JP5538025B2 - Hydrogen production apparatus and fuel cell system - Google Patents

Description

  The present invention relates to a hydrogen production apparatus and a fuel cell system.

  As a conventional hydrogen production apparatus, an apparatus including a selective oxidation reaction unit that selectively oxidizes carbon monoxide in a reformed gas generated by reforming raw fuel such as hydrocarbon is known (for example, , See Patent Document 1). In order to control the temperature of the selective oxidation reaction unit, an external heater such as a heater is usually used. For example, water evaporation for generating water vapor at a position adjacent to the inner peripheral side of the cylindrical selective oxidation reaction unit. In the hydrogen production apparatus in which the section is arranged, the temperature of the selective oxidation reaction section can be controlled by using the water temperature supplied to the water evaporation section without using a heater. In addition, the reformed gas selectively oxidized by the selective oxidation reaction unit is supplied to the outside of the hydrogen production apparatus via an outlet pipe connected to the selective oxidation reaction unit.

JP 2009-280408 A

  Here, in the hydrogen production apparatus as described above, the selective oxidation reaction unit supplies the reformed gas after selective oxidation to the outside through the outlet pipe in a high temperature state. Therefore, by effectively utilizing the heat of the outlet gas of the selective oxidation reaction unit (for example, improving the reforming efficiency by supplying the heat to the reforming unit), the reforming efficiency of the entire hydrogen production apparatus There was a need to improve. On the other hand, when a heat exchanger is provided in the piping related to the outlet gas of the selective oxidation reaction section, there is a problem that the apparatus becomes large and the structure becomes complicated. From the above, it has been required to improve the reforming efficiency of the entire hydrogen production apparatus with a simple structure.

  Therefore, an object of the present invention is to provide a hydrogen production apparatus and a fuel cell system that improve the reforming efficiency of the entire hydrogen production apparatus with a simple structure.

  In order to solve the above problems, a hydrogen production apparatus according to the present invention includes a selective oxidation reaction unit that selectively oxidizes carbon monoxide in a reformed gas containing hydrogen, and an evaporation channel that generates water vapor by circulating water. And a gas flow path through which the reformed gas flows, the gas flow path being disposed between the selective oxidation reaction section and the evaporation flow path, and the reformed gas has flowed out of the selective oxidation reaction section. After that, the gas channel is circulated.

  In this hydrogen production apparatus, a gas flow path through which the reformed gas flows is disposed between the evaporation flow path for flowing water to generate water vapor and the selective oxidation reaction section. In addition, the reformed gas that has flowed out of the selective oxidation reaction section, that is, the outlet gas of the selective oxidation reaction section can be circulated through the gas flow path. According to such a configuration, the reformed gas as the outlet gas of the selective oxidation reaction unit can flow in the gas flow path along the evaporation flow path through which water and water vapor flow. Therefore, the reformed gas as the exit gas of the selective oxidation reaction unit can be sufficiently cooled by water or water vapor in the evaporation channel without providing a separate heat exchanger. Water and water vapor in the evaporation channel can recover the heat of the reformed gas in the gas channel, thereby improving the evaporation efficiency in the gas channel or increasing the temperature of the water vapor in the gas channel. be able to. Thus, the reforming efficiency as the whole hydrogen production apparatus can be improved by supplying the steam which efficiently recovered the heat of the reformed gas to, for example, the reforming unit. In the hydrogen production apparatus according to the present invention, the heat of the reformed gas as the exit gas of the selective oxidation reaction unit is effectively used with a simple configuration in which a gas channel is formed between the selective oxidation reaction unit and the evaporation flow channel. Can be used. Accordingly, it is possible to prevent the apparatus from becoming large and the structure from becoming complicated as compared with the case where a separate heat exchanger is provided. In addition, the configuration in which the gas channel is disposed between the selective oxidation reaction unit and the evaporation channel allows the selective oxidation reaction unit to use the gas channel as a heat medium without directly contacting the evaporation channel through which water flows. Can function. Thereby, it is possible to prevent the temperature of the selective oxidation catalyst in the selective oxidation reaction part from becoming too low, and to improve the reaction efficiency of the selective oxidation reaction part. As described above, according to the hydrogen production apparatus of the present invention, the reforming efficiency of the entire hydrogen production apparatus can be improved with a simple structure.

