalyst layer, the present inventor has taken into consideration the high temperature operation and does not react with the perovskite type oxide forming the porous intermediate catalyst layer, and the porous intermediate catalyst layer. As a result of diligent search for a material having compatibility with the material (no peeling during baking, etc.), MgO having extremely low reactivity is suitable as a catalyst carrier used for the porous reaction catalyst layer, and further, as a reaction catalyst. N
It has been found that it is preferable to support one or more active metal species selected from i, Co, Ru, Rh, Pt, Pd, Ir and Re on a carrier.

In the case where there is no porous reaction catalyst layer but only a porous intermediate catalyst layer containing a mixed conductive oxide,
Since the complete oxidation reaction of hydrocarbon is promoted as the reaction on the anode side, it is not suitable for the purpose of producing synthesis gas. Therefore, this case is not included in the scope of the present invention.

In the present invention, the relationship between what the present inventor intends and the prior art will be described.

The structure of the porous catalyst layer and the dense continuous layer (dense film portion) on the cathode side is not much different from the prior art, but in the present invention, a material suitable for this portion will be specifically described. Presenting. Next, regarding the configuration on the anode side, this portion is greatly different from the conventional technique. The present inventor divides the reaction on the anode side into a complete oxidation reaction of hydrocarbons and a reforming reaction of complete oxidation reaction products,
We have invented a new strategy to generate synthesis gas by a method of sequentially advancing these reactions in two adjacent layers. By making the reaction on the anode side into two stages, it becomes possible for the first time to stably carry out the partial oxidation reaction of hydrocarbons while obtaining a high oxygen permeation rate. The complete oxidation reaction of hydrocarbons is performed by the mixed conductive porous intermediate catalyst layer.

A mixed conductive oxide is suitable as a catalyst for rapidly advancing this complete oxidation reaction. This is because the material promotes an anodic reaction in which oxygen ions that have diffused through the dense continuous layer are converted to oxygen atoms on the surface of the material, and the oxygen atoms immediately transfer the hydrocarbon molecules adsorbed on the catalyst surface. This is because it has a characteristic of being oxidatively decomposed.

The porosity of the porous intermediate catalyst layer increases the reaction surface area to increase the rate of complete oxidation reaction, and at the same time, the source gas such as hydrocarbon and the exchange of steam and carbon dioxide as reaction products are It is essential to be done quickly.

For reforming reaction of hydrocarbons and the like with steam and carbon dioxide gas (synthesis gas generating reaction), Ni, Co, Ru, Rh, Pt and P known as reforming reaction catalysts are used.
One or more active metal species selected from d, Ir, and Re may be used, but the reaction surface area is increased to increase the reaction rate, and a source gas such as hydrocarbon,
In order to quickly exchange various gas species such as steam, carbon dioxide, and syngas, it is necessary to support them on a carrier to form a porous reaction catalyst layer. The present inventor not only invented the above new structure for the reaction on the anode side, but also specifically presents a material suitable for this site.

Regarding the perovskite type oxides preferably used in the catalyzed ceramic composite material of the present invention,
This will be described in more detail.

The perovskite type oxide has the general formula ABO
A large number of compounds having a perovskite oxide structure have been reported, which are composed of a structure having a closely packed lattice of ₃ (A and B are metal ions). If the conditions for the physicochemical and crystallographic factors of the metal ions A and B are fulfilled, they crystallize in the form of ABO ₃ .

Here, if the sum of the valences of the metal ions is the sum of the valences of the oxygen ions, that is, if the sum of the valences of − (minus) is + (plus) hexavalent, oxygen vacancies do not occur, but the metal When the total valence of ions is less than hexavalent, oxygen ions are removed to maintain electrical equilibrium and oxygen vacancies are formed, which are considered to give oxygen ion conductivity. On the other hand, electronic conductivity is generally considered to be due to hopping conduction due to a change in the valence of the transition element between the bonds between the transition element and oxygen. Therefore, in the perovskite oxide having mixed conductivity, a transition element is arranged at the B site, and a combination of a lanthanoid element and an alkaline earth element that causes oxygen vacancies at the A site, or an alkaline earth metal alone is used. Are arranged, which impart electronic and ionic conductivity. Due to the combination of these A-site element and B-site element, different mixed conductivity or reduction resistance is exhibited.

