JP2002126529A - Method for preparing reforming catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a reforming catalyst in producing a synthetic methane gas by allowing to react a hydrocarbon such as methane with a reforming substance such as steam in such a manner that carbon is not deposited and further the deposition of carbon does not occur even at a relatively low temperature range such as 873 to 1023 K of the reaction temperature. SOLUTION: This method for preparing a catalyst is characterized by adding a co-precipitation agent to an aqueous solution of a water soluble salt of following each constitution element to precipitate a hydroxide, drying the resultant precipitate and then calcining the precipitate at a temperature range of 1273 to 1573 K, wherein the catalyst that is a complex oxide derived from CoO, NiO or MOx and MgO/CaO and that highly disperses Co, Ni or M (M is an element such as Mn, Rh, Ru, and the like) therein is used as a reforming catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
A method for producing a reforming catalyst for obtaining a synthesis gas, which is a mixed gas of O) and hydrogen (H ₂ ), from a hydrocarbon such as methane and a reforming substance such as water, carbon dioxide, oxygen and air; The present invention relates to a reforming catalyst obtained by this method and a method for producing a synthesis gas using the reforming catalyst.

[0002]

2. Description of the Related Art Conventionally, hydrocarbons such as methane, natural gas, petroleum gas, naphtha, heavy oil, crude oil, water, air,
A reforming process is performed in which a reforming substance such as oxygen or carbon dioxide is reacted at a high temperature in the presence of a catalyst to produce a synthesis gas composed of highly reactive carbon monoxide and hydrogen. Methanol and liquid fuel oil are produced using gas as a raw material.

As a reforming catalyst used for this reforming, a nickel / alumina catalyst, a nickel / magnesia / alumina catalyst, or the like is used. However, in reactions using these reforming catalysts, there is a problem that a large amount of carbonaceous material (carbon) precipitates when, for example, methane and water vapor are reacted in a stoichiometric manner. For this purpose, a large excess of steam is supplied to promote the reforming reaction.

[0004] For this reason, in the conventional reforming, a large amount of steam is required, so that the energy cost is increased and the equipment is disadvantageously increased in size. Therefore, the present applicant has proposed a reforming catalyst capable of suppressing the deposition of carbonaceous material (carbon) without first supplying a large excess of steam, as disclosed in Japanese Patent Application Nos. 10-103203 and 10-103204.
And Japanese Patent Application No. 11-104634.

[0005] These reforming catalysts are as follows. First, the first catalyst is composed of a composite oxide having a composition represented by the following formula, in which Co is highly dispersed in the composite oxide. aCo.bMg.cCa.dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.20, 0.80 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. )

[0006] The second catalyst comprises a composite oxide having a composition represented by the following formula, and Ni is highly dispersed in the composite oxide. aNi.bMg.cCa.dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.20, 0.80 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. )

Further, the third catalyst comprises a composite oxide having a composition represented by the following formula, in which M and Ni are highly dispersed in the composite oxide. aM · bNi · cMg · dCa · eO (where a, b, c, d, and e are mole fractions, and a + b
+ C + d = 1, 0.0001 ≦ a ≦ 0.10, 0.00
01 ≦ b ≦ 0.20, 0.80 ≦ (c + d) ≦ 0.99
98, 0 <c ≦ 0.9998, 0 ≦ d <0.9998,
e = number of elements required to keep charge balance with oxygen.
M is a group 6A element, a group 7A element, Ni
Group 8 transition elements except for Group 1B elements, Group 2B elements,
It is at least one element of a Group 4B element and a lanthanoid element. ) M is manganese, rhodium,
Ruthenium, platinum, palladium, zinc, lead, lanthanum,
At least one selected from cerium is used.

However, in this reforming catalyst, the reaction temperature during the reforming reaction is 1123 to
In the range of 1173K, although the effect of suppressing carbon deposition was excellent, it was clarified that carbon was precipitated in a lower reaction temperature range of 873 to 1023K.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to add a chemical equivalent or a similar amount of a modifying substance to a hydrocarbon so as to prevent carbon deposition during reforming. , Lower 873-10
It is to prevent carbon deposition even in a reaction temperature range of 23K.

