WO2008029682A1

WO2008029682A1 - Hydrogen generation device and fuel cell system with the same

Info

Publication number: WO2008029682A1
Application number: PCT/JP2007/066740
Authority: WO
Inventors: Tomonori Aso; Yoichi Kimura; Yutaka Yoshida
Original assignee: Panasonic Corporation
Priority date: 2006-09-01
Filing date: 2007-08-29
Publication date: 2008-03-13
Also published as: JP2009280408A

Abstract

A hydrogen generation device having a combustor (10), a first wall for forming a combustion space (13) for gas flowing out of the combustor (11), a second wall placed outside the combustion space (13) so as to face the first wall, a reforming catalyst layer (14) outside the second wall, and a reformer (15) for generating hydrogen by a reforming reaction between a raw material and water vapor flowing in the reforming catalyst layer (14). A combustion gas flow path (11) in which combustion gas created in the combustion space (13) flows is formed in the space between the first and second walls. The first wall is made of metal having a smaller thermal expansion coefficient than the second wall.

Description

Specification

Hydrogen generator and fuel cell system including the same

Technical field

[0001] The present invention relates to a hydrogen generator and a fuel cell system including the same, and more particularly to the structure of a hydrogen generator.

Background art

[0002] In a polymer electrolyte fuel cell power generation system or the like, hydrogen or the like is used as a raw material, and the raw material is subjected to a steam reforming reaction using a catalyst to generate a reformed gas mainly composed of hydrogen. A generator is used. Since the steam reforming reaction is carried out at a high temperature of 600 to 800 ° C, it is necessary to efficiently heat the catalyst, and a hydrogen generator that improves the thermal efficiency and shortens the startup time is known (for example, And Patent Document 1).

FIG. 2 is a schematic diagram showing a schematic configuration of the hydrogen generator disclosed in Patent Document 1. In FIG. 2, the vertical direction in the hydrogen generator is shown as the vertical direction in the figure.

[0004] As shown in FIG. 2, this conventional hydrogen generator has a casing 75, and the casing 75 has first to third cylinders 7 sharing a central axis; ! ~ 73 are arranged. A panner 74 is provided in the internal space of the first cylinder 71, and the cylindrical space between the first cylinder 71 and the second cylinder 72 constitutes an exhaust passage 76. A reforming catalyst layer 78 filled with a reforming catalyst 77 is provided below the space between the second cylinder 72 and the third cylinder 73. Further, a shift catalyst layer 80 filled with a shift catalyst 79 is provided in a substantially central portion of the space between the third cylinder 73 and the casing 75, and a selective oxidation catalyst 81 is filled above the shift catalyst layer 80. A selective oxidation catalyst layer 82 is provided.

[0005] Then, combustion gas and air are supplied to the burner 74, and these gases are burned at the tip of the burner 74 to generate combustion exhaust gas. The generated combustion exhaust gas flows through the exhaust passage 76, whereby the second cylindrical body 72 is heated by heat transfer from the combustion exhaust gas. As a result, the fluid flowing in the space between the reforming catalyst layer 78 and the second cylinder 72 and the third cylinder 73 is heated.

[0006] In addition, a raw material (for example, methane) is supplied to the hydrogen generator from a raw material supplier 83, and water is supplied. Water is supplied from a supplier 84. The supplied raw material and water are heated while flowing downward from the upper part through the space between the second cylinder 72 and the third cylinder 73, and the supplied water becomes steam. When the heated raw material and steam pass through the reforming catalyst layer 78, a steam reforming reaction is performed, and a hydrogen-rich reformed gas is generated. The generated reformed gas is reduced in carbon monoxide concentration in the shift catalyst layer 80. The reformed gas that has passed through the shift catalyst layer 80 is mixed with the selective oxidation air supplied from the selective oxidation air supply device 85, and the carbon monoxide concentration is reduced when passing through the selective oxidation catalyst layer 82. Further reduced.

