JP2003038957A - Dimethyl ether reforming catalyst and method for producing hydrogen-containing gas using the catalyst - Google Patents

Abstract

(57) [Problem] To develop a catalyst having high activity in the steam reforming of dimethyl ether by a self-heat supply type reaction in producing hydrogen by reacting dimethyl ether with steam.
Provided is a method for easily producing a hydrogen-containing gas with a small device. A dimethyl ether reforming catalyst is prepared by mixing a precursor mixture containing copper, zinc and aluminum with activated alumina.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a hydrogen-containing gas by steam reforming dimethyl ether. Hydrogen gas is widely used for chemical industries such as ammonia synthesis, hydrogenation of various organic compounds, petroleum refining and desulfurization, atmosphere gas for semiconductors and metallurgy, glass manufacturing and the like. Further, recently, it has been drawing attention as a raw material for a fuel cell which is a power source for automobiles and the like, and it is expected that the demand for hydrogen gas will greatly expand in the future.

[0002]

2. Description of the Related Art As a method for producing hydrogen gas, for example, a steam reforming method for hydrocarbons such as naphtha, natural gas and petroleum liquefied gas is known. This method has drawbacks such as the need for desulfurization of the raw material and the very high reaction temperature of 800 to 1000 ° C. Also, the steam reforming method using methanol as a raw material is well known, and has the advantage that desulfurization is not required and the reaction temperature is low, and has attracted attention in recent years, and many small to large-scale facilities have been installed. There is.

On the other hand, as another hydrogen production method by steam reforming method, a method using dimethyl ether as a raw material can be mentioned. Dimethyl ether is expected to be used as a clean fuel for automobiles and power generation.
Since it liquefies easily at atmospheric pressure, it can be handled in the same way as liquefied propane gas for storage and transportation. Although dimethyl ether is currently produced by the dehydration reaction of methanol and is expensive, the possibility of supplying it in large quantities at low cost has arisen since the direct synthesis method from synthesis gas was developed.

It is considered that the steam reforming reaction of dimethyl ether proceeds in a two-step reaction of the formulas (1) and (2). _{CH 3 OCH 3 + H 2 O} = 2CH 3 OH + 23.5kJ / mol (1) CH 3 OH + H 2 O = CO 2 + 3H 2 + 49.5kJ / mol (2) In addition to the above main reaction A small amount of carbon monoxide and methane are by-produced by the shift reaction of the formula (3) and the methanation reaction of the formula (4). CO ₂ + H ₂ = CO + H ₂ O + 41.17kJ / mol (3) CO + 3H ₂ = CH ₄ + H ₂ O-206.2kJ / mol (4)

Carbon monoxide and methane by-produced by these reactions are difficult to remove during purification to high-purity hydrogen, and it is preferable that the amount is as small as possible. From thermodynamic equilibrium, the lower the temperature, the more the molar ratio of water vapor and dimethyl ether (hereinafter, S / D ratio)
The larger is, the lower the by-product concentration in the reformed gas can be. Dimethyl ether steam reforming reaction (2)
Although it is possible to generate twice the stoichiometric amount of hydrogen as compared with the methanol reforming reaction of the formula alone, the hydration reaction of the formula (1) is an endothermic reaction, so the reaction at a higher temperature Conditions are required. Therefore, if the catalyst has high activity even at a lower temperature, the external heat supply system can be downsized and the thermal efficiency can be improved.

On the other hand, a self-heat supply type in which air is introduced together with dimethyl ether and water vapor to oxidize a part of dimethyl ether and utilize the heat to cause an endothermic reaction which is a main reaction of formulas (1) and (2). There is a reaction. In this method, a part of dimethyl ether is oxidized into hydrogen and carbon dioxide as shown in formula (5), and the heat is used to carry out the main reactions of formulas (1) and (2). CH ₃ OCH ₃ + 3 / 2O ₂ = 3H ₂ + 2CO ₂ -603.7kJ / mol (5) According to this method, except that heat is raised to a temperature level required at the start of the reaction, the reaction is continued. It has the feature that it does not require heat supply.

The catalyst used in the steam reforming reaction of dimethyl ether includes, for example, a catalyst containing oxides of copper, zinc and aluminum (US Pat. No. 5,498,370) and oxides of copper, zinc and aluminum. Catalyst and mixed catalyst of zeolite or silica-alumina (Patent Document 9-
118501), copper catalyst and γ-alumina, zeolite,
A catalyst in which silica-alumina is physically mixed (JP 2001-96159 A).
No. publication) is proposed.

