阅读说明：本技术 Co变换或逆变换催化剂结构体及其制造方法、co变换或逆变换反应装置、二氧化碳和氢的制造方法、以及一氧化碳和水的制造方法 (Catalyst structure for CO conversion or reverse conversion and method for producing same, reaction apparatus for CO conversion or reverse conversion, method for producing carbon dioxide and hydrogen, ) 是由 增田隆夫 中坂佑太 吉川琢也 加藤祯宏 福岛将行 高桥寻子 马场祐一郎 关根可织 于 2018-05-31 设计创作，主要内容包括：本发明提供一种能够抑制催化功能的降低来实现寿命延长的CO变换或逆变换催化剂结构体及其制造方法、CO变换或逆变换反应装置、二氧化碳和氢的制造方法、以及一氧化碳和水的制造方法。CO变换或逆变换催化剂结构体(1)具备：多孔质结构的载体(10),其由沸石型化合物构成；以及至少一种CO变换或逆变换催化剂物质(20),其存在于所述载体(10)内,所述载体(10)具有相互连通的通道(11),所述CO变换或逆变换催化剂物质(20)存在于所述载体(10)的至少所述通道(11)。(The invention provides a catalyst structure for CO conversion or reverse conversion and a method for manufacturing the same, a reaction apparatus for CO conversion or reverse conversion, a method for manufacturing carbon dioxide and hydrogen, and a method for manufacturing carbon monoxide and water, wherein the reduction of catalytic function can be suppressed to prolong the service life. A CO conversion or reverse conversion catalyst structure (1) is provided with: a porous support (10) composed of a zeolite-type compound; and at least one CO-shift or reverse-shift catalyst substance (20) present within said carrier (10), said carrier (10) having mutually communicating channels (11), said CO-shift or reverse-shift catalyst substance (20) being present in at least said channels (11) of said carrier (10).)

1. A CO conversion or reverse conversion catalyst structure comprising:

a porous support composed of a zeolite-type compound; and

at least one CO shift or reverse shift catalyst species present within the support,

the carrier has channels that are in communication with each other,

the CO shift or reverse shift catalyst species is present in at least the channels of the support.

2. The CO shift or reverse shift catalyst structure of claim 1,

the channel has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and a diameter expanding portion that is different from any of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole, and that expands the diameter of the hole

The CO shift or reverse shift catalyst substance is present at least in the diameter expansion section.

3. The CO shift or reverse shift catalyst structure of claim 2,

the diameter expanding portion causes a plurality of holes constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole to communicate with each other.

4. CO shift or reverse shift catalyst structure according to claim 2 or 3,

the CO shift or reverse shift catalyst material is a metal particulate.

5. The CO shift or reverse shift catalyst structure of claim 4,

the metal fine particles are fine particles composed of at least one metal or metal oxide selected from the group consisting of cobalt, nickel, iron, and copper.

6. The CO shift or reverse shift catalyst structure of claim 5,

the metal fine particles are fine particles composed of at least one metal or metal oxide selected from the group consisting of cobalt, iron, and copper.

7. The CO shift or reverse shift catalyst structure according to any one of claims 4 to 6,

the metal fine particles have an average particle diameter larger than an average inner diameter of the channel and equal to or smaller than an inner diameter of the enlarged diameter portion.

8. CO shift or reverse shift catalyst structure according to any of claims 4 to 7,

the catalyst structure for CO conversion or reverse conversion contains 0.5 to 2.5 mass% of the metal element (M) of the metal fine particles.

9. CO shift or reverse shift catalyst structure according to any of claims 4 to 8,

the metal fine particles have an average particle diameter of 0.08 to 30 nm.

10. CO shift or reverse shift catalyst structure according to claim 9,

the metal fine particles have an average particle diameter of 0.4 to 11.0 nm.

11. CO shift or reverse shift catalyst structure according to any of claims 4 to 10,

the ratio of the average particle diameter of the metal fine particles to the average inner diameter of the channel is 0.05 to 300.

12. The CO shift or reverse shift catalyst structure of claim 11,

the ratio of the average particle diameter of the metal fine particles to the average inner diameter of the channel is 0.1 to 30.

13. CO shift or reverse shift catalyst structure according to claim 12,

the ratio of the average particle diameter of the metal fine particles to the average inner diameter of the channel is 1.4 to 3.6.

14. CO shift or reverse shift catalyst structure according to any of claims 2 to 13,

the average inner diameter of the channel is 0.1 nm-1.5 nm,

the inner diameter of the diameter-expanded portion is 0.5nm to 50 nm.

15. CO shift or reverse shift catalyst structure according to any of claims 1 to 14,

at least one other CO shift or reverse shift catalyst material is also provided, which is retained on the outer surface of the support.

16. The CO shift or reverse shift catalyst structure of claim 15,

the at least one CO shift or reverse shift catalyst species is present in the support in an amount greater than the amount of the at least one other CO shift or reverse shift catalyst species remaining on the outer surface of the support.

17. CO shift or reverse shift catalyst structure according to any of claims 1 to 16,

the zeolite-type compound is a silicate compound.

18. A CO shift or reverse shift reaction apparatus having the CO shift or reverse shift catalyst structure of any one of claims 1 to 17.

19. A method for manufacturing a catalyst structure for CO conversion or reverse conversion, comprising:

a firing step of firing a precursor material (B) obtained by impregnating a precursor material (a) with a metal-containing solution, the precursor material (a) being used for obtaining a support having a porous structure made of a zeolite-type compound;

a hydrothermal treatment step of subjecting a precursor material (C) obtained by firing the precursor material (B) to hydrothermal treatment; and

and a step of subjecting the precursor material (C) after the hydrothermal treatment to a reduction treatment.

20. The method for manufacturing a CO shift or reverse shift catalyst structure according to claim 19,

before the firing step, 50 to 500 mass% of a nonionic surfactant is added to the precursor material (A).

21. The method for manufacturing a CO shift or reverse shift catalyst structure according to claim 19 or 20, wherein the catalyst structure is a catalyst structure for CO shift or reverse shift,

the metal-containing solution is impregnated into the precursor material (a) by adding the metal-containing solution to the precursor material (a) a plurality of times before the firing step.

22. The method for manufacturing a CO-conversion or reverse-conversion catalyst structure according to any one of claims 19 to 21,

when the precursor material (A) is immersed in the metal-containing solution before the firing step, the amount of the metal-containing solution added to the precursor material (A) is adjusted so that the atomic ratio Si/M, which is the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing solution added to the precursor material (A), is 10 to 1000.

23. The method for manufacturing a CO shift or reverse shift catalyst structure according to claim 19,

in the hydrothermal treatment step, the precursor material (C) is mixed with a structure-directing agent.

24. The method for manufacturing a CO shift or reverse shift catalyst structure according to claim 19,

the hydrothermal treatment step is performed in an alkaline environment.

25. A method for producing carbon dioxide and hydrogen, characterized in that,

the method for producing carbon dioxide and hydrogen by using a catalyst to produce carbon dioxide and hydrogen from carbon monoxide and water,

the catalyst contains a CO-conversion catalyst structure, and the CO-conversion catalyst structure includes:

a porous support composed of a zeolite-type compound; and

at least one metal particulate present within the carrier,

the carrier has channels that are in communication with each other,

the metal microparticles are present in at least the expanded diameter portion of the channel of the carrier.

26. A method for producing carbon dioxide and hydrogen, characterized in that,

carbon dioxide and hydrogen are produced from carbon monoxide and water using the CO shift catalyst structure of any one of claims 1 to 17.

27. A method for producing carbon dioxide and hydrogen, characterized in that,

the CO shift reactor according to claim 18, wherein carbon monoxide and water are shifted to carbon dioxide and hydrogen.

