JP6382737B2 - Self-heating reformer - Google Patents

Description

  The present invention relates to an autothermal reformer.

  The steam reforming method is a typical method for producing hydrogen. In this steam reforming method, a mixed gas of a hydrocarbon-containing gas such as natural gas, naphtha, kerosene, and methanol and steam is reformed in the presence of a reforming catalyst to generate carbon monoxide and hydrogen. This reforming reaction is an endothermic reaction, and as a heat source necessary for the reforming reaction, a self-heating reformer using heat of oxidation reaction of the hydrocarbon, that is, combustion heat is known.

  In general, an autothermal reformer includes an oxidation reforming layer that includes a catalyst that promotes an oxidation reaction and a catalyst that promotes the reforming reaction. A small amount of oxygen-containing gas is supplied in addition to the mixed gas. By doing so, a part of the hydrocarbon is oxidized, that is, combusted by the presence of the oxidation catalyst in the oxidation reforming layer, and the reforming reaction can be advanced using this combustion heat.

  If the oxygen concentration in the mixed gas in the oxidation reforming layer is high, an excessive oxidation reaction may occur and the temperature may increase excessively, and the activity of the catalyst may be lost. For this reason, in the conventional autothermal reformer, the supply amount of the oxygen-containing gas to the oxidation reforming layer is limited, but oxygen is insufficient on the downstream side of the oxidation reforming layer, and the reforming reaction is sufficiently performed. You may not be able to proceed.

  Therefore, in order to prevent an oxidation reaction from occurring locally in the oxidation reforming layer, an oxygen supply pipe is provided so as to extend into the oxidation reforming layer, and a plurality of openings are provided in the oxygen supply pipe. Thus, it has been proposed to supply oxygen into the oxidation reforming layer from a plurality of locations with respect to the oxidation catalyst (see Japanese Patent Application Laid-Open No. 2007-153665).

  However, even if the oxygen-containing gas is supplied using an oxygen supply pipe having a plurality of openings as disclosed in the above publication, the oxidation reaction in the vicinity of the openings may be locally excessive. It has not reached its full potential, and there is room for further improvement in catalyst utilization.

JP 2007-153665 A

  This invention is made | formed based on the above situations, and makes it a subject to provide the self-heat-type reformer which can improve the utilization factor of a catalyst.

  The self-thermal reformer of the present invention includes an oxidation reforming layer including an oxidation and reforming catalyst, and a part of the hydrocarbons contained in the mixed gas of hydrocarbon and steam is burned in the oxidation reforming layer. An autothermal reformer that performs a steam reforming reaction of the hydrocarbon by the combustion heat, and is attached to a pipe for supplying an oxygen-containing gas to the oxidation reforming layer, and a tip of the pipe. A porous body that disperses and jets the mixed gas, and at least a part of the porous body is inserted into the oxidation-modified layer.

  Since the self-heating reformer disperses and jets oxygen-containing gas into the oxidation reforming layer through the porous body, it is possible to suppress a local increase in the oxygen concentration in the oxidation reforming layer. For this reason, while preventing local temperature rise in the oxidation reforming layer, oxygen can be supplied to the entire oxidation reforming layer to improve the utilization rate of the catalyst and promote the reforming reaction.

  The porous body may be bonded to the tip of the pipe. In this way, by joining the porous body to the tip of the pipe, the oxygen-containing gas can be easily ejected from the entire peripheral surface of the porous body, and the local increase in the oxygen concentration is more efficiently suppressed. it can.

  The porous body may be fitted in the pipe, and the pipe may have a plurality of openings through which the porous body is exposed in the porous body insertion region. In this way, by fitting the porous body in the pipe and forming the opening in the pipe, the oxygen-containing gas can be dispersed and ejected and the strength of the porous body can be reinforced by the pipe. It is possible to prevent damage to the porous body due to thermal stress at the time of stopping.

  The average pore diameter of the porous body is preferably 0.1 μm or more and 10 μm or less. Thus, since the average pore diameter of the porous body is within the above range, it is possible to prevent the oxygen-containing gas from being ejected toward the upstream portion of the porous body, so that the oxygen-containing gas from the porous body Ejection can be made more uniform.