[0008]

When hydrogen is produced by steam reforming dimethyl ether, it is generally 350-
A reaction temperature of 450 ° C. is required, and in consideration of energy cost, a catalyst showing high activity for heat supply at a lower temperature is required. Further, in the self-heat supply type reaction, heat supply is sufficient only at the start of the reaction, which is very advantageous. However, in the self-heat-supplied reaction in which dimethyl ether is reacted with steam and air to produce hydrogen,
Since a part of the dimethyl ether is oxidized, the temperature in the vicinity of the reaction is much higher than that in the steam reforming reaction. Therefore, a catalyst for a self-heat supply type reaction is required to have high heat resistance. In addition, when hydrogen is produced for a fuel cell, which is a power source for automobiles, etc., it is necessary to downsize the reforming reactor due to the limitation of the installed capacity. , GHSV), a catalyst with higher activity is required.

As described above, various catalysts have been proposed as steam reforming catalysts for dimethyl ether using dimethyl ether and steam as raw materials. However, conventionally known steam reforming catalysts for dimethyl ether have insufficient heat resistance and activity, and cannot be used as they are for a self-heat supply type reaction. For example, a catalyst in which an oxide catalyst of copper or zinc and a solid acid catalyst are physically mixed at a certain particle size can be used in a dimethyl ether steam reforming reaction of a self-heat supply type reaction. The activity decreases in a short time due to the sintering of copper and zinc and the pulverization of catalyst particles. Copper, zinc, and aluminum-based catalysts to which aluminum oxide is added in order to increase heat resistance are known, but these catalysts are not sufficient for the self-heat supply type reaction. In addition, although the reaction rate is high with a catalyst in which copper is supported on a solid acid or the like, the concentration of by-products such as carbon monoxide and residual methanol is high, and when used for a fuel cell, carbon monoxide is generated. , The electrode is poisoned and shortens the life of the electrode. An object of the present invention is to develop a catalyst having high activity in steam reforming of dimethyl ether in a self-heat supply type reaction, and to provide a method for easily producing a hydrogen-containing gas in a small-sized apparatus.

[0010]

Means for Solving the Problems As a result of diligent research on the above problems in the method for producing a hydrogen-containing gas by steam reforming of dimethyl ether, the present inventors have found that a catalyst prepared by a specific method has high activity. Moreover, they have heat resistance and have been found to be suitable for self-heat supply type reaction, and have reached the present invention. That is, the present invention is a method for producing a dimethyl ether reforming catalyst, which comprises preparing a precursor mixture containing copper, zinc and aluminum and activated alumina, and a catalyst prepared by the method,
And a method for producing a hydrogen-containing gas using the catalyst.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The catalyst of the present invention is prepared by mixing a precursor mixture containing copper, zinc and aluminum with activated alumina. The precursor mixture containing copper, zinc and aluminum is a slurry-like mixture containing a precipitate containing each metal component. The precipitate containing each metal component is obtained by treating the compound containing the metal, and as the raw material, a metal compound that can be converted into an oxide when the precipitate is fired is used.

As the copper compound, for example, water-soluble salts of organic acids such as copper acetate and water-soluble salts of inorganic acids such as copper chloride, copper sulfate and copper nitrate can be used. As the zinc compound, for example, a water-soluble salt of an organic acid such as zinc acetate, a water-soluble salt of an inorganic acid such as zinc chloride, zinc sulfate, zinc nitrate or zinc oxide can be used. As the aluminum compound, for example, a water-soluble salt of an organic acid such as aluminum acetate or a water-soluble salt of an inorganic acid such as aluminum chloride, aluminum sulfate or aluminum nitrate can be used.

By allowing a precipitating agent to act on an aqueous solution of these metal salts, a precipitate containing the metal can be obtained. As the precipitant, a water-soluble alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate or sodium hydrogen carbonate is used. When zinc oxide is used, it can be dispersed in water and brought into contact with carbon dioxide gas to obtain a precipitate of zinc carbonate.

Further, it is more preferable that a boron compound is allowed to coexist during the preparation of these precipitates, since the activity of the catalyst after the preparation is improved. For example, boric acid can be preferably used as the boron compound.

