JP2015189648A - fuel reformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel reformer capable of suppressing production cost and further improving the freedom degree of the formation position of a flow passage.SOLUTION: Provided is a fuel reformer 10 in which a reforming gas is reformed and a fuel gas is fed to a fuel battery, including: a cylindrical inner tube 11 storing a burner 14 inside; and a cylindrical outer tube 12 storing the inner tube 11 inside. The cylindrical space divided by the outer circumferential face of the inner tube 11 and the inner circumferential face of the outer tube 12 is made into an evaporation part 21, and the evaporation part 21 is disposed with a cylindrical water absorbable member 22 previously formed with a spiral flow passage 24.

Description

  The present invention relates to a fuel reformer for generating a fuel gas by steam reforming a gas to be reformed and supplying the fuel gas to a fuel cell.

  Patent Document 1 discloses a fuel reformer that generates a fuel gas by steam reforming a gas to be reformed that is a raw fuel. The fuel reformer includes an inner cylinder that accommodates the combustor and an outer cylinder that accommodates the inner cylinder. Between the inner cylinder and the outer cylinder (cylindrical space), an evaporation section is formed that heats water and generates steam for reforming. Further, a water absorbing member is disposed in the evaporation portion.

  For example, as shown in FIG. 5 of Patent Document 1, the water absorbing member includes a metal felt wound around the outer peripheral surface of the inner cylinder, and a metal wire spirally wound around the metal felt from the outside. , Is composed of. When the wire is spirally wound and the metal felt is pressed against the outer peripheral surface of the inner cylinder, the metal felt has a spiral constriction along the wire. And a flow path through which the mixed gas passes.

  Most of the water supplied from the outside flows along the spiral flow path formed in this way. Meanwhile, the water is heated by the heat from the combustor to become water vapor, and further flows along the flow path, and is then discharged from the evaporation section toward the catalyst section.

Japanese Patent No. 4870491

  In manufacturing the fuel reforming device described in Patent Document 1, it is necessary to wind a metal felt around the outer peripheral surface of the inner cylinder and then wind a wire around the metal felt. For this reason, a plurality of parts and a plurality of assembly steps are required, and the manufacturing cost increases. Moreover, since a wire is wound from the outer side of a metal felt, a flow path can be formed only along the outer peripheral surface of a metal felt. That is, the fuel reformer described in Patent Document 1 has a low degree of freedom in the formation position of the flow path.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel reformer that can suppress the manufacturing cost and improve the degree of freedom of the formation position of the flow path.

  In order to achieve the above object, a fuel reformer according to the present invention is a fuel reformer for generating a fuel gas by steam reforming a gas to be reformed and supplying the fuel gas to a fuel cell. A cylindrical inner cylinder that houses the combustor, and a cylindrical outer cylinder that accommodates the inner cylinder inside, and are partitioned by the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder The cylindrical space serves as an evaporation section for heating the supplied water to form steam for reforming, and the evaporation section has a cylindrical water absorption structure in which a spiral channel is formed in advance. The member is arranged.

  In such a fuel reformer, a cylindrical water-absorbing member in which a spiral flow path is formed in advance in an evaporation section formed in a cylindrical space defined between an inner cylinder and an outer cylinder. Is arranged. Since it is such a structure, for example, it is not necessary to attach a pipe formed in a spiral shape, and a member (such as a wire) for maintaining the spiral space is also unnecessary. Therefore, the manufacturing cost can be suppressed. Moreover, the spiral flow path is not formed after the water absorbent member is wound around the inner cylinder, but is formed in the water absorbent member in advance, so the position of the flow path is the position of the water absorbent member. It is not limited to the outer peripheral surface, and the flow path can be formed at an arbitrary position. That is, according to the present invention, the degree of freedom of the formation position of the flow path can be improved.

  In the fuel reformer according to the present invention, the flow path may be a groove formed along the outer peripheral surface of the water absorbent member, or formed along the inner peripheral surface of the water absorbent member. It may be a groove. Furthermore, the flow path may be formed inside the water absorbent member so as not to be exposed to either the inner peripheral surface or the outer peripheral surface of the water absorbent member.

