JP2016117028A - Catalyst structure and hydrogen production apparatus - Google Patents

Abstract

Hydrogen is efficiently and stably separated from a reformed gas produced by reforming a raw material gas. A catalyst layer for reforming a raw material gas to generate a reformed gas containing hydrogen, a cylinder having a porous portion at least partially, and a hydrogen permeable membrane provided on the outer surface of the porous portion And a hydrogen separation means for separating the hydrogen in the reformed gas into the cylindrical body through the hydrogen permeable membrane and the porous portion, and the catalyst layer has at least a part of the outer surface of the hydrogen permeable membrane. It is provided on the outer surface of the hydrogen separation means in an exposed state. [Selection] Figure 2

Description

  The present invention relates to a catalyst structure that performs reforming of a source gas and separation of hydrogen from the reformed gas, and a hydrogen production apparatus that produces hydrogen using the catalyst structure.

  As one of the hydrogen production technologies, for example, as described in Patent Document 1, a technology for producing hydrogen by a membrane reactor is known. This membrane reactor has a multiple tube structure in which a hydrogen separation tube is arranged in a reaction tube (outer tube). A reforming catalyst such as particles is filled between the reaction tube and the hydrogen separation tube to form a reforming catalyst layer. When a raw material gas containing a hydrocarbon gas is supplied to the reforming catalyst layer, the raw material gas is reformed by the reforming catalyst layer to generate a reformed gas containing hydrogen. Then, hydrogen is separated from the reformed gas by a hydrogen permeable membrane such as a palladium (Pd) membrane provided in the hydrogen separation tube. In this way, hydrogen is purified.

Japanese Patent No. 4184037

  In the membrane reactor described above, the reforming catalyst is filled between the reaction tube and the hydrogen separation tube, so that the reforming catalyst is in contact with the entire surface of the hydrogen permeable membrane provided in the hydrogen separation tube. . For this reason, the rate at which hydrogen is separated into the hydrogen separation pipe through the hydrogen permeable membrane, that is, the purification efficiency is low. In addition, the hydrogen permeable membrane may be damaged by the reforming catalyst due to a difference in thermal expansion coefficient between the reforming catalyst and the hydrogen permeable membrane that are in contact with each other. As a result, it has been difficult to stably and efficiently produce hydrogen from the source gas.

  This invention is made | formed in view of the said subject, and it aims at providing the technique which can isolate | separate hydrogen efficiently and stably from the reformed gas produced | generated by reforming raw material gas. .

  1st aspect of this invention is a catalyst structure, Comprising: The catalyst layer which reforms raw material gas and produces | generates the reformed gas containing hydrogen, The cylinder provided with a porous part in at least one part, A hydrogen permeable membrane provided on the outer surface of the mass part, and a hydrogen separation means for separating hydrogen in the reformed gas into the cylindrical body through the hydrogen permeable membrane and the porous part, and the catalyst layer is The hydrogen separation means is provided on the outer surface of the hydrogen permeable membrane with at least a part of the outer surface exposed.

  The second aspect of the present invention is a hydrogen production apparatus comprising: a catalyst structure; a source gas supply unit that supplies source gas to the catalyst layer; and a hydrogen recovery unit that recovers hydrogen from the inside of the cylinder. It is characterized by providing.

  According to the catalyst structure and the hydrogen production apparatus according to the present invention, the catalyst layer is provided on the outer surface of the hydrogen separation means. Therefore, the integration of the catalyst layer and the hydrogen separation means prevents the hydrogen permeable membrane from being damaged by the catalyst layer. The catalyst layer is provided in a state in which at least a part of the outer surface of the hydrogen permeable membrane is exposed, and hydrogen in the reformed gas passes through the exposed region and the porous portion of the outer surface of the hydrogen permeable membrane. Permeated inside and separated. Therefore, hydrogen can be purified with excellent efficiency.