[0007] It should be noted that since the shift reaction is an exothermic reaction, heating is not required while power is being generated by the fuel cell, but the shift heater 86 is mounted until the temperature required for the shift reaction is reached at startup. In some cases, heating is performed outside the body 75. Similarly, the selective oxidation reaction is also an exothermic reaction, but a selective oxidation heater 87 may be provided outside the housing 75 for activation. Further, although not described in the above-mentioned Patent Document 1, a spacer 88 for making the width dimension of the exhaust passage 76 uniform may be provided in order to make the temperature of the reforming catalyst layer 78 appropriate and uniform. is there.

Patent Document 1: International Publication No. 02/098790 Pamphlet

Disclosure of the invention

Problems to be solved by the invention

However, in the hydrogen generator disclosed in Patent Document 1, the steam reforming reaction in the reforming catalyst layer 78 is an endothermic reaction, and the raw material and the inflow of the reforming catalyst layer 78 are also included. It is structured to increase the temperature by supplying heat from the surroundings while flowing along the hydraulic cylinder S and the second cylinder 72. For this reason, since the temperature of the first cylinder 71 is higher than that of the second cylinder 72, the deformation of the first cylinder 71 is greater than the deformation of the second cylinder 72 due to thermal expansion. For this reason, the width dimension of the exhaust passage 76 becomes nonuniform, and the combustion exhaust gas does not flow uniformly through the exhaust passage 76, so that the temperature of the reforming catalyst layer 78 becomes nonuniform. At the low temperature portion of the reforming catalyst layer 78, the reaction rate of the water vapor reforming reaction decreased, and at the high temperature portion, the durability of the catalyst decreased.

[0009] In addition, by providing the spacer 88, the force that can suppress the reduction in the width dimension of the exhaust passage 76 cannot suppress the thermal expansion itself, which is not a fundamental measure. . [0010] The present invention has been made to solve the above-described problems. A hydrogen generator capable of improving reforming performance and preventing deterioration of a reforming catalyst, and a fuel cell system including the same The purpose is to provide.

Means for solving the problem

In order to solve the above problems, a hydrogen production apparatus according to the present invention includes a combustor, a first wall that forms a combustion space for gas flowing out of the combustor, and the outside of the combustion space. A second wall disposed opposite the first wall; and a reforming catalyst layer on the outside of the second wall, and containing hydrogen by a reforming reaction of a raw material and steam flowing through the reforming catalyst layer And a reformer that generates gas, and a combustion gas flow path through which the combustion gas generated in the combustion space flows is configured in the space between the first wall and the second wall The first wall is made of a metal having a smaller coefficient of thermal expansion than the second wall.

[0012] This prevents dimensional deformation due to thermal expansion of the first wall from becoming larger than dimensional deformation of the second wall provided outside the first wall, and the width dimension of the combustion gas flow path is smaller than the initial dimension. It is possible to suppress S. In addition, since the width dimension of the combustion gas channel can be made substantially constant, the temperature distribution of the reforming catalyst layer disposed outside the second wall can be made uniform, and the reforming catalyst is deteriorated. Can be prevented. In addition, when the first wall is made of metal, the processing of the first wall is facilitated and the sealing performance of the hydrogen generator is easily ensured.

[0013] Further, in the hydrogen generator according to the present invention, the first wall is constituted by a cylindrical first tube member whose internal space forms the combustion space, and the second wall is It is composed of a cylindrical second cylindrical member arranged coaxially on the outside of the first cylindrical member, and the combustion gas flow path is a cylindrical shape between the first cylindrical member and the second cylindrical member. You may be comprised in space.

[0014] Further, in the hydrogen generating apparatus according to the present invention is not more than the first and second metal constituting the walls of the thermal expansion coefficient force of 8 X 10- ⁶ / K or higher 19 X 10- ⁶ / K, the difference force of thermal expansion of the metal of the first metal constituting the walls constituting the second wall S, 4 X 10_ ⁶ / K or 11 X 10 - ⁶ / Κ may be less.

