JP5390448B2 - Membrane separation reactor and method for producing hydrogen - Google Patents

Description

  The present invention relates to a membrane separation reactor and a method for producing hydrogen using the same, and in particular, a steam reforming catalyst layer for steam reforming a raw material such as hydrocarbon to generate a reformed gas containing hydrogen, The present invention relates to a membrane separation reactor having palladium and a hydrogen separation membrane mainly composed of copper that selectively permeate and separate hydrogen from the reformed gas.

  In recent years, technological developments such as fuel cells using hydrogen as energy and hydrogen engines have attracted attention as environmental measures and greenhouse gas measures. Therefore, efficient and inexpensive production of hydrogen will help solve environmental problems.

  Up to now, as a method for producing hydrogen, a method using a hydrogen permeable membrane that selectively permeates only hydrogen from a mixed gas containing hydrogen is known. For example, a thin film mainly composed of palladium formed by a plating method as described in Patent Document 1 (Japanese Patent Laid-Open No. 63-295402), or described in Patent Document 2 (Japanese Patent Laid-Open No. 2003-135943). Conventionally, a thin film mainly composed of palladium formed by a CVD method has been widely used as a film material for separating hydrogen from a mixed gas at high temperature and high purity. Among these film materials, an alloy film mainly composed of palladium and copper is a film excellent in sulfur resistance and hydrogen embrittlement, and a palladium-copper alloy film having a copper content of 40% by mass. Is widely used.

JP 63-295402 A Japanese Patent Laid-Open No. 2003-135943

  However, although the palladium-copper alloy film having a copper content of 40% by mass has excellent hydrogen permeation performance in the temperature range of 350 to 450 ° C. as that of a single palladium membrane, the hydrogen permeation performance in a temperature range of 450 ° C. or higher. Is known to decrease significantly, and it is difficult to efficiently obtain hydrogen at temperatures of 450 ° C. or higher.

  In contrast, a palladium-copper alloy film having a copper content higher than 40% by mass is inferior to a palladium-copper alloy film having a copper content of 40% by mass in the temperature range of 350 to 450 ° C. In a temperature range of 450 ° C. to 600 ° C., hydrogen permeation performance is superior to a film having a copper content of 40% by mass.

  As described above, it has been understood that the temperature at which the maximum hydrogen permeation performance of the alloy film mainly composed of palladium and copper varies depending on the composition.

  On the other hand, in the steam reforming reaction, the higher the temperature, the higher the hydrogen partial pressure from the thermochemical equilibrium composition, which is an advantageous condition for hydrogen permeation and separation.

  Accordingly, an object of the present invention is to provide a membrane separation type reactor capable of efficiently performing a steam reforming reaction and hydrogen separation and purification utilizing the characteristics of such a palladium-copper alloy membrane. .

  As a result of intensive investigations to achieve the above object, the present inventors have found that in a membrane separation reactor comprising a hydrogen separation membrane containing palladium and copper and a steam reforming catalyst layer, the upstream side and the downstream side of the hydrogen separation membrane. By changing the copper content on the side and arranging the one with the higher copper content in the hydrogen separation membrane on the upstream side and downstream side of the steam reforming catalyst layer, the higher the average temperature, It has been found that the reforming reaction and the separation and purification of hydrogen can be performed efficiently, and the present invention has been completed.

That is, the membrane separation reactor of the present invention is
A hydrogen separation membrane comprising palladium and copper and having an average copper content of 38 to 48% by mass;
Comprising a steam reforming catalyst for steam reforming hydrocarbons, comprising a steam reforming catalyst layer disposed on the outer peripheral side of the hydrogen separation membrane,
The hydrogen separation membrane is characterized in that the difference in average copper content between the upstream half and the downstream half is 4 to 10% by mass with the hydrocarbon and water vapor inlets being upstream.

  In a preferred embodiment of the membrane separation reactor of the present invention, the hydrogen separation membrane has an average copper content of 44 to 48 mass% in one of the upstream half and the downstream half, and the other average copper content. Is 38 to 44 mass%.