Regarding the porous intermediate catalyst layer material, the present invention pays attention to Fe having high oxygen ion conductivity and relatively high resistance to reduction when it is arranged at the B site,
Further, regarding the dense continuous layer and porous catalyst layer materials, B
Focusing on Co, which has a very large oxygen ion conductivity when it is arranged on the site,
Or for various combinations of B-site elements including Co,
It was made as a result of vigorous examination.

In the constituent elements of B in the above formula (1), Cr is
And the total number of moles of Ga are 20% with respect to the total number of moles of B element
The reason for limiting to the following is that, when the content of Cr and Ga exceeds 20%, the oxygen ion conductivity decreases. B '
The reason for limiting the range of b in the case where is only In, only Y, and only In and Y is that the stability of the perovskite structure is deteriorated when b is outside these ranges.
When B ′ contains an element other than In and Y, 0 ≦ b ≦
The perovskite structure is stable in the range of 1.0. a
The range of + b is limited because if a + b is out of this range, the oxygen ion conductivity is lowered. Limiting the range of y to 0.5 or less is that Nb exceeding this range,
If Ta, Ti, Zr, In, and Y are contained, the oxygen ion conductivity will decrease. The range of z is limited to 0.2 or less, because if Zn, Li, or Mg is contained in excess of this range, the oxygen ion conductivity will be reduced, and the stability of the perovskite structure will be reduced. Is. Further, limiting the range of x + y + z is x + y
This is because if + z is out of this range, there is a problem that the oxygen ion conductivity is lowered. The dense continuous layer material, the porous catalyst material, and the mixed conductive oxide of the porous intermediate catalyst layer do not have to have the same composition.

In the present invention, a multilayer structure comprising a porous catalyst layer, a dense continuous layer, a porous intermediate catalyst layer and a porous reaction catalyst layer may be formed as a coating layer on the porous support. With this structure, the mechanical strength can be increased, so that the resistance is increased when the pressures of the raw material gases on the cathode side and the anode side are different and there is a difference in the total pressure through the dense continuous layer. The porous support material may be any as long as it has mechanical strength and is compatible with the multilayer structure,
For example, it may be a mixed conductive oxide. Further, the porous catalyst layer may be thickened so that it also has a function as a porous support.

The thickness of the dense continuous layer according to the present invention is 1 μm.
2 mm or less, preferably 10 μm or more and 1.5
mm or less, and more preferably 30 μm or more and 1 mm or less. If the dense continuous layer is too thick, the oxygen permeation rate cannot be increased, and conversely, if it is too thin, the mechanical reliability becomes poor, so the thickness has an appropriate range as described above.

The thicknesses of the porous intermediate catalyst layer and the porous catalyst layer according to the present invention are in the range of 1 μm or more and 1 mm or less and 1 μm or more and 5 mm or less, respectively. The porosity of the porous intermediate catalyst layer and the porous catalyst layer is 20% or more and 80% or more.
% Or less, preferably 30% or more and 60% or less. If the porosity is less than 20%, the movement of the raw material gas and the reaction product is hindered, and the oxygen permeation rate (synthesis gas production rate) does not increase. On the contrary, if it exceeds 80%, the mechanical reliability becomes poor.

Regarding the porous reaction catalyst layer material according to the present invention, as described above, Ni, Co, Ru, Rh having the activity of reforming hydrocarbons by steam and carbon dioxide is used on the carrier containing MgO as the main component. , Pt, Pd, Ir, and Re carrying one or more active metal species selected from Re are preferable from the viewpoint of activity and compatibility with the porous intermediate catalyst layer. The porous reaction catalyst layer transfers heat generated in the porous intermediate catalyst layer where not only hydrocarbon reforming but also complete oxidation reaction of hydrocarbons etc. occurs to the porous reaction catalyst layer (endothermic reaction occurs). By doing so, it plays an important role of avoiding hot spot formation which leads to material deterioration.

Next, a method for producing the material of the present invention will be described.

The raw materials of the ceramic material constituting the porous catalyst layer, the dense continuous layer, the porous intermediate catalyst layer and the porous reaction catalyst layer according to the present invention are metal salts such as metal oxides and carbonates. It is prepared by mixing and firing them. The powder raw material may be prepared by a coprecipitation method, a metal alkoxide method (sol-gel method), or a preparation method equivalent thereto. The mixed raw material powder is calcined at 800 ° C. or higher and 1500 ° C. or lower.