28. A process for producing carbon monoxide and water, characterized in that,

the method for producing carbon monoxide and water by using a catalyst to produce carbon monoxide and water from carbon dioxide and hydrogen,

the catalyst contains a reverse conversion catalyst structure, and the reverse conversion catalyst structure comprises:

a porous support composed of a zeolite-type compound; and

at least one metal particulate present within the carrier,

the carrier has channels that are in communication with each other,

the metal microparticles are present in at least the expanded diameter portion of the channel of the carrier.

29. A process for producing carbon monoxide and water, characterized in that,

generating carbon monoxide and water from carbon dioxide and hydrogen using the reverse shift catalyst structure of any of claims 1 to 17.

30. A process for producing carbon monoxide and water, characterized in that,

converting carbon dioxide and hydrogen to carbon monoxide and water using the reverse shift reaction apparatus of claim 18.

Technical Field

The present invention relates to a CO conversion or reverse conversion catalyst structure including a carrier having a porous structure and a CO conversion or reverse conversion catalyst, a method for producing the CO conversion or reverse conversion catalyst structure, a CO conversion or reverse conversion reaction apparatus, a method for producing carbon dioxide and hydrogen, and a method for producing carbon monoxide and water.

Background

In recent years, in order to suppress global warming, further reduction of CO has been demanded in a thermal power plant or the like₂The emission amount can be further reduced by, for example, performing efficient power generation₂Discharging amountThe coal gasification combined power generation. The integrated coal gasification combined cycle power generation is a power generation in which coal is converted into a combustible gas by a high-temperature and high-pressure gasification furnace, the converted generated gas is used as a fuel for power generation, and waste heat released when the converted gas is converted into the combustible gas is used to generate power by a steam turbine.

In addition, most of the compounds present in the generated gas are carbon monoxide (CO), carbon dioxide (CO)₂) Hydrocarbon (C)_nH_m) Is a few percent. Therefore, in order to recover CO from the generated gas₂It is necessary to convert CO present in the produced gas into CO₂. To CO₂While changing, water vapor (H)₂O) is added to the product gas, and the product gas is converted into CO by a CO conversion reaction represented by the following formula (1) using a CO conversion catalyst₂By means of CO₂A recovery plant for recovering the shifted CO₂。

CO+H₂O→CO₂+H₂···(1)

As CO shift catalysts, there are: a Cu-Zn catalyst having CO conversion reaction activity in a low temperature range of 300 ℃ or lower; an Fe-Cr catalyst having CO shift reaction activity in a high temperature range of 300 ℃ or higher. Furthermore, in the CO shift catalyst having activity in a high temperature range, it is necessary to add excessive steam to CO in order to prevent carbon deposition. On the other hand, from the viewpoint of lowering the power generation efficiency due to excessive addition of steam, it is required to reduce the amount of steam added while making the amount of steam added excessive with respect to CO.

Therefore, a CO shift catalyst has been proposed in which an active component is composed mainly of any one of molybdenum (Mo) and iron (Fe), and a subcomponent is composed of any one of nickel (Ni) and ruthenium (Ru), and a composite oxide containing any two or more of titanium (Ti), zirconium (Zr), cerium (Ce), silicon (Si), aluminum (Al), and lanthanum (La) supporting the active component is calcined at 550 ℃ or higher to increase the average pore diameter of the catalyst, thereby exhibiting excellent durability even when carbon deposition occurs, and enabling stable maintenance of a CO shift reaction for a long period of time (patent document 1).

Further, the generated gas may contain H₂S is poisoned by sulfur components depending on the kind of catalyst, and therefore, it is necessary to perform a desulfurization operation in a preceding stage. Therefore, as in H₂A catalyst having CO shift reaction activity even in the presence of S, which contains at least Mo and Ni, and which comprises TiO as an oxide supporting these active components₂As a carrier (patent document 2).

However, most of the generated gas is CO, and since the CO shift reaction is an exothermic reaction, the temperature of the CO shift catalyst increases due to the CO shift reaction. Thus, when the CO conversion catalyst particles are exposed to a high temperature for a long time, the CO conversion catalyst particles and the carrier component are likely to aggregate (sinter). When the coagulation occurs between the catalyst particles, the effective surface area as a catalyst decreases, whereby the catalytic activity decreases and the life of the catalyst is shorter than usual. Therefore, the catalyst itself must be replaced and regenerated in a short period of time, which causes a problem that the replacement operation is complicated and the resource saving cannot be achieved.

In recent years, reduction and effective utilization of emission of carbon dioxide have become problems to be solved in view of the fact that carbon dioxide is a main cause of global warming. Further, although hydrocarbon-based gases are produced in the technical fields of petroleum refining, petrochemistry, and the like, a method for efficiently converting the gases into more effective substances has been desired.

Under such circumstances, a method of producing a synthesis gas containing generated carbon monoxide and unreacted hydrogen by performing a reverse shift reaction using hydrogen and carbon dioxide has been proposed. Further, it can be considered that: many of the catalysts for promoting the shift reaction also have activity as catalysts for the reverse shift reaction represented by the following formula (2).

CO₂+H₂→CO+H₂O···(2)

However, in the reverse shift reaction, it is desirable to carry out the reaction at a high temperature of 600 ℃ or higher in consideration of the composition (equilibrium composition) of the synthesis gas generated by the reaction. However, since the temperature of 600 ℃ or higher is usually much higher than the temperature at which the shift reaction proceeds, it is difficult to use a catalyst for the usual shift reaction in the present situation from the viewpoint of seizure resistance of the catalyst metal (patent document 3).

In recent years, Ni/Al as a catalyst for reverse shift reaction has been reported₂O₃And Ni-based catalysts such as NiO/ZnO (non-patent document 1). However, the Ni-based catalyst has a problem that methanation is caused to generate methane and the carbon monoxide concentration is lowered. Thus, it is desired to develop a catalyst for reverse shift reaction which can suppress the generation of methane as much as possible.

Disclosure of Invention

Problems to be solved by the invention

An object of the present invention is to provide a CO shift or reverse shift catalyst structure and a method for producing the same, a CO shift or reverse shift reaction apparatus, a method for producing carbon dioxide and hydrogen, and a method for producing carbon monoxide and water, which can suppress a decrease in catalytic function and prolong the life.

Technical scheme

As a result of intensive studies to achieve the above object, the present inventors have found the following facts, and have completed the present invention based on the findings, and have obtained a catalyst structure for CO conversion or reverse conversion, comprising: a porous support composed of a zeolite-type compound; and at least one CO shift or reverse shift catalyst substance present in the carrier, the carrier having mutually communicating channels, the CO shift or reverse shift catalyst substance being present in at least the channels of the carrier, whereby a life extension can be achieved by suppressing a decrease in catalytic activity of the CO shift or reverse shift catalyst substance.

That is, the gist of the present invention is as follows.

[1] A CO conversion or reverse conversion catalyst structure comprising: a porous support composed of a zeolite-type compound; and at least one CO shift or reverse shift catalyst species present within said support, said support having interconnected channels, said CO shift or reverse shift catalyst species being present in at least said channels of said support.

[2] The CO shift or reverse shift catalyst structure according to [1], wherein the channel has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and an expanded diameter portion which is different from any of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole, and in which at least the CO conversion or reverse conversion catalyst substance is present in the expanded diameter portion.

[3] The CO conversion or reverse conversion catalyst structure according to [2], wherein the diameter-enlarged portion causes a plurality of holes constituting any one of the one-dimensional holes, the two-dimensional holes, and the three-dimensional holes to communicate with each other.

[4] The CO shift or reverse shift catalyst structure according to [2] or [3], wherein the CO shift or reverse shift catalyst substance is a metal fine particle.

[5] The catalyst structure for CO conversion or reverse conversion according to item [4], wherein the metal fine particles are fine particles composed of at least one metal or metal oxide selected from the group consisting of cobalt, nickel, iron, and copper.