  The hydrogen production apparatus according to the present invention further includes an exhaust gas passage through which the exhaust gas of the burner used for generating the reformed gas flows, and the exhaust gas passage is adjacent to the evaporation passage on the opposite side of the gas passage. It is preferable to arrange in the position. Since the exhaust gas flow channel is disposed at a position adjacent to the evaporation flow channel, the water in the evaporation flow channel can be efficiently evaporated by receiving heat from the high temperature exhaust gas.

  Further, in the hydrogen production apparatus according to the present invention, air is supplied to the reformed gas that removes carbon monoxide in the reformed gas by a shift reaction and the reformed gas that travels from the shift reactor to the selective oxidation reactor And an air supply unit, wherein the shift reaction unit has an outlet for flowing out the reformed gas after the shift reaction, and the air supply unit is configured to supply the reformed gas to the reformed gas flowing out from the outlet. It is preferable to supply air from the direction opposite to the flow. The reformed gas from which carbon monoxide has been removed by the shift reaction is collected at the outlet when it flows out of the shift reaction section. At this time, the air supply unit can supply air to the reformed gas collected at the outlet. Thereby, the air and the reformed gas can be mixed efficiently. Furthermore, since the air supply unit can supply air from the direction opposite to the flow of the reformed gas, the reformed gas and the air collide and are mixed more efficiently.

  A fuel cell system according to the present invention includes the above-described hydrogen production apparatus and a fuel cell stack that generates electric power using the reformed gas generated by the hydrogen production apparatus.

  Also in this fuel cell system, since the hydrogen production apparatus is provided, the above-described effect of improving the reforming efficiency of the entire hydrogen production apparatus with a simple structure is achieved.

  According to the present invention, it is possible to improve the reforming efficiency of the entire hydrogen production apparatus with a simple structure.

It is a schematic block diagram which shows a part of fuel cell system which concerns on one Embodiment of this invention. It is a schematic front end view which shows the hydrogen production apparatus of FIG. FIG. 3 is an enlarged view of a configuration around a selective oxidation reaction unit shown in FIG. 2. It is a block diagram which shows the flow of the heat | fever around the selective oxidation reaction part shown in FIG. It is a schematic front end view which shows the other example of the hydrogen production apparatus of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. The terms “upper” and “lower” correspond to the vertical direction of the drawing and are for convenience.

  FIG. 1 is a schematic block diagram showing a part of a fuel cell system according to an embodiment of the present invention. As shown in FIG. 1, a hydrogen production apparatus (FPS: Fuel Processing System) 1 is used as a hydrogen supply source in, for example, a household fuel cell system 100. The hydrogen production apparatus 1 here uses petroleum-based hydrocarbons as a raw fuel, and supplies a reformed gas containing hydrogen to a cell stack (fuel cell stack) 20.

  In addition, as raw fuel, you may use alcohol, ethers, biofuel, natural gas, and city gas. Further, as petroleum-based hydrocarbons, naphtha, light oil, etc. can be used as raw fuel in addition to kerosene and LP gas. As the cell stack 20, various types such as a solid polymer type, an alkaline electrolyte type, a phosphoric acid type, a molten carbonate type, or a solid oxide type may be used.

  FIG. 2 is a schematic front end view showing the hydrogen production apparatus of FIG. As shown in FIGS. 1 and 2, the hydrogen production apparatus 1 includes a desulfurization part 2 having a cylindrical outer shape with a central axis as an axis G, and a main body part 3 with a cylindrical outer shape having a central axis as an axis G. These are accommodated in the housing 4. Further, in the casing 4, the surroundings of the desulfurization part 2 and the main body part 3 are filled with a powdery heat insulating material (not shown) to be insulated. The desulfurization unit 2 may be installed outside the housing 4.

  The desulfurization unit 2 desulfurizes the raw fuel introduced from the outside with a desulfurization catalyst to remove sulfur, and supplies the raw fuel to a feed unit 5 described later. The desulfurization part 2 is fixed to the side plate 4x of the housing 4 by a pipe 21 and is held so as to surround the upper part of the main body part 3 with a predetermined gap. The main body 3 includes a feed unit 5, a reforming unit 6, a shift reaction unit 7, a selective oxidation reaction unit 8, and an evaporation unit 9, which are integrally configured. The main body 3 is fixed and held on a floor plate 4 y of the housing 4 by a cylindrical stay 22.