[0015] Further, in the hydrogen generating apparatus according to the present invention is the first coefficient of thermal expansion of the metal constituting the walls force S8 X 10- ⁶ / Κ least 12 X 10- ⁶ / Κ below, the second The heat of the metal that makes up the wall The expansion coefficient may be 14 X 10_ ⁶ / K or more and 19 X 10_ ⁶ / Κ or less!

[0016] As a result, the dimensional deformation due to thermal expansion of the first wall becomes substantially the same as the dimensional deformation of the second wall provided outside the first wall, so that the first wall and the second wall are in contact with each other. Is prevented from

Since unnecessary stress is not applied to the first and second walls, it is possible to suppress deterioration of durability in the first and second walls.

[0017] Further, in the hydrogen generator according to the present invention, even if the metal constituting the first wall is ferritic stainless steel and the metal constituting the second wall is austenitic stainless steel. Good.

[0018] Further, a fuel cell system according to the present invention includes the hydrogen generator and a fuel cell that generates electric power using fuel gas supplied from the hydrogen generator.

The invention's effect

[0019] According to the hydrogen generator of the present invention and the fuel cell system including the same, the temperature of the reforming catalyst layer is kept constant by keeping the width dimension of the combustion gas flow path through which the combustion gas flows uniform. That power S. In addition, according to the hydrogen generator of the present invention and the fuel cell system equipped with the hydrogen generator, the temperature of the reforming catalyst layer is kept constant, so that the reforming catalyst can be sufficiently prevented from deteriorating.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing a schematic configuration of a fuel cell system according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of a hydrogen generator disclosed in Patent Document 1.

Explanation of symbols

[0021] 1 First cylinder member

2 Second cylinder member

3 Third cylinder member

3a Step

4 Fourth cylinder member Plate member Plate member Plate member Combustor a Base b Panaer Combustion gas flow path Spacer Combustion space Reformer catalyst layer Reformer Transformer catalyst layer Transformer Mixing unit Evaporator Selective oxidation catalyst layer Selective oxidizer Transformer heater Selective oxidation heater No. 1 1 cylinder 2nd cylinder 3rd cylinder Pana Case

Exhaust passage Reforming catalyst Reforming catalyst layer Transformation catalyst 80 Metamorphic catalyst layer

81 selective oxidation catalyst

82 Selective oxidation catalyst layer

83 Raw material feeder

84 Water supply

85 Air supply for selective oxidation

86 Metamorphic heater

87 Selective oxidation heater

88 Spacer

100 Fuel cell system

101 Hydrogen generator

102 Oxidant gas supply

104 Fuel cell

105 Control unit

106 Raw material feeder

107 Water supply

108 Combustion air supply

109 Air supply for selective oxidation

121 Raw material supply channel

122 Water supply channel

123 Fuel gas supply path

124 Oxidant gas supply path

127 Oxidant gas discharge passage

128 Off-gas supply path

129 Combustion air supply path

130 Combustion gas discharge passage

131 Air supply path for selective oxidation

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)

[Configuration of fuel cell system]

First, the configuration of the fuel cell system according to Embodiment 1 will be described.

[0023] The fuel cell system 100 according to the first embodiment includes a hydrogen generation device 101 having a banner 10b, an oxidant gas supply device 102, and a fuel cell 104.

A raw material supplier 106 is connected to the hydrogen generator 101 via a raw material supply path 121. Further, the downstream end of the water supply path 122 is connected to the middle of the raw material supply path 121, and the upstream end is connected to the water supply unit 107. As a result, the raw material (for example, desulfurized city gas) is supplied from the raw material supplier 106 to the hydrogen generator 101 through the raw material supply path 121, and the liquid water is supplied from the water supplier 107. Together with the raw material, it flows through the raw material supply path 121 and is supplied to the hydrogen generator 101.

[0025] In the hydrogen generator 101, the supplied raw material and water undergo a reforming reaction to generate a reformed gas (hydrogen-containing gas) containing hydrogen, carbon monoxide, and carbon dioxide. Carbon monoxide in the reformed gas is reduced by a shift reaction and a selective oxidation reaction, and fuel gas is generated.