[6] The catalyst structure for CO conversion or reverse conversion according to item [5], wherein the fine metal particles are fine particles made of at least one metal or metal oxide selected from the group consisting of cobalt, iron, and copper.

[7] The catalyst structure for CO conversion or reverse conversion according to any one of [4] to [6], wherein an average particle diameter of the metal fine particles is larger than an average inner diameter of the channel and is equal to or smaller than an inner diameter of the enlarged diameter portion.

[8] The CO shift or reverse conversion catalyst structure according to any one of [4] to [7], characterized by containing the metal element (M) of the metal fine particles in an amount of 0.5 to 2.5 mass% relative to the CO shift or reverse conversion catalyst structure.

[9] The catalyst structure for CO conversion or reverse conversion according to any one of [4] to [8], wherein the metal fine particles have an average particle diameter of 0.08nm to 30 nm.

[10] The catalyst structure for CO conversion or reverse conversion according to item [9], wherein the metal fine particles have an average particle diameter of 0.4nm to 11.0 nm.

[11] The catalyst structure for CO shift or reverse shift according to any one of [4] to [10], wherein a ratio of an average particle diameter of the metal fine particles to an average inner diameter of the channels is 0.05 to 300.

[12] The catalyst structure for CO conversion or reverse conversion according to item [11], wherein a ratio of an average particle diameter of the metal fine particles to an average inner diameter of the channels is 0.1 to 30.

[13] The catalyst structure for CO conversion or reverse conversion according to [12], wherein a ratio of an average particle diameter of the metal fine particles to an average inner diameter of the channels is 1.4 to 3.6.

[14] The catalyst structure for CO conversion or reverse conversion according to any one of [2] to [13], wherein the average inner diameter of the channel is 0.1nm to 1.5nm, and the inner diameter of the expanded diameter portion is 0.5nm to 50 nm.

[15] The CO shift or reverse conversion catalyst structure according to any one of [1] to [14], further comprising at least one other CO shift or reverse conversion catalyst substance held on an outer surface of the carrier.

[16] The CO shift or reverse shift catalyst structure according to [15], wherein a content of the at least one CO shift or reverse shift catalyst substance present in the carrier is greater than a content of the at least one other CO shift or reverse shift catalyst substance held on the outer surface of the carrier.

[17] The CO shift or reverse shift catalyst structure according to any one of [1] to [16], wherein the zeolite-type compound is a silicate compound.

[18] A CO shift or shift conversion reaction apparatus having the CO shift or shift conversion catalyst structure according to any one of [1] to [17 ].

[19] A method for manufacturing a catalyst structure for CO conversion or reverse conversion, comprising: a firing step of firing a precursor material (B) obtained by impregnating a metal-containing solution into a precursor material (a) for obtaining a support having a porous structure composed of a zeolite-type compound; a hydrothermal treatment step of subjecting a precursor material (C) obtained by firing the precursor material (B) to hydrothermal treatment; and a step of subjecting the precursor material (C) after the hydrothermal treatment to a reduction treatment.

[20] The method for producing a catalyst structure for CO or reverse conversion according to [19], wherein 50 to 500 mass% of a nonionic surfactant is added to the precursor material (A) before the firing step.

[21] The method for producing a catalyst structure for CO or reverse conversion according to [19] or [20], wherein the metal-containing solution is impregnated into the precursor material (A) by adding the metal-containing solution to the precursor material (A) a plurality of times before the firing step.

[22] The method for producing a catalyst structure for CO or reverse conversion according to any one of [19] to [21], wherein when the metal-containing solution is impregnated into the precursor material (A) before the firing step, the amount of the metal-containing solution added to the precursor material (A) is adjusted so that the atomic ratio Si/M, which is the ratio of silicon (Si) constituting the precursor material (A) to the metal element (M) contained in the metal-containing solution added to the precursor material (A), is 10 to 1000.

[23] The method for producing a catalyst structure for CO or reverse conversion according to [19], wherein the precursor material (C) is mixed with a structure-directing agent in the hydrothermal treatment step.

[24] The method for producing a catalyst structure for CO or reverse conversion according to [19], wherein the hydrothermal treatment step is performed in an alkaline environment.

[25] A method for producing carbon dioxide and hydrogen, the method being a method for producing carbon dioxide and hydrogen by using a catalyst containing a CO-conversion catalyst structure, the method comprising: a porous support composed of a zeolite-type compound; and at least one metal fine particle present in the carrier, the carrier having channels communicating with each other, the metal fine particle being present in at least a diameter-expanded portion of the channels of the carrier.

[26] A method for producing carbon dioxide and hydrogen, characterized in that carbon dioxide and hydrogen are produced from carbon monoxide and water by using the CO shift catalyst structure according to any one of [1] to [17 ].

[27] A method for producing carbon dioxide and hydrogen, characterized by using the CO shift reaction apparatus according to [18] to shift carbon monoxide and water into carbon dioxide and hydrogen.

[28] A method for producing carbon monoxide and water, the method comprising producing carbon monoxide and water from carbon dioxide and hydrogen using a catalyst, the catalyst comprising a reverse conversion catalyst structure, the reverse conversion catalyst structure comprising: a porous support composed of a zeolite-type compound; and at least one metal fine particle present in the carrier, the carrier having channels communicating with each other, the metal fine particle being present in at least a diameter-expanded portion of the channels of the carrier.

[29] A method for producing carbon monoxide and water, characterized by using the reverse shift catalyst structure according to any one of [1] to [17] to produce carbon monoxide and water from carbon dioxide and hydrogen.

[30] A method for producing carbon monoxide and water, characterized in that carbon dioxide and hydrogen are converted into carbon monoxide and water by using the reverse conversion reaction apparatus according to [18 ].

Advantageous effects

According to the present invention, it is possible to provide a CO shift or reverse shift catalyst structure and a method for producing the same, a CO shift or reverse shift reaction apparatus, a method for producing carbon dioxide and hydrogen, and a method for producing carbon monoxide and water, which can suppress a decrease in catalytic function and prolong the life. Further, such CO shift catalyst structure and reverse shift catalyst structure show high catalytic activity and good heat resistance, and therefore, the reverse shift catalyst structure is particularly useful for application to a reverse shift reaction.

Drawings

Fig. 1 is a schematic view showing an internal structure of a CO conversion or reverse conversion catalyst structure according to an embodiment of the present invention, fig. 1(a) is a perspective view (partially shown in cross section), and fig. 1(b) is a partially enlarged sectional view.

Fig. 2 is a partially enlarged cross-sectional view for explaining an example of the function of the CO shift or reverse shift catalyst structure of fig. 1, fig. 2(a) is a view for explaining the sieve function, and fig. 2(b) is a view for explaining the catalyst function.

Fig. 3 is a flowchart showing an example of a method for manufacturing the CO shift or reverse shift catalyst structure shown in fig. 1.

Fig. 4 is a schematic diagram showing a modification of the CO shift or reverse shift catalyst structure of fig. 1.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[ constitution of catalyst Structure for CO conversion or reverse conversion ]

Fig. 1 is a view schematically showing the structure of a catalyst structure for CO conversion or reverse conversion according to an embodiment of the present invention, fig. 1(a) is a perspective view (partially shown in cross section), and fig. 1(b) is a partially enlarged sectional view. Note that the CO shift or reverse shift catalyst structure in fig. 1 is an example thereof, and the shape, size, and the like of each component of the present invention are not limited to fig. 1.

As shown in fig. 1(a), a CO conversion or reverse conversion catalyst structure 1 includes: a porous support 10 made of a zeolite-type compound; and at least one CO shift or reverse shift catalyst material 20 present within the carrier 10.