  The feed unit 5 mixes the raw fuel and steam (steam) desulfurized in the desulfurization unit 2 and supplies them to the reforming unit 6. Specifically, the feed unit 5 includes a mixing unit 5x that combines and mixes raw fuel and water vapor to generate a mixed gas (mixed fluid), and a mixed gas channel 5y that distributes the mixed gas to the reforming unit 6. , Including.

  The reforming section (SR: Steam Reforming) 6 steam-reforms the mixed gas supplied from the feed section 5 with a reforming catalyst (reforming catalyst section) 6x to generate a reformed gas. Supply to shift reaction unit 7. The reforming part 6 has a cylindrical outer shape with the central axis as the axis G, and is provided on the upper end side of the main body part 3 so as to be located in the cylinder of the desulfurization part 2. In this reforming section 6, since the steam reforming reaction requires a high temperature and is an endothermic reaction, the burner 10 is used as a heat source for heating the reforming catalyst 6x of the reforming section 6.

  In the burner 10, raw fuel is supplied as burner fuel from the outside and burned. The burner 10 is attached to a combustion cylinder 11 provided at the upper end of the main body 3 and having the axis G as a central axis so that a flame by the burner 10 is surrounded. In the burner 10, a part of the raw fuel desulfurized in the desulfurization unit 2 may be supplied as burner fuel and burned.

  The shift reaction unit 7 is for lowering the carbon monoxide concentration (CO concentration) of the reformed gas supplied from the reforming unit 6, and shifts the carbon monoxide in the reformed gas to generate hydrogen and Convert to carbon dioxide. Here, the shift reaction unit 7 can perform the shift reaction in two stages, and performs a high temperature shift reaction that is a shift reaction at a high temperature (for example, 400 ° C. to 600 ° C.). (HTS: High Temperature Shift) 12 and a low temperature shift reaction part (LTS: Low Temperature Shift) 13 that performs a low temperature shift reaction that is a shift reaction at a temperature lower than the temperature of the high temperature shift reaction (for example, 150 ° C. to 350 ° C.). And have. However, the high temperature shift reaction unit 12 is not necessarily provided.

  The high temperature shift reaction unit 12 causes the carbon monoxide in the reformed gas supplied from the reforming unit 6 to undergo a high temperature shift reaction with the high temperature shift catalyst 12x, thereby reducing the CO concentration of the reformed gas. The high temperature shift reaction unit 12 has a cylindrical outer shape with the central axis as the axis G, and is disposed adjacent to the radially outer side of the reforming unit 6 so that the high temperature shift catalyst 12x surrounds the lower end of the reforming catalyst 6x. ing. The high temperature shift reaction unit 12 supplies the reformed gas having a reduced CO concentration to the low temperature shift reaction unit 13.

  The low temperature shift reaction unit 13 causes the carbon monoxide in the reformed gas subjected to the high temperature shift reaction in the high temperature shift reaction unit 12 to undergo a low temperature shift reaction by the low temperature shift catalyst 13x, thereby reducing the CO concentration of the reformed gas. The low temperature shift reaction part 13 has a cylindrical outer shape with the central axis as the axis G, and is disposed on the lower end side of the main body part 3. The low temperature shift reaction unit 13 supplies the reformed gas having a reduced CO concentration to the selective oxidation reaction unit 8 via the reformed gas pipe 14x.

  A selective oxidation reaction unit (PROX) 8 further reduces the CO concentration in the reformed gas subjected to the low temperature shift reaction in the low temperature shift reaction unit 13. This is because if a high concentration of carbon monoxide is supplied to the cell stack 20, the catalyst of the cell stack 20 is poisoned and the performance is greatly reduced. Specifically, the selective oxidation reaction unit 8 oxidizes hydrogen in the reformed gas by reacting carbon monoxide in the reformed gas with air introduced through the air pipe 15 by the selective oxidation catalyst 8x. Without oxidizing, carbon monoxide is selectively oxidized and converted to carbon dioxide. The selective oxidation reaction portion 8 has a cylindrical outer shape with the central axis as the axis G, and is disposed so as to constitute the outermost peripheral side of the main body portion 3 from the lower end of the main body portion 3 to the upper end side of a predetermined length. . The selective oxidation reaction unit 8 guides the reformed gas whose CO concentration is further reduced to the outside through the reformed gas pipe 14y.