The method for producing hydrogen of the present invention is a method for producing hydrogen using the membrane separation reactor described above,
Among the upstream half and the downstream half of the steam reforming catalyst layer, the higher the average temperature, the higher the average copper content in the upstream half and the downstream half of the hydrogen separation membrane, A mixed gas of hydrocarbon and steam is supplied to the steam reforming catalyst layer to generate a reformed gas mainly composed of hydrogen by a steam reforming reaction, and hydrogen is selectively permeated by the hydrogen separation membrane. It is characterized by taking out hydrogen.

  According to the present invention, a steam separation reformer comprising a hydrogen separation membrane containing palladium and copper and a steam reforming catalyst layer, using a membrane separation reactor having different average copper contents on the upstream side and the downstream side of the hydrogen separation membrane, Efficient steam reforming reaction and hydrogen separation and purification by placing the hydrogen separation membrane with higher average copper content in the upstream and downstream sides of the catalyst layer where the average temperature is higher It can be carried out.

It is a schematic diagram which shows an example of the membrane separation type reactor of this invention. It is a schematic diagram which shows another example of the membrane separation type reactor of this invention. It is a schematic diagram which shows another example of the membrane separation type reactor of this invention. It is a fragmentary sectional view of the suitable example of the hydrogen separation membrane used for the membrane separation type reactor of this invention. It is a graph which shows the temperature dependence of the hydrogen permeability of a Pd-Cu alloy film.

  Hereinafter, the membrane separation type reactor of the present invention will be described in detail with reference to FIG. FIG. 1 is a schematic view showing an example of a membrane separation reactor according to the present invention. A membrane separation reactor 1 shown in FIG. 1 includes a hydrogen separation membrane 2 containing palladium and copper as main components, and a steam reforming catalyst layer 3 disposed on the radially outer side of the hydrogen separation membrane 2. Yeah. The illustrated membrane separation reactor 1 is provided with an inlet 4 for hydrocarbons and water vapor, and an outlet 5 for non-permeate gas that has not permeated the hydrogen separation membrane 2. A product hydrogen outlet 6 in communication with The hydrocarbon and steam inlet portion 4 communicates with the steam reforming catalyst layer 3, and the hydrocarbon and steam are supplied to the steam reforming catalyst layer 3 through the inlet portion 4 and reformed by a steam reforming reaction. Gas can be generated. The produced reformed gas passes through the hydrogen separation membrane 2 and is taken out of the reactor through the outlet 6 as product hydrogen. In addition, the reformed gas that has not permeated the hydrogen separation membrane 2 is discharged out of the reactor from the outlet portion 5 as a non-permeate gas.

  The illustrated membrane separation reactor 1 includes a heating shell 7 on the radially outer side of the steam reforming catalyst layer 3, and the heating shell 7 has a heating gas inlet 8 and a heating gas outlet. The outlet portion 9 is connected, and the steam reforming catalyst layer 3 can be heated by introducing the heating gas into the heating shell 7 through the inlet portion 8. The heated gas whose temperature has been reduced by supplying heat is discharged out of the heating shell 7 through the outlet 9.

  The hydrogen separation membrane 2 is different from the upstream half 3A of the steam reforming catalyst layer 3 in that the upstream half 2A and the downstream half 2B have different average copper contents, with the hydrocarbon and steam inlet 4 being upstream. Among the downstream halves 3B, the one with the higher average temperature is arranged in the upstream half 2A and the downstream half 2B of the hydrogen separation membrane in the higher average temperature. Here, in the membrane separation type reactor of the present invention, the difference in average copper content between the upstream half 2A and the downstream half 2B of the hydrogen separation membrane is 4 to 10% by mass. If the difference in average copper content is less than 4% by mass, it is difficult to efficiently perform the steam reforming reaction and hydrogen membrane separation, while if it exceeds 10% by mass, the upstream half 2A and the downstream side of the hydrogen separation membrane When the average copper content of at least one of the halves 2B is out of the range of 38 to 48% by mass, the palladium-copper alloy membrane becomes a membrane with low hydrogen permeation performance and the hydrogen separation and recovery efficiency is lowered.