In the CO conversion or reverse conversion catalyst structure 1, the plurality of CO conversion or reverse conversion catalyst substances 20 and 20 … … are included in the porous structure of the carrier 10. The CO shift or reverse shift catalyst material 20 may have a CO shift catalytic function (CO shift or reverse shift catalytic activity), and is preferably a metal fine particle. The metal fine particles will be described in detail later.

The carrier 10 has a porous structure, and preferably has channels 11 communicating with each other by forming a plurality of holes 11a, …, as shown in fig. 1 (b). Here, the CO shift or reverse shift catalyst material 20 is present in at least the channels 11 of the carrier 10, preferably held in at least the channels 11 of the carrier 10.

With this configuration, the movement of the CO shift or reverse shift catalyst material 20 in the carrier 10 is restricted, and the CO shift or reverse shift catalyst materials 20 and 20 are effectively prevented from being aggregated with each other. As a result, the reduction of the effective surface area of the CO shift or reverse shift catalyst material 20 can be effectively suppressed, and the CO shift or reverse shift catalytic activity of the CO shift or reverse shift catalyst material 20 can be continued for a long period of time. That is, according to the CO shift or reverse shift catalyst structure 1, it is possible to suppress a decrease in catalytic activity of CO shift or reverse shift due to aggregation of the CO shift or reverse shift catalyst substance 20, and it is possible to extend the life of the CO shift or reverse shift catalyst structure 1. Further, by extending the life of the CO shift or reverse shift catalyst structure 1, the frequency of replacement of the CO shift or reverse shift catalyst structure 1 can be reduced, the amount of waste of the CO shift or reverse shift catalyst structure 1 after use can be greatly reduced, and resource saving can be achieved.

In general, when a CO conversion or reverse conversion catalyst structure is used in a fluid which is a CO-containing gas for converting coal into a combustible gas, for example, an external force may be applied from the fluid. In this case, if the CO shift or reverse shift catalyst material 20 is held only in an attached state on the outer surface of the carrier 10, there is a problem that the catalyst material is easily detached from the outer surface of the carrier 10 under the influence of an external force from a fluid. In contrast, in the CO shift or reverse shift catalyst structure 1, the CO shift or reverse shift catalyst material 20 is present in at least the channels 11 of the carrier 10, and therefore, the CO shift or reverse shift catalyst material 20 is less likely to be detached from the carrier 10 even when it is affected by an external force from a fluid. Namely, it is considered that: when the CO shift or reverse shift catalyst structure 1 is in a fluid, the fluid flows into the channels 11 from the holes 11a of the carrier 10, and therefore the velocity of the fluid flowing through the channels 11 is lower than the velocity of the fluid flowing through the outer surfaces of the carrier 10 due to the flow path resistance (frictional force). Due to the influence of the flow path resistance, the pressure to which the CO shift or reverse shift catalyst substance 20 present in the passage 11 is subjected from the fluid is smaller than the pressure to which the CO shift or reverse shift catalyst substance 20 is subjected from the fluid outside the carrier 10. Therefore, the separation of the CO shift or reverse shift catalyst material 20 existing in the carrier 10 can be effectively suppressed, and the catalytic activity of the CO shift or reverse shift catalyst material 20 can be stably maintained for a long period of time. It should be noted that: the channel 11 of the carrier 10 has a plurality of bends and branches, and the more complicated three-dimensional structure is inside the carrier 10, the greater the flow path resistance as described above.

Furthermore, the channel 11 preferably has: any one of one-dimensional pores, two-dimensional pores, and three-dimensional pores defined by the framework structure of the zeolite-type compound; and an enlarged diameter portion 12 different from any of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole, in which case, the CO conversion or reverse conversion catalyst substance 20 is preferably present at least in the enlarged diameter portion 12, and more preferably included at least in the enlarged diameter portion 12. Further, the enlarged diameter portion 12 preferably causes a plurality of holes 11a, 11a constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole to communicate with each other. Thus, since a separate channel different from the one-dimensional hole, the two-dimensional hole, or the three-dimensional hole is provided in the carrier 10, the function of the CO-conversion or reverse-conversion catalyst material 20 can be further exerted. The one-dimensional hole referred to herein is a tunnel-type or cage-type hole in which one-dimensional channels are formed, or a plurality of holes (a plurality of one-dimensional channels) in which a plurality of one-dimensional channels are formed. In addition, the two-dimensional hole refers to a two-dimensional hole formed by two-dimensionally connecting a plurality of one-dimensional holes, and the three-dimensional hole refers to a three-dimensional hole formed by three-dimensionally connecting a plurality of one-dimensional holes. This can further restrict the movement of the CO shift or reverse shift catalyst substance 20 within the carrier 10, and can further effectively prevent the CO shift or reverse shift catalyst substance 20 from being detached, and the CO shift or reverse shift catalyst substances 20 and 20 from being aggregated with each other. Inclusion means a state in which the CO conversion or reverse conversion catalyst substance 20 is contained in the carrier 10. In this case, the CO shift or reverse shift catalyst substance 20 and the carrier 10 do not necessarily need to be in direct contact with each other, and the CO shift or reverse shift catalyst substance 20 may be indirectly held on the carrier 10 with another substance (for example, a surfactant) interposed between the CO shift or reverse shift catalyst substance 20 and the carrier 10.

Fig. 1(b) shows a case where the CO shift or reverse shift catalyst substance 20 is enclosed in the enlarged diameter portion 12, but the present invention is not limited to this configuration, and the CO shift or reverse shift catalyst substance 20 may be held in the passage 11 in a state where a part thereof protrudes to the outside of the enlarged diameter portion 12. The CO-shift or reverse-shift catalyst material 20 may be partially buried or held by adhesion or the like in a part of the channel 11 other than the enlarged diameter portion 12 (for example, an inner wall portion of the channel 11).

Further, it is preferable that the channel 11 is three-dimensionally formed so as to include a branching portion or a merging portion in the carrier 10, and the diameter-enlarged portion 12 is provided in the branching portion or the merging portion of the channel 11.

The average inner diameter D of the channels 11 formed in the carrier 10 is calculated from the average of the minor diameter and the major diameter of the holes 11a constituting any one of the one-dimensional holes, the two-dimensional holes, and the three-dimensional holes_FFor example, it is 0.1nm to 1.5nm, preferably 0.5nm to 0.8 nm. Further, the inner diameter D of the enlarged diameter portion 12_EFor example, 0.5nm to 50nm, preferably 1.1nm to 40nm, and more preferably 1.1nm to 3.3 nm. Inner diameter D of enlarged diameter portion 12_EFor example, depending on the precursor material described laterThe pore diameter of the material (A) and the average particle diameter D of the enclosed CO-or reverse-conversion catalyst substance 20_C. Inner diameter D of enlarged diameter portion 12_EIs of a size capable of enclosing the CO shift or reverse shift catalyst material 20.

The support 10 is composed of a zeolite-type compound. Examples of the zeolite-type compound include: silicate compounds such as zeolite (aluminosilicate), cation-exchange zeolite, and silicalite (silicalite); zeolite-like compounds such as aluminoborate, aluminoarsenate, germanate and the like; and phosphate-based zeolite-like substances such as molybdenum phosphate. Among them, the zeolite-type compound is preferably a silicate compound.

The framework structure of the zeolite-type compound is selected from FAU-type (Y-type or X-type), MTW-type, MFI-type (ZSM-5), FER-type (ferrierite), LTA-type (A-type), MWW-type (MCM-22), MOR-type (mordenite), LTL-type (L-type), BEA-type (beta-type), etc., preferably MFI-type, more preferably ZSM-5. The zeolite-type compound has a plurality of pores formed therein and having pore diameters corresponding to respective framework structures, and for example, the MFI-type compound has a maximum pore diameter of 0.636nm

Average pore diameter of 0.560nm

Hereinafter, a case where the CO shift or reverse shift catalyst material 20 is a metal fine particle will be described in detail.

