KR101825495B1 - Cobalt-supported catalyst for low-temperature methane reformation using carbon dioxide, and the fabrication method thereof - Google Patents

Abstract

More particularly, the present invention relates to a cobalt supported catalyst for low temperature reforming reaction, and more particularly, to a process for producing a synthesis gas by reforming natural gas with carbon dioxide. The process comprises physically mixing zinc oxide and alumina, The present invention relates to a cobalt supported catalyst prepared by supporting an active component of cobalt on an amorphous zinc-aluminate support, which has a high catalytic activity and a high durability even at a low temperature of 600 ° C, To a cobalt supported catalyst obtained and a method for producing the catalyst.

Description

TECHNICAL FIELD [0001] The present invention relates to a cobalt-supported catalyst for low temperature reforming reaction and a method for producing the same,

More particularly, the present invention relates to a cobalt supported catalyst for low temperature reforming reaction, and more particularly, to a process for producing a synthesis gas by reforming natural gas with carbon dioxide. The process comprises physically mixing zinc oxide and alumina, The present invention relates to a cobalt supported catalyst prepared by supporting an active component of cobalt on an amorphous zinc-aluminate support, which has a high catalytic activity and a high durability even at a low temperature of 600 ° C, To a cobalt supported catalyst obtained and a method for producing the catalyst.

Global warming caused by greenhouse gases is intensifying, and the burden on the industry is increasing due to limiting the emission of greenhouse gases by each country. In particular, it is inevitable that the automobile, steel and petrochemical industries, which are energy consuming industries, will be hit. In order to solve this problem, the focus is on reducing carbon dioxide emissions and converting carbon dioxide into useful materials for industry. As a part of this research, a synthesis gas containing carbon monoxide (CO) and hydrogen (H ₂ ) is produced through a reforming reaction by carbon dioxide, and a synthetic gas containing high value-added synthetic products such as methanol synthesis and Fischer-Tropsch synthesis Is used as a starting material for synthesis.

The carbon dioxide reforming reaction is a reaction in which carbon monoxide and hydrogen, which are synthesized gases, are obtained as products by using methane and carbon dioxide separated by greenhouse gases as reactants. The molar ratio of carbon monoxide to hydrogen (CO / H ₂ ≒ 1 ) Is high, it is known that it is highly utilized as a chemical raw material.

[Reaction Scheme 1]

However, since the carbon dioxide dry reforming reaction proceeds with a very strong endothermic reaction as shown in Reaction Scheme 1, the reaction occurs at a temperature of 650 ° C or higher, and usually proceeds at a high temperature of 850 ° C or higher. Therefore, the carbon dioxide dry reforming reaction has a problem of deactivation of the catalyst due to its easy formation of carbon thermodynamically. Therefore, it is urgently required to develop a new catalyst which exhibits excellent activity even at a relatively low temperature and is resistant to the formation of coke and inactivation by sintering.

Nickel-based catalysts have been commercialized as catalysts for the reforming reaction of methane using carbon dioxide. However, since it has been pointed out that the durability of catalysts is limited in the life span of short catalysts, cobalt-based catalysts have been developed to overcome them.

As an example thereof, Korean Patent No. 10-1437072 (Patent Document 1) discloses a cobalt supported catalyst supported on a spinel type carrier as a catalyst for carbon dioxide reforming reaction of methane. According to Patent Document 1, AB ₂ O ₄ (A is at least one selected from the group consisting of Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Sn, At least one selected from the group consisting of In, Ti, V, Cr, Mn, Fe, Ni and Co. it was possible to maintain stable and high catalytic activity at a high space velocity of < RTI ID = 0.0 > _cat -hr. < / RTI > That is, the catalyst disclosed in Patent Document 1 is a catalyst optimized for a high-temperature reaction at 850 ° C, and there is a problem that the catalyst activity is drastically reduced at a low temperature of 800 ° C or lower.

Korean Patent No. 10-1437072

The present invention relates to a catalyst which is used in a reaction for producing a syngas by reforming natural gas with carbon dioxide and which is capable of maintaining the catalytic activity even at a low reaction temperature of 800 ° C or less and inhibiting deactivation by coke formation and sintering. And to provide a supported catalyst.

In addition, the present invention relates to a method for producing an amorphous zinc-aluminate, which comprises amorphous zinc-aluminate obtained by physically mixing zinc oxide (ZnO) and alumina (Al ₂ O ₃ ) The present invention also provides a method for producing a cobalt supported catalyst for carbon dioxide reforming reaction.