  In the membrane separation reactor 1 shown in FIG. 1, a mixed gas of hydrocarbon and water vapor flows from the upper part to the lower part of the membrane separation reactor 1, and further, the heated gas flows into the lower part of the membrane separation reactor 1. Flows from the top to the top. Here, the steam reforming reaction in the steam reforming catalyst layer 3 is an endothermic reaction, and the endothermic reaction occurs abruptly on the upstream side, and the temperature of the heated gas is higher at the inlet 8 than at the outlet 9. Therefore, the membrane separation reactor 1 has a high temperature at the bottom and a low temperature at the top. Accordingly, in the membrane separation type reactor 1 shown in FIG. 1, the average temperature of the downstream half 3B is higher than that of the upstream half 3A of the steam reforming catalyst layer 3, and therefore the upstream half of the hydrogen separation membrane. The average copper content of the downstream half 2B is made higher than 2A. For example, the average copper content of the upstream half 2A of the hydrogen separation membrane is preferably 38 to 44% by mass, and the average copper content of the downstream half 2B is preferably 44 to 48% by mass.

  In general, when hydrogen is separated and recovered from a reformed gas containing hydrogen obtained by steam reforming hydrocarbons, in order to increase the amount of hydrogen recovered, It is advantageous to increase the area. However, when the area of the hydrogen separation membrane is increased, as shown in the figure, the length of the hydrogen separation membrane in the gas flow direction is increased, and the temperature gradient in the heating shell 7 is increased. For this reason, a temperature gradient also occurs in the hydrogen separation membrane, and even if a palladium-copper alloy membrane having a copper content of 40% by mass, which is considered to have the best hydrogen permeation performance, is disposed, a place where the temperature is high is low. When the temperature is high, the hydrogen permeation performance deteriorates, and a sufficient amount of hydrogen recovered cannot be obtained. On the other hand, in the present invention, the average copper content is changed between the upstream side 2A and the downstream side 2B of the hydrogen separation membrane, and the average temperature becomes higher among the upstream side 3A and the downstream side 3B of the steam reforming catalyst layer. In addition, by arranging the hydrogen separation membrane having the higher average copper content, it is possible to efficiently perform the steam reforming reaction and the hydrogen membrane separation.

  FIG. 2 is a schematic view showing another example of the membrane separation type reactor of the present invention. The membrane separation reactor 1 shown in FIG. 2 has substantially the same configuration as the membrane separation reactor 1 shown in FIG. 1, but an heating gas inlet portion 8 is provided on the upper part of the heating shell 7 and is used for heating. The difference is that an outlet 9 for heated gas is provided at the bottom of the shell 7. Therefore, in the membrane separation reactor 1 shown in FIG. 2, the heated gas flows from the upper part to the lower part of the membrane separation reactor 1, and the upper temperature is lower than the lower temperature in the heating shell 7. Also gets higher. Here, for example, when a pre-reformer (not shown) is provided further upstream of the inlet part 4 and the pre-reformed high-temperature gas is introduced into the membrane separation reactor 1 from the inlet part 4, Although the steam reforming reaction in the steam reforming catalyst layer 3 is an endothermic reaction, the endothermic reaction occurs slowly. In this case, since the endotherm due to the steam reforming reaction is sufficiently supplemented by the supply of heat from the heated gas, the average temperature of the downstream half 3B is lower than the upstream half 3A of the steam reforming catalyst layer 3. Become. Therefore, in FIG. 2, the average copper content of the downstream half 2B is made lower than the upstream half 2A of the hydrogen separation membrane. For example, the average copper content of the upstream half 2A of the hydrogen separation membrane is preferably 44 to 48% by mass, and the average copper content of the downstream half 2B is preferably 38 to 44% by mass.