The concentration of the metal salt aqueous solution at the time of preparing the precipitate is 0.2
-3 mol / l, preferably 0.5-2 mol / l. The amount of the precipitating agent with respect to the metal salt is 1 to 2 times, preferably 1.1 to 1.6 times the chemical equivalent amount. Also,
The temperature at the time of adjusting the precipitation is 20 to 90 ° C., preferably 35 to 8
It is 5 ° C.

The composition of the catalyst according to the present invention has a copper / zinc atomic ratio of 0.2 to 12, preferably 0.5 to 10.
The composition of copper, zinc and aluminum as a metal is copper 1.
The range of 5 to 40% by weight, zinc 15 to 40% by weight, and aluminum 15 to 40% by weight is preferable. When a boron compound is allowed to coexist, the content of boron is 0.1 to 3% by weight.
Is.

The precursor mixture containing copper, zinc and aluminum of the present invention is (1) mixed with the precipitate obtained by the above-mentioned method, (2) another metal in the presence of a certain metal precipitate. It can be obtained by various methods such as precipitation or (3) simultaneous precipitation of three kinds of metals. In the present invention, a slurry containing a precipitate of copper and zinc and a slurry containing a precipitate of aluminum are separately prepared, and when these slurries are mixed, the catalyst components are intimately mixed and excellent catalyst performance is provided, which is preferable. .

The slurry containing the precipitates of copper and zinc is preferably prepared by a coprecipitation method. For example, a method of precipitating with an aqueous solution containing copper and zinc and a precipitating agent such as alkali carbonate, a copper precipitation slurry. It can be prepared by a method of dispersing zinc oxide in, and carbonating with carbon dioxide gas. More preferably, it is prepared by using an aqueous solution of an inorganic acid salt of copper, an alkaline precipitant, and zinc oxide and carbon dioxide in the coexistence of a boron compound.

The mixed slurry thus obtained is usually washed with pure water or the like. When sulfate is used as the raw material, it is preferable to wash it with a dilute aqueous alkali solution.

The washed mixed slurry prepared by the above method is dried and calcined. Drying temperature is 50
At -150 ° C, calcination is carried out in air at 180 ° C-500 ° C, preferably 200-400 ° C.

The dry powder or calcined powder thus obtained is crushed and mixed well with the powder of activated alumina.
When the activated alumina and the dry powder are mixed, the firing is performed thereafter. Further, the mixed slurry and the activated alumina may be mixed and then dried and fired. In the present invention, various activated aluminas can be used, but γ-alumina, δ-alumina, θ
-Alumina is preferred and γ-alumina is particularly preferred.
The mixing ratio of activated alumina to dry powder or calcined powder is
The volume ratio of activated alumina is 1/3 to 2, preferably 1/5.
It is a ratio of 3/2. The same applies to the case of mixed slurries.

The fired powder thus obtained can be used by making it into tablets having the same size and crushing it to have the same particle size. Further, a mixture of activated alumina and dry powder may be suspended in water, and a binder such as alumina sol may be added as necessary to support it on a carrier or a carrier structure. After supporting, it can be dried and used as it is, or can be used after firing. Similarly, a mixture of activated alumina and calcined powder can be supported on a carrier or a carrier structure, and can be used after being supported and dried, or after being calcined.

In the use of the catalyst, in the self-heat supply type reaction in which dimethyl ether is reacted with steam and air, the activation treatment may be carried out with a gas containing hydrogen or carbon monoxide, as in the case of the steam reforming reaction. Then
It can also be used in the reaction without activation treatment.

In the steam reforming reaction of reacting dimethyl ether with steam or the self-heat-supplying reaction of introducing air, the steam / dimethyl ether ratio (S / D) is 3 to 1.
0, preferably 3 to 6, and the air / dimethyl ether ratio (A / D) is 0.5 to 10, preferably 1.5 to 5.
Is. When introducing air, conditions are selected so as to avoid the explosive range of dimethyl ether and to balance the heat generation by the combustion reaction and the heat absorption by the steam reforming reaction.

The reaction temperature is 150 to 600 ° C., preferably 200 to 500 ° C., and the pressure is normal pressure. The gas hourly space velocity (GHSV) of steam and dimethyl ether per unit catalyst is 300 to 8000 (1 / h), preferably 500 to 3 in the steam reforming reaction in which air does not coexist.
000 (1 / h), and 300 for the self-heat supply type reaction
~ 100,000 (1 / h), preferably 1000-25
000 (1 / h).