  The porosity of the porous body is preferably 20% or more and 80% or less. As described above, even when the porosity of the porous body is within the above range, the oxygen-containing gas from the porous body is prevented from being ejected toward the upstream portion of the porous body. Can be made more uniform.

  The melting point of the porous body is preferably higher than the melting points of the reforming catalyst and the oxidation catalyst carrier. As described above, since the melting point of the porous body is higher than the melting points of the reforming catalyst and the support of the oxidation catalyst, even if the temperature in the oxidation reforming layer rises excessively, the porous body is prevented from being damaged. Therefore, the life of the autothermal reformer can be extended.

  The downstream end of the porous body is upstream from the downstream end of the oxidation reforming layer, and downstream of the point 0.2 times upstream of the length of the oxidation reforming layer with respect to the downstream end of the oxidation reforming layer. Good location. Thus, when the downstream end of the porous body is located within the above range, almost all oxygen can be combusted in the oxidation reforming layer while improving the utilization rate of the catalyst in the oxidation reforming layer.

  The upstream end of the porous body is upstream from the upstream end of the oxidation reforming layer, and downstream from the point upstream of the oxidation reforming layer by 0.2 times the length of the oxidation reforming layer with reference to the upstream end of the oxidation reforming layer. It should be located on the side. Thus, when the upstream end of the porous body is located within the above range, excessive combustion at the upstream end of the oxidation reforming layer can be prevented while improving the utilization rate of the catalyst in the oxidation reforming layer.

  The difference between the average pressure in the piping in the vicinity of the porous body and the average pressure in the oxidation-modified layer in the vicinity of the porous body is 0 for the average pressure in the oxidation-modified layer in the vicinity of the porous body. 0125 or more and 0.25 or less is preferable. Thus, the difference between the average pressure in the pipe near the porous body and the average pressure in the oxidation reforming layer, that is, the ratio of the average pressure loss in the porous body to the average pressure in the oxidation reforming layer is in the above range. By being inside, it becomes easy to appropriately adjust the ejection amount of the oxygen-containing gas from the porous body.

  Here, the “oxidation and reforming catalyst” includes, in addition to a mixture of an oxidation catalyst and a reforming catalyst, a catalyst having both a catalytic function for an oxidation reaction and a catalytic function for a reforming reaction. The “porous body” means a member formed of a material having continuous pores, and does not include a member that does not have continuous pores and is provided with independent through holes. Further, “average pore diameter of porous body” and “porosity of porous body” are values measured by a pore distribution measuring device.

  As described above, the autothermal reformer of the present invention can improve the utilization rate of the catalyst.

FIG. 1 is a schematic cross-sectional view showing an autothermal reformer according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along line AA of the autothermal reformer of FIG. FIG. 3 is a schematic enlarged cross-sectional view of the porous body at the pipe tip of the self-heating reformer of FIG. FIG. 4 is a schematic enlarged cross-sectional view of the porous body at the distal end portion of the pipe of the self-heating reformer of the embodiment different from FIG. FIG. 5 is a schematic enlarged side view of the porous body at the tip end of the pipe of the self-heating reformer of the embodiment different from FIGS. 3 and 4. 6 is a cross-sectional view of the porous body at the tip end of the pipe in FIG. 5 taken along the line BB. FIG. 7 is a schematic enlarged cross-sectional view of a porous body at the tip end of a pipe of an autothermal reformer of an embodiment different from those in FIGS. 3 to 6. FIG. 8 is a schematic enlarged cross-sectional view of a porous body at the tip of a pipe of an autothermal reformer of an embodiment different from those in FIGS. 3 to 7. FIG. 9 is a schematic enlarged cross-sectional view of the porous body at the distal end portion of the pipe of the self-heating reformer of the embodiment different from FIGS. 3 to 8.

[Description of Embodiment of the Present Invention]
Hereinafter, each embodiment of the self-heating reformer according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
The self-heating reformer of FIGS. 1 and 2 burns a part of hydrocarbons contained in a mixed gas of hydrocarbon and steam, and the reforming containing hydrogen by the steam reforming reaction of hydrocarbons by this combustion heat. This is a device for generating a quality gas.