  In particular, when a groove formed along the outer peripheral surface of the water absorbing member is used as a flow path, the heat from the combustor is directly transferred to the water from the outer peripheral surface of the inner cylinder, so that the water is very efficiently Can be evaporated. Note that the position of the water absorbent member in which the flow path is formed may be appropriately selected according to the amount of heat generated in the combustor, the flow rate of supplied water, and the like.

  Further, according to the fuel reforming apparatus of the present invention, the water absorption rate at the bottom of the groove formed along the inner peripheral surface or the outer peripheral surface of the water absorbing member is lower than the water absorption rate at other portions. According to such a configuration, since the water absorption rate at the bottom of the groove is lower than the water absorption rate at other portions, a phenomenon in which water flows in the vertical direction through the wall surface of the groove (through the inside of the water absorbing member), so-called The occurrence of a short path can be suppressed. As a result, most of the water flows along the spiral space, so that the water can be efficiently evaporated.

  In the fuel reformer according to the present invention, the flow path includes a first flow path formed along the outer peripheral surface of the water absorbent member and a second flow path formed along the inner peripheral surface of the water absorbent member. It is also preferable that the first flow path and the second flow path are alternately formed along the vertical direction in a cross section when the water absorbing member is cut along its central axis. .

  In the fuel reformer of such an aspect, since the helical pitch of each flow path (first flow path, second flow path) becomes long, even if a short path of water occurs, water absorbs water. While passing through the inside of the member (portion between the flow paths), it is sufficiently heated to become water vapor. That is, it is possible to reduce the possibility that the water will be short-passed while being liquid.

  In the fuel reformer according to the present invention, the width of the spirally formed flow path (the dimension along the direction perpendicular to the flow path direction) is narrow on the upper side of the water absorbent member, It is also preferable that it is wide on the lower side of the member. In the fuel reformer of such an aspect, water can be reliably evaporated in the upper portion of the water absorbing member, that is, the portion where liquid water is supplied and flows. Further, in the lower portion of the water-absorbing member, that is, the portion where most of the water is evaporated, the flow path resistance is reduced, so that water vapor can be discharged smoothly from the evaporation portion.

  In the fuel reformer according to the present invention, it is also preferable that the pitch of the spirally formed flow path is narrow on the upper side of the water absorbent member and wide on the lower side of the water absorbent member. In the fuel reformer of such an aspect, the length of the flow path in the upper portion of the water absorbing member, that is, the portion where liquid water is supplied and flows is increased, so that water can be reliably evaporated. Moreover, since the flow path length in the lower part of the water-absorbing member, that is, the part where most of the water is evaporated is shortened, water vapor can be discharged smoothly from the evaporation part.

  In the fuel reformer according to the present invention, it is also preferable that the water absorption rate of the water absorbing member is low on the upper side of the water absorbing member and high on the lower side of the water absorbing member. In the fuel reformer of such an aspect, since the water absorption rate is low in the upper portion of the water absorbing member, that is, the portion where liquid water is supplied and flows, the occurrence of a short pass can be suppressed. As a result, most of the water flows along the spiral space, so that the water can be efficiently evaporated. Moreover, since the water absorption rate in the lower part of the water absorbent member, that is, the part where most of the water is evaporated is high (the air permeability is high), the water vapor is not only in the spiral space but also in the water absorbent member. It is smoothly discharged from the evaporation section through the inside.

  As described above, according to the present invention, it is possible to provide a fuel reformer that can suppress the manufacturing cost and improve the degree of freedom of the formation position of the flow path.

1 is a vertical sectional view schematically showing the structure of a fuel reformer according to a first embodiment of the present invention. It is a vertical sectional view which shows roughly the structure of a part of fuel reformer concerning a second embodiment of the present invention. It is a vertical sectional view which shows roughly the structure of a part of fuel reformer concerning a third embodiment of the present invention. FIG. 6 is a vertical sectional view schematically showing a partial structure of a fuel reformer according to a fourth embodiment of the present invention. FIG. 9 is a vertical sectional view schematically showing a partial structure of a fuel reformer according to a fifth embodiment of the present invention. It is a vertical sectional view which shows roughly the structure of a part of fuel reformer concerning a 7th embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a vertical sectional view schematically showing the structure of a fuel reformer 10 according to a first embodiment of the present invention. FIG. 1 shows a cross section of the fuel reformer 10 cut perpendicularly along a central axis of a water absorbing member 22 described later. The fuel reformer 10 reforms a raw fuel gas (for example, a hydrocarbon-based fuel such as city gas or LPG) using a steam reforming reaction to generate a fuel gas containing hydrogen as a main component. A fuel gas is supplied to a fuel cell (not shown).

