JPH1147607A - Catalyst and method for reforming hydrocarbon with carbon dioxide, its production and isolating production of hydrogen and carbon monoxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a highly active catalyst for reforming hydrocarbons with carbon dioxide, and to effectively produce H2 and CO by supporting Ni on synthetic zeolite ZSM-5 and if necessary, additionally supporting Pt or Au on the zeolite. SOLUTION: The ZSM-5 catalyst supporting Ni is prepared by adding ZSM-5 which is used as the carrier into a nickel nitrate ammine solution, which has been obtained by solubilizing nickel nitrate in excess ammonium solution, and heating the resulting solution to evaporate up to dryness and if necessary, adding a platinum solution as a promoter. The platinum solution can be obtained by first solubilizing hexachloroplatinum(IV) acid in nitric acid, then evaporating the nitric acid solution to dryness and further resolubilizing the resulting residue in an excess ammonium solution. A gold solution may also be used as a promoter component, which solution is prepared by evaporating an aqua regia solution of a gold foil or a gold wire up to dryness, adding nitric acid to the resulting residue, further evaporating the solution, and resolubilizing the resulting residue in an excess ammonium solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CO2 reforming catalyst for hydrocarbons, and more particularly to a CO2 reforming catalyst for hydrocarbons of about C1 to C3. It is possible to reduce carbon dioxide, which is one of the substances, to produce synthesis gas which is very useful in industry, and to produce pure hydrogen and carbon monoxide respectively.

[0002] The reforming reaction with carbon dioxide is represented by the following formula (1) when methane is used as an example of a hydrocarbon.
This is indicated by (5). CH4 + CO2 → 2CO + 2H2 (1) CH4 → C + 2H2 (2) (2) C + CO2 → 2CO (3) H2 + CO2 → CO + H2O (4) C + H2O → CO + H2 (5) )

As described above, in this reaction, CH4 is first converted to C and H
2 and then reacts with C in the presence of CO2 to form C
O will be generated.

[0004]

2. Description of the Related Art The CO2 reforming reaction of hydrocarbons is a subject which has recently been studied and is not well known at present. For example, Ni-supported α which is often used in steam reforming reactions of hydrocarbons It is shown below that the alumina catalyst is very poor in durability, while the Ni-supported MgO catalyst is still insufficient in activity and has poor durability. (Catalyst Deactivation 1994,
Studies in SurfaceScience and Catalysis, Vol.88)

The reforming reaction of hydrocarbons with CO2 is a problem of CO2 as a global warming substance.
It is possible to produce H2 and CO by effectively utilizing, and it is an important reaction in environmental protection and industrial aspects. There is a need for a catalyst with high activity and less deterioration.

[0005]

Means for Solving the Problems The present inventor studied the effect of a carrier and the effect of a cocatalyst on a Ni-based catalyst in order to solve the above-mentioned problems.
The catalyst which carried Ni on -5 was converted from the conventional α-alumina to N
The catalyst was found to be more durable than the catalyst supporting i and the catalyst supporting Ni on MgO.
It has been confirmed that a more highly active catalyst can be obtained by adding t or Au, and the present invention has been completed by further detailed studies.

The nickel solution that can be used in the present invention is a solution obtained by dissolving nickel nitrate in an excess of ammonia (3) near-water, and the catalyst is prepared by an evaporation to dryness method. After adding ZSM-5 as a support, the mixture is heated and evaporated to dryness to obtain a nickel-supported ZSM-5 catalyst.

[0007] The platinum solution of the co-catalyst component, which is added as required, may be a solution in which hexachloroplatinic (tetravalent) acid is dissolved in nitric acid, evaporated to dryness, and then dissolved in excess ammonia water. After dissolving a gold foil or a gold wire in aqua regia and evaporating to dryness, then adding nitric acid and evaporating to dryness again, a solution in which excess ammonia water is added and dissolved can be used.

In the preparation of a catalyst containing a co-catalyst component, the co-catalyst component is first added to the ZSM-5 carrier by an evaporation to dryness method to obtain a catalyst intermediate.

Then, an intermediate platinum-supported ZSM-5 or gold-supported ZSM-5 is added to the nickel solution and evaporated to dryness. Finally, a nickel-platinum-supported ZSM-5 catalyst or nickel-gold-supported ZSM-5 is obtained. -5 catalyst is obtained.

When the obtained catalyst was subjected to a hydrocarbon reforming reaction with CO 2, it was found that the catalyst had excellent activity durability compared to a conventional hydrocarbon reforming catalyst such as α-alumina supported on Ni or Mg supported on Ni. When the hydrocarbon and CO2 as reactants were allowed to flow independently under the reaction conditions, no H2 or CO was produced with the normal catalyst.
2 is generated, CO generation is recognized by CO2 distribution,
It has been confirmed that H2 and CO can be separated and produced, and the present invention has been completed.