  The evaporation unit 9 stores the water supplied from the water pipe 17x and moves the water from the low temperature shift reaction unit 13 and the selective oxidation reaction unit 8 (the low temperature shift reaction unit 13 and the selective oxidation reaction unit 8). The water vapor is generated by the heat of the gas and the heat of the exhaust gas from the burner 10 to generate water vapor. The evaporator 9 is of a jacket type and has a cylindrical shape with the central axis as the axis G. The evaporation unit 9 is located radially outside the high temperature shift reaction unit 12 and the low temperature shift reaction unit 13 and inside the selective oxidation reaction unit 8 (that is, between the shift reaction unit 7 and the selective oxidation reaction unit 8). It is arranged to be located. The evaporation unit 9 supplies the generated water vapor to the mixing unit 5x of the feed unit 5 via the water vapor pipe 17z.

  In such a hydrogen production apparatus 1, first, at least one of burner fuel and off-gas from the cell stack 20 (residual gas not used for reaction in the cell stack 20) and air are supplied to the burner 10 and burned, and such combustion is performed. As a result, the reforming catalyst 6x is heated. And the exhaust gas of the burner 10 distribute | circulates the exhaust gas flow path L1 and the gas piping 18, and is exhausted outside.

  At the same time, the raw fuel desulfurized in the desulfurization unit 2 and the water vapor from the evaporation unit 9 are mixed in the mixing unit 5x to generate a mixed gas. The mixed gas is supplied to the reforming unit 6 through the mixed gas flow path 5y and is steam reformed by the reforming catalyst 6x, thereby generating a reformed gas. Then, after the generated reformed gas has its carbon monoxide concentration lowered to, for example, about several thousand ppm by the shift reaction section 7, and after its carbon monoxide concentration has been lowered to about 10 ppm or less by the selective oxidation reaction section 8. Then, it is cooled and led out to the cell stack 20 in the subsequent stage.

  In the present embodiment, for example, the temperature of each part is set as follows in order to suitably perform the catalytic reaction with each of the catalysts 6x, 12x, 13x, and 8x. That is, the temperature of the mixed gas flowing into the reforming unit 6 is about 300 to 550 ° C., the temperature of the reformed gas flowing out of the reforming unit 6 is 550 to 800 ° C., and flows into the high temperature shift reaction unit 12 The temperature of the reformed gas is 400 to 600 ° C., and the temperature of the reformed gas flowing out from the high temperature shift reaction unit 12 is 300 to 500 ° C. Further, the temperature of the reformed gas flowing into the low temperature shift reaction unit 13 is set to 150 ° C. to 350 ° C., and the temperature of the reformed gas flowing out from the low temperature shift reaction unit 13 is set to 150 ° C. to 250 ° C. The temperature of the reformed gas flowing into 8 is 90 ° C. to 210 ° C. (120 ° C. to 190 ° C.).

  Next, the peripheral configuration of the low temperature shift reaction unit 13 and the selective oxidation reaction unit 8 in the present embodiment will be described in more detail.

  FIG. 3 is an enlarged view of the configuration around the selective oxidation reaction unit shown in FIG. As shown in FIG. 3, the carbon monoxide removal structure of the hydrogen production apparatus 1 according to the present embodiment has a low-temperature shift reaction unit 13, a shift reaction inlet gas flow path 31, an exhaust gas flow from the axis G side toward the outer peripheral side. The channel 32, the water evaporation channel 33, the selective oxidation reaction outlet gas channel 34, and the selective oxidation reaction unit 8 are provided in this order. The low temperature shift reaction section 13, the shift reaction inlet gas flow path 31, the exhaust gas flow path 32, the water evaporation flow path 33, the selective oxidation reaction outlet gas flow path 34, and the selective oxidation reaction section 8 all have the axis G as the central axis. It has a cylindrical shape and is arranged so as to be adjacent to each other in the radial direction.

