JPH10310403A - Hydrogen separation member, reaction tube and method for producing hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen separation member having excellent mechanical strength, excellent handling properties, and high hydrogen separation efficiency, a reaction tube having the hydrogen separation member therein, and hydrogen using the reaction tube. And a method for producing the same. SOLUTION: In a hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, the whole is made of a porous body, a plurality of communication holes are formed in the inside thereof, and hydrogen separation is performed on an inner surface of the communication hole. A hydrogen separation member, wherein a membrane is laminated. What is claimed is: 1. A reaction tube having a catalyst layer therein for use in a reaction involving hydrogen generation, wherein the hydrogen separation member is disposed inside the catalyst layer. In a method for producing hydrogen by flowing a raw material gas composed of a carbon-containing organic compound and steam in a reaction tube to produce hydrogen, the raw material gas is supplied to the reaction tube by using the above-mentioned reaction tube as the reaction tube. Reaction at a temperature, and contacting the reaction product gas with the hydrogen separation member to selectively permeate the hydrogen in the reaction product gas into communication holes formed in the hydrogen separation member. Production method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, a reaction tube having a catalyst layer and a hydrogen separating member therein, and a method for producing hydrogen.

[0002]

2. Description of the Related Art In order to produce hydrogen, a raw material gas comprising a carbon-containing organic compound such as methane, naphtha, methanol, etc. and steam is passed through a reaction tube having a catalyst layer to 800 to 9 times.
It is known to carry out a flow reaction at 00 ° C. In addition, in such a reaction to generate hydrogen, the reaction product gas is brought into contact with a hydrogen separation membrane, and the hydrogen in the reaction product gas is selectively passed through the membrane, so that hydrogen gas is separated and recovered from the reaction product gas at the same time as the reaction. A known method is also known (for example, JP-A-6-40701). In the method using the hydrogen separation membrane, since the generated hydrogen gas is removed from the reaction system, the reaction does not equilibrate, is always promoted to the product side, and the high raw material gas conversion is performed even at a low reaction temperature of 700 ° C. or less. Rate can be obtained. By the way, in the case of the method using a hydrogen separation membrane as described above, it is important to quickly and efficiently separate hydrogen from the reaction product gas, and the structure of the hydrogen separation member is problematic. A structure having a structure in which a hydrogen release film is laminated and supported on the outer surface of a tube has been proposed. However, since such a hydrogen separation member is mainly made of a porous tube, it has a problem that it is extremely difficult to insert and dispose the hydrogen separation member in a reaction tube because the mechanical strength is weak and the member is easily damaged. Met. On the other hand, if the porous tube is made of a thick-walled material having a large diameter and hardly causing breakage, in this case, the contact area between the mixed gas and the hydrogen separation member is reduced, and a problem that the hydrogen separation efficiency is deteriorated occurs.

[0003]

An object of the present invention is to provide a hydrogen separation member having excellent mechanical strength, excellent handling properties, and high hydrogen separation efficiency, a reaction tube having the hydrogen separation member therein, and a reaction tube having the hydrogen separation member. It is an object of the present invention to provide a method for producing hydrogen using hydrogen.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention. That is, according to the present invention, in a hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, the whole is made of a porous body, a plurality of communicating holes are formed therein, and an inner surface of the communicating hole is formed. Is provided with a hydrogen separation membrane. Also,
According to the present invention, in a hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, the whole is formed of a porous body that selectively allows hydrogen to pass therethrough, and a plurality of communication holes are formed therein. A hydrogen separation member is provided. Further, according to the present invention, there is provided a reaction tube having a catalyst layer therein for use in a reaction involving hydrogen generation,
A reaction tube is provided, wherein the hydrogen separation member is disposed inside the catalyst layer. Still further, according to the present invention, there is provided a reaction tube having a catalyst layer inside which is used for reacting a raw material gas comprising a carbon-containing organic compound and steam to generate hydrogen. The present invention provides a reaction tube provided with the hydrogen separation member. Furthermore, according to the present invention,
In a method of producing hydrogen by causing a raw material gas comprising a carbon-containing organic compound and steam to flow through a reaction tube,
(I) using the reaction tube as the reaction tube, supplying a raw material gas to the reaction tube to cause a reaction at a temperature of 700 ° C. or less, and bringing the reaction product gas into contact with the hydrogen separation member to cause the reaction product gas to contain A reaction step of selectively permeating hydrogen into communication holes formed in the hydrogen separation member; (ii) recovering hydrogen gas permeating into the communication holes as product hydrogen without performing a shift reaction and a decarboxylation reaction And a method for producing hydrogen gas.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a front view of one embodiment of a hydrogen separation member of the present invention, and FIG.
FIG. 3 shows a cross-sectional view of FIG. 3A, and FIG.
1 to 3, reference numeral 1 denotes a unit hydrogen separating member;
Indicates a connecting member, 3 indicates a porous body, 4 indicates a communication hole formed in the porous body, and 5 indicates a hydrogen separation membrane laminated on the inner surface of the communication hole. P indicates an end gap formed at the ends of the two unit hydrogen separation members. The porous body 3 may be any porous body that is resistant to the temperature of the mixed gas containing hydrogen, such as 300 ° C. or higher, preferably 500 ° C. or higher, and more preferably 300 to 1000 ° C. A porous body made of a material having heat resistance to a temperature of ° C. is advantageously used. The heat-resistant porous body includes conventionally known ceramic porous bodies and metal porous bodies. In this case, as ceramics in the ceramic porous body, alumina, silica,
Silica-alumina, zirconia, titania, silicon carbide,
Silicon nitride and the like. Examples of the metal in the metal porous body include iron, nickel, cobalt, tungsten, chromium, and alloys of these metals (Haines alloy, Inconel). The average pore diameter of the porous body is 0.001 to 10 μm, preferably 0.001 to 10 μm.
1 to 1 μm. The porosity is 20 to 80.
%, Preferably 30 to 60%.