  This self-heating reformer is formed of a double pipe, and houses an inner container 1 that forms an internal space that serves as a gas flow path having a circular cross section between the double pipe and the inner container 1. The inner container 1 extends in the axial direction through the inside of the inner tube of the inner container 1 and branches into a plurality of upstream sides of the inner container 1, each tip being upstream of the inner space of the inner container 1. An oxygen supply pipe 3 inserted into the end portion and a plurality of porous bodies 4 respectively attached to a plurality of tip portions of the oxygen supply pipe 3 are provided.

<Inner container>
The inner container 1 includes an oxidation reforming layer 5 formed therein and containing an oxidation and reforming catalyst, and a CO conversion layer 6 located on the downstream side of the oxidation reforming layer 5. In the self-heating reformer of FIG. 1, since a mixed gas is supplied from the upper end as will be described later, a CO conversion layer 6 is formed below the oxidation reforming layer 5. Further, the inner container 1 of FIG. 1 has an upper end opened and a lower end sealed, and a discharge pipe 7 for allowing the reformed gas to flow out is connected in the vicinity of the lower end portion of the outer pipe.

(Oxidation modified layer)
The oxidation reforming layer 5 is formed by laminating a support member 8 having air permeability disposed in the inner container 1 and laminating an oxidation and reforming catalyst supported on a particulate carrier, for example. It is formed so that gas can pass by having an air gap. In the autothermal reformer, a part of the hydrocarbon contained in the mixed gas of hydrocarbon and steam is combusted in the oxidation reforming layer 5 and the steam reforming reaction of the hydrocarbon is performed by the combustion heat. .

  As the oxidation and reforming catalyst, a mixture of an oxidation catalyst that promotes hydrocarbon oxidation, that is, combustion, and a reforming catalyst that promotes a steam reforming reaction in which hydrocarbon reacts with steam is generally used.

  The oxidation catalyst oxidizes hydrocarbons to obtain heat necessary for the steam reforming reaction. The oxidation catalyst is not particularly limited, and a known catalyst can be used. Examples thereof include platinum, palladium, rhodium, and ruthenium. These can be used alone or in combination of two or more.

  The content of the oxidation catalyst relative to the total of the oxidation catalyst and the reforming catalyst is appropriately selected depending on the type of hydrocarbon used, and is, for example, 1% by mass to 15% by mass. In addition, when using methane as a hydrocarbon, 1 to 5 mass% is preferable, and when using methanol, 1 to 3 mass% is preferable.

  The reforming catalyst promotes a steam reforming reaction in which hydrocarbon is reacted with steam to generate hydrogen. In this steam reforming reaction, hydrocarbon and steam are reacted to produce carbon monoxide and hydrogen, but the generated carbon monoxide reacts with steam to produce carbon dioxide and hydrogen. Accompanied by.

The reforming catalyst is not particularly limited and a known catalyst can be used. For example, NiO—A1 ₂ O, NiO—SiO ₂ .A1 ₂ O ₃ , WO ₂ —SiO ₂ .A1 ₂ O ₃ , NiO _{-WO 2 · SiO 2 · A1 2} O 3 and the like. These can be used alone or in combination of two or more.

As the oxidation and reforming catalyst, a catalyst having both a catalyst function for promoting the oxidation reaction and a catalyst function for promoting the reforming reaction can be used instead of using the oxidation catalyst and the reforming catalyst in combination. For example, NiO-A1 ₂ O, NiO-SiO ₂ · A1 ₂ O ₃ , WO ₂ -SiO ₂ · A1 ₂ O ₃ , NiO-WO ₂ · SiO ₂ · A1 ₂ O _{3 and the} like are used as base materials. For example, a catalyst having platinum, palladium, rhodium, ruthenium or the like attached thereto can be used as an oxidation reaction active species that imparts an oxidation function to the surface.

  Such oxidation and reforming catalysts are supported by a support. The carrier is not particularly limited, and a known carrier can be used. For example, alumina, silica, zeolite or the like is used.