  The low temperature shift reaction unit 13 includes a peripheral wall 41, a peripheral wall 42, a lower end wall 43, a punching plate 44, a punching plate 45, and a low temperature shift catalyst 13x. The peripheral wall 41 and the peripheral wall 42 have a cylindrical shape (circular tubular shape) with the central axis as the axis G. A gap for filling the low temperature shift catalyst 13x is formed between the peripheral wall 41 and the peripheral wall 42. The lower end wall 43 has a disk shape extending along the radial direction, and blocks the lower side of the low temperature shift reaction unit 13 continuously from the lower ends of the peripheral wall 41 and the peripheral wall 42. The peripheral wall 42 extends further upward than the peripheral wall 41. The punching plate 44 has a disk shape extending along the radial direction, and is provided between the peripheral wall 41 and the peripheral wall 42 at a position spaced upward from the lower end wall 43. The punching plate 45 has a disk shape extending along the radial direction, and is provided between the peripheral wall 41 and the peripheral wall 42 at a position on the upper end side of the peripheral wall 41. The low temperature shift catalyst 13x is filled in a space formed by the peripheral wall 41, the peripheral wall 42, the punching plate 44, and the punching plate 45. Moreover, the low temperature shift reaction part 13 has the exit 52 which flows out the reformed gas after shift reaction. In addition, the low temperature shift reaction part 13 is good also as a structure which does not use a punching board. A mixing structure 50 for efficiently mixing the reformed gas and the air after the shift reaction is provided below the low temperature shift reaction unit 13.

  The mixing structure 50 includes an internal space 51, an outlet 52, a reformed gas pipe 14x, and an air pipe (air supply unit) 15. The internal space 51 is an annular space formed between the lower end wall 43 and the punching plate 44. The internal space 51 can efficiently collect the reformed gas after the shift reaction at the outlet 52. The outlet 52 is a through hole formed in the lower end wall 43 of the low temperature shift reaction unit 13. Since the outlet 52 is formed only at one place on the lower end wall 43, the reformed gas after the shift reaction can be collected at one place. The reformed gas pipe 14 x is a pipe connected to the outlet 52. The reformed gas pipe 14 x allows the reformed gas after the shift reaction to flow to the selective oxidation reaction outlet gas channel 34. The reformed gas pipe 14 x has a cylindrical shape with the central axis as the axis G, and includes a pipe part 14 a that extends upward from below the low temperature shift reaction part 13 and is connected to the outlet 52. The tip of the air pipe 15 is inserted into the reformed gas pipe 14x. The distal end portion of the air pipe 15 is disposed coaxially with the pipe portion 14 a inside the pipe portion 14 a of the reformed gas pipe 14 x and extends upward toward the outlet 52.

  With such a configuration, the outlet 52 can collect the reformed gas after the shift reaction in one place and flow the reformed gas downward into the pipe portion 14a of the reformed gas pipe 14x. On the other hand, the air pipe 15 can supply air to the reformed gas passing through the outlet 52 from the lower side to the upper side (that is, from the direction facing the flow of the reformed gas). Thus, the mixing structure 50 can efficiently mix the reformed gas and air after the shift reaction in the vicinity of the outlet 52. The mixing position of the reformed gas and air is not particularly limited, and may be a position other than the pipe portion 14a. However, a position closer to the outlet 52 is preferable because the flow rate of the reformed gas is high and mixing efficiency is good.

  The shift reaction inlet gas channel 31 is a channel through which the inlet gas for the low temperature shift reaction unit 13 is circulated, and is constituted by the peripheral wall 42 and the peripheral wall 61. The peripheral wall 61 has a cylindrical shape (circular tube) with the central axis as the axis G. The shift reaction inlet gas flow path 31 is constituted by a gap between the peripheral wall 41 and the peripheral wall 61. The peripheral wall 61 is connected to a lower end wall 62 arranged so as to be spaced downward from the lower end wall 43 of the low temperature shift reaction unit 13. The reformed gas flowing through the shift reaction inlet gas channel 31 flows so as to wrap around the lower end wall 43 and the peripheral wall 41 of the low temperature shift reaction unit 13 and is supplied to the low temperature shift reaction unit 13 from above. In the present invention, the reformed gas supplied to the low temperature shift reaction unit 13 is not limited to such a flow, and may be supplied to the low temperature shift reaction unit 13 through any flow path. Therefore, the shift reaction inlet gas flow path 31 may not be provided in such an arrangement.

