JPH10174871A - Catalyst for production of synthesis gas and production of synthesis gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce synthesis gas at a low temp. in a high yield from dimethyl ether and steam or CO2 by using a cobalt-contg. catalyst. SOLUTION: This catalyst for production of synthesis gas contains metal cobalt and/or a cobalt compd., preferably cobalt oxide such as cobaltous oxide or cobaltic oxide. This cobalt catalyst is used after carrying on a catalyst carrier such as alumina, silica gel or silica. A gaseous mixture contg. dimethyl ether and steam and/or CO2 is brought into contact with the cobalt-contg. catalyst to produce the objective synthesis gas. At this time, about 1-20 times (mol) as much steam as dimethyl ether as starting material is fed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst for producing a synthesis gas from a mixed gas containing dimethyl ether and water vapor and / or carbon dioxide, and a method for producing a synthesis gas using the same.

[0002]

2. Description of the Related Art Synthetic gas is a gas composed of carbon monoxide and hydrogen, and is directly used as a raw material gas for methanol synthesis, oxo synthesis, Fischer-Tropsch synthesis, etc., and is widely used as a raw material for ammonia synthesis and various chemical products. Has a use.

Conventionally, several methods for producing synthesis gas are known.

For example, (1) a method by gasification of coal,
(2) a method for steam reforming of hydrocarbons using natural gas, LPG, naphtha, etc. as raw materials; (3) a method for natural gas, LPG, naphtha,
There is a method of partially oxidizing hydrocarbons using heavy oil or the like as a raw material.

[0005]

SUMMARY OF THE INVENTION
In the coal gasification method (1), an extremely complicated and expensive coal gasification furnace is required, and there is a problem that the equipment becomes a large-scale plant. Further, in the hydrocarbon steam reforming method (2), since the reaction is a large endothermic and requires a high temperature of 700 to 1200 ° C. for the progress of the reaction,
There is a problem that a special reforming furnace is required, and that the catalyst used is required to have high heat resistance. Also in the method for partially oxidizing hydrocarbons of the above (3), 1200 to 1500 ° C.
Requires a special partial oxidation furnace because of the high temperature required, and a large amount of soot is generated during the reaction. However, there is a problem that a large amount of the catalyst precipitates to deteriorate the catalyst.

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 obtaining a synthesis gas at a low temperature and a high yield.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have come to focus on dimethyl ether as a raw material gas. As a catalyst for producing synthesis gas by reacting dimethyl ether with water vapor and / or carbon dioxide, it has been found that cobalt is extremely effective and can efficiently produce synthesis gas at low temperatures to complete the present invention. did it.

That is, the present invention provides a catalyst for producing a synthesis gas from dimethyl ether and steam or carbon dioxide, characterized by containing cobalt, and a catalyst containing cobalt in dimethyl ether and a mixed gas containing at least steam or carbon dioxide. The present invention relates to a method for producing a synthesis gas, which comprises contacting a catalyst to be produced.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst of the present invention contains a metal and / or a compound of cobalt. The cobalt compound is preferably a cobalt oxide, and the cobalt oxide is cobaltous oxide (CoO), cobaltic oxide (Co ₂ O ₃ ), or a mixture thereof.

This cobalt catalyst can be used by being supported on a catalyst carrier. Preferred catalyst carriers include
Oxides such as alumina, silica gel, silica / alumina, zeolite, titania, zirconia, zinc oxide, tin oxide, lanthanum oxide, and cerium oxide are preferred, but alumina is preferred because of its high synthesis gas yield. The content of cobalt in the catalyst is about 1 to 30% by weight, preferably 3% by weight.
１５15% by weight. If the cobalt content is less than about 1% by weight and 30% by weight or more, the yield of synthesis gas decreases.

The catalyst of the present invention may use other metals or compounds in addition to the copper metal and / or compound. Examples of other metals and compounds include nickel and iron metals and / or compounds. These metals and compounds may be used alone or in combination of two or more. The content of these third components is 20% by weight or less, particularly 10% by weight or less, and when they are contained, they are usually about 1 to 5% by weight.

For the production of this catalyst, a general method for preparing this type of catalyst can be applied. For example, as a raw material for producing a catalyst, inorganic compounds such as nitrates, carbonates and halides and organic acid salts such as cobalt acetate and cobalt oxalate are used as a compound of cobalt. For the operation of supporting cobalt on the catalyst carrier, techniques such as ordinary precipitation, kneading, impregnation, and ion exchange can be used. The catalyst composition thus prepared is calcined by a conventional method, if necessary. The calcination is preferably performed by heating at 350 to 800 ° C. for 1 to 10 hours in nitrogen or air.

The catalyst is generally subjected to an activation treatment before performing the reaction.
The treatment is preferably performed at a temperature of 00 ° C. for 1 to 10 hours.

By passing a mixed gas of dimethyl ether, steam and / or carbon dioxide through the catalyst thus prepared, a synthesis gas can be obtained in high yield.

