JP2003144928A - Catalyst for manufacturing urban gas raw material and method for manufacturing urban gas raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst capable of forming methane in a high yield to obtain an urban gas raw material containing methane in a high concentration, and a method for manufacturing the same. SOLUTION: The catalyst contains at least one kind of an element selected from the group consisting of iron, cobalt, silver, copper, molybdenum, platinum, palladium, rhodium and iridium and forms the urban gas raw material from mixed gas containing dimethyl ether and steam. The method for manufacturing the urban gas raw material using the catalyst is also disclosed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for producing a city gas raw material containing methane as a main component from a mixed gas containing dimethyl ether and steam, and a method for producing a city gas raw material using the same.

[0002]

2. Description of the Related Art Conventionally, the following methods are known for producing city gas raw materials from dimethyl ether.

Japanese Patent Laid-Open No. 2000-336381 discloses that
Disclosed is a method for producing a city gas raw material, which comprises contacting a catalyst with dimethyl ether in the presence of water vapor to reform the catalyst to produce a gas mainly containing methane.
Further, it is described in the publication that a catalyst containing ruthenium or a catalyst containing nickel which is conventionally known for reforming hydrocarbons can be used as the catalyst.

[0004]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
In the method disclosed in Japanese Patent Laid-Open No. 000-336381, the reaction rate of dimethyl ether to methane is small and the proportion of methane in the produced gas is small. Therefore, a plurality of reactors are connected in series to increase the reaction rate. There was also a problem that it was necessary to connect a methanation reactor in the latter stage to increase the proportion of methane.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a catalyst and a production method capable of producing methane at a high yield and obtaining a city gas raw material containing a high concentration of methane. To do.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present invention is one selected from the group consisting of iron, cobalt, silver, copper, molybdenum, platinum, palladium, rhodium and iridium. Further, the inventors have found that a catalyst containing two or more kinds can efficiently produce a city gas raw material mainly containing methane from a mixed gas containing dimethyl ether and steam, and thus the present invention can be completed.

That is, the present invention relates to iron, cobalt, silver,
A catalyst for producing a city gas raw material from a mixed gas containing dimethyl ether and water vapor, which contains one or more selected from the group consisting of copper, molybdenum, platinum, palladium, rhodium and iridium. The present invention relates to a method for producing a city gas raw material, which comprises bringing the catalyst into contact with a mixed gas containing dimethyl ether and steam.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst of the present invention comprises iron, cobalt,
Silver, copper, molybdenum, platinum, palladium, rhodium and
And iridium metal and / or compound
Containing one or more of the following as an active ingredient
is there. As the iron compound, iron oxide is preferable,
Oxides are FeO and Fe₂O₃And Fe₃O_FourIs. Koba
The cobalt compound is preferably a cobalt oxide,
Baltic oxides are CoO and Co ₂O₃And Co₃O_FourAnd
It As the silver compound, silver oxide is preferable, and silver acid is preferable.
Compound is Ag₂It is O. Copper oxide as a copper compound
Is preferred, and the oxide of copper is CuO and Cu.₂Is O
It As a molybdenum compound, molybdenum oxide is
Preferably, the oxide of molybdenum is MoO₃Is. platinum
Platinum oxides and chlorides are preferred as compounds of
Gold oxide is PtO₂And chloride is PtCl_Fourso
is there. Oxidation of palladium as a compound of palladium
And the chloride is preferable, and the oxide of palladium is PdO.
Yes, and chloride is PdCl₂Is. Rhodium compound
Rhodium oxides and chlorides are preferable
The oxide of um is Rh₂O₃And chloride is RhCl
₃Is. Iridium acid as a compound of iridium
And chloride are preferable, and the oxide of iridium is Ir.₂
O₃And chloride is IrCl₃Is.

The catalyst containing one or more selected from the metals and / or compounds of iron, cobalt, silver, copper, molybdenum, platinum, palladium, rhodium and iridium is used by being supported on a catalyst carrier. can do. Preferred catalyst carriers are oxides of alumina, silica gel, silica-alumina, zeolite, titania, zirconia, etc. Of these, alumina is preferable because it has a high city gas raw material yield.

