JP2007001792A - Method and apparatus for producing hydrogen and carbon monoxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing hydrogen and carbon monoxide under a mild reaction condition at high yield and an apparatus for producing the same. <P>SOLUTION: The method of producing hydrogen and carbon monoxide from dimethyl ether (DME) used as a raw material uses a reactor having a steam reforming catalyst packed in the upstream side, a carbon dioxide gas reforming catalyst packed in the downstream side and a hydrogen separation membrane attached adjacent to the hydrogen reforming catalyst and the carbon monoxide reforming catalyst to separate produced hydrogen and comprises a step for injecting DME and steam into the reactor, a step for producing hydrogen and carbon dioxide gas from the injected DME and steam with the steam reforming catalyst, a step for separating only hydrogen from produced hydrogen and carbon dioxide gas by the hydrogen separation membrane, a step for producing hydrogen and carbon monoxide from carbon dioxide gas produced simultaneously with hydrogen and DME remaining in the reactor with the carbon dioxide gas reforming catalyst, and a step for separating only hydrogen from produced hydrogen and carbon monoxide by the hydrogen separation membrane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing hydrogen and carbon monoxide, and more particularly to a method and a production apparatus for producing hydrogen and carbon monoxide from dimethyl ether using a catalyst.

  Hydrogen gas is widely used for chemical industries such as ammonia synthesis, hydrogenation of various organic compounds, petroleum refining, desulfurization, etc., or atmosphere gases of semiconductors and metallurgical metals. Recently, it has been attracting attention as a raw material for fuel cells that serve as a power source for automobiles and the like, and the demand for hydrogen gas is expected to increase significantly.

  Conventionally, as a method for producing hydrogen gas, for example, a method for producing hydrogen gas by a steam reforming method of hydrocarbons such as naphtha, natural gas, and petroleum gas is known. However, this method has drawbacks such as a very high reaction temperature of 800 to 1000 ° C.

  Recently, a method of generating hydrogen gas from dimethyl ether and steam by a steam reforming method has attracted attention. For example, patent document 1 is mentioned. In Patent Document 1, hydrogen is generated by a catalyst composed of a substance containing copper and a substance having solid acidity.

On the other hand, carbon monoxide can be used as a chemical raw material useful for the production of acetic acid. An example of a method for generating carbon monoxide is Patent Document 2. This is to generate carbon monoxide and hydrogen by a catalyst containing copper.
JP 2003-10684 A JP-A-10-174869

  However, the technique described in Patent Document 1 generates carbon dioxide simultaneously with hydrogen generation. Since this carbon dioxide gas is a stable gas, there is no particular use method, and it is released into the atmosphere, which is problematic as a global warming effect gas.

  Further, the technique described in Patent Document 2 requires carbon dioxide gas as a reaction raw material. The concentration of carbon dioxide in the gas containing carbon dioxide, such as combustion exhaust gas, is low, and in order to recover the carbon dioxide from these gases, the carbon dioxide must be absorbed by a solvent and the carbon dioxide must be desorbed. However, it requires a large-scale facility and requires a lot of heat energy and electric energy.

  In view of the above circumstances, an object of the present invention is to provide a method and an apparatus for producing hydrogen and carbon monoxide under mild reaction conditions (temperature and pressure) and with a high reaction yield.

As a result of intensive studies to solve the above problems, the present inventors have found the following points.
1) When hydrogen is produced, a reaction between dimethyl ether and water vapor is used, a hydrogen separation membrane is provided so that the produced hydrogen can be separated, and the reforming reaction proceeds while hydrogen is separated.
2) In the above 1), the carbon dioxide gas generated simultaneously with hydrogen produces a mixture of carbon monoxide and hydrogen by reaction with the remaining dimethyl ether.
3) In order to advance the reactions 1) and 2) above, a reactor equipped with a steam reforming catalyst upstream, a carbon dioxide reforming catalyst downstream, and a hydrogen separation membrane attached thereto was used. DME and water vapor are injected from above.
4) Hydrogen can be used as clean energy by removing hydrogen separately from the upper part of the reactor and carbon monoxide from the lower part of the reactor through the hydrogen separation membrane, and carbon monoxide can be used for acetic acid production, etc. It can be used as a useful chemical raw material.