[0010]

The object of the present invention is to provide a method for producing the following first to third catalysts by a coprecipitation method. The problem is solved by setting the temperature in the range of 1273 to 1573K. The surface area of the catalyst obtained under such calcination conditions is 0.2 to ⁵ m ² / g.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
First, the cobalt-based catalyst for reforming in the present invention will be described. The first reforming cobalt-based catalyst of the present invention comprises a composite oxide having a composition represented by the following formula, in which Co is highly dispersed in the composite oxide. The composition here is expressed on an anhydride basis after firing. aCo.bMg.cCa.dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.30, 0.70 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. )

In this composition, the cobalt content (a)
Is 0.005 ≦ a ≦ 0.30, preferably 0.01 ≦ a
≦ 0.25, more preferably 0.01 ≦ a ≦ 0.20
Range. If the cobalt content (a) is less than 0.005, the content of cobalt is too small and the activity is low, and if it exceeds 0.30, high dispersion described later is inhibited, and the effect of preventing carbonaceous deposition cannot be obtained.

The total amount (b + c) of the magnesium content (b) and the calcium content (c) is 0.70 ≦ (b +
c) ≦ 0.995, preferably 0.75 ≦ (b + c)
≦ 0.99, more preferably 0.80 ≦ (b + c) ≦
0.99. Among them, the magnesium content (b) is 0 <b ≦ 0.995, preferably 0.25 <
b ≦ 0.99, more preferably 0.5 <b ≦ 0.9
9, and the calcium content (c) is 0 ≦ c ≦ 0.9.
95, preferably 0 ≦ c ≦ 0.5, more preferably 0 ≦ c ≦ 0.3.

The total amount (b + c) of the magnesium content (b) and the calcium content (c) is determined by the balance with cobalt. The addition ratio of magnesium and calcium is excellent in the reforming reaction at any ratio as long as it is within the above range.However, although calcium is effective in suppressing carbon deposition, its activity is lower than that of magnesium. If the activity is emphasized, the calcium content (c) is preferably 0.5 or less.

The second catalyst is composed of a composite oxide having a composition represented by the following formula, and Ni is highly dispersed in the composite oxide. aNi.bMg.cCa.dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.30, 0.70 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. )

In this composition, the nickel content (a)
Is 0.005 ≦ a ≦ 0.30, preferably 0.01 ≦ a
≦ 0.25, more preferably 0.01 ≦ a ≦ 0.20
Range. If the nickel content (a) is less than 0.005, the nickel content is too small and the activity is low. If the nickel content (a) exceeds 0.30, high dispersion described later is inhibited, and the effect of preventing carbonaceous deposition cannot be obtained.

The total amount (b + c) of the magnesium content (b) and the calcium content (c) is 0.70 ≦ (b +
c) ≦ 0.995, preferably 0.75 ≦ (b + c)
≦ 0.99, more preferably 0.80 ≦ (b + c) ≦
0.99. Among them, the magnesium content (b) is 0 <b ≦ 0.995, preferably 0.25 <
b ≦ 0.99, more preferably 0.5 <b ≦ 0.9
9, and the calcium content (c) is 0 ≦ c ≦ 0.9.
95, preferably 0 ≦ c ≦ 0.5, more preferably 0 ≦ c ≦ 0.3.

The total amount (b + c) of the magnesium content (b) and the calcium content (c) is determined by the balance with cobalt. The addition ratio of magnesium and calcium is excellent in the reforming reaction at any ratio as long as it is within the above range.However, although calcium is effective in suppressing carbon deposition, its activity is lower than that of magnesium. If the activity is emphasized, the calcium content (c) is preferably 0.5 or less.

Further, the third catalyst comprises a composite oxide having a composition represented by the following formula, and M and Ni are highly dispersed in the composite oxide. aM · bNi · cMg · dCa · eO (where a, b, c, d, and e are mole fractions, and a + b
+ C + d = 1, 0.0001 ≦ a ≦ 0.10, 0.00
01 ≦ b ≦ 0.30, 0.60 ≦ (c + d) ≦ 0.99
98, 0 <c ≦ 0.9998, 0 ≦ d <0.9998,
e = number of elements required to keep charge balance with oxygen.
M is a group 6A element, a group 7A element, Ni
Group 8 transition elements except for Group 1B elements, Group 2B elements,
It is at least one element of a Group 4B element and a lanthanoid element. As the M, at least one selected from manganese, molybdenum, rhodium, ruthenium, platinum, palladium, copper, silver, zinc, tin, lead, lanthanum, and cerium is used.