  The shape of the support in which the oxidation and reforming catalyst is supported by a carrier is not particularly limited, and a pellet type or monolith type can be used.

  The support member 8 that supports the oxidation and reforming catalyst may be any member as long as the support for the oxidation and reforming catalyst does not pass therethrough, allows gas to pass therethrough, and has sufficient strength. Formed by.

(CO metamorphic layer)
The CO shift layer 6 is formed by laminating a CO support catalyst supported on a particulate carrier, for example, on a support member 9 having air permeability disposed in the inner container 1, and has a void. Thus, the gas is formed to pass therethrough.

  The CO shift catalyst promotes an aqueous shift reaction between carbon monoxide remaining in the reformed gas flowing out from the oxidation reforming layer and water vapor on the downstream side of the oxidation reforming layer.

The CO shift catalyst is not particularly limited, and a known catalyst can be used, and a two-stage configuration of a high temperature shift catalyst layer and a low temperature shift catalyst layer may be used. The above-mentioned modification catalyst is not particularly limited, and a known catalyst can be used, and examples thereof include CuO—ZnO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , copper oxide and the like. These can be used alone or in combination of two or more.

  Similar to the oxidation and reforming catalyst, the CO shift catalyst is supported on a carrier to form a granular material, and is laminated in the inner vessel 1 to form the CO shift layer 6.

  The support member 9 that supports the CO shift catalyst is the same as the support member 9 that supports the oxidation and reforming catalyst.

<Outer container>
The outer container 2 is a cylindrical container that houses the inner container 1 and is sealed at both ends. The outer container 2 is provided with a supply path 10 through which a mixed gas is supplied near the lower end. With such a configuration, the outer container 2 guides the mixed gas along the inner surface of the inner tube of the inner container 1 and the outer surface of the outer tube, preheats the mixed gas with the heat of the inner container 1, and then the inner container 1. Supply to the top.

<Piping>
The oxygen supply pipe 3 supplies an oxygen-containing gas containing oxygen to the oxidation reforming layer 5 in the inner container 1. The oxygen supply pipe 3 penetrates the outer wall on the downstream side of the outer container 2 and extends the space further inside the inner tube of the inner container 1 in the vertical direction, and the tip portion branches into a plurality above the inner container 1. Yes. The plurality of tip portions of the oxygen supply pipe 3 are disposed at substantially equal intervals in the region of the oxidation reforming layer 5 in plan view. The oxygen supply pipe 3 has an effect of preheating the oxygen-containing gas by being arranged so that the upstream portion before branching passes through the inside of the inner pipe of the inner container 1.

  The oxygen-containing gas supplied through the oxygen supply pipe 3 may be any gas containing oxygen, but usually air or pure oxygen is used.

<Porous body>
The porous body 4 is formed in a cylindrical shape and is disposed so as to extend vertically along the flow direction of the mixed gas. At least a part of the porous body 4 is inserted into the oxidation reforming layer 5, and the oxygen-containing gas supplied from the oxygen supply pipe 3 is dispersed and ejected. As shown in FIG. 3, the porous body 4 in the self-heating reformer of FIG. 1 is a tubular member joined to the tip of the oxygen supply pipe 3, and the tip is sealed by the sealing member 11. Yes.

  As a method for joining the porous body 4 to the oxygen supply pipe 3 and a method for joining the sealing member 11 to the porous body 4, for example, welding, diffusion joining, mechanical joining by screws or the like can be applied.

  As the material of the porous body 4, any material can be used as long as it has heat resistance that can withstand the combustion heat of hydrocarbons and has continuous pores (small pores communicated with each other) that can disperse and jet oxygen-containing gas. For example, sintered metal or ceramics is used.

  The melting point of the porous body 4 is preferably higher than the melting point of the oxidation and reforming catalyst carrier. When the melting point of the porous body 4 is lower than the melting point of the oxidation and reforming catalyst carrier, the porous body 4 may melt and shorten the life of the self-heating reformer. Examples of the porous material having a high melting point include ceramics such as zirconia, spinel and yttria, and porous sintered metal bodies.