It is a figure which shows an example of the hydrogen production apparatus equipped with 1st Embodiment of the catalyst structure concerning this invention. It is the elements on larger scale of the hydrogen production apparatus of FIG. It is a figure which shows typically an example of the internal structure of the catalyst part shown in FIG. It is a figure which shows typically the other example of the internal structure of a catalyst part. It is a figure which shows 2nd Embodiment of the catalyst structure concerning this invention. It is a figure which shows 3rd Embodiment of the catalyst structure concerning this invention. It is a figure which shows 4th Embodiment of the catalyst structure concerning this invention. It is a figure which shows 5th Embodiment of the catalyst structure concerning this invention.

  FIG. 1 is a diagram showing an example of a hydrogen production apparatus equipped with a first embodiment of a catalyst structure according to the present invention. FIG. 2 is a partially enlarged view of the hydrogen production apparatus of FIG. In the following drawings, the scale of each component and each gas component is shown different from the actual scale so that each component and each gas component can be recognized.

  As shown in FIG. 1, the hydrogen production apparatus 1 has a reaction tube 2 extending in the X direction. A catalyst structure 3 is provided so as to penetrate the inside of the reaction tube 2 in the X direction. The reaction tube 2 and the catalyst structure 3 form a double tube structure, and the space sandwiched between the inner surface of the reaction tube 2 and the outer surface of the catalyst structure 3 reforms the raw material gas to reform gas. In contrast, the inside of the catalyst structure 3 is a space for taking out hydrogen 6 (white circles in FIG. 2) separated from the reformed gas as will be described later. .

  As shown in FIG. 1, an inlet 22 is provided at the (−X) side end of the reaction tube 2. A raw material gas supply unit 4 is connected to the inlet 22 via a pipe 51. The raw material gas supply unit 4 supplies a mixed gas of hydrocarbon gas and water vapor as the raw material gas in accordance with a supply command from a control unit (not shown) that controls the entire apparatus. When the supply of the raw material gas is started, the raw material gas is fed into the reforming space 21 through the inlet 22.

  In order to reform the raw material gas in the reforming space 21 and separate the hydrogen 6 (FIG. 2) from the reformed gas, the catalyst structure 3 is configured as follows. The catalyst structure 3 includes a cylindrical body 31 extending in the X direction, a hydrogen permeable film 32 formed of a hydrogen permeable material such as Pd, and a catalyst layer 33. The cylindrical body 31 has a hollow cylindrical shape extending in the X direction. A central portion of the cylindrical body 31 is a porous portion 311 made of a porous stainless steel tube or a porous ceramic tube. On the other hand, the (−X) side end portion 312 and the (+ X) side end portion 313 of the cylindrical body 31 are both configured by a non-porous tube such as a normal stainless steel tube. For example, the cylindrical body 31 is obtained by connecting a non-porous stainless steel tube to both ends of the porous stainless steel tube 311 and welding each connecting portion. The side of the (−X) side end portion 312 is closed by welding a non-porous member such as a normal stainless steel plate, and penetrates the hollow portion of the cylindrical body 31 as described below. The coming hydrogen 6 can be taken out from the (+ X) side end.

A hydrogen permeable membrane 32 is provided on the outer surface of the porous stainless steel tube 311 of the cylindrical body 31. For this reason, only the hydrogen 6 in the reformed gas generated by the catalyst layer 33 having the configuration described below permeates through the hollow portion of the cylindrical body 31 through the hydrogen permeable membrane 32 and the porous stainless steel tube 311, and more specifically. In particular, it can be dissolved and diffused and exists in the hydrogen permeable membrane 32 in the form of hydrogen ions. On the other hand, the reformed gas and the raw material gas excluding hydrogen (H ₂ ) are blocked by the hydrogen permeable membrane 32 and are prevented from being dissolved and diffused into the hollow portion of the cylindrical body 31 via the porous stainless steel tube 311.

  As shown in FIGS. 1 and 2, a catalyst portion 331 is provided on the outer surface of the hydrogen permeable membrane 32 so as to be spirally wound, and the catalyst layer 33 is formed by the catalyst portion 331. For this reason, the region where the catalyst portion 331 is not formed on the outer surface of the hydrogen permeable membrane 32 is an exposed region, and the hydrogen 6 is hollowed through the hydrogen permeable membrane 32 and the porous stainless steel tube 311. It becomes an area AR (hereinafter referred to as a “hydrogen dissolution diffusion area”) AR that is dissolved and diffused in the portion.