  The exhaust gas channel 32 is a channel through which the exhaust gas from the burner is circulated, and includes a peripheral wall 61, a peripheral wall 63, a lower end wall 64, and an outer peripheral wall 66. The peripheral wall 63 has a cylindrical shape (circular tube) with the central axis as the axis G. The exhaust gas flow path 32 is configured by a gap between the peripheral wall 61 and the peripheral wall 63. A lower end portion of the peripheral wall 63 is connected to an annular lower end wall 64 spaced upward from the lower end wall 62. Further, the outer peripheral end portions of the lower end wall 64 and the lower end wall 62 are closed by a cylindrical outer peripheral wall 66. The exhaust gas flow channel 32 circulates the exhaust gas from the reforming unit 6 side from above to below.

  The water evaporation channel 33 is a channel through which water or water vapor of the evaporation unit 9 is circulated, and is constituted by a peripheral wall 63, a lower end wall 64, a peripheral wall 67, and an upper end wall 68. The peripheral wall 67 has a cylindrical shape (circular tube shape) having an axis G as a central axis. The water evaporation channel 33 is constituted by a gap between the peripheral wall 63 and the peripheral wall 67. A lower end portion of the peripheral wall 67 is connected to the lower end wall 64. The lower end wall 64 has a disk shape extending in the radial direction, and closes the lower side of the water evaporation channel 33 continuously to the lower ends of the peripheral wall 63 and the peripheral wall 67. The upper end wall 68 has a disk shape extending in the radial direction, and continuously closes the upper ends of the peripheral wall 63 and the peripheral wall 67 and closes the upper side of the water evaporation channel 33. Near the lower end of the peripheral wall 67, a water pipe 17x is connected. The water evaporation channel 33 circulates the water supplied from the water pipe 17x from below to above. Since water evaporates in the water evaporation channel 33, the water evaporation channel 33 has a lower water layer and an upper steam layer. The position of the water surface in the water evaporation channel 33 is not particularly limited, but is preferably at least above the upper end position of the selective oxidation catalyst 8x. Further, the upper end of the water evaporation channel 33, that is, the position of the upper end wall 68 is not particularly limited, and may be arranged at a position higher than the position shown in the figure.

  The selective oxidation reaction outlet gas channel 34 is a channel through which the outlet gas flows to the selective oxidation reaction unit 8, and includes a peripheral wall 67, a peripheral wall 69, a lower end wall 71, and an upper end wall 72. The lower end wall 71 has a disk shape extending along the radial direction, and is provided on the outer peripheral surface of the peripheral wall 67. The lower end wall 71 is disposed above the connection position of the water pipe 17x. The upper end wall 72 has a disk shape extending along the radial direction, and is provided on the outer peripheral surface of the peripheral wall 67. The peripheral wall 69 has a cylindrical shape (circular tubular shape) with the central axis as the axis G, and extends between the lower end wall 71 and the upper end wall 72. The lower end of the peripheral wall 69 is connected to the lower end wall 71, and the upper end of the peripheral wall 69 is separated from the upper end wall 72 (or a through hole for allowing the reformed gas to flow is provided). The selective oxidation reaction outlet gas channel 34 is formed by a gap between the peripheral wall 67 and the peripheral wall 69. A reformed gas pipe 14 y is connected to the vicinity of the lower end of the peripheral wall 69. The selective oxidation reaction outlet gas flow path 34 causes the reformed gas supplied from the selective oxidation reaction unit 8 to flow from the upper side to the lower side, and flows out from the reformed gas pipe 14y. The positions of the upper end and the lower end of the selective oxidation reaction outlet gas channel 34, that is, the positions of the upper end wall 72 and the lower end wall 71 are not limited to the positions shown in the drawing.