The active components in the catalyst are iron, cobalt, silver,
In the case of copper and molybdenum, their content (in the case of a compound, the weight thereof, and in the case of two or more kinds, the total amount) is about 0.5 to 99.5% by weight, preferably 1 to 99% by weight. is there. When the content of iron, cobalt, silver, copper, and molybdenum is less than about 0.5% by weight and 99.5% by weight or more,
The yield of city gas feedstock is reduced. The content of these metals and compounds in the active component that reacts dimethyl ether in the catalyst with water vapor to generate methane is 2% by weight or more, preferably 3% by weight or more.

When the active component in the catalyst is platinum, palladium, rhodium or iridium, their content is about 0.01 to 20% by weight, preferably 0.05 to 10% by weight.
% By weight. When the contents of platinum, rhodium and iridium are less than about 0.01% by weight and 20% by weight or more,
The yield of city gas feedstock is reduced.

The content of these metals and compounds in the active component for reacting dimethyl ether in the catalyst with water vapor to produce methane is 0.1% by weight or more, preferably 0.2% by weight or more.

The catalyst of the present invention includes iron, cobalt,
In addition to silver, copper, molybdenum, platinum, palladium, rhodium and iridium, other metals or compounds can be used together. Examples of other metals and compounds include chromium, manganese, tungsten, zinc, lead, tin, antimony, bismuth, lanthanum, cerium metals and / or
Or a compound can be mentioned. The compound is an oxide,
Carbonate, sulfate, chloride and the like. These metals and compounds may be used alone or in combination of two or more. The content of these third components is 30% by weight, and when contained, it is usually 1 to 20% by weight.

For the production of this catalyst, the general methods for preparing this type of catalyst can be applied. For example, the raw material for producing the catalyst is a compound of iron, cobalt, silver, copper, molybdenum, platinum, palladium, rhodium, or iridium, and its respective inorganic salt such as nitrate, carbonate, halide, acid ammonium salt and acetate. , Organic acid salts such as oxalate are used. Further, for the loading operation on the catalyst carrier, a usual precipitation method, kneading method, impregnation method and ion exchange method can be used.

By bringing the mixed gas containing dimethyl ether and water vapor into contact with the catalyst thus prepared, dimethyl ether is decomposed to produce methane (Equation (1)), and the city gas raw material can be produced in high yield. Obtainable. 2CH ₃ OCH ₃ → 3CH ₄ + CO ₂ (1)

In the production of the city gas raw material according to the present invention, steam is supplied together with the raw material dimethyl ether. The amount of water vapor supplied is 0.1 to 5 mole times, preferably 0.2 to 3 mole times, relative to the raw material dimethyl ether. The raw material gas may contain components other than dimethyl ether and water vapor. Other components may include a gas inert to the reaction, such as nitrogen or an inert gas. It is appropriate that the content of these is 30% by volume or less, and if it is more than 30% by volume, the decrease in reaction rate becomes a problem.
On the other hand, air (oxygen) should be removed as much as possible because dimethyl ether burns, and the allowable content is 5% or less as air.

The reaction temperature is such that the active ingredients are iron, cobalt,
In the case of silver, copper and molybdenum, it is 200 to 650 ° C, preferably 250 to 550 ° C, and in the case of platinum, palladium, rhodium and iridium, it is 200 to 600 ° C, preferably 250 to 500 ° C. If the reaction temperature is lower than 200 ° C. or higher than 650 ° C. or 600 ° C., a high dimethyl ether conversion cannot be obtained and the yield of the city gas raw material is lowered, which is not preferable.

The reaction pressure is preferably atmospheric pressure to 20 kg / cm ² . When the reaction pressure is higher than 20 kg / cm ² , the conversion rate of dimethyl ether decreases.

The space velocity (feed rate m ³ / h of the mixed gas in a standard state per 1 m ^{3 of} catalyst) is 1000 to 3
0000 m ³ / m ³ · h is preferable. Space velocity is 3000
If it is larger than 0 m ³ / m ³ · h, the conversion rate of dimethyl ether is low, and if it is smaller than 1000 m ³ / m ³ · h, the reactor becomes extremely large, which is not economical.

In the method of the present invention, a fixed bed,
Any device of the fluidized bed may be used.

Incidentally, the Wappe index and the burning rate of city gas are regulated by the Gas Business Law. The product gas obtained by the method of the present invention contains a relatively large amount of carbon dioxide gas, and as it is, it does not comply with the city standard.