The present invention has been made based on the above findings, and the gist thereof is as follows.
[1] A method for producing hydrogen and carbon monoxide using DME as a raw material, which is filled with a steam reforming catalyst upstream and a carbon dioxide reforming catalyst downstream, and further a hydrogen separation membrane is produced. Using a reactor attached adjacent to the steam reforming catalyst and the carbon dioxide reforming catalyst so that hydrogen can be separated, and injecting DME and steam into the reactor, and from the injected DME and steam A step of producing hydrogen and carbon dioxide gas under the steam reforming catalyst, a step of separating only hydrogen from the produced hydrogen and carbon dioxide gas by the hydrogen separation membrane, and the carbon dioxide gas produced simultaneously with hydrogen and the reactor A step of generating hydrogen and carbon monoxide from the DME remaining in the catalyst under the carbon dioxide reforming catalyst, and only hydrogen from the generated hydrogen and carbon monoxide is separated by the hydrogen separation membrane. Method for producing hydrogen and carbon monoxide consisting extent.

  [2] In the above [1], the steam reforming catalyst is a mixture of a copper / alumina catalyst and a solid acid catalyst, and the carbon dioxide reforming catalyst is a catalyst containing copper-zinc-alumina. A method for producing carbon oxide.

  [3] A tubular reactor for producing hydrogen and carbon monoxide using DME as a raw material, and having an inlet for injecting DME as a raw material and water vapor into the tube of the reactor, A steam reforming catalyst for generating hydrogen and carbon dioxide gas from the upstream side, and a carbon dioxide reforming catalyst for generating hydrogen and carbon monoxide are respectively packed in a ring, and further, A hydrogen separation membrane for separating hydrogen produced under the gas reforming catalyst from carbon dioxide or carbon monoxide is provided inside the packed bed of the steam reforming catalyst and the carbon dioxide reforming catalyst, and with the packed bed An apparatus for producing hydrogen and carbon monoxide characterized by being concentrically attached.

  According to the present invention, hydrogen can be obtained in a high yield even at a low temperature of less than 300 ° C. In addition, hydrogen is produced using dimethyl ether, which is clean, non-toxic and easy to handle, as a raw material, so that it is useful as an energy source for household and automotive fuel cells. Furthermore, carbon dioxide gas that has conventionally been generated simultaneously with the production of hydrogen is also effectively used for the production of carbon monoxide, and thus does not adversely affect global warming.

In the present invention, when hydrogen and carbon monoxide are produced using DME, a steam reforming catalyst is packed upstream and a carbon dioxide reforming catalyst is packed in a ring shape on the upstream side, and a hydrogen separation membrane is formed on the steam reforming catalyst and The first feature is to apply a tubular reactor attached inside the packed bed of the carbon dioxide reforming catalyst and concentrically with the packed bed. The second feature is that hydrogen and carbon dioxide gas are produced from DME and water vapor under a steam reforming catalyst using the reactor, and the produced hydrogen is separated from the reaction system by the hydrogen separation membrane. To do. Further, a third step is to generate hydrogen and carbon monoxide from the carbon dioxide gas generated simultaneously with hydrogen by the reaction and the DME remaining in the reactor under a carbon dioxide gas reforming catalyst to effectively use the carbon dioxide gas. Features.
By having these characteristics, hydrogen and carbon monoxide can be obtained with a high reaction yield under mild reaction conditions (temperature and pressure).

  This will be described in detail below.

  First, the reactor used in the present invention will be described. The reactor of the present invention is a tubular reactor for producing hydrogen and carbon monoxide using DME as a raw material, and an inlet for injecting raw material DME and water vapor is provided in the reactor tube. Have. A steam reforming catalyst for generating hydrogen and carbon dioxide gas from the upstream side, a carbon dioxide reforming catalyst for generating hydrogen and carbon monoxide are each packed in a ring, and the steam A hydrogen separation membrane for separating hydrogen produced under the reforming catalyst or carbon dioxide reforming catalyst from carbon dioxide or carbon monoxide is provided inside the packed bed of the steam reforming catalyst and the carbon dioxide reforming catalyst. And it is attached concentrically with the packed bed.

  The inlet for injecting the raw material DME and water vapor is not particularly limited. It is only necessary to supply a sufficient amount for producing the hydrogen and carbon monoxide of the present invention.

The packed bed made of the steam reforming catalyst is provided to generate hydrogen and carbon dioxide gas from DME and steam, and is installed so that the catalyst is packed in an annular layer inside the reactor. . At this time, the ratio of the steam reforming catalyst layer to the reactor, the packing density of the catalyst and the like are not particularly limited. It is set as appropriate depending on manufacturing conditions.
A packed bed comprising a carbon dioxide reforming catalyst is provided to generate hydrogen and carbon monoxide from the carbon dioxide gas generated simultaneously with hydrogen and DME remaining in the reactor, It is installed in a downstream portion of the steam reforming catalyst packed bed so that the catalyst is packed in a ring shape. At this time, the ratio of the carbon dioxide reforming catalyst layer to the reactor, the packing density of the catalyst, and the like are not particularly limited. It is set as appropriate depending on manufacturing conditions. A catalyst for producing hydrogen and a catalyst for producing synthesis gas filled in the catalyst layer will be described later.