  Although it does not specifically limit as an average outer diameter of the porous body 4, For example, you may be 1 mm or more and 10 mm or less. On the other hand, the average inner diameter of the porous body 4 is not particularly limited, but is, for example, 0.5 mm or more and 8.0 mm or less.

  The downstream limit position of the downstream end of the porous body 4 is preferably the downstream end of the oxidation reforming layer 5, and the length in the flow direction of the oxidation reforming layer 5 is based on the downstream end of the oxidation reforming layer 5. A point 0.05 times upstream is more preferable. On the contrary, the limit position on the upstream side of the downstream end of the porous body 4 is a point on the upstream side 0.2 times the length in the flow direction of the oxidation reforming layer 5 with respect to the downstream end of the oxidation reforming layer 5. Is preferable, and a point 0.15 times upstream of the length of the oxidation-modified layer 5 in the flow direction is more preferable. When the downstream end of the porous body 4 is located downstream from the downstream limit position, oxygen supplied by the oxygen-containing gas cannot be consumed, and oxygen may carry over from the oxidation reforming layer 5 to the downstream side. There is. On the contrary, when the downstream end of the porous body 4 is located upstream from the upstream limit position, a region where oxygen on the downstream side of the oxidation reforming layer 5 is not supplied becomes large, and the catalyst utilization rate decreases. There is a fear.

  As the limit position on the downstream side of the upstream end of the porous body 4, the upstream end of the oxidation modified layer 5 is preferable, and the length in the flow direction of the oxidation modified layer 5 is based on the upstream end of the oxidation modified layer 5. A point 0.05 times upstream is more preferable. On the contrary, the upstream limit position of the upstream end of the porous body 4 is a point on the upstream side of the length in the flow direction of the oxidation reforming layer 5 with respect to the upstream end of the oxidation reforming layer 5. Is preferable, and a point 0.15 times upstream of the length of the oxidation-modified layer 5 in the flow direction is more preferable. When the upstream end of the porous body 4 is located downstream of the downstream limit position, a region where oxygen on the upstream side of the oxidation reforming layer 5 is not supplied becomes large, and the utilization rate of the oxidation and reforming catalyst is increased. May be insufficient. On the contrary, when the upstream end of the porous body 4 is located upstream from the upstream limit position, oxygen is excessively supplied to the upstream end of the oxidation reforming layer 5 and excessive combustion occurs, resulting in oxidation and oxidation. The reforming catalyst may lose its activity.

  The lower limit of the average pore diameter of the porous body 4 is preferably 0.1 μm, and more preferably 0.5 μm. On the other hand, the upper limit of the average pore diameter of the porous body 4 is preferably 10 μm and more preferably 5 μm. When the average pore diameter of the porous body 4 is less than the lower limit, the passage resistance of the mixed gas in the porous body is too large, and a sufficient amount of oxygen-containing gas cannot be ejected, and the mixed gas may not be sufficiently modified. There is. On the contrary, when the average pore diameter of the porous body 4 exceeds the above upper limit, the passage resistance of the mixed gas in the porous body 4 is too small, and the ejection amount of the mixed gas from the upstream portion of the porous body 4 becomes large, In some cases, oxygen is excessively supplied and the oxidation and reforming catalyst may lose its activity.

  Moreover, as a minimum of the porosity of the porous body 4, 20% is preferable and 25% is more preferable. On the other hand, the upper limit of the porosity of the porous body 4 is preferably 80%, more preferably 60%. When the porosity of the porous body 4 is less than the lower limit, the passage resistance of the mixed gas in the porous body is too large, and a sufficient amount of oxygen-containing gas cannot be ejected, and the mixed gas may not be sufficiently modified. There is. On the contrary, when the porosity of the porous body 4 exceeds the above upper limit, the passage resistance of the mixed gas in the porous body 4 is too small, and the amount of the mixed gas ejected from the upstream portion of the porous body 4 becomes large, In some cases, oxygen is excessively supplied and the oxidation and reforming catalyst may lose its activity.