The hydrogen separation membrane 5 laminated on the inner surface of the communication hole 4
As long as it has excellent hydrogen permselectivity, a conventionally known hydrogen separation membrane can be used. Such a hydrogen separation membrane includes a ceramic membrane and a metal membrane. Examples of the ceramic film include films formed using ceramics such as silica, zeolite, alumina, titania, zirconia, and carbon. When the heat-resistant porous body 3 is formed of such a ceramic having hydrogen selective permeability, the formation of the hydrogen separation membrane on the inner surface of the communication hole can be omitted. Examples of the metal film include a palladium film, an iron / palladium alloy film, an Ag / Pd alloy film, a V / Pd alloy film, and a nickel film. When a ceramics membrane is used as the hydrogen separation membrane, the formation of the hydrogen separation membrane on the inner surface of the communication hole is performed by applying a slurry liquid composed of the hydrogen separation membrane component to the inner surface of the communication hole, drying, and further firing. be able to. On the other hand, when a metal membrane is used as the hydrogen separation membrane, it can be implemented by a chemical plating method or the like.

The hydrogen separating member shown in FIGS. 1 to 3 is obtained by connecting a plurality of unit hydrogen separating members 1 with a connecting member 2.
It is formed into two rods. In this rod-shaped hydrogen separation member, the length L1 of the unit hydrogen separation member ₁ is usually 30 to 200 cm, preferably 80 to 120 cm. The diameter D ₁ of the unit hydrogen separation member ₁ is usually 1 to
It is 14 cm, preferably 2-4 cm. Distance L ₂ between the adjacent ends of the two units hydrogen separation member, usually 1-3
0 cm, preferably 2 to 10 cm. The length L ₃ of the connecting member 2 is usually 2 to 40 cm, preferably ₃ to 1 cm.
5 cm. In the communication hole 4, the inner diameter of the communication hole after laminating the hydrogen separation membrane is usually 0.1 to 2c.
m, preferably 0.2-0.6 cm. The ratio L ₁ of the length L ₁ and the diameter D ₁ of the unit hydrogen separating member 1.
/ D ₁ is usually 10 to 100, preferably 30 to 40.
It is. The ratio S ₂ / S of the total area S ₂ of the cross-sectional area of the communication hole 4 to the cross-sectional area S ₁ of the unit hydrogen separating member 1.
₁ is usually 0.1 to 0.5, preferably 0.3 to 0.5.
4.

The connecting member 2 is used to connect a plurality of unit hydrogen separating members to form a single hydrogen separating member, and is formed of a material that does not easily transmit hydrogen. Further, the connection member having a resistance to the temperature of the mixed gas is used. Further, it is preferable that the connecting member is formed of a flexible material so that the connecting member is not easily deformed and damaged when subjected to an external force. In the present invention, Fe, Ni, C
It is preferable to use a metal such as r or Co. In the case of such a connecting member formed of a metal, its thickness is preferably 0.1 to 20 mm, and more preferably 1 to 10 mm. The connecting member 2 used in the present invention is disposed at the ends of the two unit hydrogen separating members so as to hermetically surround the end gap P. The connecting member 2 can be a cylindrical body having an inner diameter corresponding to the outer diameter of the unit hydrogen separating member. In this case, the inner surface of the cylindrical body and the outer surface of the unit hydrogen separating member are in close contact with each other, so that the hydrogen gas present in the end gap P is not substantially escaping from the connection portion to the outside. Further, the inner surface of the cylindrical body and the outer surface of the unit hydrogen separating member may be in close contact with each other via an adhesive layer. In this case, the adhesive may be any as long as it has resistance to the temperature of the mixed gas, and an inorganic adhesive is preferably used.

