JP6197301B2 - Hydrogen production equipment - Google Patents

Description

  The present invention relates to a hydrogen production apparatus for producing hydrogen by reforming a raw material gas with a reforming catalyst and selectively separating hydrogen gas from the reformed gas by a hydrogen separator.

  As an apparatus for producing hydrogen to be supplied to a fuel cell, Patent Documents 1 and 2 describe a catalyst for reforming a raw material gas such as natural gas to generate hydrogen, and a metal hydrogen permeable membrane (hydrogen) that allows only hydrogen to permeate. A hydrogen production apparatus is described in which a cylindrical hydrogen separator having a separation metal layer is disposed in a reactor (device shell).

  In the hydrogen production apparatus of Patent Document 1, a hydrogen separator having a hydrogen permeable membrane on the outer surface is disposed inside a metal reaction tube, and between the hydrogen separator and the inner wall of the reaction tube, a pellet shape is provided. (Bead-shaped) catalyst is filled.

  In the hydrogen production apparatus of Patent Document 2, an annular catalyst-supporting ceramic porous body is externally fitted to a cylindrical hydrogen separator instead of a pellet-shaped catalyst.

  In the hydrogen production apparatuses disclosed in Patent Documents 1 and 2, a raw material gas containing a hydrocarbon gas and steam comes into contact with the catalyst, and a steam reforming reaction or the like occurs, whereby a reformed gas containing hydrogen gas is generated.

For example, in steam reforming of methane, a reformed gas containing hydrogen, carbon monoxide, and carbon dioxide is generated according to the reaction formulas of the following formulas (1) and (2).
CH ₄ + H ₂ O → CO + 3H ₂ (reforming reaction) (1)
CO + H ₂ O → CO ₂ + H ₂ (shift reaction) (2)

  By selectively separating hydrogen from the reformed gas by a hydrogen separator, high-purity hydrogen gas can be obtained.

JP 2005-58823 A WO2006 / 082933

  The hydrogen production apparatus is subjected to a heat cycle in which the temperature is high during use and low when not in use, so that the reaction tube repeatedly expands and contracts. For this reason, the hydrogen production apparatuses disclosed in Patent Documents 1 and 2 have a problem that the hydrogen separator is easily damaged.

  That is, in the case of the hydrogen production apparatus of Patent Document 1, when the metal reaction tube (device shell) expands at a high temperature, the pellet-shaped catalyst descends to fill the expanded space. When it shrinks at a low temperature, the molded catalyst clogged below it can hardly move, so it is pressed inward by the reaction tube. As a result, the catalyst pressed inward presses the ceramic hydrogen separator, and the hydrogen separator may be damaged by this pressing force.

  In addition, in the hydrogen production apparatus of Patent Document 1, the catalyst can be packed densely since the catalyst is directly packed between the reaction tube and the module. The amount (packing density) is different, and the ventilation resistance (pressure loss) is different in each module. As a result, a module in which the source gas easily flows and a module in which the source gas does not easily flow are generated, which causes a problem that the performance of the entire system is deteriorated. Further, when packing the catalyst densely, it is necessary to apply an external force to the reaction tube, and the module may be damaged.

  Further, in any of the hydrogen production apparatuses disclosed in Patent Documents 1 and 2, the catalyst and the hydrogen separator slide frictionally with the thermal expansion / contraction caused by the temperature rise and fall, and the hydrogen separator (particularly the hydrogen separation membrane) is damaged. Is likely to occur.

  The catalyst of Patent Document 2 is made of an annular ceramic porous body, but it is difficult to optimize the pore distribution of such a ceramic porous body. In addition, since firing shrinkage occurs when firing ceramics, if the dimensional tolerances of the inner and outer diameters of the annular body are reduced, the hydrogen separator is likely to be damaged. It is also necessary to increase the tolerance of the distance from the inner peripheral surface of the porous body, and in this case, the hydrogen production efficiency may be reduced.

  The present invention solves the above-mentioned conventional problems, and has a catalyst container in which a predetermined amount of granular catalyst is uniformly filled in a gas permeable case, so that it is excellent in hydrogen production efficiency and prevents damage to the hydrogen separator. An object of the present invention is to provide a hydrogen production apparatus.