  The hydrogen separation membrane is a hydrogen selective separation membrane, and the produced hydrogen can be separated from carbon dioxide and carbon monoxide. For example, a ceramic film, a metal film, an alloy film, a composite film thereof, or the like can be used.

  In the present invention using the above reactor, first, a steam reforming reaction of dimethyl ether is performed based on the following formula (1) to generate hydrogen and carbon dioxide (carbon dioxide gas).

_{(CH 3) 2 O + 3H} 2 O → 2CO 2 + 6H 2 --- (1)
At this time, a steam reforming catalyst filled in the reactor is used to advance the reaction. The catalyst is not particularly limited as long as it is a catalyst for producing hydrogen by steam reforming dimethyl ether, and an existing catalyst can be used. For example, a catalyst containing copper, zinc, aluminum oxide, a catalyst containing copper, zinc, aluminum oxide and a zeolite or silica-alumina mixed catalyst, a copper catalyst and γ-alumina, zeolite, silica-alumina, Examples include a mixed catalyst of an acidic substance such as activated clay, a mixed catalyst of a basic substance such as a copper catalyst and magnesium oxide, and calcium oxide.

  In injecting DME and water vapor into the reactor, the ratio of DME and water vapor to be injected is 0.5 to 1.5. If the ratio of DME and water vapor is less than 0.5, a high hydrogen yield cannot be obtained, and if it is more than 1.5, it is not economical.

  Furthermore, in proceeding with the above reaction, the reaction temperature may be 200 ° C. to 350 ° C. and the reaction pressure may be 1 MPa or less, and is not particularly defined. For example, it can be performed at 280 ° C. and normal pressure. Among these, the reaction temperature is preferably 250 ° C to 320 ° C. When the reaction temperature is lower than 250 ° C, a high hydrogen yield cannot be obtained. On the other hand, when the reaction temperature is higher than 320 ° C, the deterioration of the catalyst becomes remarkable, and the ratio of hydrogen gas and carbon monoxide in the product decreases. End up. The reaction pressure is preferably normal pressure to 1 MPa. If the reaction pressure is higher than 1 MPa, the hydrogen yield decreases. The residence time (defined by a value obtained by dividing the catalyst weight (g) by the gas flow rate (mol / hr)) varies depending on the catalyst used, but is preferably 1 or more, and particularly preferably 5 or more. The concentration of DME and water contained in the raw material gas is preferably 50% or more, and may contain hydrogen and carbon monoxide as an inert gas and product, and carbon dioxide as an intermediate. However, it is not preferable that hydrogen sulfide and molecular oxygen are contained. Hydrogen sulfide poisons the catalyst and reduces its activity. Further, molecular oxygen burns DME to reduce the yield, and it may cause explosion due to DME or hydrogen. Hydrogen sulfide needs to be reduced to 10 ppm or less, and oxygen needs to be reduced to 1% or less.

  Hydrogen produced by the reforming reaction is separated from carbon dioxide gas and remaining DME by a hydrogen separation membrane.

  On the other hand, the carbon dioxide gas produced simultaneously with hydrogen and remaining in the reactor reacts with the remaining DME under the carbon dioxide gas reforming catalyst filled in the reactor to produce a mixture of carbon monoxide and hydrogen. . And the hydrogen produced | generated here is isolate | separated by the said hydrogen separation membrane similarly to the hydrogen produced | generated by the above (1) Formula.

  As described above, hydrogen is efficiently obtained from the upper part of the reactor through the hydrogen separation membrane, and carbon monoxide is efficiently obtained from the lower part of the reactor on the catalyst layer side.

  (Steam reforming catalyst): γ-alumina (Neobead) manufactured by Mizusawa Chemical was pulverized and classified into 0.5 to 1.0 mmφ. This was impregnated with an aqueous copper nitrate solution, evaporated to dryness, dried and calcined to obtain a 5% copper / alumina catalyst. This copper / alumina catalyst and the raw material γ-alumina were mixed at a ratio of 2: 1 to obtain a steam reforming catalyst.

  (Carbon dioxide gas reforming catalyst): MDC-3 catalyst (copper-zinc-alumina catalyst) manufactured by Zoot Chemie was pulverized with a ball mill. The copper / alumina catalyst prepared by the same method as the copper / alumina catalyst prepared at the time of manufacturing the steam reforming catalyst was pulverized by a ball mill. The pulverized products of both catalysts were mixed at a ratio of 2: 1, and after molding, classified to 0.5 to 1.0 mmφ to obtain a carbon dioxide gas reforming catalyst.