In this composition, the content (a) of M is
0.0001 ≦ a ≦ 0.10, preferably 0.0
001 ≦ a ≦ 0.05, more preferably 0.0001
≦ a ≦ 0.03. M content (a) is 0.000
If it is less than 1, no effect of suppressing carbonaceous deposition is recognized, and 0.1
If it exceeds 0, the activity of the reforming reaction is lowered, which is inconvenient.

The nickel content (b) is 0.0001 ≦
b ≦ 0.30, preferably 0.0001 ≦ b ≦
0.25, more preferably 0.0001 ≦ b ≦ 0.2
0. If the nickel content (b) is less than 0.0001, the nickel content is too small and the reaction activity is low.
If it exceeds 30, high dispersion described later is impeded, and the effect of preventing carbonaceous deposition cannot be sufficiently obtained.

The total amount (c + d) of the magnesium content (c) and the calcium content (d) is 0.60 ≦ (c +
d) ≦ 0.9998, preferably 0.70 ≦ (c
+ D) ≦ 0.9998, more preferably 0.77 ≦
(C + d) ≦ 0.9998. Among them, the magnesium content (c) is 0 <c ≦ 0.9998, preferably 0.20 ≦ c ≦ 0.9998, more preferably 0.37 ≦ c ≦ 0.9998, and the calcium content is (D) is 0 ≦ d <0.9998, preferably 0 ≦ d ≦
0.5, more preferably 0 ≦ d ≦ 0.3, and may lack calcium.

The total amount (c + d) of the magnesium content (c) and the calcium content (d) is determined by the balance between the M content (a) and the nickel content (b).
(C + d) exhibits an excellent effect on the reforming reaction at any ratio as long as it is within the above range, but a large content of calcium (d) and M (a) is effective in suppressing carbonaceous precipitation. , The catalytic activity is lower than when magnesium (c) is high. Therefore, if the activity is emphasized, it is not preferable that the calcium content (c) exceeds 0.5 and the M content (a) exceeds 0.1 because the activity is reduced.

The composite oxide in each of the first to third catalysts according to the present invention means that MgO and CaO have a rock salt type crystal structure, and a part of Mg or Ca atoms located in the lattice is Co, Ni or It is a kind of solid solution substituted with M and forms a single phase, and does not refer to a mixture of single oxides of each element. And in the present invention, Co,
Ni or M is in a highly dispersed state in this composite oxide.

The dispersion in the present invention is generally defined in the field of catalysts, and is, for example, as described in “Catalyst Course Vol. 5, Catalyst Design”, page 141 (edited by the Catalysis Society of Japan, published by Kodansha). And the ratio of the number of atoms exposed on the catalyst surface to the total number of atoms of the supported metal.

The present invention will be described in detail with reference to the schematic diagram of FIG. 1. The surface of a catalyst 1 made of a composite oxide has fine particles 2, 2,...
The microparticles 2 are made of Co and M metal elements or compounds thereof after the activation (reduction) treatment described later. Co forming the fine particles 2,
Assuming that the number of atoms of the Ni or M metal element or its compound is A and the number of these atoms exposed on the surface of the particle 2 is B, B / A is the degree of dispersion.

If it is considered that the atoms involved in the catalytic reaction are the atoms exposed on the surface of the fine particles 2, those having a dispersity close to 1 have many atoms distributed on the surface. It is thought that the number of active centers increases, and high activity can be achieved. Also, if the particle size of the microparticles 2 becomes infinitely small,
Most of the atoms forming the microparticles 2 are exposed on the surface of the particles 2, and the degree of dispersion approaches 1. Therefore, the particle size of the fine particles 2 can be an index indicating the degree of dispersion.