The hydrogen production apparatus of the present invention has a hydrogen separator that selectively permeates hydrogen from one side to the other side, and a granular reforming catalyst disposed on one side of the hydrogen separator, In the hydrogen production apparatus in which the hydrogen separator and the reforming catalyst are arranged in the apparatus shell, the hydrogen production apparatus in which the reforming catalyst is housed in a gas permeable case to form a catalyst housing body , The hydrogen separator is formed in a cylindrical shape so that hydrogen can permeate from the outer peripheral side to the inner peripheral side, and the breathable case has an inner peripheral wall along the outer peripheral surface of the hydrogen separator, and is coaxial with the inner peripheral wall. An outer peripheral wall of the inner peripheral wall and a first end wall connected to one end side in the axial direction of the inner peripheral wall and the outer peripheral wall. It is characterized by being fitted on the separator .

  The breathable case may have a second end wall in which the other end side in the axial direction of the inner peripheral wall and the outer peripheral wall is continuous.

  Preferably, the length of the breathable case in the axial direction is smaller than the axial length of the hydrogen separator, and a plurality of the catalyst containers are arranged in the axial direction of the hydrogen separator.

  An engagement portion that engages adjacent catalyst containers may be provided in each of the air permeable cases.

  The breathable case is preferably made of a mesh or a perforated plate.

  In the hydrogen production apparatus of the present invention, a gap is formed between the gas permeable case housing the reforming catalyst and the hydrogen separator, preventing frictional sliding between the catalyst container and the hydrogen separator, and damage to the hydrogen separator. Can be prevented.

  In the hydrogen production apparatus of the present invention, the granular reforming catalyst is accommodated in the air permeable case, and a prescribed amount of catalyst particles can be uniformly filled in the air permeable case. Accordingly, even when a plurality of hydrogen production apparatuses of the present invention are installed in parallel, gas flows evenly through each hydrogen production apparatus, and hydrogen is stably produced. Further, even when a plurality of modules comprising a breathable case containing a reforming catalyst and a hydrogen separator are installed in parallel in one apparatus shell, gas flows evenly through each module, Is manufactured stably.

  In the present invention, the reforming catalyst is housed in a gas permeable case to form a catalyst housing, and the catalyst housing can be easily attached to and detached from the hydrogen separator. By installing a plurality of catalyst containers in the apparatus shell, the size of each catalyst container becomes appropriate, and handling becomes easy.

  In the hydrogen production apparatus of the present invention, it is not necessary to separately prepare a reforming catalyst with optimized catalyst loading, porosity, etc., and a general granular reforming catalyst can be used.

  In the present invention, the hydrogen separator is formed in a cylindrical shape so that hydrogen can permeate from the outer peripheral side to the inner peripheral side, and the breathable case includes an inner peripheral wall along the outer peripheral surface of the hydrogen separator, The catalyst comprising an outer peripheral wall coaxial with the inner peripheral wall, and a first end wall connected to one end side in the axial direction of the inner peripheral wall and the outer peripheral wall, and containing the reforming catalyst in the breathable case By adopting a configuration in which the container is fitted on the hydrogen separator, the hydrogen gas generated in the reforming reaction can be efficiently separated by the hydrogen separator.

  In this case, it is preferable that the length of the breathable case in the axial direction is smaller than the length of the hydrogen separator in the axial direction, and a plurality of breathable cases are arranged in the axial direction of the hydrogen separator. If comprised in this way, since the axial direction length of an air permeable case will become comparatively short, a granular reforming catalyst can be easily and uniformly filled in an air permeable case. In addition, since the length of the gas permeable case is relatively short, the catalyst container can be easily fitted to the hydrogen separator even if the catalyst container is slightly deformed.

  When the second end wall is provided on the other end side of the gas permeable case, the reforming catalyst does not flow out of the gas permeable case even if the catalyst container is tilted, so that the catalyst container can be easily handled.

  By providing the engaging part for engaging the catalyst containers with each other in the air-permeable case, the displacement of the catalyst containers is prevented.