In the present invention, steam and / or carbon dioxide are supplied together with the raw material dimethyl ether. The steam to be supplied may be a stoichiometric amount or more based on the dimethyl ether as the raw material, and may be 1 to 20 times, preferably 1 to 20 times.
It is 10 mole times. If the supply of steam is less than 1 mole, a high dimethyl ether conversion cannot be obtained, and
It is not economical if it is more than mole times. The supplied carbon dioxide is 0.8 to 2.0 times, preferably 0.9 to 1.5 times, the molar amount of dimethyl ether as the raw material. If the supply of carbon dioxide is less than 0.8 mol times, a high dimethyl ether conversion cannot be obtained, and if it is more than 2.0 mol times, a large amount of carbon dioxide remains in the synthesis gas, and the removal of carbon dioxide is reduced. It is necessary and not preferable. When both steam and carbon dioxide are supplied, the sum of the steam and carbon dioxide is 1 to 10 times, preferably 1 to 5 times the molar amount of dimethyl ether. If the sum of water vapor and carbon dioxide is less than 1 mole, a high dimethyl ether conversion cannot be obtained, and if it is more than 10 moles, it is not economical and carbon dioxide must be removed, which is not preferable.
The raw material gas may contain components other than dimethyl ether, water vapor, and carbon dioxide. Other components which are inert to the reaction, such as nitrogen, inert gas, C
O, H ₂ , methane and the like can be included. The content of these is suitably not more than 30% by volume. If the content is more than 30% by volume, the reduction of the reaction rate becomes a problem. On the other hand, air (oxygen) burns dimethyl ether, so it is better to remove it as much as possible. The allowable content is 5% or less as air.

When dimethyl ether and steam are supplied, the reaction temperature is 200 to 500 ° C., preferably 250 to 500 ° C.
400 ° C. If the reaction temperature is lower than 200 ° C., a high dimethyl ether conversion cannot be obtained, and the production ratio of carbon dioxide increases to decrease the yield of synthesis gas. If the reaction temperature is higher than 500 ° C., methane is mainly used. Hydrocarbon production becomes remarkable, and the ratio of synthesis gas in the product is undesirably reduced. When dimethyl ether and carbon dioxide are supplied, 200 to 600 ° C., preferably 300 to 200 ° C.
５００500 ° C. If the reaction temperature is lower than 200 ° C., a high conversion of dimethyl ether cannot be obtained, and if it is higher than 600 ° C., the generation of hydrocarbons mainly composed of methane becomes remarkable, and the ratio of synthesis gas in the product decreases, which is not preferable. .

The reaction pressure is preferably normal pressure to 10 kg / cm ² . If the reaction pressure is higher than 10 kg / cm ² , the conversion of dimethyl ether decreases.

The space velocity (the supply rate m ³ / h of the mixed gas in a standard state per m ^{3 of the} catalyst) is 1000 to 2
0000 m ³ / m ³ · h is preferred. Space velocity 2000
If it is greater than 0 m ³ / m ³ · h, the conversion of dimethyl ether is low, and if it is less than 1000 m ³ / m ³ · h, the reactor becomes extremely large and is not economical.

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

Thus, the conversion of dimethyl ether is 70 to
The synthesis gas can be obtained at about 100%, usually about 80 to 100%, and the yield of synthesis gas is about 70 to 100%, usually about 80 to 95%. The H ₂ / CO of the obtained synthesis gas is about 0.5 to 4 in molar ratio, usually about 0.6 to 3. As for by-products, methanol is 2 or less, usually 1 or less, and hydrocarbon is 20 or less, usually 10 or less.

[0021]

【Example】

I. Preparation of Catalyst 49.4 g of cobalt acetate (Co (NO ₃ ) ₂ .6H ₂ O) was dissolved in about 300 ml of ion-exchanged water, and 90 g of γ-alumina (manufactured by Nikki Chemical, N612) was added to the aqueous solution, and the solution was evaporated. To dryness. And put this in the air, 120
C. for 24 hours, and calcined in air at 500.degree. C. for 3 hours. Then, a treatment was performed at 500 ° C. for 3 hours in a hydrogen stream to obtain a catalyst.

The composition of the obtained catalyst is Co: Al ₂ O ₃ =
The ratio was 10:90 (weight ratio).

II. Reaction Method A predetermined amount of the above catalyst was charged into a stainless steel reaction tube having an inner diameter of 20 mm. A predetermined amount of dimethyl ether, steam and / or carbon dioxide was supplied to the reaction tube and reacted at a predetermined temperature.

The reaction products and unreacted products obtained by the above operations were analyzed by gas chromatography.

III. Reaction conditions and experimental results Reaction conditions and experimental results are shown in Tables 1 and 2.

[0026]

(Equation 1)

[0027]

(Equation 2)

[0028]

(Equation 3)

[0029]

(Equation 4) All units of each speed are [mol / g-cat · h]

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

According to the method for producing synthesis gas using the catalyst of the present invention, a mixed gas of dimethyl ether and steam and / or carbon dioxide is brought into contact with a catalyst containing cobalt at a low temperature of 200 to 600 ° C. This has an effect that a high synthesis gas yield can be obtained.

Continuing on the front page (72) Inventor Takeshi Furukawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Takuya Kadowaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Stock In company

Claims (2)

[Claims] Claims: 1. A composition containing cobalt.
Catalyst for generating synthesis gas from dimethyl ether and water vapor or carbon dioxide 2. A method for producing a synthesis gas, comprising contacting a catalyst containing cobalt with a mixed gas containing dimethyl ether and at least water vapor or carbon dioxide.