In order to solve the above problems, the present invention relates to a cobalt supported catalyst for carbon dioxide reforming reaction in which a cobalt active component is supported on an amorphous zinc-aluminate carrier prepared by mixing zinc oxide and alumina by powder mixing method and then firing It is characterized by.

Also, the present invention is a method for producing a synthesis gas by carbon dioxide reforming reaction of natural gas, characterized in that the reforming reaction is carried out at a low temperature of 600 to 800 ° C. in the presence of the cobalt supported catalyst.

The present invention also provides a method for producing a cobalt supported catalyst for a carbon dioxide reforming reaction,

Mixing the zinc oxide and alumina by a powder mixing method to prepare a metal powder mixture (step 1);

Drying and firing the metal powder mixture to prepare an amorphous zinc-aluminate carrier (step 2); And

Supporting a cobalt active component on the amorphous zinc-aluminate support such that cobalt is supported in an amount of 5 to 30% by weight based on the weight of the carrier, followed by drying and firing to prepare a cobalt supported catalyst (step 3); And a control unit.

The cobalt supported catalyst according to the present invention has a remarkable effect of lowering the reaction temperature to 600 캜 by being applied to the reforming reaction of carbon dioxide. Therefore, the cobalt supported catalyst provided by the present invention is excellent in economical efficiency because the catalyst activity at low temperature is enhanced and the energy consumption is remarkably reduced.

In addition, the cobalt supported catalyst according to the present invention has an effect of suppressing the formation and sintering of coke by being applied to a reforming reaction. Therefore, the cobalt-supported catalyst provided by the present invention is excellent in durability and can proceed the catalytic reaction for a long time.

In addition, the powder mixing method which is carried out for the production of a carrier of the present invention is simple and inexpensive in comparison with a conventional carrier production method such as coprecipitation, and is useful for mass production.

1 is a graph showing the results of X-ray powder diffraction (XRD) analysis of an amorphous zinc-aluminate carrier prepared by a physical powder mixing method according to Example 1 and a ZnAl ₂ O ₄ carrier having a spinel structure prepared by coprecipitation according to Comparative Example 1 And the internal structure of the carrier is analyzed through analysis.

The present invention is characterized in that amorphous zinc-aluminate is applied as a carrier for supporting a cobalt active component, which is a cobalt supported catalyst applied to a reaction for producing synthesis gas by reforming natural gas with carbon dioxide.

As a related prior art, Patent Document 1 discloses a cobalt supported catalyst for carbon dioxide reforming reaction in which a cobalt active component is supported on a carrier of a composite metal oxide having an AB ₂ O ₄ spinel structure. That is, the composite metal oxide having a spinel structure used as a carrier in the Patent Document 1 is created and the oxygen atom is a face-centered cubic lattice, metal A entered the gap in tetrahedral metal B fits in the gap in the octahedral form a AB ₂ O ₄ composition formula Composite metal oxide. In Patent Document 1, a carrier of a spinel structure is prepared by co-precipitation. The coprecipitation method has a variety of process parameters (temperature, coprecipitation speed, pH, precipitant type, etc.) It is difficult to produce a composite metal oxide having a spinel structure.

On the other hand, in the present invention, the powder mixing method proposed in the production method of the carrier does not form a lattice structure such as a spinel structure because zinc oxide (ZnO) and alumina (Al ₂ O ₃ ) Lt; / RTI >

1 shows an amorphous zinc-aluminate carrier prepared by a physical powder mixing method according to the present invention and a ZnAl ₂ O ₄ carrier having a spinel structure prepared by coprecipitation according to Patent Document 1, The results of the diffraction analysis are shown. As can be seen from FIG. 1, it can be seen that the amorphous zinc-aluminate support proposed by the present invention is significantly different from the ZnAl ₂ O ₄ carrier of the spinel structure due to its physicochemical properties.

Therefore, the cobalt supported catalyst proposed by the present invention and the cobalt supported catalyst disclosed in Patent Document 1 are different catalysts. This can be confirmed by the following comparative experiments of Experimental Example 1 and Experimental Example 2, wherein the starting catalyst of Patent Document 1 exhibits the maximum catalytic activity at 850 ° C and the catalytic activity decreases sharply at a temperature of 800 ° C or lower However, the cobalt supported catalyst proposed by the present invention can maintain excellent catalytic activity even when the temperature of the reforming reaction is lowered up to 600 < 0 > C.

Hereinafter, a method for preparing a cobalt-supported catalyst supported on a zinc-aluminate support according to the present invention will be described in detail.