It is a longitudinal cross-sectional view of the hydrogen production apparatus which concerns on embodiment. It is an expanded sectional view of the front-end | tip part of a hydrogen separator. It is a perspective view of a breathable case. It is a longitudinal view of a breathable case. It is the VV sectional view taken on the line of FIG. It is a systematic diagram of the hydrogen production apparatus which concerns on another embodiment. It is a longitudinal cross-sectional view of the hydrogen production apparatus which concerns on another embodiment. (A) is a perspective view of another shape of the breathable case, and (b) is a longitudinal sectional view thereof. (A) is a perspective view of a breathable case of another shape, and (b) is a longitudinal sectional view thereof.

  Hereinafter, embodiments will be described with reference to the drawings.

  1 to 5 show a hydrogen production apparatus 1 according to an embodiment. As shown in FIG. 1, the hydrogen production apparatus 1 includes an apparatus shell (a vessel) 2, a hydrogen separator 3 and a catalyst container 4 installed in the apparatus shell 2. The apparatus shell 2 has a cylindrical shape, and is provided with a source gas inlet 5 and a hydrogen gas outlet 6 on one end side (upper end side in FIG. 1), and an off-gas outlet 7 on the other end side. Yes. The hydrogen gas outlet 6 is disposed at the axial center of the canopy of the device shell 2. In this embodiment, the raw material gas inlet 5 and the off-gas outlet 7 are provided on the side periphery of the device shell 2, respectively, but are not limited thereto.

  A hydrogen separator 3 is connected to the hydrogen gas outlet 6 through a joint 8. The hydrogen separator 3 has a cylindrical shape in which the lower end side in FIG. 1 is sealed, and is installed coaxially with the device shell 2. As shown in FIG. 2, the hydrogen separator 3 has a main body 3a made of a gas-permeable ceramic porous body, and three porous layers 3b, 3c and 3d formed on the outer surface of the main body 3a. Among the three porous layers 3b to 3d, a part of the pores of the intermediate porous layer 3c is filled with hydrogen permeable metal material such as Pd, Pd alloy, etc. The hydrogen separator 3 is configured to permeate from the outer peripheral side to the inner peripheral side. The outermost porous layer 3d is a protective layer.

  The catalyst container 4 is obtained by filling the gas-permeable case 10 shown in FIGS. The air permeable case 10 has a double cylindrical shape having an inner peripheral wall 11 and an outer peripheral wall 12 having air permeability made of a mesh or a punching plate (mesh in this embodiment). In this embodiment, one end side (the lower end side in FIGS. 3 and 4) of the inner peripheral wall 11 and the outer peripheral wall 12 in the axial direction is connected to the first end wall 13, and a vent hole 14 is formed in the end wall 13. Is provided. The end wall 13 may be made of mesh.

  A space between the inner peripheral wall 11 and the outer peripheral wall 12 is filled with a granular reforming catalyst 15. After the reforming catalyst 15 is filled, a second end wall (not shown in FIGS. 3 and 4) may be attached to the upper end portion. A second end wall having the same configuration as that of the first end wall 13 is suitable. By providing the second end wall, the reforming catalyst 15 does not flow out of the breathable case 10 even when the catalyst container 4 is tilted, and the handling of the catalyst container 4 is facilitated.

  The reforming catalyst 15 preferably has a spherical shape with a substantially uniform particle diameter of about 1 to 5 mm, particularly about 1 to 3 mm. As this granular reforming catalyst, a commercially available product with known catalytic properties can be used. When the average particle diameter of the reforming catalyst 15 is a (mm), the distance b between the inner peripheral wall 11 and the outer peripheral wall 12 is preferably 1 to 3 times, particularly about 1.5 to 2 times a. The length L in the axial direction of the breathable case 10 is preferably about 1/10 to 1/2, particularly about 1/5 to 1/3 of the length of the hydrogen separator. When such a condition is satisfied, the reforming catalyst 15 can be easily and uniformly filled into the breathable case 10. In addition, since L is relatively small, even when the reforming catalyst 15 is filled, the inner peripheral wall 11 and the outer peripheral wall 12 do not deform into a bulging shape, and the shape retaining property (shape retaining property) is good. Even if the catalyst container 4 is slightly deformed, the catalyst container 4 can be easily fitted to the hydrogen separator 3.