The material constituting the dense continuous layer is formed by finely crushing the sample after calcination and mixing it uniformly. Molding was carried out by applying any suitable ceramics manufacturing technique such as CIP (cold isostatic press), HIP (hot isostatic press), die press, injection molding method, slip casting method, extrusion molding method and the like. Sample is 1050 ℃ or more 1500
The main firing is performed at a temperature of ℃ or below.

Unlike the production of the dense continuous layer, the porous catalyst layer material and the porous intermediate catalyst layer material are prepared without mixing, after the raw material is prepared, mixed, calcined, and crushed, and 1050 without forming.
The main firing is performed at a temperature of not less than ℃ and not more than 1500 ℃. Here, if the raw materials are uniformly mixed, the intermediate calcination may be omitted and the main calcination may be performed. The temperature range of the main calcination is 1050 ° C. or higher and 1500 at which a perovskite structure that exhibits mixed conductivity is obtained.
℃ or less. The main-baked sample is finely pulverized by a suitable method such as a ball mill. The particle size of the crushed powder is preferably 10 μm or less for the reason described below.

The porous catalyst layer and the porous intermediate catalyst layer are formed by mixing the pulverized powder with an organic solvent or the like to form a slurry, coating and drying the slurry so as to cover the surface of the dense continuous layer, and then baking (baking). By doing. In general, the smaller the particle size of the powder to be applied, or the thinner the particle size, the more uniform the adhesion to the film surface. Specifically, it is desirable that the particle size of the powder be 10 μm or less. In addition to the above, as a means for forming the porous intermediate catalyst layer, a CVD (chemical vapor deposition) method, an electrophoresis method, a sol-gel method, or any other suitable method can be used.

The porous layer formed by these methods is such that the porous layer and the dense continuous layer are firmly bonded to each other in order to ensure continuity regarding mixed conductivity at the interface with the dense continuous layer. To be fired. The firing temperature is selected to be a suitable temperature that is less than the melting point of a low material of the materials forming the porous layer and the dense continuous layer and can obtain a strong bond.
The materials specifically proposed in the present invention are preferable because a strong bond can be obtained at a baking temperature of 950 ° C or higher and 1500 ° C or lower.

The catalyst material constituting the porous reaction catalyst layer is
Ni, Co, Ru,
It is desirable to carry one or more active metal species selected from Rh, Pt, Pd, Ir and Re.
The catalyst preparation method includes an impregnation supporting method, an equilibrium adsorption method, a coprecipitation method, and the like.
You can choose anything. The supported amount of the active metal species is 3 to 30 mol% for Ni and Co, and R
In the case of u, 0.1 to 10% by mass, Rh, Pt, Pd, I
In the case of r and Re, 0.01 to 3 mass% is desirable, and these may be combined. Further, Ni or Co may be solid-dissolved in magnesia in order to highly disperse the active metal species. In this case, a coprecipitation method or a ceramics method is used.

The porous reaction catalyst layer is prepared by adding 0.1% by mass or more and 30% by mass or less of the material fine powder of the porous intermediate catalyst layer to the finely pulverized powder of the prepared catalyst, and thoroughly mixing the mixed powder. It is formed by coating the porous intermediate catalyst layer as a slurry by mixing with an organic solvent or the like, drying, and then baking (baking). Generally, the smaller the particle size of the powder to be applied and the smaller the particle size applied, or the thinner the applied powder, the more uniform the adhesion to the film surface. Specifically, it is desirable that the particle size of the powder be 0.5 μm or more and 10 μm or less. The firing temperature should be at least 50 ° C. higher than the actual operating temperature of the membrane reactor and lower than the melting point of the ceramic composite material. Is desirable. In the case of the materials specifically proposed in the present invention, the baking temperature is 9
A strong bond can be obtained at a temperature of 50 ° C or higher and 1500 ° C or lower. Further, the catalyst mass per unit membrane area is 20 to 50 mg /
It is preferable that it is cm ² . Further, depending on the operating conditions of the membrane reactor, there is also a method of sizing the reaction catalyst and arranging it on the porous intermediate catalyst layer without baking. Furthermore, there is also a method of combining the slurry coating and the sizing catalyst arrangement.

[0056]

EXAMPLES The present invention will be described below with reference to examples. The present invention is not limited to the embodiments.