  The selective oxidation reaction unit 8 includes a peripheral wall 69, a peripheral wall 73, an upper end wall 72, a lower end wall 77, a punching plate 74, and a selective oxidation catalyst 8x. The peripheral wall 73 has a cylindrical shape (circular tubular shape) with the central axis as the axis G on the outer peripheral side of the peripheral wall 69. A gap for filling the selective oxidation catalyst 8x is formed between the peripheral wall 69 and the peripheral wall 73. A part on the lower end side of the peripheral wall 73 is a small diameter portion 73a in which a step is formed and the diameter is reduced. The lower end wall 77 has a disk shape extending along the radial direction, and blocks the lower side of the selective oxidation reaction unit 8 continuously from the outer peripheral surface of the peripheral wall 69 and the lower end portion of the small diameter portion 73a of the peripheral wall 73. The punching plate 74 has a disk shape extending in the radial direction, and is provided between the peripheral wall 69 and the peripheral wall 73 at a stepped portion of the peripheral wall 69. The selective oxidation catalyst 8 x is filled in a space formed by the peripheral wall 69, the peripheral wall 73, the punching plate 74, and the upper end wall 72. A reformed gas pipe 14 x is connected to the small diameter portion 73 a of the peripheral wall 73. Note that the selective oxidation reaction unit 8 may be configured not to use a punching plate.

  Next, the reformed gas RG, water (or steam) W, exhaust gas EG flow, and heat flow around the selective oxidation reaction unit 8 will be described with reference to FIGS. FIG. 4 is a block diagram showing the heat flow around the selective oxidation reaction unit 8 shown in FIG.

  First, the reformed gas RG flows through the shift reaction inlet gas channel 31 and is supplied to the low temperature shift reaction unit 13. The reformed gas RG whose carbon monoxide concentration has been reduced by the low temperature shift catalyst 13x is collected at one location in the internal space 51 toward the outlet 52. The temperature of the reformed gas RG flowing out from the low temperature shift reaction unit 13 is 150 ° C. to 250 ° C. as described above. The reformed gas RG collected at the outlet 52 flows downward toward the pipe portion 14a of the reformed gas pipe 14x. At this time, the reformed gas RG collides with the air supplied upward from the air pipe 15 and is efficiently mixed with the air. The reformed gas RG mixed with air flows through the reformed gas pipe 14 x and is supplied to the selective oxidation reaction unit 8. At this time, the reformed gas RG radiates heat to the outside through the reformed gas pipe 14x while flowing through the reformed gas pipe 14x. Further, the reformed gas RG flows in the selective oxidation reaction outlet gas flow with the water evaporation channel 33 in the gap between the small diameter portion 73a of the peripheral wall 73 and the peripheral wall 69 (that is, the space below the selective oxidation catalyst 8x). Heat exchange is performed via the path 34. Thus, the reformed gas RG is brought to an appropriate temperature before flowing into the selective oxidation reaction unit 8. That is, a part of the reformed gas pipe 14 x and the selective oxidation reaction outlet gas flow path 34 can function as the heat exchange part A. The reformed gas pipe 14 x exchanges heat with the outside of the pipe, and the selective oxidation reaction outlet gas flow path 34 exchanges heat with the water evaporation flow path 33. The reformed gas pipe 14x can be set to an appropriate length for temperature adjustment. The temperature of the reformed gas RG is maintained at 80 to 180 ° C. immediately before flowing into the selective oxidation reaction unit 8.

  Carbon monoxide is removed from the reformed gas RG flowing into the selective oxidation reaction unit 8 by the selective oxidation catalyst 8x. Here, since the selective oxidation reaction is an exothermic reaction, heat is generated from the selective oxidation catalyst 8x. At this time, the selective oxidation reaction unit 8 can exchange heat with the water evaporation channel 33 via the selective oxidation reaction outlet gas channel 34. Thereby, it is possible to prevent the vicinity of the inlet of the selective oxidation reaction unit 8 from becoming unnecessarily high. At this time, the selective oxidation reaction outlet gas channel 34 can function as a heat exchange unit B that performs heat exchange between the selective oxidation reaction unit 8 and the water evaporation channel 33. The temperature of the reformed gas RG is set to 110 to 190 ° C. immediately after flowing out of the selective oxidation reaction unit 8.