  The mesh openings of the inner peripheral wall 11 and the outer peripheral wall 12 and the hole diameter of the vent hole 14 are preferably 20 to 80%, particularly about 30 to 50% of the minimum particle diameter of the reforming catalyst 15.

  When the reforming catalyst 15 is filled in the breathable case 10, the weight of each catalyst housing 4 can be made uniform by filling a predetermined amount of the reforming catalyst 15 weighed in advance. Further, by applying vibration or light impact with a vibrator or a tapping machine while the reforming catalyst 15 is being filled in the breathable case 10, the granular reforming catalyst 15 is uniformly filled in the breathable case 10. It can be filled as follows.

  After filling the specified amount of the reforming catalyst 15 in the air-permeable case 10, heat-resistant wool (glass wool, rock wool, slag wool, alumina wool, etc.) may be filled on the upper side of the catalyst to prevent the catalyst from falling. The second end wall described above may be attached. The second end wall may be attached after filling with heat-resistant wool.

  A catalyst container 4 in which the reforming catalyst 15 is accommodated in the gas permeable case 10 is externally fitted to the hydrogen separator 3 and arranged so as to be stacked in multiple stages in the apparatus shell 2 as shown in FIG. . The hydrogen separator 3 is installed so as to pass through the inner hole of each catalyst housing 4. A gap of about 0.5 to 20 mm, particularly about 0.5 to 2 mm is preferably formed between the inner peripheral surface of the catalyst housing 4 and the hydrogen separator 3. If this gap is too small, there is a possibility that both may come into contact with each other. If it is too large, the performance may be lowered. The inner diameters of the catalyst housings 4 may be the same or different.

  Although not shown, a chamber is provided so as to surround the device shell 2, and a high-temperature gas such as a combustion gas is circulated between the chamber and the device shell 2, so that the interior of the device shell 2 is 300 to 600. It is constituted so that it can be heated at a temperature of about 500 to 550 ° C.

In order to produce hydrogen by the hydrogen production apparatus 1 configured as described above, the raw material gas is supplied from the inlet 5 to the apparatus shell in a state where the temperature of the hydrogen production apparatus 1 is raised to about 300 to 600 ° C., particularly about 500 to 550 ° C. 2 is introduced. When the raw material gas comes into contact with the reforming catalyst 15, the reforming reaction proceeds according to the above reaction formula, and a reformed gas containing hydrogen gas is generated. The produced hydrogen selectively permeates the hydrogen separator 3 and is taken out from the outlet 6. Off-gas consisting of CO, CO ₂ , H ₂ O, etc. flows out from the outlet 7.

  FIG. 6 is a hydrogen production system diagram in which a plurality of hydrogen production apparatuses 1 shown in FIG. 1 are installed in parallel. The raw material gas is supplied to each hydrogen production apparatus 1 through a raw material gas line 20, and each hydrogen production apparatus is produced through a hydrogen line 21. 1 is taken out, and off-gas from each hydrogen production apparatus 1 is taken out by the off-gas line 22.

  In FIG. 6, the hydrogen production apparatus 1 is individually installed, but in FIG. 7, a plurality of hydrogen separation modules 24 are installed in one apparatus shell 25. Each module 24 includes a hydrogen separator 3 and a plurality of catalyst containers 4 that are externally fitted to the hydrogen separator 3. The configuration of the hydrogen separator 3 and the catalyst container 4 surrounding it is the same as that of the hydrogen production apparatus 1.

  A plurality of cylindrical module storage chambers 26 are defined in the apparatus shell 25, and the modules 24 are installed in the respective module storage chambers 26. The apparatus shell 25 is provided with a raw material gas inlet 27 and an off-gas outlet 30.

  In this embodiment, each module housing chamber 26 extends in the vertical direction, and the inflow port 27 communicates with the lower portion of each module housing chamber 26 via the lower header portion 28. The upper portion of each module housing chamber 26 communicates with the outlet 30 via the upper header portion 29.

  Note that, contrary to the illustration, the inlet 27 may be installed on the upper side of the device shell 25 and the outlet 30 may be installed on the lower side.