In the catalyst according to the present invention, the diameter of the fine particles 2 is less than the measurement limit of 3.5 nm by various measuring methods, for example, X-ray diffraction method. I can say that there is. For this reason, the number of atoms of cobalt, nickel or M involved in the reaction increases, the activity becomes high, the reaction proceeds stoichiometrically, and the deposition of carbonaceous material (carbon) is prevented.

Next, the method for producing the reforming cobalt-based catalyst of the present invention will be described in detail. The method for producing the catalyst of the present invention is performed by a so-called coprecipitation method for any of the above catalysts. The production by the coprecipitation method first includes cobalt, magnesium, calcium, a 6A element of the periodic table, and a 7th element.
Group A element, Group 8 transition element excluding Co, Group 1B element,
A complete aqueous solution is prepared by dissolving water-soluble salts such as organic salts such as acetates of Group 2B elements, Group 4B elements and lanthanoid elements, and inorganic salts such as nitrates in water. While the aqueous solution is being stirred, a precipitant is added at 293 to 393K to generate a precipitate. In order to highly disperse the catalyst component, it is preferable to stir when generating the precipitate, and it is preferable to stir for 10 minutes or more after the formation of the precipitate to complete the formation of the precipitate.

Preferred sedimenting agents are sodium and / or potassium carbonates, bicarbonates, oxalates and hydroxides. Also, ammonium carbonate, ammonium hydroxide, ammonia (aqueous ammonia) and the like can be used as the precipitating agent. The addition of a sedimentation agent raises the pH,
The compound consisting of the above components precipitates in the form of a thermally decomposable hydroxide. The final pH of the mixture is preferably 6 or more, more preferably a pH in the range of 8-11.

When a precipitate is obtained, the precipitate is filtered, washed repeatedly with water or an aqueous solution of ammonium carbonate, and then dried at a temperature of 373K or more. Next, the dried sediment is heated in air at a temperature of 1273 to 1573K, preferably 1373 to 1523K for 1 to 20 hours.
Preferably, it is calcined under the conditions of 2 to 10 hours to thermally decompose the thermally decomposable hydroxide to obtain a desired reforming catalyst.

In the production method of the present invention, the temperature during the calcination is important. If the calcination temperature is less than 1273 K, a catalyst capable of preventing the deposition of carbon during the reforming reaction at a low temperature can be obtained. On the other hand, when the temperature exceeds 1573K, the catalytic activity is greatly reduced. The specific surface area of the catalyst obtained by such a production method is in the range of 0.2 to ⁵ m ² / g. When the firing temperature is lower than 1273K, the specific surface area exceeds 5 m ² / g.

The catalyst thus obtained can be pulverized and used as a powder. However, if necessary, the catalyst can be molded by a compression molding machine and used as a tablet or ring. In addition, these catalysts can be used in combination with quartz sand, alumina, magnesia, calcia, and other diluents.

Next, a method for producing a synthesis gas using such a reforming catalyst will be described. First, an activation process of the reforming catalyst is performed in advance. In this activation treatment, the catalyst is treated in the presence of a reducing gas such as hydrogen gas at 773 to
1273K, preferably 873-1273K, more preferably 923-1273K in a temperature range of 0.5-30.
It is performed by heating for about an hour. The reducing gas may be diluted with an inert gas such as nitrogen gas. This activation treatment can be performed in a reactor for performing a reforming reaction.

By the activation treatment, the fine particles 2, 2,... On the surface of the catalyst 1 in FIG. 1 are reduced to Co, Ni or M metal elements or compounds thereof, and the catalytic activity is exhibited. The activation treatment in the present invention is performed at a higher temperature than the activation of the conventional Co oxide-based catalyst. Conventional Co oxide-based catalysts are all performed at less than 773K, and such an activation treatment at a high temperature in the present invention may contribute to the above-described high dispersion.

The hydrocarbons used as raw materials for the synthesis gas include:
Natural gas, petroleum gas, naphtha, heavy oil, crude oil, coal,
There is no particular limitation as long as hydrocarbons or the like obtained from coal sand or the like are used and a part thereof contains a hydrocarbon such as methane. Two or more of these may be mixed. Further, as the modifying substance, water (steam), carbon dioxide, oxygen, air or the like is used, and two or more kinds may be mixed. Preferred modifying substances are water or carbon dioxide or a mixture of water and carbon dioxide.