In addition, a fuel cell 104 is connected to the hydrogen generator 101 via a fuel gas supply path 123. On the other hand, an oxidant gas supply path 102 is connected to the fuel cell 104 via an oxidant gas supply path 124. As a result, the fuel gas generated by the hydrogen generator 101 flows through the fuel gas 1S fuel gas supply path 123 and is supplied to the anode (not shown) of the fuel cell 104. Further, the oxidant gas ( Air) is supplied to a power sword (not shown) of the fuel cell 104 through the oxidant gas supply passage 124.

[0027] In the fuel cell 104, the fuel gas supplied to the anode and the oxidant gas supplied to the power sword react electrochemically to generate electric power and heat.

[0028] The surplus fuel gas that has not been used in the fuel cell 104 flows through the off-gas flow path 128 as off-gas and is supplied to the burner 10b of the hydrogen generator 101. Also off In the middle of the gas flow path 128, a downstream end of the combustion air supply path 129 is connected, and an upstream end thereof is connected to the combustion air supply unit 108. As a result, combustion air is supplied to the burner 10b through the offgas passage 128 together with the offgas. In the burner 10b, the supplied off gas and combustion air are combusted. Excess oxidant gas that has not been used in the fuel cell 104 flows through the oxidant gas discharge passage 127 and is discharged out of the fuel cell system 100.

[0029] It should be noted that the fuel cell system 100 according to the first embodiment is subjected to various controls by a control device 105 configured by a computer such as a microcomputer.

[0030] [Configuration of hydrogen generator]

Next, the configuration of the hydrogen generator 101 of the fuel cell system 100 according to Embodiment 1 will be described in detail.

As shown in FIG. 1, the hydrogen generator 101 includes cylindrical first to fourth cylindrical members 1 to 4 that share a central axis. The fourth cylinder member 4 constitutes a casing, and the first to third cylinder members are accommodated in the fourth cylinder member 4. The lower end of the fourth cylinder member 4 is closed by a lid member 5, and the upper end thereof is closed by an annular plate member 6 connected to the third cylinder member 3. The third cylinder member 3 is formed of a stepped cylinder having a step portion 3a, and the lower end thereof is closed by an annular plate member 7 connected to the second cylinder member 2. The lower end of the second cylindrical member 2 is connected to the lid member 5, and the upper end thereof is closed by an annular plate member 8 connected to the first cylindrical member 1. The lower end of the first cylinder member is open, and the upper end thereof is closed by the base 10a of the combustor 10.

[0032] The combustor 10 has a base 10a and a panner 10b. The panner 10b is disposed so as to extend downward from the base 10a in the first cylindrical member 1. The internal space formed by the inner wall (first wall) of the first tubular member 1 constitutes the combustion space 13. Further, the space between the first cylindrical member 1 and the second cylindrical member 2 (the space formed by the outer wall of the first cylindrical member 1 and the inner wall (second wall) of the second cylindrical member 2) is a combustion gas flow. Configure road 11. The plate member 8 arranged on the downstream side of the combustion gas channel 11 has an outlet of the combustion gas channel 11 formed therein, and an upstream end of the combustion gas discharge channel 130 is connected to the outer outlet. Its downstream end is open to the atmosphere. [0033] Thereby, the combustion gas and combustion air supplied to the burner 10b burn in the combustion space 13 to generate combustion gas, and the generated combustion gas flows out from the lower end of the first cylinder member 1. Then, it comes into contact with the inner surface of the lid member 5, reverses, and flows through the combustion gas passage 11. At this time, the reformer 15 and the evaporation unit 19 described later are heated by heat transfer from the second cylindrical member 2 constituting the combustion gas flow path 11. Then, the combustion gas that has flowed through the combustion gas flow path 11 flows through the combustion gas discharge path 130 and is discharged out of the fuel cell system 100.