  Each hydrogen separator 3 extends upward through the ceiling of the device shell 25. A chamber 40 is provided so as to surround the device shell 25. A heating gas (combustion gas) is introduced from the inlet 41 into the space between the device shell 25 and the chamber 40, and after heating the device shell 25 and the inside thereof, the gas flows out from the outlet 42 as exhaust gas. . On the ceiling surface of the chamber 40, a hydrogen gas outlet 43 is provided above the modules 24, and the upper end of the hydrogen separator 3 is connected to the outlet 43 via a joint 44.

  In the hydrogen production apparatus of FIG. 7, the raw material gas is supplied from the inlet 27 in the state where each module 24 is heated to about 300 to 600 ° C., for example, about 500 to 550 ° C. It is introduced into the body 25. This raw material gas is distributed and supplied from the lower header portion 28 to each module housing chamber 26 and comes into contact with the reforming catalyst of the catalyst housing 4 to generate a reformed gas containing hydrogen gas. The generated hydrogen gas passes through the hydrogen separator 3 and is taken out from the take-out port 43 through the hydrogen take-out line 46. The off gas flows out from the outlet 30 through the upper header portion 29.

  As described above, since each catalyst container 4 is filled with a specified amount of the reforming catalyst 15 at a uniform packing density, a plurality of hydrogen production apparatuses 1 or hydrogen separation modules 24 are arranged in parallel as shown in FIGS. Even in the case of installation, the gas flows uniformly to each hydrogen production apparatus 1 or module 24. Therefore, the deterioration with time of the catalyst is equivalent in each hydrogen production apparatus 1 or module 24.

  Further, if a slight gap (for example, about 0.5 to 20 mm) is provided between the inner peripheral surface of the catalyst container 4 and the outer peripheral surface of the hydrogen separator 3, the catalyst container 4 and the hydrogen separator 3 are separated from each other. There is no frictional sliding with the outer peripheral surface, and damage to the hydrogen separation membrane of the hydrogen separator 3 is also prevented.

  In the present invention, in order to position the catalyst containers 4 stacked one above the other, an engaging portion that engages the catalyst containers 4 may be provided in the air-permeable case. 8 and 9 show an example of a breathable case provided with such an engaging portion.

  8 has a first end wall 13 and a second end wall 16 that are tapered so that the tapered portions of the breathable cases 10A and 10A engage with each other when they are stacked one above the other. It is a thing.

  9 has a convex portion 18 on the second end wall 16 and a concave portion 19 on the first end wall 13, and the convex portion 18 of the lower side air-permeable case 10B when vertically stacked. Is engaged with the recess 19 of the upper side air-permeable case 10B. A vent hole 17 is provided in the second end wall 16 of each breathable case 10B. When the air permeable cases 10B are stacked, it is preferable that the air holes 14 of the upper air permeable case 10B and the air holes 17 of the lower air permeable case 10B overlap and communicate with each other.

  Next, although suitable materials, such as a catalyst, a hydrogen separator, and an apparatus shell, are described, the present invention is not limited to the following.

  Examples of the catalyst of the reforming catalyst 15 include nickel, ruthenium, copper, iron, platinum, palladium, zinc, and mixtures and alloys thereof.

  Examples of the support for supporting the catalyst include porous ceramics. Examples of the porous ceramics include alumina, zirconia, stabilized zirconia, ceria, doped ceria, mullite, silica, and mixtures thereof.

  Examples of the porous ceramic constituting the main body 3a and the layers 3b to 3d of the hydrogen separator 3 include yttria stabilized zirconia, stabilized zirconia, alumina, magnesia, ceria, doped ceria, and a mixture thereof.

  Examples of the hydrogen separation metal (hydrogen permeable metal) constituting the hydrogen separation metal layer include Pd simple substance, Pd alloy (for example, PdAg alloy, PdCu alloy, PdAu alloy) and the like. From the viewpoint of suppressing hydrogen embrittlement, a PdAg alloy is preferable to Pd alone. In the case of a hydrogen production apparatus used at a high temperature of 450 ° C. or higher, a PdAg alloy is desirable.

  In addition, you may join the precise | minute part which does not have gas permeability to the axial direction edge part of the main body 3a. For example, in the hydrogen separator 3 of FIG. 7, it is preferable that a portion extending upward from the ceiling surface of the device shell 25 is constituted by this dense portion. Here, “without gas permeability” is only required to prevent the permeation of the raw material gas and the reformed gas, and for example, a denseness with a relative density of 70% or more can be mentioned. Examples of the material constituting the dense part include ceramics. Examples of the ceramics include yttria stabilized zirconia, stabilized zirconia, alumina, magnesia, ceria, doped ceria, and mixtures thereof.