FIG. 3 is a diagram schematically showing the internal structure of the catalyst portion shown in FIG. The catalyst portion 331 includes a supported catalyst 334 that supports catalyst particles 333 having a smaller diameter than the catalyst support 332 on the surface of the catalyst support 332 and exhibits a catalytic function. Since the spiral catalyst portion 331 is formed by discharging from a discharge nozzle portion (not shown) as described below, powdered silica (SiO ₂ ) having a particle size of 1 to 100 [μm] is used. , Alumina (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and the like are used as the catalyst carrier 332. In addition, in order to exert a catalytic function by the supported catalyst 334, in the present embodiment, simple elements such as gold (Au), platinum (Pt), palladium (Pd) having a smaller diameter than the catalyst carrier 332, oxides thereof, Hydroxide is used as the catalyst particles 333.

In providing the catalyst portion 331 on the outer surface of the hydrogen permeable membrane 32, a paste-like fluid material is prepared by mixing the supported catalyst 334, a photocurable binder resin, and a liquid component such as water or an organic solvent. The fluid material is discharged from the discharge nozzle portion to the outer surface of the hydrogen permeable membrane 32 to apply the catalyst portion 331. The fluid material is a non-Newtonian fluid and has a viscosity of 10 to 500 [Pascal second] at a shear rate of 10 [s ⁻¹ ] in consideration of maintaining the shape after discharging to the hydrogen permeable membrane 32. desirable. As the binder resin, polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), or the like can be used.

  Further, the catalyst part 331 is cured by irradiating the applied catalyst part 331 with ultraviolet rays. Inside the catalyst unit 331, as schematically shown in FIG. 3, the supported catalyst 334 is coupled to each other by the binder resin 335, and a part of the liquid component is discharged while the fluid material is discharged and irradiated with light. However, many voids 336 are formed by evaporation, and the total volume of the voids 336 reaches about 10 to 30% with respect to the volume of the catalyst portion 331.

  As described above, in this embodiment, a fluid material prepared by mixing the supported catalyst 334, a photocurable binder resin (binder), and a liquid component such as water or an organic solvent is spirally applied. Thus, a catalyst layer 33 composed of one catalyst portion 331 is formed. In the catalyst layer 33 thus formed, as shown in FIG. 3, a plurality of supported catalysts 334 in which catalyst particles 333 having a diameter smaller than that of the catalyst support 332 are dispersed and supported on the surface of the granular catalyst support 332 are bound with a binder resin 335. The specific surface area can be improved. Moreover, in this embodiment, after application | coating of fluid material, since the liquid component in fluid material is evaporated and the space | gap 336 is formed in each catalyst part 331, a specific surface area can be improved further. As a result, an excellent catalytic function can be obtained.

  The specific surface area is improved not only inside the catalyst layer 33 but also outside the catalyst layer 33. That is, each catalyst portion 331 has a three-dimensional shape that is self-supporting on the outer surface of the hydrogen permeable membrane 32 as shown in FIG. 2, and exhibits a catalytic reaction not only on the ceiling surface but also on the side surface of the catalyst portion 331. Therefore, the specific surface area can be further improved, and the catalytic function can be further enhanced.

  Returning to FIG. 1, the description will be continued. With the porous stainless steel tube 311 positioned in the reforming space 21, the (−X) side end 312 and the (+ X) side end 313 are the (−X) side surface and (+ X) side surface of the reaction tube 2, respectively. It is arranged through. Since the (−X) side end 312 of the cylindrical body 31 is closed, the hydrogen 6 dissolved and diffused in the hollow portion as described above flows to the (+ X) side end 313 and is supplied via the pipe 54 to the hydrogen. It is sent to the collection unit 7. The hydrogen recovery unit 7 recovers the hydrogen 6 in a cylinder (not shown).

  As described above, in the present embodiment, the cylindrical body 31 and the hydrogen permeable membrane 32 function as hydrogen separation means for separating the hydrogen 6, and the catalyst structure 3 is provided by including the hydrogen separation means and the catalyst layer 33. Has both the reforming function of the source gas and the purification function of the reformed gas.