  The fuel reformer 10 includes a cylindrical inner cylinder 11, a cylindrical outer cylinder 12 that accommodates the inner cylinder 11 therein, and a housing 13 that accommodates the outer cylinder 12 therein. A cylindrical combustion cylinder 16 is disposed inside the inner cylinder 11, and a burner 14 (combustor) is accommodated therein. The inner cylinder 11, the outer cylinder 12, the housing 13, the combustion cylinder 16, and the burner 14 are all formed of stainless steel.

  The burner 14 is arranged inside the combustion cylinder 16 so that its central axis is along the vertical direction. A gas flow path (not shown) is formed in the burner 14 along the vertical direction, and a supply port 15 is formed at the upper end of the burner 14 as an inlet of the gas flow path.

  A gas mixture of combustion air and gas (in this embodiment, the same gas as the raw fuel gas) is supplied to the supply port 15. The mixed gas flows downward through the gas flow path in the burner 14 and is injected from the lower end of the burner 14 to burn. A space below the lower end of the burner 14 in the combustion cylinder 16 is a combustion space 116. By burning the mixed gas, high-temperature combustion exhaust gas is generated in the combustion space 116.

  The lower end of the inner cylinder 11 is closed by the bottom 111. Further, the lower end of the combustion cylinder 16 is open, and the lower end and the bottom 111 are separated from each other. Therefore, the combustion exhaust gas generated in the combustion space 116 flows from the lower end of the combustion cylinder 16 into a space between the inner cylinder 11 and the combustion cylinder 16 (hereinafter referred to as “exhaust gas passage 17”), It flows upward in the exhaust gas flow path 17.

  In the vicinity of the upper end portion of the inner cylinder 11, a discharge port 18 that is an outlet of the exhaust gas passage 17 is formed. The high-temperature combustion exhaust gas flows upward in the exhaust gas flow channel 17 while heating the inner cylinder 11 from the inside, and is then discharged from the discharge port 18. As will be described later, the high-temperature combustion exhaust gas serves as a heat source for causing a steam reforming reaction in the reforming section 25.

  The outer cylinder 12 includes an upper cylinder 12a that is an upper part and a lower cylinder 12b that is a lower part. The upper cylinder 12a and the lower cylinder 12b are both cylindrical, and are lined up and down in a state of sharing their central axes. The diameter of the lower cylinder 12b is larger than the diameter of the upper cylinder 12a.

  The lower end of the housing 13 is closed by the bottom 131, and the bottom 131 and the bottom 111 are separated from each other. Moreover, the lower end of the outer cylinder 12 (lower cylinder 12b) is open, and the lower end and the bottom 131 are spaced apart. A space on the cylindrical shape formed between the inner cylinder 11 and the outer cylinder 12 is a space for generating fuel gas by steam reforming. The fuel gas generated in the space flows from the lower end of the outer cylinder 12 (lower cylinder 12b) into the space between the outer cylinder 12 and the combustion cylinder 16, and flows upward in the space.

  Near the upper end of the outer cylinder 12 (upper cylinder 12a), a water supply port 19 that is an inlet of water and a raw fuel supply port 20 that is an inlet of raw fuel gas are formed. The water (liquid) supplied from the water supply port 19 is heated by the heat of the combustion exhaust gas in the space between the inner cylinder 11 and the upper cylinder 12a and becomes steam. For this reason, the space is also referred to as “evaporator 21” below. The internal configuration of the evaporation unit 21 will be described in detail later.

  A space is also formed between the inner cylinder 11 and the lower cylinder 12b, and a reforming catalyst is disposed in the space. As the reforming catalyst, for example, a ruthenium-based or nickel-based steam reforming catalyst is used.