There are cases where the fine metal particles 20 are primary particles and cases where the fine metal particles 20 are secondary particles formed by aggregating the primary particles, but the average particle diameter D of the fine metal particles 20_CPreferably greater than the average internal diameter D of the channel 11_FAnd is not more than the inner diameter D of the enlarged diameter part 12_E(D_F<D_C≤D_E). Such fine metal particles 20 are preferably present in the enlarged diameter portion 12 in the channel 11 to restrict the movement of the fine metal particles 20 in the carrier 10. Therefore, for example, even in the case where the fine metal particles 20 contain CO and water vapor (H) as the fluid₂O) and the fine metal particles 20 are suppressed from being present on the carrier even when the mixed gas containing CO is subjected to an external forceThe movement in the channel 10 can effectively prevent the metal fine particles 20, 20 … … respectively existing in the diameter-enlarged parts 12, 12 … … of the channel 11 dispersedly arranged in the carrier 10 from contacting each other.

The average particle diameter D of the fine metal particles 20_CIn the case of either the primary particles or the secondary particles, the particle size is preferably 0.08nm or more and 30nm or less, more preferably 0.08nm or more and less than 25nm, still more preferably 0.4nm to 11.0nm, and particularly preferably 0.8nm or more and 2.7nm or less. Further, the average particle diameter D of the fine metal particles 20_CRelative to the mean internal diameter D of the channel 11_FRatio (D)_C/D_F) Preferably 0.05 to 300, more preferably 0.1 to 30, further preferably 1.1 to 30, and particularly preferably 1.4 to 3.6. The content of the metal element (M) in the fine metal particles 20 is preferably 0.5 to 2.5% by mass relative to the CO shift or reverse shift catalyst structure 1, and more preferably 0.5 to 1.5% by mass relative to the CO shift or reverse shift catalyst structure 1. For example, in the case where the metal element (M) is Co, the content (mass%) of the Co element is represented by { (mass of Co element)/(mass of all elements of the Co-shift or reverse-shift catalyst structure 1) } × 100.

The metal fine particles may be fine particles composed of at least one metal or metal oxide, and may be composed of a single metal or metal oxide, or may be composed of a mixture of two or more metals or metal oxides, for example. In the present specification, "metal" constituting (as a material of) the metal fine particles means a single metal containing one metal element (M) and a metal alloy containing two or more metal elements (M), and is a generic term for metals containing one or more metal elements. Further, "metal oxide" is meant to include an oxide containing one metal element (M) and a composite oxide containing two or more metal elements (M), and is a generic term for oxides containing one or more metal elements (M).

Examples of such metals include: platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), cobalt (Co), molybdenum (Mo), tungsten (W), iron (Fe), chromium (Cr), cerium (Ce), copper (Cu), magnesium (Mg), aluminum (Al), and the like, and preferably any one or more of these as a main component.

Examples of such metal oxides include: cobalt oxide (CoO)_x) Nickel oxide (NiO)_x) Iron oxide (FeO)_x) Copper oxide (CuO)_x) Zirconium oxide (ZrO)_x) Cerium oxide (CeO)_x) Aluminum oxide (AlO)_x) Niobium oxide (NbO)_x) Titanium oxide (TiO)_x) Bismuth oxide (BiO)_x) Molybdenum oxide (MoO)_x) Vanadium Oxide (VO)_x) Chromium oxide (CrO)_x) And the like, preferably any one or more of the above as a main component.

Among the above-mentioned metal fine particles composed of a metal or a metal oxide, the metal fine particles are preferably fine particles composed of at least one metal or metal oxide selected from the group consisting of cobalt, nickel, iron, and copper, more preferably fine particles composed of at least one metal or metal oxide selected from the group consisting of cobalt, iron, and copper, and particularly preferably fine particles composed of copper or copper oxide.

The ratio (atomic ratio Si/M) of silicon (Si) constituting the carrier 10 to the metal element (M) constituting the fine metal particles 20 is preferably 10 to 1000, and more preferably 50 to 200. If the above ratio is more than 1000, the catalytic activity for CO shift or reverse shift may be lowered, and thus the function as a catalyst substance for CO shift or reverse shift may not be sufficiently obtained. On the other hand, if the ratio is less than 10, the ratio of the fine metal particles 20 is too large, and the strength of the carrier 10 tends to decrease. The fine metal particles 20 referred to herein are particles held or carried in the carrier 10, and do not include fine metal particles attached to the outer surface of the carrier 10.

[ function of catalyst Structure for CO conversion and reverse conversion ]

As described above, the CO-shift or reverse-shift catalyst structure 1 includes: a support 10 having a porous structure; and at least one CO shift or reverse shift catalyst material 20 present within the support 10. The CO shift catalyst structure 1 exerts the CO shift catalytic function by the CO shift catalyst material 20 by bringing the CO shift catalyst material 20 present in the carrier 10 into contact with the CO-containing mixed gas. Specifically, the CO-containing mixed gas that has contacted the outer surface 10a of the CO-shift catalyst structure 1 flows into the inside of the carrier 10 through the holes 11a formed in the outer surface 10a, is guided into the channels 11, moves through the inside of the channels 11, and flows out to the outside of the CO-shift catalyst structure 1 through the other holes 11 a. In the path in which the CO-containing mixed gas moves through the inside of the passage 11, the CO-shift catalytic reaction of the CO-shift catalyst substance 20 occurs by contact with the CO-shift catalyst substance 20 held in the passage 11.

Similarly, in the reverse shift catalyst structure 1, the reverse shift catalyst substance 20 present in the carrier 10 is mixed with the CO-containing gas₂And H₂Containing CO of₂The mixed gas of (a) is brought into contact with each other to exert the reverse shift catalytic function by the reverse shift catalyst substance 20. Specifically, the CO-containing catalyst in contact with the outer surface 10a of the reverse shift catalyst structure 1₂The mixed gas (2) flows into the inside of the carrier 10 from the holes 11a formed in the outer surface 10a, is guided into the passage 11, moves through the passage 11, and flows out to the outside of the reverse shift catalyst structure 1 through the other holes 11 a. In the presence of CO₂The mixed gas (b) moves through the path in the channel 11, and by contacting with the reverse shift catalyst substance 20 held in the channel 11, a reverse shift catalytic reaction of the reverse shift catalyst substance 20 occurs.

Since the carrier 10 has a porous structure, the CO-shift or reverse-shift catalyst structure 1 has a molecular sieve function. First, H contained in a synthesis gas as a fluid in the CO conversion or reverse conversion catalyst structure 1₂、H₂O、CO、CO₂The function of the molecular sieve penetrated is illustrated. As shown in FIG. 2(a), the inner diameter of the hole 11a, i.e., the inner diameter of the passage 11, is equal to or smaller than H₂、H₂O, CO and CO₂Can flow into the carrier 10. On the other hand, other molecules 15 having a size larger than the pore diameter of the pores 11a cannot flow into the carrier 10. Thus, in the mixed gas containing CO, the mixed gas containing CO₂When the mixed gas (2) contains a plurality of compounds, the reaction of the compounds which cannot flow into the carrier 10 is restricted, and the compounds which can flow into the carrier 10 can be caused to flowThe materials are reacted.

In addition, among the compounds produced in the carrier 10 by the above reaction, only compounds composed of molecules having a size not larger than the pore diameter of the pores 11a can be obtained as reaction products by flowing out of the carrier 10 through the pores 11 a. On the other hand, if the compound that cannot flow out of the pores 11a to the outside of the carrier 10 is converted into a compound composed of molecules having a size that can flow out of the carrier 10, the compound can flow out of the carrier 10. In this way, by using the CO shift or reverse shift catalyst structure 1, a specific reaction product can be selectively obtained.