  In the membrane separation reactor of the present invention, the hydrogen separation membrane may continuously change the copper content from the upstream side to the downstream side, or may connect a plurality of hydrogen separation membranes having different copper content rates. Thus, the average copper content on the upstream side and the downstream side may be changed. Here, as a method of continuously changing the copper content of the hydrogen separation membrane, when forming a palladium-copper alloy film on the support by plating, the palladium is plated by slowly pulling up the support from the plating bath. Plating the thickness of the palladium plating film, and then plating the copper, the next time the copper is plated, the support is reversed and the copper plating is similarly performed while pulling up from the plating bath. For example, a method of continuously changing the composition of palladium-copper may be used. On the other hand, when connecting a plurality of hydrogen separation membrane modules having different copper contents, for example, a method of welding and connecting hydrogen separation membrane modules having different copper contents, or plating a palladium-copper alloy membrane on a support. When forming, there is a method of performing plating with a different composition for each part of the plating film. In addition, although there is no restriction | limiting in particular, The shape of the said support body may be flat form, and may be cylindrical (tubular), for example, cylindrical shape is used preferably.

  FIG. 3 is a schematic view showing another example of the membrane separation type reactor of the present invention. The membrane separation reactor 1 shown in FIG. 3 has substantially the same configuration as that of the membrane separation reactor 1 shown in FIG. 1, but the hydrogen separation membrane 2 is the most upstream with the hydrocarbon and water vapor inlets 4 upstream. The part 2a with a low copper content is located on the upstream side, the part 2c with the highest copper content is located on the downstream side, and the part 2b with the copper content in between is located between them It is different. As described above, the hydrogen separation membrane 2 having this configuration may be prepared by connecting the portions 2a, 2b, and 2c by welding or the like, or when the palladium-copper alloy membrane is formed on the support by plating. The plating may be performed by changing the composition for each part for plating the alloy film corresponding to each part 2a, 2b, 2c. Here, for example, the copper content of the upstream 1/3 portion 2a of the hydrogen separation membrane is 38 to 41% by mass, and the copper content of the downstream 1/3 portion 2c is 45 to 48% by mass. By making the copper content of the portion 2b of the middle stream 1/3 between 41 and 45% by mass, the steam reforming reaction and the separation and purification of hydrogen can be performed more efficiently.

[Raw material hydrocarbon]
As the hydrocarbon used as a raw material for producing hydrogen by the reforming reaction, a hydrocarbon having a boiling point of 300 ° C. or less and a mixture thereof can be used. For example, methane, ethane, propane, butane, pentane, natural gas, LP gas and other hydrocarbons in the gaseous state at room temperature, as well as naphtha fraction, gasoline fraction, kerosene fraction, light oil fraction, etc. The following petroleum-based hydrocarbons can be used.

  A naphtha fraction is a fraction having a boiling point within a range of 30 ° C. to 180 ° C. as a boiling point range among fractions obtained by distillation separation of crude oil, natural gas condensate, and the like. Examples of the naphtha fraction include a light naphtha fraction having a boiling range of about 30 ° C. to 80 ° C., a heavy naphtha fraction having a boiling range of about 80 ° C. to 180 ° C., and a hole having a boiling range of about 30 ° C. to 180 ° C. Includes naphtha fractions.

  The gasoline fraction is a fraction having a boiling point in the range of 30 ° C. to 200 ° C. as a boiling range, and the boiling point used for the preparation of automobile gasoline is within the above range in addition to commercial automobile gasoline and industrial gasoline. Intermediate products (also referred to as base materials), intermediate products having a boiling range in the above range, and fractions corresponding to automobile gasoline are also included.

  A kerosene fraction is a fraction having a boiling point within a range of 140 ° C. to 270 ° C. as a boiling point among fractions obtained by distillation separation of crude oil, natural gas condensate, and the like. In addition to commercially available kerosene such as for use, a fraction corresponding to kerosene having a boiling range within the above range is included.