  The water vapor generated in the evaporation unit 21 and the raw fuel gas supplied from the raw fuel supply port 20 and passed through the evaporation unit 21 are mixed and reach the reforming catalyst. By the action of the reforming catalyst, a steam reforming reaction occurs between the steam from the evaporation section 21 and the raw fuel gas, and a hydrogen-containing gas containing hydrogen as a main component, that is, a fuel gas is generated. For this reason, the space between the inner cylinder 11 and the lower cylinder 12b (the space in which the reforming catalyst is disposed) is hereinafter also referred to as “reforming section 25”.

  Since the steam reforming reaction is a so-called endothermic reaction, it is necessary to continue to apply heat from the surroundings in order to cause a stable reaction. In the present embodiment, the high-temperature combustion exhaust gas that is generated in the combustion space 116 and flows upward in the exhaust gas passage 17 is used as a heat source for causing the steam reforming reaction. That is, the combustion exhaust gas flowing through the exhaust gas passage 17 heats the reforming catalyst disposed in the reforming unit 25 (via the inner cylinder 11), so that a steam reforming reaction that is an endothermic reaction occurs stably. It has a configuration.

  In the vicinity of the upper end of the housing 13, a fuel gas discharge port 29, which is a fuel gas outlet, is formed. The fuel gas generated in the reforming unit 25 flows upward in the space between the casing 13 and the outer cylinder 12, and then is discharged from the fuel gas discharge port 29 and used as fuel for the fuel cell. .

  Note that the fuel gas generated in the reforming unit 25 contains carbon monoxide in addition to hydrogen. For this reason, in the space between the housing 13 and the outer cylinder 12, a metamorphic portion 26 and a selective oxidation (PROX) portion 27 are arranged for the purpose of reducing the concentration of carbon monoxide. . The transformation unit 26 is disposed on the upstream side (lower side) of the selective oxidation unit 27.

  A shift catalyst is disposed in the shift unit 26. The shift catalyst lowers the concentration of carbon monoxide in the reformed gas to about 0.5% or less by the CO shift reaction.

  A selective oxidation catalyst is disposed in the selective oxidation unit 27. The selective oxidation catalyst lowers the concentration of carbon monoxide in the reformed gas to about 10 ppm or less by a selective oxidation reaction. An air supply port 28 for introducing selective oxidation air into the casing 13 and supplying it to the selective oxidation unit 27 is formed at a position between the transformation unit 26 and the selective oxidation unit 27 in the housing 13. ing.

  The fuel gas having a reduced carbon monoxide concentration is discharged from the fuel gas discharge port 29 by passing through the transformation unit 26 and the selective oxidation unit 27 as described above in order.

  Next, the internal configuration of the evaporation unit 21 will be specifically described. As already described, the evaporating section is formed between the inner cylinder 11 and the upper cylinder 12a, and generates steam necessary for steam reforming and discharges (supplies) it to the reforming section 25.

  A cylindrical water absorbing member 22 is disposed in the evaporation unit 21. The water-absorbing member 22 is formed by forming a mesh-like metal felt into a cylindrical shape, and has water absorption and air permeability.

  The entire inner surface of the water absorbing member 22 is in contact with the outer surface of the inner cylinder 11, and the entire outer surface is in contact with the inner surface of the outer cylinder 12. Further, a spiral groove is formed on the outer side surface of the water absorbing member 22, and a space defined by the groove and the inner side surface of the outer cylinder 12 is a flow of water supplied from the water supply port 19. Road 24. A space above the water absorbent member 22 (a space in which water from the water supply port 19 first flows) and a space below the water absorbent member 22 (the reforming unit 25) are separated by a flow path 24. Communicate.

  The water supplied from the water supply port 19 mainly flows downward through the flow path 24. In the meantime, it is heated by the heat of the combustion exhaust gas flowing inside the inner cylinder 11 to become water vapor. Most of the water vapor and the raw fuel gas supplied from the raw fuel supply port 20 reach the reforming section 25 through the flow path 24, but some of them (has air permeability). ) Passes through the inside of the water absorbing member 22 and reaches the reforming section 25.