In the reaction, the supply ratio of the hydrocarbon to the reforming substance is represented by a molar ratio based on the number of carbon atoms in the hydrocarbon, and the reforming substance / carbon ratio is preferably 0.3 to 100, and more preferably 0.3 to 100. Is from 0.3 to 10, more preferably from 0.5 to 3. In the present invention, it is not necessary to supply a large excess of the modifying substance. An inert gas such as nitrogen may coexist as a diluent in the mixed gas of the hydrocarbon and the reforming substance.

As a specific reaction, a raw material gas composed of a hydrocarbon and a reforming substance is supplied to a reaction tube filled with the above-mentioned cobalt-based catalyst for reforming, and the temperature is 773 to 1
273K, preferably 873 to 1273K, more preferably 923 to 1273K, but in the present invention, a relatively low temperature of 873 to 1023K may be used. The pressure conditions are 0.1 to 10 MPa,
Preferably 0.1 to 5 MPa, more preferably 0.1
The reaction is performed in the range of 3 MPa.

Space velocity of raw material gas (GHSV: raw material gas
(The value obtained by dividing the feed rate of the catalyst by the volume-converted amount of catalyst) is 500
~ 200000h^-1, Preferably 1,000 to 10,000
0h ^-1, More preferably 1000 to 70000h^-1of
It is desirable to set the range. The form of the catalyst bed is fixed.
Well-known forms such as fixed bed, moving bed and fluidized bed can be arbitrarily selected.
Wear.

In such a reforming catalyst and a method for producing a synthesis gas using the same, CoO, NiO or MOx is made into a composite oxide of MgO or MgO / CaO, and cobalt, nickel and M are highly dispersed. It is highly active, and even if a hydrocarbon such as methane and a reforming substance such as steam react with each other in a stoichiometric amount or a similar amount, the deposition of carbonaceous material (carbon) is suppressed, and the efficiency is improved. Syngas can be produced well. For this reason, it is not necessary to supply a reforming substance such as steam in a large excess, the reforming substance is not wasted, and the synthesis gas can be produced at low cost. Also, since the catalyst is not contaminated with carbonaceous material,
A decrease in the catalyst activity over time is suppressed, and the life of the catalyst is prolonged.

Further, since the calcining temperature of the precipitate of the thermally decomposable hydroxide obtained by coprecipitation was set at 1273 to 1573 K, the crystal structure of the catalyst was made uniform (elimination of inconsistencies such as kinks and steps) and the like. As the diffusion in the solid progresses, the active components (Co, Ni, M) become more highly dispersed, and carbon deposition is prevented even when the reforming reaction temperature is set at a relatively low temperature range of about 873 to 1023K. be able to. At the same time, the reforming reaction temperature was increased from 1123 to 11
Even if the temperature is increased to around 73K, the coking resistance is improved and the catalyst life can be prolonged.

Hereinafter, the operation and effect of the present invention will be clarified by showing specific examples, but the present invention is not limited to these specific examples. (Example 1) 16.2 g of cobalt nitrate hexahydrate and 270.7 g of magnesium nitrate hexahydrate were dissolved in 500 ml of water. Then, while maintaining the temperature of this solution at 323 K, a 2 mol / L aqueous potassium carbonate solution 59 as a coprecipitant was used.
The pH was adjusted to 9 by adding 0 ml, and a precipitate of hydroxide consisting of two components, cobalt and magnesium, was formed. This precipitate was filtered, washed, and dried in air at 393 K for 12 hours or more. Then, it was calcined in air at a calcining temperature of 1453 K for 5 hours to obtain a catalyst (A). The specific surface area of the catalyst (A) was 0.8 m ² / g.

Example 2 A catalyst (B) was obtained in the same manner as in Example 1 except that the firing temperature was 1,423K. The specific surface area of the catalyst (B) was 1.0 m ² / g.