(Example 1) SrC having a purity of 99% or more
Commercially available powders of O ₃ , Fe ₂ O ₃ , and Nb ₂ O ₅ were weighed so that the molar ratio was Sr: Fe: Nb = 1: 0.9: 0.1, and the planetary ball mill was used for 2 hours. Wet mixed. The obtained raw material powder was put into a crucible made of alumina and baked in air at 1350 ° C. for 5 hours to obtain a composite oxide. The room temperature powder X-ray diffraction measurement result of this composite oxide shows that the main component is a cubic perovskite structure, and that the composition is a composite oxide represented by SrFe _0.9 Nb _0.1 O _{3 -δ.} confirmed. This composite oxide was powdered with an automatic mortar and having a particle size of 10 μm or less to obtain a porous intermediate catalyst layer material.

Next, BaCO ₃ and Sr with a purity of 99% or more are used.
Commercially available powders of CO ₃ , CoO, and Fe ₂ O ₃ were used in a molar ratio of Ba: Sr: Co: Fe = 0.5: 0.5: 0.
It was weighed to be 8: 0.2 and wet-mixed for 2 hours using a planetary ball mill. The obtained raw material powder was put into an alumina crucible and calcined in the air at a temperature of 950 ° C. for 20 hours to obtain a composite oxide. This composite oxide was wet-milled for 2 hours with a planetary ball mill, and 3 g of this powder was shaped into a disk at 25 MPa with a mold having a diameter of 20 mm. This molded body was placed in an airtight bag, deaerated, and evacuated. Then, while applying a pressure of 200 MPa, the CIP was adjusted to 15
For 1 minute, and main calcination in air at a temperature of 1130 ° C. for 5 hours,
A densified sintered body having a relative density of 95% or more was obtained. The room temperature powder X-ray diffraction measurement result of this sintered body showed that the main component was a cubic perovskite structure, and the composition was Ba.
It was confirmed to be a composite oxide represented by _{0.5 Sr 0.5 Co 0.8 Fe 0.2 O} 3-δ. Both surfaces of this sintered body were ground and polished to form a disk shape having a diameter of 12 mm and a thickness of 0.7 mm, which was used as a dense continuous layer.

Subsequently, the composition obtained by the same method is B
The sintered body represented by a _0.5 Sr _0.5 Co _0.8 Fe _0.2 O _3-δ was pulverized to have a particle size of 10 μm or less to obtain a porous catalyst layer material.
This was suspended in an organic solvent to form a slurry, which was applied to the first surface of the disk-shaped dense continuous layer. further,
The porous intermediate layer material was similarly slurried and applied to the second surface of the dense continuous layer. This was dried at 120 ° C. for 5 minutes and then calcined in air at 1050 ° C. for 5 hours to obtain a porous catalyst layer and a porous intermediate catalyst layer firmly bonded to the dense continuous layer. At this time, the thicknesses of the porous catalyst layer and the porous intermediate catalyst layer were 0.3 and 0.2 mm, respectively.

On this porous intermediate catalyst layer, 28 mg of a powder of a hydrocarbon reforming catalyst in which Ni was dissolved in magnesia in an amount of 10 mol% with respect to Mg and having a particle size of 10 μm or less was added to the powder of the porous intermediate catalyst layer. 5 mg of powder was added, and the mixture was thoroughly mixed and suspended in an organic solvent for slurry coating. This is dried at 120 ° C. for 5 minutes, and then calcined in air at 1050 ° C. for 5 hours to bond the hydrocarbon reforming catalyst layer (porous reaction catalyst layer) to the porous intermediate catalyst layer to form the catalyst of the present invention. The obtained ceramic composite material was obtained and subjected to an oxygen permeation (synthesis gas production) experiment.

In the experiment, the catalyzed ceramics composite material was sandwiched between two mullite tubes via a silver ring, and the temperature was kept at 900 ° C. and the pressure was 10 atm while maintaining the airtightness on the cathode side and the anode side. I went. Regarding the source gas, 200 cc / min of air was supplied to the cathode side and 40 cc / min of methane was supplied to the anode side. The outlet gas at the anode side was measured by a gas chromatograph, and the oxygen permeation rate in a stable state from the air side to the methane side was calculated by element balance. The result was 21 cc / min.
Was / cm ² . At this time, the methane reaction conversion rate was 58%, CO selectivity (CO ratio in CO and CO ₂ )
80%, H ₂ / CO ratio was 1.8.