In the CO-shift or reverse-shift catalyst structure 1, as shown in fig. 2(b), the CO-shift or reverse-shift catalyst substance 20 is included in the enlarged diameter portion 12 of the passage 11. When the catalyst material 20 for CO or reverse conversion is a metal fine particle, the average particle diameter D of the metal fine particle is_CGreater than the average internal diameter D of the channel 11_FAnd is smaller than the inner diameter D of the diameter-enlarged part 12_EIn the case of (D)_F<D_C<D_E) Small passages 13 are formed between the fine metal particles and the diameter-enlarged portion 12. Therefore, as shown by the arrows in FIG. 2(b), the CO-containing mixed gas or CO-containing mixed gas flowing into the small passage 13₂The mixed gas of (2) is brought into contact with the metal fine particles. Since each fine metal particle is wrapped in the enlarged diameter portion 12, the movement of the fine metal particles in the carrier 10 is restricted. This prevents the metal microparticles in the carrier 10 from aggregating with each other. As a result, the mixed gas of the metal fine particles and the CO-containing fluid or the CO-containing fluid can be stably maintained₂Large contact area of the mixed gas of (2).

Furthermore, when the mixed gas containing CO or the mixed gas containing CO flows into the passage 11₂Is contacted with the CO shift or reverse shift catalyst material 20, CO and H are produced in the CO shift reaction by the catalytic reaction carried out by the CO shift or reverse shift catalyst material 20₂O is converted to CO₂And H₂In the reverse shift reaction, CO₂And H₂Is converted into CO and H₂O。

[ CO conversion or inverse conversion reaction apparatus ]

Further, a CO shift or reverse shift reaction apparatus having a CO shift or reverse shift catalyst structure may be formed using the CO shift or reverse shift catalyst structure 1. By using the CO shift or reverse shift catalyst structure 1 of the embodiment described above, a CO shift or reverse shift reaction apparatus having the same effects as described above can be obtained.

[ method for producing catalyst structure for CO conversion or reverse conversion ]

Fig. 3 is a flowchart showing a method of manufacturing the CO shift or reverse shift catalyst structure 1 of fig. 1. Hereinafter, an example of a method for producing a CO shift or reverse shift catalyst structure will be described by taking as an example a case where the CO shift or reverse shift catalyst material present in the carrier is fine metal particles.

(step S1: preparation Process)

As shown in fig. 3, first, a precursor material (a) for obtaining a support having a porous structure made of a zeolite-type compound is prepared. The precursor material (a) is preferably a regular mesoporous substance, and may be appropriately selected depending on the kind (composition) of the zeolite-type compound constituting the support of the CO shift or reverse shift catalyst structure.

Here, when the zeolite-type compound constituting the carrier of the CO shift or reverse shift catalyst structure is a silicate compound, the regular mesoporous material is preferably a compound containing an Si — O framework in which pores having a pore diameter of 1nm to 50nm are uniformly and regularly spread in one-dimensional, two-dimensional or three-dimensional size. Such a ordered mesoporous material is obtained as various compositions according to synthesis conditions, and specific examples of the compositions include: SBA-1, SBA-15, SBA-16, KIT-6, FSM-16, MCM-41 and the like, wherein MCM-41 is preferred. The pore diameter of SBA-1 is 10nm to 30nm, the pore diameter of SBA-15 is 6nm to 10nm, the pore diameter of SBA-16 is 6nm, the pore diameter of KIT-6 is 9nm, the pore diameter of FSM-16 is 3nm to 5nm, and the pore diameter of MCM-41 is 1nm to 10 nm. Examples of such a regular mesoporous material include: mesoporous silica, mesoporous aluminosilicates, mesoporous metallosilicates, and the like.

The precursor (a) may be any of commercially available products and synthetic products. In the case of synthesizing the precursor material (a), it can be carried out by a known method for synthesizing a regular mesoporous substance. For example, a mixed solution containing a raw material containing a constituent element of the precursor material (a) and a template agent for specifying the structure of the precursor material (a) is prepared, and hydrothermal treatment (hydrothermal synthesis) is performed by adjusting the pH as necessary. Then, the precipitate (product) obtained by the hydrothermal treatment is recovered (for example, filtered), washed and dried as necessary, and further fired, whereby the precursor material (a) as a regular mesoporous substance in a powder form can be obtained. Here, as the solvent of the mixed solution, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used. The raw material is selected depending on the kind of the carrier, and examples thereof include: silicon agents (silica agents) such as Tetraethoxysilane (TEOS), fumed silica, quartz sand, and the like. Further, as the template agent, various surfactants, block copolymers and the like can be used, and it is preferably selected according to the kind of the composition of the ordered mesoporous material, and for example, in the case of preparing MCM-41, a surfactant such as cetyltrimethylammonium bromide is preferred.

The hydrothermal treatment may be carried out, for example, in a closed vessel under the treatment conditions of 80 to 800 ℃ for 5 to 240 hours and 0 to 2000 kPa. The firing treatment may be performed, for example, in air at 350 to 850 ℃ for 2 to 30 hours.

(step S2: impregnation step)

Next, the prepared precursor material (a) is immersed in a metal-containing solution to obtain a precursor material (B).

The metal-containing solution may be a solution containing a metal component (for example, metal ion) corresponding to the metal element (M) constituting the metal fine particles of the CO shift or reverse shift catalyst structure, and may be prepared, for example, by dissolving a metal salt containing the metal element (M) in a solvent. Examples of such metal salts include: metal salts such as chlorides, hydroxides, oxides, sulfates, nitrates, etc., among which nitrates are preferable. As the solvent, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used.

The method for immersing the metal-containing solution in the precursor material (a) is not particularly limited, and for example, it is preferable to add the metal-containing solution to the precursor material (a) in small amounts in a plurality of times while stirring the powdery precursor material (a) before the firing step described later. In addition, from the viewpoint that the metal-containing solution is more likely to infiltrate into the inside of the pores of the precursor material (a), it is preferable to add a surfactant as an additive in advance before adding the metal-containing solution to the precursor material (a). It is considered that such an additive has an effect of covering the outer surface of the precursor material (a), and it suppresses the metal-containing solution added later from adhering to the outer surface of the precursor material (a), and the metal-containing solution is more likely to infiltrate into the inside of the pores of the precursor material (a).

Examples of such additives include nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl ether. Consider that: these surfactants have large molecular sizes and cannot enter the pores of the precursor material (a), and therefore do not adhere to the inside of the pores and do not inhibit the metal-containing solution from entering the inside of the pores. As a method for adding the nonionic surfactant, for example, it is preferable to add 50 to 500 mass% of the nonionic surfactant to the precursor material (a) before the firing step described later. If the amount of the nonionic surfactant added to the precursor material (a) is less than 50 mass%, the above-described inhibiting effect is difficult to be exhibited, and if the amount of the nonionic surfactant added to the precursor material (a) is more than 500 mass%, the viscosity is excessively increased, which is not preferable. Therefore, the amount of the nonionic surfactant added to the precursor material (a) is set to a value within the above range.

The amount of the metal-containing solution added to the precursor material (a) is preferably adjusted as appropriate in consideration of the amount of the metal element (M) contained in the metal-containing solution impregnated in the precursor material (a) (that is, the amount of the metal element (M) present in the precursor material (B)). For example, the amount of the metal-containing solution added to the precursor material (a) is preferably adjusted so that the ratio (atomic ratio Si/M) of silicon (Si) constituting the precursor material (a) to a metal element (M) contained in the metal-containing solution added to the precursor material (a) is 10 to 1000, more preferably 50 to 200, before the firing step described later. For example, when a surfactant is added as an additive to the precursor material (a) before the metal-containing solution is added to the precursor material (a), the content of the metal element (M) in the metal fine particles can be set to 0.5 to 2.5 mass% relative to the CO-shift or reverse-shift catalyst structure by setting the amount of the metal-containing solution added to the precursor material (a) to 50 to 200 in terms of the atomic ratio Si/M.