Example 3 Nickel nitrate hexahydrate 9.6
9g and 276.3 g of magnesium nitrate hexahydrate in 50 parts of water.
Dissolved in 0 ml. Next, the temperature of this solution was increased to 323K.
While maintaining the pH, a 2 mol / L aqueous solution of potassium carbonate (590 ml) was added as a coprecipitant to adjust the pH to 9, thereby producing a hydroxide precipitate composed of two components, nickel and magnesium. This precipitate was filtered, washed, and dried in air at 393 K for 12 hours or more. Thereafter, the mixture was calcined in air at a calcining temperature of 1453 K for 5 hours to obtain a catalyst (C). The specific surface area of the catalyst (C) is 0.7 m
² / g.

Example 4 A catalyst (D) was obtained in the same manner as in Example 3 except that the calcination temperature was 1,423K. The specific surface area of the catalyst (D) was 0.9 m ² / g.

Example 5 Nickel nitrate hexahydrate
5 g, magnesium nitrate hexahydrate 272.1 g, and manganese nitrate hexahydrate 3.19 g were dissolved in water 500 ml.
Then, while maintaining the temperature of this solution at 323 K, 590 ml of a 2 mol / L aqueous solution of potassium carbonate was added as a coprecipitant to adjust the pH to 9, thereby producing a hydroxide precipitate comprising three components of nickel, magnesium and manganese. . This precipitate was filtered, washed, and dried in air at 393 K for 12 hours or more. Thereafter, the mixture was calcined in air at a calcining temperature of 1453 K for 5 hours to obtain a catalyst (E). The specific surface area of the catalyst (E) was 0.8 m ² / g.

Example 6 A catalyst (F) was obtained in the same manner as in Example 5 except that the firing temperature was changed to 1373K. The specific surface area of the catalyst (F) was 0.9 m ² / g.

(Comparative Example 1) A catalyst (E) was obtained in the same manner as in Example 1 except that the firing temperature was set to 1223K. The specific surface area of this catalyst (E) was 5.4 m ² / g.

(Reaction Example 1) 30 cc of the catalyst (A) prepared in Example 1 was charged into a pressurized fixed-bed flow reactor, and reforming was performed using carbon dioxide and steam of methane. After subjecting the catalyst (A) to a reduction treatment in advance at 1173 K in a hydrogen stream, the methane: carbon dioxide molar ratio = 1: 0.4,
A raw material gas having a methane: steam molar ratio of 1: 1 was applied under a pressure of 2.
1MPa, temperature 1123K, GHSV = 6000 / hr
The reaction was performed under the following conditions. The methane conversion after a lapse of 100 hours from the start of the reaction was 59% (the equilibrium conversion of methane under the reaction conditions was 59%), and the methane conversion after a lapse of 3000 hours was 59%. The amount of deposited carbon 100 hours after the start of the reaction was 0.2 wt%.

(Reaction Example 2) The same reforming as in Reaction Example 1 was performed except that the catalyst (B) prepared in Example 2 was used. The methane conversion after 100 hours from the start of the reaction is 59% (the equilibrium conversion of methane under the reaction conditions is 59%).
%)Met. The carbon deposition amount at this time is 0.2 w
t%.

(Reaction Example 3) Reforming was performed in the same manner as in Reaction Example 1 except that the catalyst (C) prepared in Example 3 was used. The methane conversion after 100 hours from the start of the reaction is 59% (the equilibrium conversion of methane under the reaction conditions is 59%).
%)Met. The carbon deposition amount at this time is 0.2 w
t%.

(Reaction Example 4) Reforming was carried out in the same manner as in Reaction Example 1, except that the catalyst (D) prepared in Example 4 was used. The methane conversion after 100 hours from the start of the reaction is 59% (the equilibrium conversion of methane under the reaction conditions is 59%).
%)Met. The carbon deposition amount at this time is 0.2 w
t%.

(Reaction Example 5) The same reforming as in Reaction Example 1 was performed except that the catalyst (E) prepared in Example 5 was used. The methane conversion after 100 hours from the start of the reaction is 59% (the equilibrium conversion of methane under the reaction conditions is 59%).
%)Met. The carbon deposition amount at this time is 0.2 w
t%.

(Comparative Reaction Example) The same reforming as in Reaction Example 1 was performed except that the catalyst (F) prepared in Comparative Example 1 was used. The methane conversion after 100 hours from the start of the reaction is 57% (the equilibrium conversion of methane under the reaction conditions is 59%).
%)Met. At this time, the amount of deposited carbon was 5.2 w
t%.