In addition, a spacer 12 made of island-shaped protrusions is formed on the outer surface of the first cylindrical member 1. Thereby, the width dimension of the combustion gas channel 11 can be kept constant. Note that the spacer 12 may be formed on the inner surface of the second cylindrical member 2.

[0035] The plate member 6 connected to the upper portion of the second cylindrical member 2 is formed with an inlet communicating with a cylindrical space formed between the second cylindrical member 2 and the third cylindrical member 3. The downstream end of the raw material supply path 121 is connected to the inlet. As a result, the raw material is supplied from the raw material supply device 106 through the raw material supply path 121 to the cylindrical space between the second cylindrical member 2 and the third cylindrical member 3, and from the water supply device 107, the hydraulic power S, It flows through the water supply path 122 and the raw material supply path 121 and is supplied to the upper part of the cylindrical space between the second cylindrical member 2 and the third cylindrical member 3 (hereinafter referred to as the evaporation section 19). The raw material and water supplied to the evaporation unit 19 are heated by heat transfer from the second cylindrical member 2 while flowing through the evaporation unit 19.

In addition, a reforming catalyst layer 14 filled with a reforming catalyst is provided in the lower part of the cylindrical space between the second cylindrical member 2 and the third cylindrical member 3. The space in which the reforming catalyst layer 14 in the cylindrical space is provided, the reforming catalyst layer 14, and the reformer 15 are also configured. As a result, the reformer 17 undergoes a reforming reaction between the raw material and water vapor, and a reformed gas is generated. The plate member 7 is provided with a large number of through holes in the thickness direction so that the generated reformed gas can flow downstream.

[0037] A shift catalyst layer 16 filled with a shift catalyst is provided above the step 3a of the cylindrical space formed between the third tube member 3 and the fourth tube member 4. A shifter 17 is composed of the space in which the shift catalyst layer 16 in the cylindrical space is provided and the shift catalyst layer 16. As a result, the reformed gas generated in the reformer 15 is reduced in carbon monoxide by the shift reaction in the shift converter 17. [0038] Further, a portion of the outer surface of the fourth cylindrical member facing the transformer 17 is provided with a transformer heater 22 made of, for example, a known sheathed heater. As a result, the transformer 17 can be quickly heated when the fuel cell system 100 is started.

[0039] The upper portion of the transformer 17 in the cylindrical space between the third cylindrical member 3 and the fourth cylindrical member 4 constitutes a mixing unit 18. The fourth cylinder member 4 is formed with an inlet so as to communicate with the mixing unit 18, and the downstream end of the selective oxidation air supply path 131 is connected to the inlet. On the other hand, the upstream end of the selective oxidation air supply path 131 is connected to the selective oxidation air supply 109. As a result, the selective oxidation air is supplied from the selective oxidation air supply 109 through the selective oxidation air supply passage 131 and supplied to the mixing unit 18, where the reformed gas after the shift reaction and the reformed gas are supplied. The selective oxidation air is mixed to form a mixed gas.

[0040] A selective oxidation catalyst layer 20 filled with a selective oxidation catalyst is provided on the upper portion of the mixing portion 18 in the cylindrical space of the third cylindrical member 3 and the fourth cylindrical member 4. A selective oxidizer 21 is composed of the space provided with the selective oxidation catalyst layer 20 in the cylindrical space and the selective oxidation catalyst layer 20. As a result, carbon monoxide in the mixed gas is reduced to about several ppm by selective oxidation reaction, and fuel gas is generated.

[0041] Further, the fourth cylinder member 4 is formed with an outlet so as to communicate with the upper space of the selective oxidizer 21 in the cylindrical space between the third cylinder member 3 and the fourth cylinder member 4. The upstream end of the fuel gas supply path 123 is connected to the outlet. Thus, the fuel gas power generated by the selective oxidizer 21 of the hydrogen generator 101 flows through the fuel gas supply path 123 and is supplied to the fuel cell 104.