[0026]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

<Preparation of catalyst> Example 1 140.4 g of ammonium hydrogencarbonate and 1186 ml of ion-exchanged water were placed in a 5 liter round bottom flask and dissolved, and the mixture was kept at 40 ° C. Also, copper nitrate (pentahydrate) 195
g and 18.8 g boric acid 1290 ml of ion-exchanged water
Was added to the above ammonium hydrogen carbonate solution. Subsequently, zinc oxide 49.
A slurry in which 35 g was dispersed in 500 ml of ion-exchanged water was added, and carbon dioxide gas was immediately blown in at a flow rate of 6 L / h.
After 1 hour, the temperature was raised to 80 ° C. and kept for 30 minutes. Carbon dioxide was stopped in 2 hours and cooled to 60 ° C. After filtration and washing, the filtered precipitate was alumina sol (Nissan Chemical Industries # 2
00 g) and 60 ml of ion-exchanged water were added and kneaded. Then, it was dried at 80 ° C. and then baked at 380 ° C. An equal volume of commercially available γ-alumina (specific surface area: 230 m ² / g) was added to 20 ml of this baked powder, well mixed by a dry method, and tablet-molded into a cylindrical shape of 3 mmφ × 5 mmh to be crushed to 20 to 35 mesh, The size was adjusted. Thus, the catalyst A containing copper, zinc and aluminum as the main components
Got

Example 2 A mixed slurry prepared in the same manner as in Example 1 was dried, and then an equal volume of commercially available γ-alumina (specific surface area: 230 m ² / g) was added, and the mixture was mixed well in a dry system at 380 ° C. Baked. The obtained calcined powder was tablet-molded into a cylindrical shape of 3 mmφ × 5 mmh, which was crushed into 20 to 35 mesh and sized. Thus, a catalyst B containing copper, zinc and alumina as main components was obtained.

Example 3 A commercially available γ-alumina (specific surface area: 230 m ² / g) was added to a calcined powder prepared in the same manner as in Example 1 in an equal volume, and
Wet milling was carried out using ion-exchanged water for an hour. The resulting slurry was supported on a cordierite honeycomb of 400 cells / square inch by about 200 g / L to obtain a catalyst C.

Comparative Example 1 Commercially available copper and zinc based catalyst (CuO 30% by weight, ZnO 70% by weight)
The cylindrical molded product of is crushed to 20-35 mesh, sized,
Catalyst D was obtained.

COMPARATIVE EXAMPLE 2 The catalyst obtained in Comparative Example 1 and a commercially available γ-alumina (specific surface area 230 m ² / g) were used as a cylindrical molded product, and a product obtained by pulverizing and sizing to 20 to 35 mesh was physically prepared. Mix and catalyst E
Got

Comparative Example 3 An equal volume of commercially available zeolite (hydrogen-type mordenite) was added to a calcined powder prepared in the same manner as in Example 1, well mixed in a dry system, and tablet-molded into a cylindrical shape of 3 mmφ × 5 mmh. The product was crushed to 20-35 mesh and sized. Thus, catalyst F was obtained.

Comparative Example 4 An equal volume of aluminum phosphate as a reagent was added to a calcined powder prepared in the same manner as in Example 1 and mixed well in a dry system to obtain 3 m.
20 ~ for tablet molding in the shape of a cylinder of mφ x 5 mmh
It was crushed into 35 mesh and sized. In this way the catalyst G
Got

Comparative Example 5 A calcined powder prepared in the same manner as in Example 1 was 3 mmφ × 5.
A tablet-molded product having a cylindrical shape of mmh was crushed into 20 to 35 mesh and sized. Thus, catalyst H was obtained.

Comparative Example 6 An equal volume of the catalyst obtained in Comparative Example 1 and a commercially available γ-alumina (specific surface area 230 m ² / g) was added and wet pulverized for 1 hour using ion-exchanged water. Approximately 200 g of the obtained slurry into a cordierite honeycomb of 400 cells / inch 2.
/ L was carried to obtain a catalyst I.