A method for producing a cobalt supported catalyst characterized by the present invention comprises:

Mixing the zinc oxide and alumina by a powder mixing method to prepare a metal powder mixture (step 1);

Drying and firing the metal powder mixture to prepare an amorphous zinc-aluminate carrier (step 2); And

Supporting a cobalt active component on the amorphous zinc-aluminate support such that cobalt is supported in an amount of 5 to 30% by weight based on the weight of the carrier, followed by drying and firing to prepare a cobalt supported catalyst (step 3); .

The process for preparing the cobalt-supported catalyst according to the present invention will be described in more detail as follows.

Step 1 is a step of physically mixing the zinc oxide and alumina.

The mixing ratio of zinc oxide to alumina may be in the range of 1 to 10 molar equivalents, preferably 1 to 6 molar equivalents, based on 1 mol of zinc oxide. In the present invention, there are no particular restrictions on the kind and particle size of the zinc oxide and alumina used in the preparation of the carrier, and any solid sample in powder form which can be used in general can be applied. Nevertheless, if the size of the powder is limited, zinc oxide having an average particle diameter in the range of 50 to 300 nm can be used, and alumina having an average particle diameter in the range of 10 to 100 nm can be used.

The powder mixing method practiced by the present invention is a method of physically mixing a powder sample, typically through miling. The milling may be a dry milling carried out without the use of a solvent or a wet milling carried out with a small amount of organic solvent. In contrast to dry milling, wet milling has the advantage of achieving a more evenly dispersed powder mixture because the dispersing power between the two powders can be increased by organic solvents. The organic solvent used for the wet milling may be at least one selected from alcohols (methanol, ethanol, propanol, butanol), aldehydes (formaldehyde, acetaldehyde), hydrocarbons (hexane, benzene, toluene etc.) And it is best to use alcohol. Alcohols have a relatively low boiling point, have no safety problems, and are excellent in price competitiveness. The milling equipment can be used without any particular limitation as long as it is commonly used in the art, and specifically, a mechanism such as a mortar bowl, a crushing crusher, and a ball mill can be utilized. The milling temperature is preferably from room temperature (25 ° C) to 60 ° C. If the temperature is outside the above range, the uniformity of the powder mixture may be lowered. The milling time is sufficient for the two powders to be sufficiently mixed. The milling time is preferably 3 to 5 hours based on 100 g of the powder to be mixed.

Step 2 is a step of drying and firing the metal powder mixture to prepare an amorphous zinc-aluminate carrier.

The carrier may be dried at a temperature of 80 to 100 DEG C under an air atmosphere. The carrier may be calcined at a temperature of 500 to 800 ° C. in an air atmosphere. If the calcination temperature is less than 500 ° C, it is difficult to keep the uniformly mixed state of the zinc oxide and alumina. Therefore, the catalytic activity may be rapidly lowered. If the calcination temperature exceeds 800 ° C, It is preferable to keep the above range because it may affect the activity.

Step 3 is a step of preparing a cobalt supported catalyst by supporting a cobalt active component on an amorphous zinc-aluminate carrier.

The loading amount of the cobalt active ingredient may be 5 to 30 wt%, preferably 5 to 20 wt%, based on the weight of the carrier. If the loading amount of the cobalt active ingredient is less than 5% by weight, the rate of the reforming reaction may be significantly slowed. If the loading amount of the cobalt active ingredient exceeds 30% by weight, the catalyst deactivation is accelerated due to sintering of the active material, There may be a problem that the lifetime is reduced. The precursor for supporting the cobalt active ingredient is a compound containing cobalt (Co), for example, cobalt nitrate (Co (NO ₃ ) ₂ ) can be used as a representative.

The method of supporting the cobalt active ingredient is not particularly limited, and any method that is commonly used in the field of catalyst production can be applied. Examples of the ordinary method of carrying out the present invention include various drying methods such as a heat drying method, a normal temperature drying method, a vacuum drying method, a normal pressure drying method, a vapor drying method, a forefilling method, an incipient wetness method, a dipping method, a spraying method, Can be applied.

After supporting the cobalt active component, the cobalt supported catalyst is dried and calcined to produce a desired cobalt supported catalyst. The catalyst may be dried at a temperature of 80 to 100 ° C in an air atmosphere. The calcination of the catalyst may be carried out at a temperature of 300 to 700 ° C. in an air atmosphere. If the sintering temperature of the catalyst is less than 300 ° C, the catalyst may be kept in a dry state only, so that the carrier component and the cobalt active component may not chemically bond to each other and may not exhibit activity as a catalyst. If the firing temperature of the catalyst exceeds 700 ° C., the degree of oxidation of the catalyst is excessively high, and since the cobalt active component does not play a role in the actual reaction due to the strong binding force between the carrier component and the cobalt active component, Lt; RTI ID = 0.0 >

The cobalt-supported catalyst prepared through the above process can be used as a catalyst for reforming carbon dioxide, thereby lowering the reforming reaction temperature to 600 ° C. Accordingly, the present invention features a method for producing a syngas by performing the carbon dioxide reforming reaction of natural gas using the cobalt-supported catalyst.