  The light oil fraction is a fraction having a boiling point in the boiling range of 160 ° C. to 370 ° C. In addition to commercially available light oil used for diesel engines, a fraction corresponding to light oil having a boiling range in the above range is included. included.

  From the viewpoint of product distribution, cost, and availability, liquid hydrocarbons such as gaseous hydrocarbons such as methane and LPG, naphtha, gasoline, kerosene, light oil and their corresponding fractions are preferred. The corresponding fraction is preferred. Further, these hydrocarbons preferably have a low sulfur content, particularly those having a sulfur content of 50 mass ppb or less, from the viewpoint of poisoning the steam reforming catalyst.

[Steam reforming catalyst, steam reforming catalyst layer]
As the steam reforming catalyst used in the present invention, a normal steam reforming catalyst can be used. For example, at least one catalytically active component selected from Fe, Co, Ni, Ru, Rh, Pd, Ir, and Pt is used as an oxide of Mg, Al, Si, Ti, Zr, Ba, La and / or Those supported on a carrier containing at least one carrier component selected from hydrated oxides can be used. From the viewpoint of suppressing the occurrence of coking, it is preferable to use Ru or Rh as the catalyst active component.

  These steam reforming catalysts are filled outside the hydrogen separation membrane 2 to form the steam reforming catalyst layer 3. The amount of the steam reforming catalyst to be included in the steam reforming catalyst layer 3 can be appropriately determined depending on the type of hydrocarbon as a raw material, the reforming reaction temperature, the steam / carbon ratio, and the like.

[Hydrogen separation membrane]
As the hydrogen separation membrane of the membrane separation reactor of the present invention, a palladium-copper alloy membrane is used. The hydrogen separation membrane contains palladium and copper, the average copper content is 38 to 48% by mass, and the average palladium content is preferably in the range of 52 to 62% by mass. When the average copper content is less than 38% by mass, the hydrogen recovery efficiency at high temperature is lowered, while when it exceeds 48% by mass, the hydrogen recovery efficiency at low temperature is lowered. The hydrogen separation membrane may be composed of a palladium-copper alloy membrane, or may be one in which a palladium-copper alloy membrane is formed on the outer surface of the support. In addition, it is preferable that the film thickness of the hydrogen permeable film of this invention is 0.5-50 micrometers.

  As the hydrogen separation membrane, as shown in FIG. 4, a barrier layer 43 is provided on the sintered filter portion 41 of the metal tube 42 having the sintered filter portion 41, and a palladium-copper alloy film is formed on the barrier layer 43. It is preferable to use a hydrogen separation membrane provided with 44. Here, the sintered filter portion 41 and the metal tube 42 are preferably made of stainless steel, and the barrier layer 43 is preferably made of zirconia, alumina, or the like. The barrier layer 43 prevents the metal component of the sintered filter portion 41 from diffusing into the palladium-copper alloy film 44, thereby deteriorating the hydrogen permeation performance of the film 44, and increases the surface smoothness to increase the palladium- The copper alloy film 44 has an effect of preventing defects. The palladium-copper alloy film 44 can be formed by plating, for example.

[Hydrogen production method]
The method for producing hydrogen using the membrane separation reactor of the present invention is performed as follows. First, in the hydrogen production method of the present invention, the average reaction temperature of the upstream half 3A and the downstream half 3B of the steam reforming catalyst layer is determined in advance from the structure, design, and operating conditions of the membrane separation reactor and the hydrogen production apparatus. Is assumed or set. When the average temperature of the upstream half 3A is higher than the average temperature of the downstream half 3B, the average copper content of the upstream half 2A of the hydrogen separation membrane is higher than the average copper content of the downstream half 2B. Thus, the hydrogen separation membrane 2 is disposed. Conversely, when the average temperature of the upstream half 3A is lower than the average temperature of the downstream half 3B, the average copper content of the upstream half 2A of the hydrogen separation membrane is lower than the average copper content of the downstream half 2B. The hydrogen separation membrane 2 is arranged so as to be. Next, the above-mentioned mixed gas of hydrocarbon and steam is supplied to the steam reforming catalyst layer 3 to perform a steam reforming reaction to generate a reformed gas containing hydrogen as a main component. Here, the ratio of hydrocarbon to water vapor is preferably in the range of 2.5 to 4.0 as the steam / carbon ratio (S / C ratio), and more preferably in the range of 2.8 to 3.5. When the S / C ratio is low, coking occurs and the activity of the steam reforming catalyst is reduced. On the other hand, when the S / C ratio is higher than necessary, the hydrogen concentration of the reformed gas is lowered and the efficiency is lowered.