Carbon dioxide can be removed by any method
Good, but one of the following proven methods is suitable
To be done. Alkanolamine aqueous solution or hot potassium carbonate
Absorb with aqueous solution. Both reactions are reversible
The absorption liquid can be regenerated. By pressure swing method
High for adsorption silica gel, molecular sieve, activated carbon, etc.
CO under pressure₂Is adsorbed and CO₂To
Desorb. Selective separation CO by separation membrane₂Transparency
Large number of membranes, such as polyimide membrane, cellulose ester
CH with a poly film, polysulfone film, etc._FourAnd CO₂With
CO from mixed gas ₂Only can be selectively separated.

In addition to removing carbon dioxide, carbon monoxide, hydrogen and carbon dioxide contained can be methanated to increase the calorific value. This CO, CO
₂ , for methanation of H ₂ , in addition to the catalyst containing nickel and cobalt (Co) and the catalyst containing ruthenium (Ru) described in JP-B-57-24835, JP-B-63-
The catalyst containing alumina, nickel and barium oxide (BaO) disclosed in 8810 is preferably used. The methanation may be performed before or after removing carbon dioxide, and the order thereof is not limited.

Since the product gas obtained by the method of the present invention still lacks the calorific value even if the carbon dioxide gas is removed,
Add G or dimethyl ether to increase the calorific value to meet the city gas standard.

[0025]

EXAMPLE I. Preparation Example 1 iron nitrate catalyst _{(Fe (NO 3) 3 ·} 9H 2 O) 75.9g was dissolved in deionized water to about 300 ml, further to the aqueous solution γ- alumina (Catalysis Society, "ALO-4") 85 g was added and evaporated to dryness. And this thing in the air, 12
It was dried at 0 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The composition of the obtained catalyst was Fe ₂
O ₃ : Al ₂ O ₃ = 15: 85 (weight ratio).

Example 2 Iron nitrate (Fe (NO₃)₃・ 9H₂O) 50.6 g and nitric acid
Chrome (Cr (NO₃) ₃・ 9H₂O) 26.3 g
Dissolve in about 300 ml of on-exchanged water, and then add this aqueous solution
Gamma-alumina (catalysis society, "ALO-4") 85g
It was charged and evaporated to dryness. And this thing in the air, 1
Dry at 20 ° C for 24 hours and then in air at 500 ° C for 3 hours.
It was calcined for an hour to obtain a catalyst. The composition of the obtained catalyst is Fe
₂O₃: Cr₂O₃: Al₂O₃= 10: 5: 85 (weight ratio)
Met.

Example 3 36.3 g of cobalt nitrate (Co (NO ₃ ) ₃ .6H ₂ O)
Was dissolved in about 300 ml of ion-exchanged water, and γ-alumina (Catalyst Society, “ALO-4”) 85 was added to this aqueous solution.
g, and evaporated to dryness. Then, this was dried in air at 120 ° C. for 24 hours, and further dried in air at 500
The catalyst was obtained by calcining at ℃ for 3 hours. The composition of the obtained catalyst was Co ₂ O ₃ : Al ₂ O ₃ = 10: 90 (weight ratio).

Example 4 7.3 g of silver nitrate (Ag (NO ₃ )) was added to about 3 parts of deionized water.
It was dissolved in 00 ml, and further 95 g of γ-alumina (Catalytic Society of Japan, “ALO-4”) was added to this aqueous solution and evaporated to dryness. Then, this was dried in air at 120 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The composition of the obtained catalyst was Ag ₂ O: Al ₂ O ₃
= 5: 95 (weight ratio).

Example 5 30.4 g of copper nitrate (Cu (NO ₃ ) ₂ .3H ₂ O) was dissolved in about 300 ml of deionized water, and γ-alumina was added to this aqueous solution (Catalysis Society of Japan, "ALO-4"). 90 g was added and evaporated to dryness. And this thing in the air, 12
It was dried at 0 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The composition of the obtained catalyst was Cu
O: Al ₂ O ₃ = 10: 90 (weight ratio).

[0030] Example 6 ammonium molybdate _{((NH 4) 6 MoO 24} · 4H
₂ O) of 12.3 g was dissolved in about 300 ml of ion-exchanged water, and this aqueous solution was further mixed with γ-alumina (Catalyst Society, “A
LO-4 ″) 90 g was added and the mixture was evaporated to dryness. And
This was dried in air at 120 ° C. for 24 hours, and further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The composition of the obtained catalyst was MoO ₃ : Al ₂ O ₃ = 10: 90 (weight ratio).