The reforming reaction of natural gas and carbon dioxide can be carried out under ordinary reaction conditions using a reactor which is customary in the art. As the reforming reactor, a gas phase fixed bed reactor, a fluidized bed reactor, a liquid slurry type reactor or a batch reactor may be used. As the reaction conditions, the reaction temperature is maintained at 500 to 1000 ° C., preferably 600 to 800 ° C., the reaction pressure is maintained at 0.01 to 1 MPa, and the space velocity of the reactant is maintained in the range of 500 to 500,000 mL / gcat · hr . In addition, the molar ratio of natural gas (typically methane) to carbon dioxide as the reaction raw material is maintained in the range of 0.5 to 2.0

The present invention will be described in more detail with reference to the following examples and experimental examples, but the present invention is not limited thereto.

[Example]

Example 1 Preparation of Cobalt Catalyst Supported on Amorphous Zinc-Aluminate Carrier

The zinc oxide powder (average particle diameter 100 nm) and gamma-alumina powder (average particle diameter 50 nm) were added to the mortar in a 1: 1 molar ratio and milled together with 20 g of ethanol on the basis of 100 g of the total powder, Mix well. The powder mixture obtained after milling was dried in an oven at 100 ° C. for 5 hours under the condition of keeping the air atmosphere, and calcined at 500 ° C. for 6 hours to prepare an amorphous zinc-aluminate carrier.

Cobalt nitrate (Co (NO ₃ ) ₃ .9H ₂ O) was weighed so that the supported amount of the cobalt (Co) active component was 20 wt% based on the weight of the amorphous zinc-aluminate carrier produced. The prepared carrier and cobalt precursor were each dissolved in distilled water and then mixed to prepare a catalyst slurry. The catalyst slurry was dried for 10 hours at 55 mbar and 50 ℃ using a rotary evaporator to obtain catalyst powder. The dried catalyst powder was dried in an oven at 100 ° C. for 6 hours under the condition of maintaining the air atmosphere and calcined at 400 ° C. for 6 hours in an air atmosphere to prepare a cobalt catalyst supported on an amorphous zinc-aluminate support.

Example 2 Preparation of Cobalt Catalyst Supported on Amorphous Zinc-Aluminate Carrier

In the preparation of the carrier according to Example 1, an amorphous zinc-aluminate support was prepared by milling zinc oxide powder and gamma-alumina powder at a molar ratio of 1: 3. Then, cobalt nitrate (Co (NO ₃ ) ₃ .9H ₂ O) was weighed so that the loading amount of the cobalt (Co) active component was 20 wt% based on the weight of the prepared amorphous carrier, To prepare a cobalt catalyst supported on an amorphous carrier.

Example 3 Preparation of Cobalt Catalyst Supported on Amorphous Zinc-Aluminate Carrier

In the preparation of the carrier according to Example 1, an amorphous zinc-aluminate support was prepared by milling zinc oxide powder and gamma-alumina powder at a molar ratio of 1: 5. Then, cobalt nitrate (Co (NO ₃ ) ₃ .9H ₂ O) was weighed so that the loading amount of the cobalt (Co) active component was 20 wt% based on the weight of the prepared amorphous carrier, To prepare a cobalt catalyst supported on an amorphous carrier.

Comparative Example 1 A cobalt catalyst supported on a spinel carrier

The precursors Zn (NO ₃ ) ₂ and Al (NO ₃ ) ₃ were dissolved in distilled water and mixed so that the molar ratio of ZnO / Al ₂ O _{3 as} the spinel structure was 1. Sodium carbonate was added as a precipitant to the precursor mixture, and the mixture was titrated so that the pH of the mixture became 7.0. The precipitate was filtered and washed with distilled water. The filtered precipitate was calcined at 500 DEG C to prepare a spinel type support.

Cobalt nitrate (Co (NO ₃ ) ₃ .9H ₂ O) was weighed so that the supported amount of the cobalt (Co) active component was 20 wt% based on the weight of the spinel type carrier thus prepared. The prepared carrier and cobalt precursor were each dissolved in distilled water and then mixed to prepare a catalyst slurry. The catalyst slurry was dried for 10 hours at 55 mbar and 50 ℃ using a rotary evaporator to obtain catalyst powder. The dried catalyst powder was dried in an oven at 100 ° C for 6 hours under the condition that the air atmosphere was maintained, and calcined at 400 ° C for 6 hours in an air atmosphere to prepare a cobalt catalyst supported on a spinel carrier.