  The temperature of the steam reforming catalyst layer 3, that is, the temperature of the reforming reaction, is preferably 450 to 800 ° C, more preferably 500 to 700 ° C, and particularly preferably 500 to 600 ° C. Here, the upper limit of the reforming reaction temperature is preferably 600 ° C. from the characteristics of the Pd—Cu alloy film. When the temperature of the reforming reaction is less than 450 ° C., the hydrogen fraction is 13 vol% or less (under the condition of a reaction pressure of 0.9 MPaG with a methane raw material), and a sufficient hydrogen permeation amount cannot be obtained. If it exceeds, a heat-resistant material (such as Kanthal, Inconel, Hastelloy) is required as the material of the reaction tube, and the cost increases. In the case of providing a pre-reformer, the upper limit of the reaction temperature of 600 ° C. is irrelevant and 600 to 700 ° C. is a particularly preferable condition.

  The pressure for the reforming reaction is preferably 0.5 to 1.5 MPaG, more preferably 0.7 to 1.2 MPaG. If the reaction pressure is too low, a sufficient amount of hydrogen permeation cannot be obtained, and if the reaction pressure is too high, the hydrocarbon reaction (reaction toward the hydrogen production side) is difficult to proceed.

When kerosene is used as the raw material hydrocarbon, SV (kerosene-based LHSV) is preferably in the range of 0.3 to 3.0 h ^{−1 in} the current catalyst, and in the range of 0.3 to 1.7 h ⁻¹ . More preferred.

  The reformed gas generated in the steam reforming catalyst layer 3 flows through the steam reforming catalyst layer 3 and hydrogen is separated and purified by the hydrogen separation membrane 2. A preferable temperature for hydrogen separation by the hydrogen separation membrane 2 is less than 600 ° C., particularly 350 ° C. or more and less than 600 ° C. In the present invention, the portion where the temperature of the hydrogen separation membrane 2 is high has a high copper content, while the portion where the temperature of the hydrogen separation membrane 2 is low has a low copper content. Hydrogen can be separated.

  The measurement results of the hydrogen permeability of the palladium-copper alloy film that forms the basis of the knowledge of the present invention are shown below.

(Reference example)
The outer surface of a tubular stainless steel sintered metal filter (filter length: 5 cm, filter diameter: 1 cm) is coated with yttrium-stabilized zirconia particles to form a ceramic porous thin film (porous ceramic film) with an average pore diameter of 0.1 μm. A porous support was prepared. This tubular sintered metal filter (porous ceramic support) was immersed in a commercially available electroless palladium plating solution, and palladium was plated on the surface of the porous ceramic film (adjusted so as to have a film thickness of 1 to 2 μm). After plating the outer surface of the porous ceramic support with palladium, the amount of palladium plated was measured from the plating weight (or change in plating solution concentration). Next, copper plating was performed on the palladium thin film with a commercially available copper plating solution so as to have a predetermined palladium-copper composition ratio (copper content: 38 to 48 mass%), thereby forming a copper thin film on the palladium thin film. The plating weight after plating (or change in plating solution concentration) was measured and confirmed.