  The gas remaining after separating the hydrogen 6 from the reformed gas, the raw material gas remaining without reforming, and water vapor are sent to the (+ X) side end of the reaction tube 2 and are provided in the reaction tube 2. The residual gas is recovered by the residual gas recovery unit 8 through the control unit 23.

  As described above, according to the present embodiment, the hydrogen-permeable membrane in which the spiral catalyst portion 331 is provided with the hydrogen-dissolving diffusion area AR with respect to the outer surface of the hydrogen-permeable membrane 32 that is one component of the hydrogen separation means. The hydrogen permeable membrane 32 is integrated on the outer surface of 32. For this reason, it is possible to effectively prevent the hydrogen permeable membrane 32 from being damaged by the catalyst layer 33. In addition, the hydrogen that has dissolved and diffused in the hydrogen dissolution and diffusion area AR in the hydrogen permeable membrane 32 further permeates through the porous portion and permeates into the cylindrical body. Accordingly, hydrogen can be purified with excellent efficiency.

  In the above embodiment, the porous stainless steel tube 311 corresponds to an example of the “porous portion” of the present invention. The hollow portion of the cylindrical body 31 corresponds to the “inside of the cylindrical body” of the present invention. The X direction corresponds to the “longitudinal direction of the cylinder” in the present invention.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the embodiment described above, the binder resin 335 having photocurability is used as an example of the “binder”, but a binder resin having thermosetting property may be used. Further, fine particles finer than the catalyst carrier may be used instead of the binder resin. More specifically, fine particles such as silica (SiO ₂ ), alumina (Al ₂ O ₃ ), and titanium oxide (TiO ₂ ) can be used. In this case, the catalyst part is formed as follows.

  A paste-like fluid material is prepared by mixing the supported catalyst 334, a photocurable binder resin, and a liquid component such as water or an organic solvent, and the fluid material is passed through the discharge nozzle portion through hydrogen. The catalyst portion 331 is applied by discharging to the outer surface of the film 32. Inside the catalyst portion 331, as shown in FIG. 4, the binder fine particles 337 enter between the supported catalysts 334 to bond the supported catalysts 334 to each other, and a large number of voids 336 are formed by evaporation of a part of the liquid component. The

  Moreover, in the said embodiment, although the catalyst layer 33 is comprised by the one catalyst part 331, you may comprise the catalyst layer 33 by a some catalyst part. For example, two or more spiral catalyst portions 331 may be formed on the hydrogen permeable membrane 32 so as to be separated from each other in the longitudinal direction X of the cylindrical body 31. Further, as shown in FIG. 5, a plurality of annular annular catalyst portions 338 surrounding the outer surface of the hydrogen permeable membrane 32 may be formed on the hydrogen permeable membrane 32 so as to be separated from each other in the longitudinal direction X of the cylindrical body 31. (Second Embodiment).

  Further, the shape of the catalyst portion is not limited to the spiral shape or the annular shape described above, and is arbitrary, for example, a strip shape (or rod shape) as shown in FIG. 6 or a strip shape (island) as shown in FIG. The catalyst layer 33 may be configured by a catalyst portion 339 having a shape or a dot shape. In particular, when the strip-shaped catalyst part 339 is provided, a plurality of catalyst parts 339 may be arranged on the hydrogen permeable membrane 32 so as to be separated from each other in the circumferential direction of the cylindrical body 31 as shown in FIG. Third embodiment). In addition, when the length of the strip-shaped catalyst part 339 in the X direction is sufficiently shorter than the hydrogen permeable membrane 32, as shown in FIG. A plurality of strip-shaped catalyst parts 339 may be arranged on the hydrogen permeable membrane 32 so as to be separated from each other in the longitudinal direction X (fourth embodiment). Further, in FIGS. 6 and 7, the catalyst portion 339 is extended in the X direction. However, in the case where the catalyst portion 339 has a shape inclined with respect to the X direction, the catalyst portion 339 is configured in the same manner as described above and shown in FIGS. The same effect as the embodiment can be obtained.