In the state of the precursor material (B), if the metal concentration of the metal-containing solution, the presence or absence of the additive, and other conditions such as temperature and pressure are the same, the amount of the metal element (M) present in the pores thereof is substantially proportional to the amount of the metal-containing solution added to the precursor material (a). Further, the amount of the metal element (M) present in the precursor material (B) is in proportional relation to the amount of the metal element constituting the metal fine particles present in the carrier of the CO shift or reverse shift catalyst structure. Therefore, by controlling the amount of the metal-containing solution added to the precursor material (a) within the above range, the metal-containing solution can be sufficiently impregnated into the pores of the precursor material (a), and the amount of the metal fine particles present in the carrier of the CO-shift or reverse-shift catalyst structure can be adjusted.

After the precursor material (a) is immersed in the metal-containing solution, a cleaning treatment may be performed as needed. As the cleaning solution, water, an organic solvent such as alcohol, or a mixed solution thereof can be used. Further, it is preferable that the metal-containing solution is immersed in the precursor material (a) and, after a cleaning treatment is performed as necessary, a drying treatment is further performed. Examples of the drying treatment include natural drying at about evening-out and high-temperature drying at 150 ℃. When the firing treatment described later is performed in a state where a large amount of moisture contained in the metal-containing solution or moisture in the cleaning solution remains in the precursor (a), the skeleton structure of the regular mesoporous material as the precursor (a) may be broken, and therefore, it is preferable to sufficiently dry the precursor (a).

(step S3: firing Process)

Next, a precursor material (B) obtained by impregnating a precursor material (a) for obtaining a support having a porous structure made of a zeolite-type compound with a metal-containing solution is fired to obtain a precursor material (C).

The firing treatment is preferably carried out in air at 350 to 850 ℃ for 2 to 30 hours, for example. By such firing treatment, the metal component crystals impregnated into the pores of the regular mesoporous material grow, and metal fine particles are formed in the pores.

(step S4: hydrothermal treatment Process)

Next, a mixed solution in which the precursor material (C) and the structure-directing agent are mixed is prepared, and the precursor material (C) obtained by firing the precursor material (B) is subjected to hydrothermal treatment to obtain a CO-conversion or reverse-conversion catalyst structure.

The structure directing agent is a template agent for specifying the framework structure of the carrier of the CO shift or reverse shift catalyst structure, and a surfactant, for example, can be used. The structure directing agent is preferably selected according to the skeletal structure of the carrier of the CO shift or reverse shift catalyst structure, and is preferably a surfactant such as tetramethylammonium bromide (TMABr), tetraethylammonium bromide (TEABr), tetrapropylammonium bromide (TPABr), or the like.

The mixing of the precursor material (C) and the structure-directing agent may be performed in the present hydrothermal treatment step, or may be performed before the hydrothermal treatment step. The method for preparing the mixed solution is not particularly limited, and the precursor material (C), the structure-directing agent, and the solvent may be mixed at the same time, or the precursor material (C) and the structure-directing agent may be dispersed in the solvent in the respective solutions and then the respective dispersed solutions may be mixed. As the solvent, for example, an organic solvent such as water or alcohol, or a mixed solvent thereof can be used. It is preferable that the pH of the mixed solution is adjusted in advance with an acid or an alkali before the hydrothermal treatment.

The hydrothermal treatment can be carried out by a known method, and is preferably carried out in a closed vessel under treatment conditions of, for example, 80 to 800 ℃ for 5 to 240 hours and 0 to 2000 kPa. Further, it is preferable to perform hydrothermal treatment in an alkaline environment. Although the reaction mechanism is not necessarily clear here, when the precursor material (C) is subjected to hydrothermal treatment as a raw material, the skeleton structure of the regular mesoporous material as the precursor material (C) is gradually destroyed, but the position of the metal fine particles inside the pores of the precursor material (C) is substantially maintained, and a new skeleton structure (porous structure) as a carrier of the CO-conversion or reverse-conversion catalyst structure is formed by the action of the structure-directing agent. The catalyst structure for CO conversion or reverse conversion obtained in this way comprises a carrier having a porous structure and metal fine particles present in the carrier, the carrier further has channels which communicate with each other through the porous structure of the carrier, and at least a part of the metal fine particles are present in the channels of the carrier. In the present embodiment, in the hydrothermal treatment step, a mixed solution in which the precursor material (C) and the structure-directing agent are mixed is prepared, and the hydrothermal treatment is performed on the precursor material (C), but the present invention is not limited thereto, and the hydrothermal treatment may be performed on the precursor material (C) without mixing the precursor material (C) and the structure-directing agent.

It is preferable that the precipitate (CO-shift or reverse-shift catalyst structure) obtained after the hydrothermal treatment is recovered (for example, filtered), and then washed, dried, and fired as necessary. As the cleaning solution, water, an organic solvent such as alcohol, or a mixed solution thereof can be used. Examples of the drying treatment include natural drying at about evening-out and high-temperature drying at 150 ℃. When the calcination treatment is performed in a state where a large amount of water remains in the precipitate, the skeleton structure of the carrier serving as the CO shift or reverse shift catalyst structure may be broken, and therefore, it is preferable to sufficiently dry the precipitate. The firing treatment can be performed, for example, in air at 350 to 850 ℃ for 2 to 30 hours. By such a firing treatment, the structure directing agent adhering to the CO shift or reverse shift catalyst structure is burned off. Further, depending on the purpose of use, the CO shift or reverse shift catalyst structure may be used as it is without subjecting the recovered precipitate to firing treatment. For example, when the environment in which the CO shift or reverse shift catalyst structure is used is a high-temperature environment such as an oxidizing environment, the structure directing agent is burned off by exposure to the use environment for a certain period of time, and the CO shift or reverse shift catalyst structure can be obtained in the same manner as in the case of performing the firing treatment, and therefore can be used as it is.

The above-described production method is an example of a case where the metal element (M) contained in the metal-containing solution impregnated into the precursor material (a) is a metal species (for example, a noble metal) that is difficult to be oxidized.

When the metal element (M) contained in the metal-containing solution impregnated in the precursor material (a) is a metal species (for example, Fe, Co, Cu, or the like) that is easily oxidized, it is preferable that the precursor material (C) after the hydrothermal treatment is subjected to a reduction treatment after the hydrothermal treatment step. When the metal element (M) contained in the metal-containing solution is a metal species that is easily oxidized, the metal component is oxidized by the heat treatment in the steps (steps S3 to S4) after the impregnation treatment (step S2). Therefore, the metal oxide fine particles are present in the carrier formed in the hydrothermal treatment step (step S4). Therefore, in order to obtain a catalyst structure for CO or reverse conversion in which fine metal particles are present in a carrier, it is preferable that the collected precipitate is subjected to a firing treatment after the hydrothermal treatment and further subjected to a reduction treatment in a reducing gas atmosphere such as hydrogen gas (step S5: reduction treatment step). By performing the reduction treatment, the metal oxide fine particles present in the carrier are reduced to form metal fine particles corresponding to the metal element (M) constituting the metal oxide fine particles. As a result, a CO shift or reverse shift catalyst structure in which the metal fine particles are present in the carrier can be obtained. When the environment in which the catalyst structure for CO conversion or reverse conversion is used is a reducing environment, for example, the metal oxide fine particles are reduced by exposure to the use environment for a certain period of time, and therefore, the same catalyst structure for CO conversion or reverse conversion as in the case of performing the reducing process can be obtained, and therefore, the catalyst structure can be used as it is in a state in which the oxide fine particles are present in the carrier.