Example 7 0.863 g of platinum chloride (PtCl ₄ ) was dissolved in about 300 ml of a 10 wt% hydrochloric acid aqueous solution, and 99.5 g of γ-alumina (Catalytic Society, “ALO-4”) was added to this aqueous solution.
Was charged and evaporated to dryness. And this thing in the air,
It was dried at 120 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours. Then, the mixture was treated in a hydrogen stream at 500 ° C. for 3 hours to obtain a catalyst. The composition of the obtained catalyst is P
t: Al ₂ O ₃ = 0.5: 99.5 (weight ratio).

Example 8 0.833 g of palladium chloride (PdCl ₂ ) was dissolved in about 300 ml of ion-exchanged water, and γ-was added to this aqueous solution.
99.5 g of alumina (Catalyst Society, "ALO-4") was added and evaporated to dryness. And this thing in the air, 12
It was dried at 0 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours. Then, the mixture was treated in a hydrogen stream at 500 ° C. for 3 hours to obtain a catalyst. The composition of the resulting catalyst is Pd: A
l ₂ O ₃ = 0.5: it was 99.5 (weight ratio).

Example 9 1.40 g of rhodium nitrate (Rh (NO ₃ ) ₃ ) was dissolved in about 300 ml of deionized water, and γ-was added to this aqueous solution.
99.5 g of alumina (Catalyst Society, "ALO-4") was added and evaporated to dryness. And this thing in the air, 12
It was dried at 0 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours. Then, the mixture was treated in a hydrogen stream at 500 ° C for 3 hours to obtain a catalyst. The composition of the resulting catalyst is Rh: A
l ₂ O ₃ = 0.5: it was 99.5 (weight ratio).

Example 10 0.777 g of iridium chloride (IrCl ₃ ) was dissolved in about 300 ml of deionized water, and γ-was added to this aqueous solution.
99.5 g of alumina (Catalyst Society, "ALO-4") was added and evaporated to dryness. And this thing in the air, 12
It was dried at 0 ° C. for 24 hours and further calcined in air at 500 ° C. for 3 hours. Then, the mixture was treated in a hydrogen stream at 500 ° C. for 3 hours to obtain a catalyst. The composition of the resulting catalyst is Ir: A
l ₂ O ₃ = 0.5: it was 99.5 (weight ratio).

II. Reaction Method A stainless steel reaction tube having an inner diameter of 20 mm was filled with a predetermined amount of the above catalyst. Dimethyl ether and water vapor were supplied to the reaction tube in predetermined amounts and reacted at a predetermined temperature. The reaction products and unreacted products obtained by the above operation were analyzed by gas chromatography.

III. Reaction conditions and experimental results The reaction conditions and experimental results are shown in Tables 1 to 4.

[0037]

[Equation 1]

[0038]

[Equation 2]

[0039]

[Equation 3]

[0040]

[Equation 4]

[0041]

[Equation 5] All units of each speed are [mol / g-cat · h]

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

IV. Production of city gas The product gas obtained by using the catalyst of Example 1 is decarbonated,
85% of this gas was added with 15% of propane to produce a gas that passed the city gas standard. The composition of this gas is shown in Table 5.

[0047]

[Table 5]

[0048]

INDUSTRIAL APPLICABILITY The catalyst of the present invention and the method for producing a city gas raw material using the same are used to prepare a mixed gas containing dimethyl ether and water vapor at a temperature of 200 to 650 ° C. By contacting with a catalyst containing one or more selected from metals and / or compounds, or one or more selected from metals and / or compounds of platinum, palladium, rhodium, iridium, It has an effect that a high city gas raw material yield can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 23/46 311 B01J 23/50 M 23/50 23/72 M 23/72 23/86 M 23/75 C01B 3/40 23/86 3/32 Z C01B 3/40 B01J 23/74 301M C10L 3/10 311M // C01B 3/32 C10L 3/00 K F term (reference) 4G040 EA01 EA06 EC01 EC02 EC03 4G069 AA03 BA01B BB02A BB02B BC31A BC31B BC32A BC32B BC59A BC59B BC66A BC66B BC67A BC67B BC71A BC71B BC72A BC72B BC74A BC74B BC75A BC75B CC17

Claims (2)

[Claims] 1. From a mixed gas containing dimethyl ether and water vapor, which contains at least one selected from the group consisting of iron, cobalt, silver, copper, molybdenum, platinum, palladium, rhodium and iridium. Catalyst for producing city gas feedstock 2. A method for producing a city gas raw material, which comprises contacting the catalyst according to claim 1 with a mixed gas containing dimethyl ether and steam.