  Further, a part of the water supplied from the water supply port 19 is heated in a state of permeating into the water absorbing member 22 to become water vapor, and passes through the water absorbing member 22 or the flow path 24 to be the reforming unit. Reach 25.

  Various methods are conceivable as a method for forming the flow path 24 in the water absorbing member 22. For example, after attaching the water absorbing member 22 to the outer peripheral surface of the inner cylinder 11, it is possible to form the wire by spirally winding a wire around the water absorbing member 22 from the outside. However, such a method is not preferable from the viewpoint of manufacturing cost because it requires a complicated process of winding the wire in a spiral shape and also requires a separate part called a wire. Furthermore, since a groove can be formed only along the outer peripheral surface of the water absorbing member 22, the degree of freedom of the formation position of the flow path 24 is low.

  On the other hand, the water absorbing member 22 in the present embodiment is attached to the outer peripheral surface of the inner cylinder 11 after a groove (flow path 24) is formed in advance on the outer surface thereof. Specifically, the outer peripheral surface of the water absorbent member 22 is spirally pressurized to deform the portion, and after forming a spiral groove in advance, this is attached to the outer peripheral surface of the inner cylinder 11 It is.

  Such a flow path 24 can be formed by a simple method as described above, and a wire or the like for maintaining the shape is unnecessary. Furthermore, it can also form in parts (for example, inner peripheral surface) other than the outer peripheral surface of the water absorbing member 22. Therefore, the manufacturing cost is suppressed and the degree of freedom of the formation position of the flow path 24 is improved.

  In addition, in this embodiment, although the cross-sectional shape of the flow path 24 is a rectangle, as embodiment of this invention, it is not restricted to such an aspect. In addition to the rectangle, other shapes such as a semicircle, a semi-ellipse, a triangle, and a trapezoid may be used.

  Other embodiments of the present invention will be described with reference to FIGS. Note that the fuel reformer shown in FIG. 2 and subsequent figures has substantially the same configuration as the fuel reformer 10 according to the first embodiment described so far, and differs only in the shape of the water absorbing member 22 and the like. It has a configuration. Therefore, in the following description, illustration and detailed description of portions common to the fuel reformer 10 according to the first embodiment are omitted. In addition, the same reference numerals are assigned to the same components as those in the first embodiment.

  FIG. 2 is a vertical cross-sectional view schematically showing a partial structure of the fuel reformer 10 according to the second embodiment of the present invention. In the fuel reformer 10 according to the present embodiment, the flow path 24 is a groove formed along the inner peripheral surface, not the outer peripheral surface of the water absorbing member 22. As described above, the groove formation at such a position is possible because the groove processing is performed before the water absorbing member 22 is attached to the outer peripheral surface of the inner cylinder 11.

  As described above, when the groove formed along the outer peripheral surface of the water absorbing member 22 is used as the flow path 24, the heat from the burner 14 (that is, the heat from the combustion exhaust gas passing through the exhaust gas flow path 17) is internal. Since it is transmitted directly to the water from the outer peripheral surface of the cylinder 11, the water can be evaporated very efficiently.

  FIG. 3 is a vertical sectional view schematically showing a part of the structure of the fuel reformer 10 according to the third embodiment of the present invention. In the fuel reformer 10, the flow path 24 is formed inside the water absorbent member 22 so as not to be exposed on either the inner peripheral surface or the outer peripheral surface of the water absorbent member 22. As described above, the groove formation at such a position is possible because the groove processing is performed before the water absorbing member 22 is attached to the outer peripheral surface of the inner cylinder 11.

  Thus, when the flow path 24 is formed inside the water absorbing member 22, the water flowing through the flow path 24 does not directly touch the inner cylinder 11 or the outer cylinder 12. For example, in a fuel reformer having a configuration in which the temperature of the inner cylinder 11 and the outer cylinder 12 becomes very high and there is a risk of bumping, it may be desirable to form the flow path 24 at such a position. . Thus, the position of the water absorbent member 22 where the flow path 24 is formed may be appropriately selected according to the amount of heat generated in the burner 14, the flow rate of supplied water, and the like.