Comparative Example 2 A cobalt catalyst supported on a spinel type carrier

In the preparation of the carrier according to Comparative Example 1, a spinel type carrier was prepared using Mg (NO ₃ ) ₂ and Al (NO ₃ ) ₃ as precursors so that the molar ratio of MgO / Al ₂ O ₃ was 1. Cobalt nitrate (Co (NO ₃ ) ₃ .9H ₂ O) was weighed so that the supported amount of the cobalt (Co) active component was 20% by weight based on the weight of the spinel type carrier produced, To prepare a cobalt catalyst supported on a spinel type carrier.

[Experimental Example]

Experimental Example 1. Comparison of Catalyst Activity

The following reforming reactions were carried out in order to compare the catalytic activities of the cobalt-supported catalysts prepared in Examples 1 to 3 and Comparative Examples 1 and 2.

That is, the reforming reaction was carried out by introducing methane and carbon dioxide at a reaction temperature of 0.1 MPa and a flow rate of 20,000 mL / g _cat · hr, as shown in Table 1 below. The molar ratio of methane to carbon dioxide was maintained at 1.0.

Table 1 below shows the results of comparing catalyst activity according to the reforming reaction temperature.

Types of catalyst Reaction temperature (캜) Conversion Rate (%) CH ₄ CO ₂
Example 1 600 51 63 700 74 77 800 89 91 900 95 96
Example 2 600 45 49 700 68 74 800 85 89 900 93 94
Example 3 600 39 44 700 68 72 800 82 85 900 92 94
Comparative Example 1 600 8 12 700 45 63 800 66 77 900 88 90
Comparative Example 2 600 7 9 700 44 57 800 78 84 900 90 93

According to the above Table 1, the catalyst having the cobalt active component supported on the amorphous zinc-aluminate support according to the present invention maintained excellent catalytic activity even at a low temperature of 600 ° C. On the other hand, the catalyst carrying the cobalt active component on the carrier of the spinel structure proposed in Patent Document 1 hardly shows activity at a low temperature of 600 ° C.

Therefore, the cobalt supported catalyst of the present invention has the effect of making it possible to lower the temperature of the reforming reaction of carbon dioxide to 600 ° C.

Claims (9)

A cobalt supported catalyst for carbon dioxide reforming reaction characterized in that a cobalt active component is supported on an amorphous zinc-aluminate carrier prepared by mixing zinc oxide and alumina by a powder mixing method by wet milling and then firing.
The method according to claim 1,
Wherein the cobalt active component is supported in an amount of 5 to 30% by weight based on the weight of the carrier.
The method according to claim 1,
Wherein the carbon dioxide reforming reaction proceeds at a low temperature of 600 to 800 ° C.
A method for producing a syngas by a carbon dioxide reforming reaction of natural gas,
Wherein the reforming reaction is carried out at a temperature of 600 to 800 ° C. in the presence of the cobalt supported catalyst of claim 1 or 2.
Mixing the zinc oxide and alumina by a powder mixing method by wet milling to prepare a metal powder mixture (step 1);
Drying and firing the metal powder mixture to prepare an amorphous zinc-aluminate carrier (step 2); And
Supporting a cobalt active component on the amorphous zinc-aluminate support such that cobalt is supported in an amount of 5 to 30% by weight based on the weight of the carrier, followed by drying and firing to prepare a cobalt supported catalyst (step 3);
The method for producing a cobalt supported catalyst for a carbon dioxide reforming reaction according to claim 1 or 2,
6. The method of claim 5,
Wherein the cobalt supported catalyst for carbon dioxide reforming reaction is used in a molar ratio of zinc oxide to alumina of 1: 1 to 10: 1.
6. The method of claim 5,
Wherein the cobalt supported catalyst for carbon dioxide reforming reaction is wet ball milled with an ethanol solvent.
6. The method of claim 5,
Wherein the drying in the step 2 is carried out at a temperature of 80 to 100 ° C. under an air atmosphere and the calcination is carried out at a temperature of 500 to 800 ° C. in an air atmosphere.
6. The method of claim 5,
Wherein the drying in the step 3 is carried out at a temperature of 80 to 100 ° C. in an air atmosphere and the calcination is carried out at a temperature of 300 to 700 ° C. in an air atmosphere.

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