During the experiment, the dense continuous layer of the catalyzed ceramics composite material of the present invention did not show any cracks, and no sign of breakage with time was observed. Further, the catalyzed ceramics composite material of the present invention showed a stable oxygen permeation (synthesis gas generation) rate except for the period immediately after the start of the experiment, and no sign of deterioration was observed.

Example 2 A disk-shaped composite comprising a porous catalyst layer, a dense continuous layer, and a porous intermediate catalyst layer prepared by the same method and conditions as in Example 1 was used, and Ni was replaced by Mg as magnesia. On the other hand, to 30 mg of a powder of a hydrocarbon reforming catalyst impregnated and supported with 5 mol% and having a particle size of 10 μm or less,
5 mg of the material fine powder for the porous intermediate catalyst layer was added and thoroughly mixed, and the mixture was suspended in an organic solvent, and this was slurry-coated on the porous intermediate catalyst layer. 120 ° C
After drying for 5 minutes at 1050 ° C. in air, the hydrocarbon reforming catalyst layer (porous reaction catalyst layer) is joined to the porous intermediate catalyst layer by firing at 1050 ° C. for 5 hours to form the catalyzed ceramic of the present invention. A composite material was obtained.

For the oxygen permeation experiment, 900 mg of a hydrocarbon reforming catalyst in which 2% by mass of Ru was impregnated and supported on magnesia sized to 20/40 mesh was placed on the porous reaction catalyst layer of this composite material. And the same method and conditions as those shown in Example 1 except that the pressure was 1 atm. The calculated oxygen permeation rate in a stable state was 25 cc / min / cm ² . At this time, the methane reaction conversion rate was 83%, the CO selectivity (CO ratio in CO and CO ₂ ) was 86%, and the H ₂ / CO ratio was 1.9.
Met.

During the experiment, the dense continuous layer of the catalyzed ceramic composite material of the present invention did not show any cracks, and no sign of breakage with time was observed. Further, the catalyzed ceramics composite material of the present invention showed a stable oxygen permeation (synthesis gas generation) rate except for the period immediately after the start of the experiment, and no sign of deterioration was observed.

Example 3 The catalyst and ceramic composite materials of the present invention shown in Table 1 were produced by the same method and conditions as in Example 1, and the oxygen permeation (synthesis gas) was performed by the same method and condition as in Example 1. When the production characteristics were evaluated, an oxygen permeation rate of 20 cc / min / cm ² or more was obtained for all of them. Further, similar to the results of Example 1, a stable oxygen permeation (synthesis gas generation) rate was shown, and no signs of deterioration and destruction with time were observed.

[Table 1]

(Comparative Example 1) By the same method and conditions as in Example 1, a catalyzed ceramics composite comprising a porous catalyst layer and a dense continuous layer was prepared, and then 20 was formed on the dense continuous layer. Reforming catalyst 900m in which 2% by mass of Ru is impregnated and supported on magnesia sized to 40/40 mesh
g was placed and subjected to an oxygen permeation experiment.

The experiment was conducted under the same method and conditions as in Example 1, and the oxygen permeation rate in a stable state was calculated. As a result, it was 18 cc / min / cm ² . At this time, the methane reaction conversion rate was 76%, the CO selectivity (CO ratio in CO and CO ₂ ) was 96%, and the H ₂ / CO ratio was 2.0.
Met.

(Comparative Example 2) The same method and conditions as in Example 1 were used except that a composite oxide represented by Ba _0.5 Sr _0.5 Co _0.8 Fe _0.2 O _{3 -δ} was used as the material for the intermediate porous catalyst layer. 2% by mass of a magnesia carrier on the porous intermediate catalyst layer after producing a catalyzed ceramics composite material comprising a porous catalyst layer, a dense continuous layer and a porous intermediate catalyst layer.
Was impregnated and supported on Ru, and 900 mg of a hydrocarbon reforming catalyst that had been sized to 20/40 mesh was placed, and subjected to an oxygen permeation experiment.

The experiment was performed under the same method and conditions as in Example 1, and after several hours from the start of the experiment, about 23 cc / min / cm.
^Although the oxygen permeation rate of ² was obtained, the oxygen permeation rate decreased with time and a stable oxygen permeation rate was not obtained.