  In the above embodiment, the catalyst layer 33 is configured by the catalyst portions 331 (338, 339) disposed on the hydrogen permeable membrane 32. However, the formation position of the catalyst portion is limited to the outer surface of the hydrogen permeable membrane 32. It may be arranged at an arbitrary position on the outer surface of the cylindrical body 31 instead of the one. For example, as shown in FIG. 8, a plurality of annular catalyst portions 338 may be arranged on the outer surface of the non-porous portion, that is, the cylindrical body 31 other than the porous portion 311. Of course, you may comprise so that the catalyst layer 33 may be arrange | positioned on the outer surface of the hydrogen permeable film 32, and the outer surface of a non-porous part (5th Embodiment). In short, one or more catalyst parts are placed on the outer surface of the hydrogen separation means (= cylinder 31 + hydrogen permeable membrane 32) so that the entire surface or a part of the hydrogen permeable membrane 32 is exposed and becomes the hydrogen dissolution diffusion area AR. The catalyst layer 33 may be formed by providing it.

  Moreover, in the said embodiment, although the cylindrical-shaped cylinder 31 is used, the shape of a cylinder is not limited to this, You may use a square-shaped cylinder.

  In the hydrogen production apparatus shown in FIG. 1, a single catalyst structure 3 is accommodated in the reaction tube 2 to purify hydrogen. However, a plurality of catalyst structures 3 are contained in the reaction tube 2. May be used to enhance the hydrogen production capacity.

  The present invention can be applied to all hydrogen production techniques for reforming a raw material gas and separating hydrogen from the reformed gas.

1 ... Hydrogen production equipment,
2 ... reaction tube,
3 ... catalyst structure,
4 ... Raw material gas supply section,
6 ... Hydrogen 7 ... Hydrogen recovery section,
21 ... reforming space,
31 ... Cylinder (hydrogen separation means),
32 ... hydrogen permeable membrane (hydrogen separation means),
33 ... catalyst layer,
311 ... porous stainless steel pipe (porous part),
331 ... (spiral) catalyst part,
338 ... (annular) catalyst part,
339 ... (strip-shaped) catalyst part,
AR ... Hydrogen dissolution and diffusion area,
X: Longitudinal direction

Claims (7)

A catalyst layer for reforming the source gas to produce a reformed gas containing hydrogen;
Hydrogen in the reformed gas having a cylindrical body provided with a porous part at least in part and a hydrogen permeable film provided on the outer surface of the porous part, through the hydrogen permeable film and the porous part Hydrogen separation means for separating the inside of the cylinder,
The catalyst structure according to claim 1, wherein the catalyst layer is provided on an outer surface of the hydrogen separation means in a state where at least a part of the outer surface of the hydrogen permeable membrane is exposed. The catalyst structure according to claim 1,
The catalyst layer is a catalyst structure formed by binding a plurality of supported catalysts in which catalyst particles having a smaller diameter than the catalyst support are dispersed and supported on the surface of a granular catalyst support by a binder. A catalyst structure according to claim 1 or 2,
The catalyst structure is a catalyst structure having a catalyst portion provided in a spiral shape with respect to the outer surface of the hydrogen separation means. A catalyst structure according to claim 1 or 2,
The catalyst layer has a plurality of catalyst portions,
The catalyst structure in which the plurality of catalyst parts are arranged on the outer surface of the hydrogen separation means apart from each other. A catalyst structure according to claim 4,
Each of the plurality of catalyst parts has an annular shape surrounding the outer surface of the hydrogen separation means,
The catalyst structure is configured such that the plurality of catalyst portions are spaced apart from each other in the longitudinal direction of the cylindrical body and disposed on the outer surface of the hydrogen separation means. A catalyst structure according to claim 4,
Each of the plurality of catalyst parts has a shape extending in the longitudinal direction of the cylindrical body or inclined with respect to the longitudinal direction,
The catalyst structure is configured such that the plurality of catalyst portions are spaced apart from each other in the circumferential direction of the cylindrical body and disposed on the outer surface of the hydrogen separation means. A catalyst structure according to any one of claims 1 to 6;
A source gas supply unit for supplying source gas to the catalyst layer;
A hydrogen production apparatus comprising: a hydrogen recovery unit that recovers hydrogen from the inside of the cylindrical body.

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