[0042] Further, a selective oxidation heater 23 made of, for example, a known sheathed heater is provided at a portion of the outer surface of the fourth cylindrical member facing the selective oxidizer 21. Thus, the selective oxidizer 21 can be quickly heated when the fuel cell system 100 is started.

Next, a characteristic configuration of the present invention will be described.

In the present embodiment, the first cylinder member 1 is disposed so that the inside thereof faces the combustion space 13 of the combustion gas that is a heat source, and the combustion gas flows along the outside thereof. On the other hand, the second cylinder member 2 is in contact with the reforming catalyst layer 15 where the combustion gas flows along the inner side and the outer side is an endothermic body (where endothermic reaction occurs), and at the normal temperature along the outer side. Supplied, It arrange | positions so that the raw material heated up to predetermined temperature and water (water vapor | steam) may flow. For this reason, since the temperature of the first cylindrical member 1 is higher than that of the second cylindrical member 2, the deformation of the first cylindrical member 1 is greater than the deformation of the second cylindrical member 2 due to thermal expansion.

However, in the present invention, the metal constituting the first cylinder member 1 is made of a metal having a smaller coefficient of thermal expansion than the metal constituting the second cylinder member 2. Specifically, in the present embodiment, the first cylindrical member 1 is made of heat-resistant ferritic stainless steel, and the second cylindrical member 2 is made of austenitic stainless steel. As a result, deformation due to thermal expansion of the first tubular member 1 can be reduced, and the width dimension of the fuel gas passage 11 can be kept constant.

[0046] The deformation due to thermal expansion of the first cylindrical member 1 and the second cylindrical member 2 (the first wall and the second wall) is reduced, and the deformation due to the thermal expansion of the first cylindrical member 1 is reduced to the second cylinder. from the viewpoint of less than deformation due to thermal expansion of the member 2, the thermal expansion coefficient of the metal constituting the first tubular member 1 and the second tubular member 2 (the first and second wall) is, 8 X 10- ⁶ / K above 19 X 10- ⁶ / K or less, the difference between the first tubular member 1 the thermal expansion coefficient of the metal constituting the metal and second tubular members 2 constituting the (first wall) (second wall) but it is preferably 4 Χ 10_ ⁶ / Κ least 11 Χ 10_ ⁶ / Κ or less. Further, from the viewpoint of making the deformation due to the thermal expansion of the first cylindrical member 1 substantially the same as the deformation due to the thermal expansion of the second cylindrical member 2, the coefficient of thermal expansion of the metal constituting the first cylindrical member 1 (first wall). There 8 X 10- ⁶ / Κ least 12 X 10- ⁶ / Κ is below, the thermal expansion coefficient of the metal constituting the second tubular member 2 (the second wall) is 14 X 10- ⁶ / Κ least 19 More preferably, it is X 10 — ⁶ / Κ or less.

[0047] Battery system operation]

Next, the operation of the fuel cell system 100 according to Embodiment 1 will be described with reference to FIG. The operation of the fuel cell system 100 shown below is controlled by the control device 105 as described above.

[0048] First, the raw material is supplied from the raw material supply device 106 to the burner 10b through a raw material supply path (not shown). Further, combustion air is supplied from the combustion air supply unit 108 through the combustion air supply path 129 and the off-gas supply path 128 to the burner 10b. In Pana 10b, the supplied raw material and combustion air are combusted to generate combustion gas. The generated combustion gas flows out from the lower end of the first cylinder member 1, hits the inner surface of the lid member 5, and reverses to burn. The gas flows through the gas channel 11 and flows through the combustion gas discharge channel 130 and is discharged out of the fuel cell system 100.

[0049] At this time, the first cylindrical member 1 and the second cylindrical member 2 are respectively heated by heat transfer from the combustion gas, but the temperature of the first cylindrical member 1 is higher than that of the second cylindrical member 2. Get higher. In the first embodiment, as described above, since the coefficient of thermal expansion of the metal constituting the first cylinder member 1 is smaller than the coefficient of thermal expansion of the metal constituting the second cylinder member 2, the first cylinder Deformation due to thermal expansion of member 1 is small. For this reason, the width dimension of the combustion gas flow path 11 formed by the space between the first cylinder member 1 and the second cylinder member 2 can be kept constant.