(Comparative Example 3) On a porous intermediate catalyst layer of a disk-shaped composite comprising a porous catalyst layer, a dense continuous layer and a porous intermediate catalyst layer prepared by the same method and conditions as in Example 1, Powder 3 of a hydrocarbon reforming catalyst having an alumina (α type) carrier impregnated with 2% by mass of Ru and having a particle size of 10 μm or less
A suspension of 0 mg suspended in an organic solvent was slurry-coated. After drying this for 5 minutes at 120 ℃, in air 1050 ℃
By firing for 5 hours, a hydrocarbon reforming catalyst layer joined to the porous intermediate catalyst layer was obtained and subjected to an oxygen permeation experiment.
The experiment was carried out by the same method and conditions as in Example 1 except that the pressure was 10 atm, and about 20 c after several hours from the start of the experiment.
Although an oxygen permeation rate of c / min / cm ² was obtained, the oxygen permeation rate decreased with time, and a stable oxygen permeation rate was not obtained.

[0072]

EFFECTS OF THE INVENTION According to the present invention, a high-performance diaphragm member that stably obtains a high oxygen permeation rate when selectively transporting an oxygen component in an oxygen-containing gas is obtained, and therefore, partial oxidation of hydrocarbons is achieved. Can be suitably used for a membrane reactor for the production of synthetic gas, etc., and contributes to high performance and cost reduction of these devices.

[Brief description of drawings]

FIG. 1 is a structural conceptual diagram of a catalyst and ceramics composite material having a multilayer structure including a porous catalyst layer, a dense continuous layer, a porous intermediate catalyst layer, and a reaction catalyst layer of the present invention.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) B01J 23/89 C01G 49/00 C 4G069 37/02 301 D 4G140 C01B 3/40 51/00 A C01G 49 / 00 B32B 18/00 A B01J 23/74 321M 51/00 23/84 301M C04B 35/00 23/64 104M // B32B 18/00 C04B 35/00 H (72) Inventor Shoichi Kaganoi Hatagaya, Shibuya-ku, Tokyo 1-31-10 Inside Teikoku Oil Co., Ltd. (72) Inventor Yohei Suzuki 1-31-10 Hatagaya, Shibuya-ku, Tokyo Inside Teikoku Oil Co., Ltd. (72) Takashi Ito 1-31-10 Hatagaya, Shibuya-ku, Tokyo Empire Petroleum Co., Ltd. (72) Inventor Tadashi Saki, 20-1 Shintomi, Futtsu City Technology Development Division, Nippon Steel Corporation (72) Inventor Wataru Ito 20-1 Shintomi, Futtsu City Nippon Steel Co., Ltd. Technology Development Division (72) Inventor Dono Mae 20-1 Shintomi, Futtsu City Shin Nippon Steel Co., Ltd. Technology Development Headquarters (72) Inventor Toru Nagai 20-1 Shintomi Futtsu City New Japan Steel Technology Co., Ltd. Technology Development Headquarters (72) Inventor Kenji Hirano 20-1 Shintomi, Futtsu City Shin-Nippon Steel Corporation Technology Development Headquarters F term (reference) 4D006 GA41 KA72 KB30 MA03 MA31 MC03X NA39 NA51 NA61 NA62 PA05 PB17 PB62 PC69 4F100 AA17A AA17B AA17C AA18D AB00D AB02C AB02D AB14C AB14D AB15C AB15D AB16D AB24C AB24D AD00A AD00B AD00C BA04 BA05 BA07 BA10B BA10D BA10E DE01B DE01C DJ00B DJ00D DJ00E EH46B EH46C EJ42B EJ42C EJ86B EJ86C GB90 JD03 JD03A JG01A JG01B JG01C JL08B JL08C JL08D YY00A YY00B YY00C 4G002 AA08 AA09 AB01 AE05 4G030 AA02 AA07 AA08 AA09 AA11 AA12 AA15 AA16 AA17 AA20 AA21 AA22 AA22 A03 A08 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A05 A08 A0 A0 A0 A5 AGA4 GA0 GA22 GA22 GA02 GA22 GA22 GA22 GA04 GA02 GA22 GA04 GA08 GA22 GA22 GA02 GA22 GA22 GA02 GA22 GA02 GA22 GA22 GA02 GA22 GA22 GA22 GA22 GA22 GA22 GA22 GA22 GA02 GA22 GA22 GA02 GA22 GA22 GA22 GA02 GA22 GA02 GA22 GA22 GA02 GA22 GA22 GA0 BA06A BA06B BC62A BC64A BC66A BC67A BC67B BC68A BC68B BC70A BC70B BC71B BC72A BC74A BC74B BC75A BC75B CB07 CC17 CC40 DA05 EA08 EC23 EC27 EC28 FA01 FA03 FB15 FB30 FC07 FC08 4G140 EA03 EA07 EB19 EC02 EC03 EC05 EC08