  FIG. 4 is a vertical sectional view schematically showing a part of the structure of the fuel reformer 10 according to the fourth embodiment of the present invention. In this fuel reformer 10, the flow path 24 is not a single flow path, but the first flow path 24 a formed along the outer peripheral surface of the water absorbent member 22 and the inner peripheral surface of the water absorbent member 22. The second channel 24b is formed with two channels. Both the first flow path 24a and the second flow path 24b are spiral flow paths, and these are arranged substantially parallel to each other (that is, like a thread of a double thread). Such arrangement of the first flow path 24a and the second flow path 24b is such that the first flow path 24a and the second flow path 24b are along the vertical direction in a cross section when the water absorbing member 22 is cut along the central axis. It can also be said that they are arranged alternately.

  In such a configuration, the pitch of the spiral of each of the first flow path 24a and the second flow path 24b becomes longer, so that the water flows vertically through the wall surface of the first flow path 24a or the like (so-called short path). ) Occurs, the water is sufficiently heated while passing through the water-absorbing member 22 to become water vapor.

  That is, the first flow path 24a exists below the second flow path 24b, but does not exist directly below, but shifts along the radial direction of the water absorbent member 22 (the left-right direction in FIG. 4). Exists in the position. For this reason, even when water permeates the inside of the water absorbing member 22 toward the lower side of the second flow path 24b, the water does not flow into the lower first flow path 24a, but further below ( That is, it penetrates further toward the second flow path 24b located far away. As a result, the water is sufficiently heated before flowing again into the second flow path 24b, and becomes water vapor with a high probability. Thus, if the flow path 24 is formed in this way, it is possible to reduce the possibility that the water will be short-passed while being liquid.

  FIG. 5 is a vertical sectional view schematically showing a part of the structure of the fuel reformer 10 according to the fifth embodiment of the present invention. In the fuel reformer 10, the water absorbing member 22 is formed with a flow path 24 similar to that described in the first embodiment. That is, the flow path 24 is formed by forming a groove on the outer peripheral surface of the water absorbing member 22.

  However, in the present embodiment, when the flow path 24 is formed, a groove (flow path 24) is formed by applying pressure from the outer peripheral surface of the water absorbing member 22 toward the inner peripheral surface to crush the metal felt. doing. As a result, the water-absorbing member 22 that is a metal felt has a density of the portion (hereinafter referred to as the groove bottom portion 22a) that is the bottom (inner peripheral side) of the flow path 24, and the other portion (hereinafter referred to as the groove portion). 22b). Thereby, the water absorption rate of the groove bottom portion 22a is lower than the water absorption rate of the inter-groove portion 22b.

  In the water absorbing member 22 of the present embodiment, the water absorption rate at the groove bottom portion 22a is lower than the water absorption rate at the inter-groove portion 22b, so that water passes through the groove bottom portion 22a in the vertical direction along the outer surface of the inner cylinder 11. Such a phenomenon, that is, a short path is more difficult to occur. As a result, most of the water flows in the spiral flow path 24, so that the water can be efficiently evaporated.

  FIG. 6 is a vertical sectional view schematically showing a part of the structure of the fuel reformer 10 according to the sixth embodiment of the present invention. In this fuel reformer 10, the groove width of the spirally formed flow path 24 (dimension along the direction perpendicular to the flow path direction of the flow path 24, that is, the dimension along the substantially vertical direction). The upper side of the water-absorbing member 22 is narrow, and the width is gradually increased toward the lower side. For this reason, while ensuring the contact area with water on the upper side and efficiently generating water vapor, the generated water vapor can be discharged smoothly on the downstream side.

  It replaces with such an aspect, or with such an aspect, the pitch (the space | interval of the adjacent flow paths 24 along a perpendicular direction is formed on the upper side of the water absorbing member 22 in the spiral. In such an aspect, the flow path in the upper side portion of the water absorbing member 22, that is, the portion in which liquid water is supplied flows. Since the length becomes longer, the water can be reliably evaporated, and the flow path length in the lower portion of the water absorbing member 22, that is, the portion where most of the water is evaporated is shortened. Water vapor can be smoothly discharged from the portion 21.

  A fuel reformer 10 according to a seventh embodiment will be described. The shape of the fuel reformer 10 according to this embodiment is the same as the shape of the fuel reformer 10 according to the first embodiment shown in FIG.