[0050] In addition, due to heat transfer from the second cylindrical member 2, the evaporator 19 and the reformer 15 are heated. Further, the shift heater 22 is operated to heat the shift converter 17, and similarly, the selective oxidation heater 23 is operated to heat the selective oxidizer 21.

[0051] On the other hand, the raw material supply device 106 flows through the raw material force S and the raw material supply channel 121 and is supplied to the hydrogen generator 101, and water from the water supply device 107 passes through the water supply channel 122 and the raw material supply channel 121. It is supplied to the evaporation unit 19 of the hydrogen generator 101. The raw material and water supplied to the evaporation unit 19 are heated while flowing through the evaporation unit 19, and the water becomes steam. Then, the heated raw material and water vapor are supplied to the reformer 15.

[0052] In the reformer 15, the raw material and steam undergo a reforming reaction in the reforming catalyst layer 14, and a reformed gas (hydrogen-containing gas) composed of hydrogen, carbon monoxide, carbon dioxide, and steam is generated. The The generated reformed gas flows out from the lower end of the reformer 15, hits the inner surface of the lid member 5, reverses, flows through the cylindrical space between the third cylindrical member 3 and the fourth cylindrical member 4. Supplied to the denaturing device 15

In the converter 17, carbon monoxide and steam in the reformed gas undergo a shift reaction in the shift catalyst layer 16, and the carbon monoxide is reduced to about several percent. The reformed gas after the shift reaction is supplied to the mixing unit 18. Then, in the mixing unit 18, the selective oxidation air is supplied from the selective oxidation air supply unit 109 through the selective oxidation air supply path 131, and the reformed gas after the shift reaction and the selective oxidation air are supplied. Mixed to form a mixed gas. This mixed gas is supplied to the selective oxidizer 21.

In the selective oxidizer 21, the selective oxidation catalyst layer 20 performs selective oxidation with carbon monoxide in the mixed gas. A selective oxidation reaction with working air (oxygen) produces fuel gas with carbon monoxide reduced to several ppm. The generated fuel gas flows through the fuel gas supply path 123 and is supplied to an anode (not shown) of the fuel cell 104.

Further, the fuel cell 104 is supplied from the oxidant gas supply device 102 through the oxidant gas (air) force oxidant gas supply path 124 and supplied to the power sword (not shown) of the fuel cell 104. . In the fuel cell 104, the fuel gas supplied to the anode and the oxidant gas supplied to the power sword react electrochemically to generate electric power and heat. The generated power is supplied to the external load. The power that is not used in the fuel cell 104 and the surplus fuel gas are supplied as an off-gas through the off-gas flow path 128 to the burner 10b of the hydrogen generator 101.

Thus, in the fuel cell system according to Embodiment 1, the coefficient of thermal expansion of the metal that constitutes the first cylinder member 1 is smaller than the coefficient of thermal expansion of the metal that constitutes the second cylinder member 2. Therefore, deformation due to thermal expansion of the first tubular member 1 is small. For this reason, the width dimension of the combustion gas flow path 11 constituted by the space between the first cylinder member 1 and the second cylinder member 2 can be kept constant. In addition, since the width dimension of the fuel gas channel 11 can be kept constant, the temperature of the reformer 15 can be kept constant, and the reforming reaction can be performed stably. Furthermore, since the temperature of the reformer 15 can be kept constant, it is possible to suppress the deterioration of the reforming catalyst constituting the reformer 15.

Example

Hereinafter, examples of the present invention will be described.