Claims (8)

[Claims] 1. A porous catalyst layer containing a mixed conductive oxide is adjacent to a first surface of a selective oxygen-permeable dense continuous layer containing a mixed conductive oxide, A porous intermediate catalyst layer comprising a mixed conductive oxide, and / or a catalyst oxide having a combustion catalyst function is adjacent to the second surface of the continuous porous layer, and further, the porous intermediate catalyst layer, A catalyzed ceramics composite material having a multi-layer structure in which porous reaction catalyst layers comprising a metal catalyst and a carrier are adjacent to each other. 2. The catalyzed ceramic composite material according to claim 1, wherein the multilayer structure is formed as a coating layer on a porous support. 3. At least one of the dense continuous layer, the porous catalyst layer, and the porous intermediate catalyst layer has a composition formula (1).
3. The catalyzed ceramics composite material according to claim 1 or 2, which comprises a mixed conductive oxide represented by: [Ln _1-ab A _a Ba _b ] [B _{x B'y} B " _z ] O _3-δ Composition formula (1) (where Ln is one or more elements selected from lanthanoid elements) Combination, A is Sr, C
a, or a combination of these elements, B is Co, F
e, Cr, and a combination of two or more elements selected from Ga, the sum of the number of moles of Cr and Ga is 0% or more and 20% or less with respect to the number of moles of all B elements, and B ′ is Nb. ,
Nb, Ta, In, a combination of one or more elements selected from Ta, Ti, Zr, In, and Y.
B ″ containing at least one of Y is Zn, Li, Mg
One or a combination of two or more elements selected from the following: 0.8 ≦ a + b ≦ 1, b is 0.4 ≦ b when B ′ is composed only of In
≦ 1.0, and if B ′ is composed of Y only, 0.5 ≦
b ≦ 1.0, when B ′ is composed only of In and Y, 0.2 ≦ b ≦ 1.0, and when B ′ includes an element other than In and Y, 0 ≦ b ≦ 1. 0, 0 <x, 0 <y ≦ 0.5, 0 ≦ z ≦ 0.2, 0.98 ≦ x + y + z ≦ 1.02, and δ are values determined so as to satisfy the charge neutral condition. ) 4. The catalyst oxide having the combustion catalyst function is one or two selected from Co, Fe, Mn and Pd.
The catalyzed ceramics composite material according to any one of claims 1 to 3, which comprises one or more kinds. 5. The main component of the carrier of the porous reaction catalyst layer is MgO, and the metal catalyst of the porous reaction catalyst layer is N.
5. A supported metal catalyst having one or more selected from i, Co, Ru, Rh, Pt, Pd, Ir and Re as an active metal species. Of catalyzed ceramic composites. 6. The catalyzed ceramic composite material according to claim 5, wherein the mass per unit area of the metal catalyst is 20 to 50 mg / cm ² . 7. A composition represented by the composition formula (1) having a particle size of 10 μm or less on the first surface and the second surface of the dense continuous layer having the mixed conductive oxide represented by the composition formula (1). Fine powder of mixed conductive oxide is mixed with an organic solvent to form a slurry, which is applied, dried, and baked at 950 ° C or higher and 1500 ° C or lower to form a porous catalyst layer and a porous intermediate catalyst layer, respectively. Further, on the porous intermediate catalyst layer, Mg
Ni, Co, Ru, Rh, P on O-based carrier
To the fine powder of the metal-supported catalyst supporting one or more active metal species selected from t, Pd, Ir and Re, the fine powder of the material of the porous intermediate catalyst layer is added and mixed with an organic solvent. A method for producing a catalyzed ceramics composite material, which comprises coating and drying a slurry, and baking at 950 ° C or more and 1500 ° C or less. 8. A ceramics membrane reactor comprising the catalyzed ceramics composite material according to claim 1.