  Next, the plated porous support is washed and dried, and then one of the plated porous supports is sealed and placed in a hydrogen permeation measuring device, under an inert gas stream of nitrogen or argon. The temperature was raised to 400 ° C., followed by heat treatment at 400 ° C. for 24 hours in a hydrogen atmosphere to obtain a hydrogen separation membrane composed of a palladium-copper alloy thin film using a porous ceramic membrane as a support. The hydrogen separation membrane made of palladium-copper alloy is evaluated by setting the hydrogen separation membrane to a predetermined temperature (400 to 600 ° C.), supplying hydrogen, measuring the hydrogen permeation amount at a predetermined pressure of 0.6 MPaG, and further adjusting the pressure. The hydrogen permeation amount at each pressure was measured as 0.5 MPaG, 0.4 MPaG, 0.3 MPaG, 0.2 MPaG, 0.1 MPaG, and 0.0 MPaG, and the hydrogen permeation coefficient was calculated. In addition, it was confirmed that nitrogen was not permeated by applying pressure in the same manner. Furthermore, after the measurement was completed, the palladium-copper film was peeled from the support, and elemental analysis was performed to confirm the palladium-copper composition ratio. The results are shown in FIG.

  From FIG. 5, the temperature of the maximum hydrogen permeation performance varies depending on the composition of the alloy film mainly composed of palladium and copper, and the upstream side and the downstream side of the steam reforming catalyst layer as in the present invention described above. It can be seen that the steam reforming reaction and the hydrogen membrane separation can be efficiently performed by arranging the hydrogen separation membrane having the higher copper content in the higher average temperature. .

  According to the present invention, it is possible to provide a membrane separation reactor capable of efficiently performing a steam reforming reaction and hydrogen membrane separation and a method for producing hydrogen using them. The membrane separation reactor of the present invention can produce high-purity hydrogen gas with high efficiency and a high recovery amount, so that it can be used in a hydrogen production apparatus for a polymer electrolyte fuel cell (PEFC) or a hydrogen station. It can be suitably used as a site-type hydrogen production apparatus.

DESCRIPTION OF SYMBOLS 1 Membrane separation type reactor 2 Hydrogen separation membrane 2A Upstream half of hydrogen separation membrane 2B Downstream half of hydrogen separation membrane 2a Upstream 1/3 portion 2b Middle stream 1/3 portion 2c Downstream side 1/3 portion 3 Steam reforming catalyst layer 3A Upstream half of steam reforming catalyst layer 3B Downstream half of steam reforming catalyst layer 4 Hydrocarbon and steam inlet part 5 Nonpermeate gas outlet part 6 Product hydrogen outlet part 7 Heating shell 8 Inlet part for heating gas 9 Outlet part for heating gas 41 Sintered filter part 42 Metal tube 43 Barrier layer 44 Palladium-copper alloy film

Claims (3)

A hydrogen separation membrane comprising palladium and copper and having an average copper content of 38 to 48% by mass;
Comprising a steam reforming catalyst for steam reforming hydrocarbons, comprising a steam reforming catalyst layer disposed on the outer peripheral side of the hydrogen separation membrane,
The hydrogen separation membrane is characterized in that the difference in average copper content between the upstream half and the downstream half is 4 to 10% by mass, with the hydrocarbon and water vapor inlets being upstream.
Membrane separation reactor.   The hydrogen separation membrane is characterized in that the average copper content of one of the upstream half and the downstream half is 44 to 48% by mass, and the other one average copper content is 38 to 44% by mass. The membrane separation type reactor according to claim 1. A method for producing hydrogen using the membrane separation reactor according to claim 1 or 2,
Among the upstream half and the downstream half of the steam reforming catalyst layer, the higher the average temperature, the higher the average copper content in the upstream half and the downstream half of the hydrogen separation membrane, A mixed gas of hydrocarbon and steam is supplied to the steam reforming catalyst layer to generate a reformed gas mainly composed of hydrogen by a steam reforming reaction, and hydrogen is selectively permeated through the hydrogen separation membrane. To extract hydrogen,
A method for producing hydrogen.

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