[ variation of catalyst Structure for CO conversion or reverse conversion ]

Fig. 4 is a schematic diagram showing a modification of the CO shift or reverse shift catalyst structure 1 of fig. 1. The CO shift or reverse shift catalyst structure 1 of fig. 1 is shown to include the carrier 10 and the CO shift or reverse shift catalyst material 20 present in the carrier 10, but the present invention is not limited to this configuration, and for example, as shown in fig. 4, the CO shift or reverse shift catalyst structure 2 may further include another CO shift or reverse shift catalyst material 30 held on the outer surface 10a of the carrier 10.

The other CO shift or reverse shift catalyst material 30 is a material that performs one or more catalytic functions. The catalytic function of the other CO shift or reverse shift catalyst material 30 may be the same as or different from the catalytic function of the CO shift or reverse shift catalyst material 20. In the case where both of the CO shift or reverse shift catalyst substances 20 and 30 have the same catalytic function, the material of the other CO shift or reverse shift catalyst substance 30 may be the same as or different from the material of the CO shift or reverse shift catalyst substance 20. According to the present configuration, the content of the CO shift or reverse shift catalyst substance held in the CO shift or reverse shift catalyst structure 2 can be increased, and the catalytic activity of the CO shift or reverse shift catalyst substance can be further promoted.

In this case, it is preferable that the content of the CO shift or reverse shift catalyst substance 20 present in the carrier 10 is greater than the content of the other CO shift or reverse shift catalyst substance 30 held on the outer surface 10a of the carrier 10. Thus, the catalytic function of the CO shift or reverse shift catalyst material 20 held in the carrier 10 becomes a dominant function, and the catalytic function of the CO shift or reverse shift catalyst material is stably exhibited.

[ Process for producing carbon dioxide and Hydrogen ]

Further, the present invention can provide a method for producing carbon dioxide and hydrogen by generating carbon dioxide and hydrogen from carbon monoxide and water (water vapor) using a catalyst. Such a catalyst includes a CO shift catalyst structure 1, and the CO shift catalyst structure 1 includes: a porous support 10 made of a zeolite-type compound; and at least one metal fine particle 20 present in the carrier 10, the carrier 10 having channels 11 communicating with each other, the metal fine particle 20 being present in at least the diameter-enlarged portion 12 of the channel 11 of the carrier 10. That is, the present invention can provide a method for producing carbon dioxide and hydrogen from carbon monoxide and water (steam) using the above CO shift catalyst structure.

The raw material for carrying out the method for producing carbon dioxide and hydrogen by the CO shift reaction is not particularly limited as long as it is a synthesis gas containing gaseous water and carbon monoxide as main components, and a synthesis gas having a molar ratio of water vapor to carbon monoxide in the raw material gas of 1 to 100 is preferred. The reaction conditions for the CO shift reaction can be set according to the concentration of the gas component in the raw material gas, the content of the catalyst component, and the like. In general, the reaction temperature of the CO shift reaction is preferably 150 to 300 ℃, the reaction pressure is preferably 1 to 100 atm (absolute pressure), and the space velocity of the raw material gas (excluding water vapor) is preferably 1000 to 100000 (1/h).

The CO shift reaction can be carried out by a known process, for example, a fixed bed, a supercritical fixed bed, a suspended bed (slurybed), a fluidized bed, or the like as a reaction process of the CO shift reaction. As described above, even when carbon dioxide and hydrogen are produced from carbon monoxide and water (steam), that is, in the CO shift reaction, the CO shift catalyst structure of the present invention is used, the same effects as those exhibited by the CO shift catalyst structure in the above-described carbon dioxide and hydrogen production method can be obtained.

The present invention also provides a method for producing carbon dioxide and hydrogen, which converts carbon monoxide and water into carbon dioxide and hydrogen using the above-described CO shift reactor. Such a CO shift reaction apparatus is not particularly limited as long as it can perform a CO shift reaction by the CO shift catalyst structure, and, for example, a commonly used reaction apparatus such as a reactor, a reaction tube, or a reaction column can be used. By using a CO shift reactor having a CO shift catalyst structure, the same effects as those exhibited by the above CO shift catalyst structure can be obtained.

[ Process for producing carbon monoxide and Water ]

Further, the present invention can also provide a method for producing carbon monoxide and water (water vapor) from carbon dioxide and hydrogen using a catalyst. Such a catalyst comprises a reverse conversion catalyst structure 1, and the reverse conversion catalyst structure 1 includes: a porous support 10 made of a zeolite-type compound; and at least one metal fine particle 20 present in the carrier 10, the carrier 10 having channels 11 communicating with each other, the metal fine particle 20 being present in at least the diameter-enlarged portion 12 of the channel 11 of the carrier 10. That is, the present invention can provide a method for producing carbon monoxide and water (water vapor) from carbon dioxide and hydrogen using the reverse conversion catalyst structure.

The raw material for carrying out the method for producing carbon monoxide and water by the reverse conversion reaction is not particularly limited as long as it is a synthesis gas containing molecular hydrogen and carbon dioxide as main components. In addition, CO and H utilizing such reverse shift reaction are carried out₂In the production method of (2), CO₂、H₂、CO、H₂The composition of O is governed by the chemical equilibrium, the composition of the resulting gas being determined by the reaction temperature and the CO of the feed gas₂/H₂The ratio is determined. Removing unreacted CO from the reacted gas to obtain synthesis gas₂And H generated₂O, thereby H of the raw material gas₂The higher the ratio of (A) is, the higher the H content of the resultant synthesis gas can be₂A ratio. The reverse conversion reaction can be efficiently performed at a reaction temperature of 300 ℃ to 900 ℃, preferably 400 ℃ to 850 ℃, and more preferably 500 ℃ to 800 ℃. If the reaction temperature is lower than 300 ℃, carbon dioxide tends not to be sufficiently converted into carbon monoxide in equilibrium. On the other hand, if the reaction temperature exceeds 900 ℃, it is necessary to improve the performance of auxiliary equipment such as piping, which is not preferable from the viewpoint of production cost.

The reverse shift reaction can also be carried out by a known process, for example, a fixed bed, a supercritical fixed bed, a suspended bed, a fluidized bed, or the like as a reaction process of the reverse shift reaction, and thus, when carbon monoxide and water (steam) are produced from carbon dioxide and hydrogen, that is, in the reverse shift reaction, by using the reverse shift catalyst structure of the present invention, effects similar to those shown by the reverse shift catalyst structure in the above-described method for producing carbon monoxide and water can also be obtained.

The present invention also provides a method for producing carbon monoxide and water, which comprises converting carbon dioxide and hydrogen into carbon monoxide and water (water vapor) using the reverse conversion reaction apparatus. The reverse shift reaction apparatus is not particularly limited as long as it is an apparatus capable of performing a reverse shift reaction by the above-mentioned reverse shift catalyst structure, and, for example, a commonly used reaction apparatus such as a reactor, a reaction tube, a reaction column, or the like can be used. By using the reverse shift reaction apparatus having the reverse shift catalyst structure, the same effects as those shown by the above-described reverse shift catalyst structure can be obtained.

As described above, the CO shift or reverse shift catalyst structure of the present invention is a catalyst that can be applied to both of the CO shift reaction and the reverse shift reaction, and can suppress a decrease in catalytic function in both reactions to extend the life. In particular, since such a CO shift or reverse shift catalyst structure exhibits high catalytic activity, for example, by using the reverse shift catalyst structure for the reverse shift reaction, it can be applied to the reverse shift reaction in a high-temperature environment which has not been used conventionally.

Although the CO shift or reverse shift catalyst structure and the method for producing the same, the CO shift or reverse shift reaction apparatus, the method for producing carbon dioxide and hydrogen, and the method for producing carbon monoxide and water according to the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.