  FIG. 1 shows an embodiment of a reaction apparatus for producing hydrogen and carbon monoxide according to the present invention, and is a cross-sectional view of the reaction apparatus. In FIG. 1, reference numeral 1 denotes a stainless tubular reactor. In the reactor 1 is a steam reforming catalyst layer 2 on the upstream side, the steam reforming catalyst is filled with a thickness of about 20 cm, and further on the downstream side is a carbon dioxide reforming catalyst layer 3, A carbon dioxide gas reforming catalyst is packed with a thickness of about 5 cm. Further, as the hydrogen separation membrane 4, a palladium membrane is concentric with the inside of the reactor 1, inside the steam reforming catalyst layer 2 and the carbon dioxide reforming catalyst layer 3, and with the steam reforming catalyst layer 2 and the carbon dioxide reforming catalyst layer 3. It is attached to the shape. In addition, an upper part in the reactor 1 has an inlet 5 for injecting DME and water vapor. Further, an outlet pipe 6 is attached to the lower part of the reactor 1 so that the generated carbon monoxide flows out. A hydrogen recovery port 7 for recovering the produced hydrogen is attached to the top of the reactor 1. Further, the reactor 1 is provided with a hot air inlet 8 and a hot air outlet 9 for absorbing reaction heat.

  DME and water vapor were injected from the inlet 1, and the operation was continued for 5 hours under the conditions of 300 ° C. and normal pressure, and the yields of hydrogen and carbon monoxide were calculated based on the following formula. In calculating the yield, the reaction product produced from the hydrogen separation membrane and the catalyst layer was analyzed by GC (gas chromatography), and the production amounts of hydrogen and carbon monoxide were determined from the analysis values.

Hydrogen yield = (Outlet hydrogen flow rate) / 4 / (Inlet DME flow rate) × 100
Carbon monoxide yield = (Outlet carbon monoxide flow rate) / 2 / (Inlet DME flow rate) × 100
The obtained results are shown in Table 1.

  From Table 1, it can be seen that in the present invention, hydrogen and carbon monoxide are efficiently produced while the reaction conditions are mild.

  Hydrogen produced according to the present invention can be used as clean energy, and carbon monoxide can be used as a chemical raw material useful for acetic acid production and the like.

It is sectional drawing which shows one Embodiment of the reaction apparatus for manufacturing hydrogen and carbon monoxide of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor 2 Steam reforming catalyst layer 3 Carbon dioxide gas reforming catalyst layer 4 Hydrogen separation membrane 5 Inlet 6 Outlet pipe 7 Hydrogen recovery port 8 Hot air inlet 9 Hot air outlet

Claims (3)

A method for producing hydrogen and carbon monoxide using DME as a raw material,
The upstream side is filled with a steam reforming catalyst, the downstream side is filled with a carbon dioxide reforming catalyst, and the hydrogen separation membrane is adjacent to the steam reforming catalyst and the carbon dioxide reforming catalyst so that the hydrogen produced can be separated. Using the attached reactor,
The step of injecting DME and steam into the reactor, the step of generating hydrogen and carbon dioxide gas from the injected DME and steam under the steam reforming catalyst, and the hydrogen separation of only hydrogen from the generated hydrogen and carbon dioxide gas The step of separating by a membrane, the step of generating hydrogen and carbon monoxide from the carbon dioxide gas generated simultaneously with hydrogen and the DME remaining in the reactor under the carbon dioxide reforming catalyst, and the generated hydrogen and carbon monoxide A method for producing hydrogen and carbon monoxide, comprising a step of separating only hydrogen from the hydrogen separation membrane.   The hydrogen and carbon monoxide catalyst according to claim 1, wherein the steam reforming catalyst is a mixture of a copper / alumina catalyst and a solid acid catalyst, and the carbon dioxide reforming catalyst is a catalyst containing copper-zinc-alumina. Production method. A tubular reactor for producing hydrogen and carbon monoxide using DME as a raw material;
The reactor has an inlet for injecting DME and water vapor as raw materials,
A steam reforming catalyst for generating hydrogen and carbon dioxide gas from the upstream side, and a carbon dioxide gas reforming catalyst for generating hydrogen and carbon monoxide are each filled in a ring,
Further, a hydrogen separation membrane for separating hydrogen produced under the steam reforming catalyst or the carbon dioxide reforming catalyst from the carbon dioxide gas or carbon monoxide includes the steam reforming catalyst and the carbon dioxide reforming catalyst. An apparatus for producing hydrogen and carbon monoxide, which is attached inside the packed bed and concentrically with the packed bed.

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