[Example 1]

In Example 1, a fuel cell system 100 according to Embodiment 1 shown in FIG. 1 was constructed. In this case, as the metal constituting the first tubular member 1 of the hydrogen generator 101, the heat resistance ferritic stainless (NSCC180 (manufactured by Nippon Steel Sumikin Stainless Co.): thermal expansion coefficient ^{11. 8 X 10- 6 / K (} 0 ˜800 ° C)) and an outer diameter of 100 mm. Further, as the metal constituting the second tubular member 2, austenitic stainless: using (SUS310S thermal expansion ^{17 · 5 X 10- 6 / K} (0~649 ° C)), the inner diameter was 106mm . The first and second cylindrical members 1 and 2 each had a thickness of lmm. [0058] Methane was supplied as a raw material to the burner 10b of the hydrogen generator 101 in the fuel cell system 100 constructed as described above to generate combustion gas. When the generated combustion gas flows through the combustion gas flow path 11, the first cylinder member 1 is heated up to 850 ° C by heat transfer from the combustion gas, and the second cylinder member 2 is 650 ° C. Heated to ° C.

[0059] At this time, the expansion of the first tubular member 1 in the radial ^{direction, 100X π X850X 11. 8X 10- 6} / π = 1. 003 . On the other hand, S of the second cylinder咅old 1 radial彭張is, 106X π X650X 17. 5 Χ 10_ 6 / π = 1. 205 , and the expansion in the first cylindrical member 1 and the second radial direction of the cylindrical member 2 was substantially the same.

Thus, in this embodiment, heat-resistant ferrite stainless steel is used as the metal constituting the first cylindrical member 1, and austenitic stainless steel is used as the metal constituting the second cylindrical member 2. By using it, it was confirmed that the deformation forces due to thermal expansion of the first cylindrical member 1 and the second cylindrical member 2 were substantially the same, and the effects of the present invention were confirmed.

[0061] From the above description, many improvements and other embodiments of the present invention are apparent to those skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Details of the structure and / or function thereof can be substantially changed without departing from the spirit of the present invention. Industrial applicability

The hydrogen generator according to the present invention is useful as a fuel cell or the like as a hydrogen generator that can stably supply hydrogen. In addition, the fuel cell system according to the present invention is useful as a fuel cell system and the like because it can generate power stably by providing the above-described hydrogen generator.

Claims

The scope of the claims

[1] a combustor,

A first wall forming a combustion space for gas flowing out of the combustor;

A second wall disposed opposite to the first wall outside the combustion space; a reforming catalyst layer outside the second wall; and a raw material and water flowing through the reforming catalyst layer A reformer that generates a hydrogen-containing gas by a steam reforming reaction,

A combustion gas flow path through which combustion gas generated in the combustion space flows is configured in a space between the first wall and the second wall,

The hydrogen generation apparatus, wherein the first wall is made of a metal having a smaller coefficient of thermal expansion than the second wall.

[2] The first wall is constituted by a cylindrical first tube member whose internal space forms the combustion space,

The second wall is composed of a cylindrical second cylindrical member disposed coaxially on the outer side of the first cylindrical member,

2. The hydrogen generation apparatus according to claim 1, wherein the combustion gas flow path is configured by a cylindrical space between the first cylinder member and the second cylinder member.

[3] the thermal expansion coefficient of the metal constituting the first and second walls, 8 X 10- ⁶ / K or 19 X 10_

⁶ / K or less,

Difference in the thermal expansion coefficient of the metal constituting the metal and the second wall forming the first wall is no more than 4 X 10- ⁶ / K or higher 11 X 10- ⁶ / Κ, in claim 1 The hydrogen generator described.

[4] the thermal expansion coefficient of the metal constituting the first wall 8 X 10- ⁶ / Κ least 12 X 10- ⁶ / Κ or less,

The metal thermal expansion coefficient of which constitutes the second wall is 19 X 10- ⁶ / Κ hereinafter more 14 X 10- ⁶ / Κ, hydrogen generator according to claim 1.

[5] The metal constituting the first wall is ferritic stainless steel,

2. The hydrogen generator according to claim 1, wherein the metal constituting the second wall is austenitic stainless steel.

[6] The hydrogen generator according to claim 1, A fuel cell system comprising: a fuel cell that generates electric power using a hydrogen-containing gas supplied from the hydrogen generator.