Comparative Example 7 Commercially available γ-alumina (specific surface area of 230 m ² / g) was added to 9.
2 g was weighed and added thereto was a 45% by weight copper nitrate aqueous solution of 3.04 g of copper nitrate trihydrate and ion-exchanged water. This slurry was heated to 70 to 90 ° C. with an evaporator, well impregnated with copper nitrate, then dried at 130 ° C., after evaporating the water content, baked at 500 ° C. for 3 hours to decompose and remove the nitric acid component. A catalyst J supporting 8% by weight of copper was obtained.

<Production of Hydrogen> Example 4 2 ml of the catalyst A was filled in the reaction tube of the fixed bed flow reactor,
Steam / dimethyl ether ratio (S / D) 5/1, GHSV1660 / h at atmospheric pressure and catalyst layer temperature of 260 to 350 ° C
The activity of the catalyst was evaluated by. The gas after the reaction was analyzed by gas chromatography, and the reaction rate of each component is shown in Table 1.

Comparative Example 7 The same as Example 4 except that the catalyst H was used in place of the catalyst A.

Table 1 Catalyst layer temperature Outlet gas composition (%) DME reaction rate (%) (° C) H2 CO CH4 CO2 H2O DME Example 4 (Catalyst A) 260 5.7 0.0 0.0 1.9 77.5 14.9 5.9 280 20.3 0.1 0.0 6.7 62.5 10.4 24.4 300 51.5 0.6 0.06 16.8 28.1 2.9 74.9 320 57.7 1.4 0.0 18.3 22.5 0.05 99.6 330 57.8 1.6 0.0 18.2 22.4 0.0 100.0 350 58.7 2.2 0.0 18.1 21.0 0.0 100.0 Comparative Example 7 (Catalyst H) 260 1.8 0.0 0.1 0.6 80.1 17.3 2.2 280 4.4 0.0 0.6 1.7 75.9 17.5 6.0 300 8.5 0.0 1.6 3.4 70.5 16.1 13.3 350 21.1 0.2 6.5 9.1 56.8 6.4 55.4 400 30.9 1.0 11.9 13.6 42.3 0.3 97.6

Example 5 2 ml of catalyst A was filled in a reaction tube of a fixed bed flow reactor,
Steam / dimethyl ether ratio (S / D) 5/1, GHSV16 at atmospheric pressure and catalyst layer temperature of 300 ° C.
The activity of the catalyst was evaluated at 60 / h. The reaction time was 20 hours, and the following values represent the average values. The gas after the reaction was analyzed by gas chromatography. Table 2 shows the reaction rates of the components and.

Example 6 The procedure of Example 5 was repeated except that the catalyst B was used in place of the catalyst A.

Comparative Example 8 The procedure of Example 5 was repeated except that the catalyst A was replaced by the catalyst D.

Comparative Example 9 The procedure of Example 5 was repeated except that the catalyst E was used instead of the catalyst A.

Comparative Example 10 The procedure of Example 5 was repeated except that the catalyst F was used in place of the catalyst A.

Comparative Example 11 The procedure of Example 5 was repeated except that the catalyst G was used instead of the catalyst A.

Table 2 Outlet gas composition (%) DME reaction rate H2 CO CH4 CO2 H2O DME (%) Example 5 (catalyst A) 46.9 0.5 0.0 15.3 33.5 3.8 67.5 Example 6 (catalyst B) 55.4 1.3 0.0 17.6 20.2 5.5 63.2 Comparative Example 8 (Catalyst D) 11.0 0.1 0.3 3.7 69.2 15.7 10.3 Comparative Example 9 (Catalyst E) 28.2 0.2 0.1 9.3 51.4 10.8 30.4 Comparative Example 10 (Catalyst F) 28.6 0.1 0.1 9.5 52.8 8.9 35.1 Comparative Example 11 (Catalyst G) 39.3 0.3 0.0 12.9 40.7 6.8 49.4

Example 7 A reaction tube of a fixed bed flow reactor was filled with catalyst C (effective volume of honeycomb was 3.73 ml), and steam was heated under normal pressure so that the gas temperature at the inlet to the catalyst layer was 290 ° C. / Dimethyl ether ratio (S / D) 5/1, GHSV3320 /
h, air to air / dimethyl ether ratio (A / D) 2.5
Introduced at ˜4.5, the activity of the catalyst in the self-heat supply type reaction was evaluated. The gas after the reaction was analyzed by gas chromatography. Hydrogen, carbon monoxide (CO), methane,
Table 3 shows residual DME and residual methanol concentration.

Comparative Example 12 The procedure of Example 7 was repeated except that the catalyst I was used instead of the catalyst C.