The hydrogen separating member of the present invention is not limited to the structure shown in FIGS. For example, the hydrogen separation member of the present invention may not be connected by the communication member but may be entirely composed of one rod-shaped porous body. It can be a polygon such as a square.

The hydrogen separating member of the present invention can selectively separate and recover the hydrogen gas in the mixed gas by bringing the member into contact with the mixed gas containing hydrogen. That is,
When the hydrogen separating member of the present invention is brought into contact with the mixed gas, the hydrogen gas in the mixed gas permeates through the porous body 3, further permeates through the hydrogen separation membrane 5 and enters the communication hole 4. 4 and flows out from one or both ends of the communication hole. In the present invention, the hydrogen gas flowing out from the end of the communication hole can be recovered as product hydrogen gas.

[0011] The hydrogen separation member of the present invention is advantageously applied as a means for separating hydrogen contained in a reaction product gas in a chemical reaction involving the generation of hydrogen from the gas. By separating the hydrogen contained in the reaction product gas from the reaction product gas, the chemical reaction can be greatly promoted toward the product side, and the reaction can proceed even at a reduced temperature. In order to apply the hydrogen separating member of the present invention as a means for separating hydrogen in a reaction product gas, the hydrogen separating member may be inserted and disposed in a reaction tube having a catalyst layer.

FIG. 4 is an explanatory sectional view of a hydrogen separation type reaction tube in which the hydrogen separation member of the present invention is inserted and arranged. 4, reference numeral 11 denotes a reaction tube, 12 denotes a heat-resistant particle layer, 13 denotes a first catalyst layer, 14 denotes a second catalyst layer, and 15 denotes a heat-resistant particle layer. F indicates a hydrogen separation member. The heat-resistant particle layers 12 and 15 are made of particles of a heat-resistant metal oxide such as alumina, silica and titania. The size of the particles is between 1 and 200 mm, preferably between 5 and 70 mm. A plurality of catalyst layers can be formed in the reaction tube 11, and in FIG.
3 and the second catalyst layer 14 are formed, but are usually a single catalyst layer. The catalyst in this case is appropriately selected according to the reaction system. The average particle size of the catalyst is usually 2 to 2
00 mm, preferably 5 to 70 mm. The reaction tube shown in FIG. 4 performs various reactions involving generation of hydrogen, for example, steam and a carbon-containing organic compound (for example, methane, ethane,
A reaction for producing hydrogen by reacting with propane, butane, naphtha, off-gas, natural gas, methanol, etc. (steam reforming), and a reaction for producing hydrogen by reacting a carbon-containing organic compound with CO ₂ (CO ₂ Reforming), a hydrogen generation reaction by partial oxidation of hydrocarbons, various dehydrogenation reactions, and the like. In the case of steam reforming, the reaction temperature is 700 ° C. or less, preferably 400 ° C.
６００600 ° C. and the reaction pressure is 5-100 kg / c
m ² G, preferably 10 to 30 kg / cm ² G. The pressure in the communication hole formed in the hydrogen separation member inserted and disposed in the reaction tube is 5 to 100 kg / c lower than the reaction pressure.
m ² , preferably 10 to 30 kg / cm ² . According to the general characteristics of a reaction tube used for steam reforming, its inner diameter is usually 5 to 20 cm, preferably 10 to 18 cm, and its length is usually 6 to
It is 12 m, preferably 8 to 10 m. Hereinafter, a reaction example of steam reforming using the reaction tube shown in FIG. 4 will be described. In this case, the reforming catalyst layer is configured to be able to accommodate both (i) a mixed gas of naphtha and steam and (ii) a mixed gas of methane and steam. That is, as the first catalyst layer 13, a catalyst layer mainly composed of Ni / Al ₂ O ₃ suitable for a reaction between naphtha and steam is used, and as the second catalyst layer 14, a reaction layer mainly composed of methane and steam is used. A suitable Ni / MgO catalyst layer was used. The heat-resistant particle layers 12 and 15 have a diameter of 15 mm.
mm alumina ball layer was used. As the reaction tube 11, a stainless steel cylindrical tube having an inner diameter of 100 mm and a height of 30 cm was used. As the hydrogen separation member F, one having the structure shown in FIGS. That is, as the heat-resistant porous body F, the unit hydrogen separation member 1 composed of the lotus root alumina porous body 3 having an effective length of 5 cm and 19 communication holes 4 having a diameter of 4 mm and having a palladium membrane 5 laminated on the inner surface thereof and having an effective length of 5 cm is used. The two were connected using the connecting member 2. In this case, a stainless flexible tube having a length of 30 mm and an inner diameter of 30 mm was used as the connecting member. The communicating hole at the end of the hydrogen separating agent F located inside the reaction tube is sealed so that hydrogen gas does not escape.