Next, the contents of the present invention will be described in detail with reference to Examples. The catalyst performance evaluation in the reforming reaction of hydrocarbons described with carbon dioxide described in the Examples is carried out in a fixed bed normal pressure flow system. The reaction was carried out using a reactor, and the conditions for catalyst performance evaluation were as follows. (4) Catalyst amount; 1 g, composition of flowing gas; CH4: CO2: H
e = 1: 1: 2, gas flow rate; 300 ml / min, S
V; 96000Hr ^-1 ,

The amount of generated CO was determined as an index of the performance of each catalyst in the performance test, and the results were compared between the catalysts, and compared with the equilibrium values of the amount of generated CO at the following temperatures. Reaction temperature (° C) Equilibrium CO generation (ml / min) 700 156 800 186 900 195

The amount of H2 produced when only CH4 was passed through the catalyst layer and the amount of CO produced when CO2 was supplied after switching to CH4 were determined under the following conditions.

Catalyst amount; 1 g, CH4 gas flow rate; 10
0 ml / min, CO2 gas flow rate; 100 ml / mi
n, reaction temperature: 900 ° C., reaction time: 10 hours

Example-1 2.48 g of nickel nitrate (hexahydrate) was placed in a magnetic dish and
Then, 20 ml of aqueous ammonia was added and dissolved, then 5 g of ZSM-5 as a carrier was added, and the mixture was evaporated to dryness on an electric heater with good stirring to obtain 10% Ni-supported ZSM-5 of Example-1.

The reforming performance test of this catalyst with carbon dioxide was performed. The results are shown in Table 1.

Example-2 (5) 0.133 g of hexachloroplatinic (tetravalent) acid (hexahydrate) was weighed on a magnetic dish, 20 ml of a 10% nitric acid solution was added, dissolved, and evaporated to dryness on an electric heater. Then, 20 ml of 10% aqueous ammonia was added and dissolved to form an ammine complex. Then, 5 g of ZSM-5 as a carrier was added, and the mixture was evaporated to dryness again to obtain 1% platinum-supported ZSM-5 as an intermediate.

Next, 2.48 g of nickel nitrate (hexahydrate)
Was taken in a magnetic dish and dissolved by adding 20 ml of 10% ammonia water, and then 1% Pt-supported ZSM-5 as the intermediate was added. The mixture was evaporated to dryness with good stirring, and 10% Ni-1 of Example-2 was used.
% Pt-supported ZSM-5 catalyst was obtained.

When the reforming performance test of this catalyst with carbon dioxide was carried out, the performance test results shown in Table 1 were obtained.
Table 2 shows the results of the distribution test of the sample No. 2 only.

Example 3 0.05 g of a gold foil was dissolved in 20 ml of aqua regia and evaporated to dryness to obtain a solid substance. 30 ml of 10% nitric acid was added, and the mixture was evaporated to dryness again. Then, 5 g of ZSM-5 as a carrier was added to this solution, and the mixture was evaporated to dryness with sufficient stirring to obtain 1% Au-supported Z as an intermediate.
SM-5 was obtained.

Next, 2.48 g of nickel nitrate (hexahydrate)
Was taken in a magnetic dish and dissolved by adding 20 ml of 10% aqueous ammonia, and then the above-mentioned intermediate, 1% Au-supported ZSM-5, was added.
Evaporate to dryness with good agitation.
A 1% Au-supported ZSM-5 catalyst was obtained.

When a reforming performance test was performed on this catalyst using carbon dioxide, the performance test results shown in Table 1 were obtained.

(6) Comparative Example-1 2.48 g of nickel nitrate (hexahydrate) was placed in a magnetic dish and
20% aqueous ammonia was added and dissolved, then 5 g of α-alumina as a carrier was added, and the mixture was evaporated to dryness on an electric heater with good stirring to obtain 10% Ni-supported α-alumina of Comparative Example-1.

When the reforming performance test of this catalyst with carbon dioxide was performed, the performance test results shown in Table 1 were obtained.
The results of conducting a circulation test of only the samples were as shown in Table-2.

Comparative Example 2 2.48 g of nickel nitrate (hexahydrate) was placed in a magnetic dish and
Then, 5 g of MgO as a carrier was added, and the mixture was evaporated to dryness on an electric heater with good stirring to obtain 10% Ni-supported MgO of Comparative Example-1.

The reforming performance test of the catalyst with carbon dioxide was performed. The results are shown in Table 1.

[0027]

[Table 1] Table 1 Performance test results (7)

[0028]

[Table 2] Table 2 CH4 and CO2 distribution test results

Claims (3)

[Claims] 1. A hydrocarbon reforming catalyst using carbon dioxide, which comprises ZSM-5 as a synthetic zeolite and nickel as essential components, and optionally carries platinum or gold as a second component. 2. The method for producing a hydrocarbon reforming catalyst using carbon dioxide according to claim 1, wherein nickel and a cocatalyst component to be added as required are supported on ZSM-5 by an evaporation to dryness method. 3. The catalyst for reforming hydrocarbons with carbon dioxide according to claim 1, which is under the condition of flow reforming with carbon dioxide, only hydrogen is produced by flowing only hydrocarbons, and then only carbon dioxide is produced. The method for separating and producing hydrogen and carbon monoxide by the catalyst according to claim 1, wherein only carbon monoxide is generated by flowing hydrogen.