  In order to manufacture the hydrogen separator 3 having a dense part, for example, yttria-stabilized zirconia granulated powder is added to a rubber mold, and then 40 to 50% by volume of organic beads are added as a pore former. Fill in order of zirconia granulated powder. When the dense part is not provided, the rubber mold is filled only with yttria-stabilized zirconia granulated powder added with organic beads. Thereafter, it is formed into a cylindrical bottomed tube shape (test tube shape) by a press forming method to produce a formed body. Next, after this degreasing | defatting, the main body 3a is created by sintering at about 1300-1500 degreeC.

  Next, a slurry in which yttria-stabilized zirconia powder is dispersed in an organic solvent is prepared, and the layers 3b and 3c are deposited on the porous portion of the main body 3a by the dip coating method. Baking is performed by heating to about ˜1300 ° C. to form layers 3b and 3c.

  Next, a known Pd nucleation process is performed on the surface of the layer 3c, and then yttria-stabilized zirconia slurry is dip coated and baked in the same manner as described above to form the layer 3d. Next, Pd nuclei inside the porous layer 3c are grown by electroless plating to form a hydrogen separation metal layer made of Pd or the like.

  Examples of the material constituting the device shells 2 and 25, the air permeable case 10, and the chamber 40 include SUS316, SUS613L, and SUS430 stainless steel.

  Each of the above embodiments is an example of the present invention, and the present invention may be configured other than illustrated. For example, the number of stacked stages of the illustrated catalyst container 4 is an example, and is not limited thereto. Only one catalyst container 4 may be externally arranged with respect to one hydrogen separator 3. In the illustrated hydrogen production apparatus, the hydrogen separator 3 is suspended from the ceiling of the apparatus shell, but may be configured to rise from the bottom of the apparatus shell. In the present invention, as in Patent Document 2, stirring means for stirring the source gas and disturbing the flow may be provided between the catalyst containers 4.

DESCRIPTION OF SYMBOLS 1 Hydrogen production apparatus 2,25 Apparatus shell 3 Hydrogen separator 4 Catalyst container 10, 10A, 10B Breathable case 11 Inner peripheral wall 12 Outer peripheral wall 13 First end wall 14, 17 Vent hole 15 Reforming catalyst 16 Second end Wall 18 Convex part 19 Concave part 24 Hydrogen separation module 40 Chamber

Claims (5)

A hydrogen separator that selectively permeates hydrogen from one side to the other;
A particulate reforming catalyst disposed on one side of the hydrogen separator,
In the hydrogen production apparatus in which the hydrogen separator and the reforming catalyst are arranged in the apparatus shell,
A hydrogen production apparatus in which the reforming catalyst is accommodated in a gas permeable case to serve as a catalyst container ,
The hydrogen separator is formed in a cylindrical shape so that hydrogen can permeate from the outer peripheral side to the inner peripheral side,
The breathable case includes an inner peripheral wall along the outer peripheral surface of the hydrogen separator, an outer peripheral wall coaxial with the inner peripheral wall, and a first end wall where one end side in the axial direction of the inner peripheral wall and the outer peripheral wall is continuous. An apparatus for producing hydrogen, comprising: a catalyst containing body formed by housing a reforming catalyst in the gas permeable case and fitted on the hydrogen separator . 2. The hydrogen production apparatus according to claim 1 , wherein the breathable case has a second end wall that is connected to the other end in the axial direction of the inner peripheral wall and the outer peripheral wall. According to claim 1 or 2, the length in the axial direction of the ventilation casing is smaller than the axial length of the hydrogen separator, a plurality of said catalyst container is arranged in the axial direction of the hydrogen separator The hydrogen production apparatus characterized by the above-mentioned. The hydrogen production apparatus according to claim 3 , wherein an engagement portion that engages the adjacent catalyst containers is provided in each of the breathable cases. In any one of claims 1 to 4, wherein the breathable case hydrogen production apparatus characterized by comprising a mesh or perforated plate.

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