  In the fuel reformer 10, the density of the water absorbent member 22, which is a metal felt, is high on the upper side of the water absorbent member 22, while it is low on the lower side of the water absorbent member 22. Since the water absorption rate in the upper side portion of the water absorbing member 22, that is, the portion where liquid water is supplied and flows is low, the occurrence of a short pass can be suppressed. As a result, most of the water flows in the spiral flow path 24, so that the water can be efficiently evaporated. Further, since the water absorption rate is high (the air permeability is high) in the lower portion of the water absorbent member 22, that is, the portion where most of the water is evaporated, the water vapor is not limited to the spiral space. The inside of 22 is smoothly discharged from the evaporation unit 21.

  In addition, you may combine each characteristic demonstrated about each above embodiment suitably. For example, in the fuel reformer 10 according to the fifth to seventh embodiments, the flow path 24 may be formed on either the inner peripheral surface or the outer peripheral surface of the water absorbing member 22, or the inner peripheral surface and the outer peripheral surface. You may form in the inside of the water absorbing member 22 so that it may not be exposed to either of the surfaces.

  As mentioned above, although embodiment of this invention was described referring a specific example, this invention is not limited to these specific examples. As long as the features of the present invention are provided, those in which those skilled in the art make design changes to these specific examples are also included in the scope of the present invention. For example, each constituent element included in each of the specific examples described above and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and may be changed as appropriate. In addition, the respective constituent elements can be combined as much as technically possible, and combinations thereof are included in the scope of the present invention as long as they include the features of the present invention.

10: Fuel reformer 11: Inner cylinder 12: Outer cylinder 12a: Upper cylinder 12b: Lower cylinder 13: Housing 14: Burner 15: Supply port 16: Combustion cylinder 17: Exhaust gas flow path 18: Discharge port 19: Water supply Port 20: Raw fuel supply port 21: Evaporating part 22: Water absorbing member 22a: Groove bottom part 22b: Inter-groove part 24: Channel 24a: First channel 24b: Second channel 25: Reforming unit 26: Transforming unit 27 : Selective oxidation unit 28: Air supply port 29: Fuel gas discharge port 111: Bottom portion 116: Combustion space 131: Bottom portion

Claims (9)

A fuel reformer for steam reforming a gas to be reformed to generate a fuel gas and supplying the fuel gas to a fuel cell,
A cylindrical inner tube that houses the combustor;
A cylindrical outer cylinder that houses the inner cylinder therein,
A cylindrical space defined by the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder serves as an evaporation section for heating the supplied water into steam for reforming,
The fuel reformer is characterized in that a cylindrical water-absorbing member having a spiral channel formed in advance is disposed in the evaporating section.   The fuel reformer according to claim 1, wherein the flow path is a groove formed along an outer peripheral surface of the water absorbing member.   The fuel reformer according to claim 1, wherein the flow path is a groove formed along an inner peripheral surface of the water absorbing member.   4. The fuel reformer according to claim 2, wherein in the water absorbing member, the water absorption rate at the bottom of the groove is lower than the water absorption rate at other portions.   2. The fuel according to claim 1, wherein the flow path is formed inside the water absorbent member so as not to be exposed to either the inner peripheral surface or the outer peripheral surface of the water absorbent member. Reformer. The flow path is
A first flow path formed along the outer peripheral surface of the water absorbing member;
A second flow path formed along the inner peripheral surface of the water absorbing member,
In the cross section when the water-absorbing member is cut along its central axis, the first flow path and the second flow path are alternately formed along the vertical direction. The fuel reformer according to claim 1.   The width of the flow path formed in a spiral shape is narrow on the upper side of the water-absorbing member and wide on the lower side of the water-absorbing member, 7. Fuel reformer.   8. The pitch of the flow path formed in a spiral shape is narrow on the upper side of the water absorbing member and wide on the lower side of the water absorbing member. 8. Fuel reformer.   9. The fuel reforming according to claim 1, wherein a water absorption rate of the water absorbing member is low on an upper side of the water absorbing member and is high on a lower side of the water absorbing member. apparatus.

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