  The average pressure in the oxygen supply pipe 3 in the vicinity of the porous body 4, that is, the supply pressure Ps of the mixed gas, and the average pressure in the oxidation reforming layer 5 in the vicinity of the porous body 4, that is, the mixed gas are reformed. The lower limit of the pressure ratio (Ps−Pc) / Pc with respect to the average pressure Pc in the oxidation-modified layer 5 in the vicinity of the porous body that is different from the reforming pressure Pc is preferably 0.0125, more preferably 0.05. preferable. On the other hand, the upper limit of the pressure ratio (Ps−Pc) / Pc is preferably 0.25, and more preferably 0.2. When the pressure ratio (Ps−Pc) / Pc is less than the lower limit, the gas cannot be sufficiently distributed, and the amount of the mixed gas ejected from the upstream portion of the porous body 4 becomes large. Oxygen is excessively supplied, and the oxidation and reforming catalyst may lose its activity. On the contrary, when the pressure ratio (Ps−Pc) / Pc exceeds the upper limit, it is necessary to increase the supply pressure of the oxygen-containing gas. The contained gas cannot be ejected, and the mixed gas may not be sufficiently reformed.

  Normally, the sealing member 11 that seals the downstream end of the porous body 4 is preferably formed of a nonporous material. However, when the distance to the support member 8 is large, the sealing member 11 is formed of a porous material. In some cases, it may be preferable. When forming the sealing member 11 with a porous material, you may use the material from which the porous body 4 and the average hole diameter and porosity of a pore differ.

  Further, the lower limit of the reforming pressure Pc is preferably 0.2 MPa, and more preferably 0.5 MPa. On the other hand, the upper limit of the reforming pressure Pc is preferably 1.5 MPa, and more preferably 1.2 MPa. If the reforming pressure Pc is less than the lower limit, a sufficient flow rate may not be secured due to pressure loss on the downstream side of the CO shift layer 6 and the like. On the other hand, when the reforming pressure Pc exceeds the upper limit, the pressure resistance of the autothermal reformer may be insufficient, or the autothermal reformer may be expensive for pressure resistance. . In particular, if the reforming pressure Pc is less than 1.0 MPa, it is not handled as a high-pressure gas in accordance with the law, so that the equipment cost and operation cost can be reduced.

<Advantages>
In the self-heating reformer, the oxygen-containing gas is ejected substantially uniformly from the entire peripheral surface of the porous body 4 joined to the tip of the oxygen supply pipe 3, so that the local increase in oxygen concentration is efficiently suppressed. Thus, it is possible to effectively prevent the bias of the oxidation reaction in the oxidation modified layer 5. Therefore, the oxygen-containing gas is sufficiently supplied to the oxidation reforming layer 5 to improve the utilization rate of the oxidation and reforming catalyst, while the temperature rises locally and the oxidation and reforming catalyst is deactivated. Can be prevented.

[Second Embodiment]
FIG. 4 shows the tip of the oxygen supply pipe 3 and the porous body 4a that can be used in place of the tip of the oxygen supply pipe 3 and the porous body 4 of the autothermal reformer of FIG.

  The porous body 4a of FIG. 4 is fitted in the oxygen supply pipe 3a, and the oxygen supply pipe 3 has a plurality of openings 12 through which the porous body 4a is exposed in the porous body 4a insertion region. ing. The tip of the oxygen supply pipe 3a is inserted into the oxidation reforming layer 5 together with the porous body 4a. Further, the tip of the oxygen supply pipe 3 a is sealed with a sealing member 11. The positional relationship of the porous body 4a in FIG. 4 with respect to the oxidation reforming layer 5 is the same as that of the porous body 4 of the self-heating reformer in FIG.

<Advantages>
By using the oxygen supply pipe 3a and the porous body 4a of FIG. 4, since the high mechanical strength is not required for the porous body 4a, the material selection possibility of the porous body 4a is expanded and the porous body 4a is oxidized. The operation of inserting into the modified layer 5 becomes easy.

  Further, since the porous body 4a is held by being fitted into the pipe 3a, the influence of thermal stress at the start and stop of the self-heat reformer can be reduced. Specifically, by adopting the configuration shown in FIG. 4, the thermal stress acting on the joint surface due to the difference in thermal expansion coefficient between the porous body 4 a and the pipe 3 a causes the porous body 4 a to be removed from the pipe 3 a. The risk of desorption can be reduced.