A mixed gas consisting of 15 vol% of methane and 85 vol% of steam was supplied from the line 16 to the reaction tube 11 at a rate of 0.24 liter per minute to react with methane and steam. In this case, the reaction temperature was maintained at about 630 ° C. by heating the reaction tube 11 from outside, and the reaction pressure was maintained at 25 kg / cm ² G. The reaction product gas is withdrawn through line 17 and the hydrogen gas is
Withdrawn through 8. As a result of performing the reaction as described above, H ₂ : 95 vol%, CO:
_{0.1vol%, CO 2: 0.6vol%} , H 2 O: 4v
% hydrogen and 0.3% by volume of CH ₄ could be recovered. On the other hand, when the component composition of the reaction product gas obtained through the line 17 is shown, H ₂ : 6.6 vo
l%, CO: 0.9vol%, CO 2: 14.6vol
_{%, H 2 O: 77.5vol%} , CH 4: 0.4vol%
Met. In addition, pentane 0.5
When a gas composed of 96.5 vol% of steam and 96.5 vol% of steam is used, H ₂ : 96 vol% and CO: 0.1 vol
_{l%, CO 2: 0.7vol%} , H 2 O: 3vol%, C
Hydrogen gas consisting of H ₄ : 0.2 vol% can be recovered, and H ₂ : 5.5 vol
l%, CO: 1.0vol%, CO 2: 18vol%,
H ₂ O: 75vol%, methane: it was possible to recover the reaction product gas consisting of 0.5 vol%.

[0014]

The hydrogen separating member of the present invention has a structure in which a plurality of communication holes are formed in one porous body.
It has good mechanical strength and is easy to handle, for example, can be easily inserted and disposed in a reaction tube without being damaged. Further, in the unit in which the unit hydrogen separation materials according to the present invention are connected by using a connecting member, the unit using a flexible tube made of a metal such as Ni, Cr, Fe, or Co as the connecting member is entirely flexible. It has the advantage that it is hard to be damaged because it is deformed even when it receives external force. In a reaction involving the generation of hydrogen, hydrogen can be separated and recovered from the reaction product gas using the hydrogen separation member of the present invention to greatly accelerate the reaction, and the recovered hydrogen gas can be used as it is or as needed. By performing a simple purification process according to the above, it can be used as product hydrogen gas.

[Brief description of the drawings]

FIG. 1 is an explanatory front view of a hydrogen separation member.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 shows a configuration diagram of a communication hole.

FIG. 4 is an explanatory sectional view of a reaction tube in which a hydrogen separation member is inserted and arranged.

[Description of Signs] 1 Unit hydrogen separation member 2 Connecting member 3 Heat resistant porous body 4 Communication hole 5 Hydrogen separation membrane 11 Reaction tube 12, 15 Heat resistant particle layer 13 First catalyst layer 14 Second catalyst layer F Hydrogen separation member

Claims (5)

[Claims] 1. A hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, the whole being made of a porous material, having a plurality of communicating holes formed therein, and having an inner surface of the communicating holes formed with hydrogen. A hydrogen separation member having a separation membrane laminated thereon. 2. A hydrogen separating member for separating hydrogen from a mixed gas containing hydrogen, the entirety of which is formed of a porous body that selectively allows hydrogen to pass therethrough, and a plurality of communication holes are formed therein. A hydrogen separation member characterized by the above-mentioned. 3. A reaction tube having a catalyst layer therein for use in a reaction involving hydrogen generation, characterized in that the hydrogen separation member according to claim 1 or 2 is disposed inside said catalyst layer. Reaction tube. 4. A reaction tube having a catalyst layer inside which is used for reacting a raw material gas comprising a carbon-containing organic compound and steam to generate hydrogen, wherein the inside of the catalyst layer has a catalyst layer. A reaction tube, wherein the hydrogen separation member is disposed. 5. A method for producing hydrogen by allowing a raw material gas comprising a carbon-containing organic compound and steam to flow through a reaction tube to produce hydrogen, wherein: (i) using the reaction tube of claim 4 as the reaction tube; And reacting the mixture at a temperature of 700 ° C. or lower, and bringing the reaction product gas into contact with the hydrogen separation member to select hydrogen in the reaction product gas into a communication hole formed in the hydrogen separation member. (Ii) a hydrogen recovery step of recovering hydrogen gas permeated into the communication holes as product hydrogen without causing a shift reaction and a decarboxylation reaction. Method.