Comparative Example 13 The procedure of Example 7 was repeated except that the catalyst J was used instead of the catalyst C.

Table 3 Catalyst layer maximum temperature A / D ratio Outlet gas composition (%) (° C) H2 CO CH4 DME MeOH Example 7 (Catalyst C) 409 3.46 25.9 0.2 0.03 2.53 0.0 416 3.77 28.9 0.2 0.01 1.19 0.0 425 4.39 28.2 0.3 0.04 0.60 0.0 Comparative Example 12 (Catalyst I) 393 3.15 25.9 0.02 0.01 1.69 0.0 403 3.77 25.2 0.23 0.01 1.73 0.0 421 4.39 25.1 0.32 0.02 1.28 0.0 Comparative Example 13 (Catalyst J) 365 3.15 26.9 0.40 0.01 1.41 1.95 391 3.77 28.0 0.38 0.03 0.40 1.52 415 4.39 30.3 1.01 0.09 0.37 1.05

Example 8 A reaction tube of a fixed bed flow reactor was filled with catalyst C (effective volume of honeycomb of 0.93 ml), and steam was introduced under normal pressure so that the inlet gas temperature to the catalyst layer was 290 ° C. / Dimethyl ether ratio (S / D) 5/1, GHSV13260 /
h, air to air / dimethyl ether ratio (A / D) 3.7
Introduced in No. 7, the activity of the catalyst in the autothermal reaction was evaluated. The gas after the reaction is analyzed by gas chromatography, and hydrogen, carbon monoxide (CO), methane, residual DM
E and residual methanol concentration are shown in Table 4.

Comparative Example 14 The procedure of Example 8 was repeated except that the catalyst J was used instead of the catalyst C.

Table 4 Catalyst layer maximum temperature Outlet gas composition (%) DME reaction rate (%) (° C) H2 CO CH4 DME MeOH Example 8 (Catalyst C) 426 30.0 0.18 0.03 1.12 0.0 85.1 Comparative Example 14 (Catalyst J) 417 25.3 0.36 0.04 1.73 1.22 81.5

[0054]

INDUSTRIAL APPLICABILITY The catalyst according to the present invention has high activity at low temperature in the steam reforming reaction in which dimethyl ether and steam are reacted, and is used as an effective catalyst for obtaining a mixed gas containing a high hydrogen concentration, and air is introduced. In the self-heat supply type reaction, a high hydrogen concentration is maintained even if the amount of air introduced is increased, and a mixed gas containing a small amount of by-products such as carbon monoxide, methane, and residual methanol can be obtained. That is, by using this dimethyl ether reforming catalyst, it is possible to easily produce a mixed gas having a high hydrogen concentration with a small-sized apparatus.

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Claims (10)

[Claims] 1. A method for producing a dimethyl ether reforming catalyst, which is prepared by mixing a precursor mixture containing copper, zinc and aluminum with activated alumina. 2. The method for producing a dimethyl ether reforming catalyst according to claim 1, wherein the precursor mixture containing copper, zinc and aluminum is a slurry mixture containing a precipitate containing each metal component. 3. The method for producing a dimethyl ether reforming catalyst according to claim 1, wherein the precursor mixture containing copper, zinc and aluminum is prepared in the presence of a boron compound. 4. The method for producing a dimethyl ether reforming catalyst according to claim 1, wherein the activated alumina is γ-alumina, δ-alumina and / or θ-alumina. 5. The method for producing a dimethyl ether reforming catalyst according to claim 1, which is prepared by mixing a precursor mixture containing copper, zinc and aluminum with activated alumina, followed by drying and firing. 6. The method for producing a dimethyl ether reforming catalyst according to claim 1, wherein the precursor mixture containing copper, zinc and aluminum is dried, then mixed with activated alumina and then calcined. . 7. The method for producing a dimethyl ether reforming catalyst according to claim 1, wherein the precursor mixture containing copper, zinc and aluminum is dried and calcined and then mixed with activated alumina. 8. A dimethyl ether reforming catalyst prepared by the method according to claim 1. 9. A method for producing a hydrogen-containing gas, which comprises reacting dimethyl ether with steam in the presence of the catalyst according to claim 8 to produce hydrogen. 10. The method for producing a hydrogen-containing gas according to claim 9, wherein the reaction is performed in the coexistence of oxygen.