[0055]

As described above, according to the present invention, CoO, NiO or MO is used as a reforming catalyst.
x is converted to a complex oxide with MgO or MgO / CaO, and cobalt, nickel, or a material in which M is highly dispersed is used. The deposition of quality (carbon) can be suppressed, the synthesis gas can be obtained efficiently, and the production cost can be reduced. In addition, since the catalyst is not contaminated with carbonaceous material, a decrease in catalytic activity with time is suppressed, and the life of the catalyst is prolonged.

The calcination temperature for calcining the precipitate obtained by coprecipitation to form a catalyst is 1273 to 1573K.
And the reforming reaction temperature was 873 to 1023.
K can be suppressed even in a relatively low temperature range of K, and the reforming temperature range is 1123 to
Even if it is as high as 1173K, the coking resistance is improved,
It is possible to obtain effects such as prolonging the catalyst life.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a surface state of a catalyst in the present invention.

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Claims (7)

[Claims] 1. A method for obtaining a reforming catalyst comprising a composite oxide having a composition represented by the following formula, wherein Co is highly dispersed in the composite oxide: aCo.bMg · CCa · dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.30, 0.70 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. ) A hydroxide is precipitated by adding a coprecipitant to an aqueous solution of a water-soluble salt of each of the above-mentioned constituent elements, and the precipitate is dried.
A method for producing a reforming catalyst, wherein the catalyst is calcined in a temperature range of 73K to 1573K. 2. A method for obtaining a reforming catalyst comprising a composite oxide having a composition represented by the following formula, wherein Ni is highly dispersed in the composite oxide: aNi.bMg · CCa · dO (where a, b, c, and d are mole fractions, and a + b + c
= 1, 0.005 ≦ a ≦ 0.30, 0.70 ≦ (b +
c) ≦ 0.995, 0 <b ≦ 0.995, 0 ≦ c ≦ 0.
995, d = number required to keep the element in charge balance with oxygen. ) A hydroxide is precipitated by adding a coprecipitant to an aqueous solution of a water-soluble salt of each of the above-mentioned constituent elements, and the precipitate is dried.
A method for producing a reforming catalyst, characterized in that it is calcined in a temperature range of 73K to 1573K. 3. A method for obtaining a reforming catalyst comprising a composite oxide having a composition represented by the following formula, wherein M and Ni are highly dispersed in the composite oxide: .BNi.cMg.dCa.eO (where a, b, c, d, and e are mole fractions and a + b
+ C + d = 1, 0.0001 ≦ a ≦ 0.10, 0.00
01 ≦ b ≦ 0.30, 0.60 ≦ (c + d) ≦ 0.99
98, 0 <c ≦ 0.9998, 0 ≦ d <0.9998,
e = number of elements required to keep charge balance with oxygen.
M is a group 6A element, a group 7A element, Ni
Group 8 transition elements except for Group 1B elements, Group 2B elements,
It is at least one element of a Group 4B element and a lanthanoid element. ) A hydroxide is precipitated by adding a coprecipitant to an aqueous solution of a water-soluble salt of each of the above-mentioned constituent elements, and the precipitate is dried.
A method for producing a reforming catalyst, characterized in that it is calcined in a temperature range of 73K to 1573K. 4. M is manganese, molybdenum, rhodium,
Ruthenium, platinum, palladium, copper, silver, zinc, tin,
The method for producing a reforming catalyst according to claim 3, wherein the catalyst is at least one selected from the group consisting of lead, lanthanum, and cerium. 5. A reforming catalyst obtained by the production method according to claim 1 and having a specific surface area of 0.2 to ⁵ m ² / g. 6. A method for producing a synthesis gas, wherein a synthesis gas is obtained from a hydrocarbon and a reforming substance using the reforming catalyst obtained by the method according to any one of claims 1 to 4. 7. The synthesis gas production method according to claim 6, wherein a supply ratio of the hydrocarbon and the reforming substance is set to a reforming substance / carbon ratio = 0.3 to 100. Recipe.