[Third Embodiment]
5 and FIG. 6 show the tip of the oxygen supply pipe 3 and the porous body 4b of another oxygen supply pipe 3b that can be used in place of the tip of the oxygen supply pipe 3 and the porous body 4 of the autothermal reformer of FIG. Indicates.

  In the porous body 4b shown in FIGS. 5 and 6, an axial engagement groove 13 is formed on the outer peripheral surface of a cylindrical member. In this engagement groove 13, an extension portion 14 is provided so as to protrude from the tip of the oxygen supply pipe 3 b in the axial direction, preferably by cutting off the other part of the pipe constituting the oxygen supply pipe 3 b. Is engaged. The sealing member 11 disposed so as to seal the downstream end of the porous body 4 b is joined to the tip of the extending portion 14.

<Advantages>
The tip of the oxygen supply pipe 3b and the porous body 4b in FIGS. 5 and 6 have higher bonding strength between the oxygen supply pipe 3b and the porous body 4b than in the embodiment of FIG. 3, and the embodiment of FIG. Since the peripheral surface of the porous body 4b is more largely exposed, the uniformity of the ejection of the oxygen-containing gas is high.

[Fourth Embodiment]
FIG. 7 shows a front end portion of an oxygen supply pipe 3c and a porous body 4c that can be used in place of the front end portion of the oxygen supply pipe 3 and the porous body 4 of the autothermal reformer of FIG.

  The porous body 4c of FIG. 7 is formed in a substantially cylindrical shape, and is fitted on the outer periphery of the distal end portion of the oxygen supply pipe 3c. A plurality of openings 12c are formed in the porous body 4c fitting region of the oxygen supply pipe 3c. The front end of the oxygen supply pipe 3c is sealed with a sealing member 11 fitted inside the downstream end of the porous body 4c.

<Advantages>
As for the front-end | tip part of the oxygen supply piping 3c of FIG. 7, and the porous body 4c, the oxygen supply piping 3c reinforces the porous body 4c from an inner side. Further, the porous body 4c further disperses the oxygen-containing gas flowing out from the plurality of openings 12c of the oxygen supply pipe 3c and releases it to the oxidation reforming layer 5, thereby locally heating the oxidation reforming layer 5. To prevent.

[Fifth Embodiment]
FIG. 8 shows a tip portion of an oxygen supply pipe 3d and a porous body 4d that can be used in place of the tip portion and the porous body 4 of the oxygen supply pipe 3 of the self-heating reformer of FIG.

  A male screw 15 is formed on the outer periphery of the distal end portion of the oxygen supply pipe 3d in FIG. 8, and is screwed into a female screw 16 formed on the inner periphery of the open end portion of the bottomed cylindrical porous body 4d. The porous body 4d has an outer diameter several times that of the oxygen supply pipe 3d.

<Advantages>
Since the tip of the oxygen supply pipe 3d and the porous body 4d in FIG. 8 are joined by screwing of the screws 15 and 16, the manufacture is easy, and it is possible to replace only the porous body 4d relatively easily. . Further, since the porous body 4d has a large surface area on the peripheral surface, the flow rate of the oxygen-containing gas ejected from the porous body 4b is small, and local heating of the oxidation-modified layer 5 can be more effectively suppressed.

[Sixth Embodiment]
FIG. 9 shows a distal end portion of an oxygen supply pipe 3e and a porous body 4e that can be used in place of the distal end portion of the oxygen supply pipe 3 and the porous body 4 of the autothermal reformer of FIG.

  The porous body 4e in FIG. 9 includes three portions 17, 18, and 19 having different porosity in the flow direction. The porosity of the midstream portion 18 is greater than that of the upstream portion 17 of the porous body 4e, and the porosity of the downstream portion 19 is greater than that of the midstream portion 18.

<Advantages>
The porous body 4e in FIG. 9 is joined to the tip of the oxygen supply pipe 3e, and the porosity is larger toward the downstream side. Therefore, the permeation resistance of the porous body 4e is decreased toward the downstream side where the pressure decreases due to the release of the oxygen-containing gas. Thus, the difference in the amount of oxygen-containing gas ejected between the upstream side and the downstream side can be reduced. Thereby, the oxidation of the oxidation reforming layer 5 and the utilization rate of the reforming catalyst can be further improved.

[Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above embodiment, each component can be omitted, replaced, or added based on the description of the present specification and common general technical knowledge, and all of them should be interpreted as belonging to the scope of the present invention.

  In the above embodiment, the mixed gas and oxygen-containing gas supplied to the oxidized reformed layer are preheated by the heat generated in the oxidized reformed layer, but the oxidized reformed layer is not preheated with the mixed gas and oxygen-containing gas. Or may be preheated by other means.

  Further, the vertical relationship of the self-thermal reformer is not limited to the description of the above embodiment. That is, the autothermal reformer may be one in which the mixed gas flows horizontally, or the mixed gas may flow in the vertical direction from bottom to top, and the mixed gas is slanted differently from the vertical and horizontal. It may flow in the direction. In this case, in order to hold | maintain each catalyst, arrangement | positioning of a supporting member is changed suitably.

  In the autothermal reformer, a plurality of porous bodies may be arranged to form a plurality of concentric rows in the oxidation reforming layer.

  The cross-sectional shape of the self-heating reformer is not limited to the annular shape as in the above embodiment, and may be one that does not form a cavity in the center, and the outer shape may be other shapes such as a square shape. . Also, the number of porous bodies and the cross-sectional shape can be modified as appropriate.

  The autothermal reformer can also be used as a pre-reformer in a reforming system that performs a steam reforming reaction in multiple stages.

  The present invention can be suitably used for a hydrogen station or the like.

DESCRIPTION OF SYMBOLS 1 Inner container 2 Outer container 3, 3a, 3b, 3c, 3d, 3e Piping 4, 4a, 4b, 4c, 4d, 4e Porous body 5 Oxidation modification layer 6 CO transformation layer 7 Exhaust pipe 8, 9 Support member 10 Supply pipe 11 Sealing member 12, 12c Opening 13 Engaging groove 14 Extension 15 Male thread 16 Female thread 17 Upstream part 18 Middle stream part 19 Downstream part

Claims (7)

An oxidation reforming layer including an oxidation and reforming catalyst is provided, and a part of the hydrocarbon contained in the mixed gas of hydrocarbon and steam is burned in the oxidation reforming layer, and the hydrocarbon steam is generated by the combustion heat. A self-heating reformer that performs a reforming reaction,
Piping for supplying an oxygen-containing gas to the oxidation reforming layer;
A porous body that is attached to the tip of the pipe and that disperses and jets the oxygen-containing gas.
At least a part of the porous body is inserted into the oxidation-modified layer ,
The porous body is fitted in the pipe,
The self-heating reformer , wherein the pipe has a plurality of openings through which the porous body is exposed in the porous body insertion region . The self-heating reformer according to claim 1, wherein the porous body has an average pore size of 0.1 µm or more and 10 µm or less. The self-heating reformer according to claim 1 or 2 , wherein the porosity of the porous body is 20% or more and 80% or less. The self-heating type reformer according to claim 1 , wherein the melting point of the porous body is higher than the melting points of the reforming catalyst and the support of the oxidation catalyst. The downstream end of the porous body is upstream from the downstream end of the oxidation reforming layer, and downstream of the point 0.2 times upstream of the length of the oxidation reforming layer with respect to the downstream end of the oxidation reforming layer. The autothermal reformer according to any one of claims 1 to 4 , wherein the autothermal reformer is located in the center. The upstream end of the porous body is upstream from the upstream end of the oxidation reforming layer, and downstream from the point upstream of the oxidation reforming layer by 0.2 times the length of the oxidation reforming layer with reference to the upstream end of the oxidation reforming layer. The autothermal reformer according to any one of claims 1 to 5 , which is located on a side. The ratio of the difference between the average pressure in the pipe near the porous body and the average pressure in the oxidation-modified layer near the porous body to the average pressure in the oxidation-modified layer near the porous body is 0. The autothermal reformer according to any one of claims 1 to 6 , wherein the self-heat reformer is from 0.125 to 0.25.

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