  The reformed gas RG flowing out from the selective oxidation reaction section 8 and supplied to the selective oxidation reaction outlet gas flow path 34 flows through the selective oxidation reaction outlet gas flow path 34 from above to below. At this time, the reformed gas RG exchanges heat with water (or water vapor) in the water evaporation channel 33 adjacent to the inner peripheral side of the selective oxidation reaction outlet gas channel 34. Thus, the reformed gas RG is cooled by supplying heat to the water evaporation channel 33. That is, the selective oxidation reaction outlet gas channel 34 can function as a heat exchange part C that performs heat exchange with the water evaporation channel 33. The reformed gas RG is sufficiently cooled and finally set to 70 to 100 ° C. As described above, the selective oxidation reaction outlet gas channel 34 can function as the three heat exchange parts A, B, and C while being a single channel.

  The water W is supplied from the water pipe 17x, flows into the water evaporation channel 33, and flows from below to above. At this time, the water W can receive heat from the exhaust gas EG in the exhaust gas channel 32 adjacent to the water evaporation channel 33 on the inner peripheral side. Further, the water W can receive the heat of the reformed gas RG as the inlet gas of the selective oxidation reaction unit 8 from the selective oxidation reaction outlet gas channel 34 that functions as the heat exchange unit A. Further, the water W can receive heat from the selective oxidation reaction from the selective oxidation reaction outlet gas channel 34 functioning as the heat exchange part B. Further, the water W can receive heat from the reformed gas RG as the outlet gas of the selective oxidation reaction section 8 from the selective oxidation reaction outlet gas flow path 34 that functions as the heat exchange section C. As described above, since the water evaporation channel 33 can receive heat efficiently through the water evaporation channel 33, the evaporation efficiency of the water W can be greatly improved. The temperature of the water W (or water vapor) is set to 100 to 500 ° C. in the region in contact with the selective oxidation reaction outlet gas flow path 34, and particularly heated to 110 to 300 ° C. near the outlet of the selective oxidation reaction unit 8. Can be done. The water W evaporates while flowing upward, becomes steam, and goes to the reforming unit 6.

  Next, operations and effects of the hydrogen production apparatus 1 and the fuel cell system 100 according to the present embodiment will be described.

  First, for comparison, a configuration is considered in which the selective oxidation reaction outlet gas flow path 34 is not provided, and the reformed gas after the selective oxidation reaction by the selective oxidation reaction unit 8 is immediately supplied to the reformed gas pipe 14y. . In such a configuration, the reformed gas after the selective oxidation reaction is supplied to the outside of the apparatus at a high temperature, and the heat of the reformed gas as the outlet gas is wasted. On the other hand, the reforming pipe 14y is provided with a heat exchanger (for example, indicated by HEX in FIG. 3), and the water W from the water pipe 17x is supplied to the evaporation section 9 after being heat-exchanged by the heat exchanger HEX. In this case, there is a problem that the structure becomes complicated as the apparatus becomes larger.

  On the other hand, in the hydrogen production apparatus 1 according to this embodiment, the selective oxidation reaction outlet gas flow path 34 in which the reformed gas RG flows between the water evaporation flow path 33 through which the water W flows and the selective oxidation reaction unit 8. Is placed. In addition, the selective oxidation reaction outlet gas channel 34 can flow the reformed gas RG flowing out from the selective oxidation reaction unit 8, that is, the outlet gas of the selective oxidation reaction unit 8. According to such a configuration, the reformed gas RG as the outlet gas of the selective oxidation reaction unit 8 can flow through the selective oxidation reaction unit 8 along the water evaporation channel 33 through which water and water vapor flow. It becomes. Therefore, the reformed gas RG as the outlet gas of the selective oxidation reaction unit 8 can be sufficiently cooled by the water W and water vapor in the water evaporation channel 33 without providing a separate heat exchanger HEX.

  The water W and water vapor in the water evaporation channel 33 can recover the heat of the reformed gas RG in the selective oxidation reaction outlet gas channel 34, thereby increasing the evaporation efficiency in the selective oxidation reaction outlet gas channel 34. Can be improved (or the temperature of water vapor can be increased). Here, since it is necessary to arrange the heat exchanger HEX at a position away from the selective oxidation reaction unit 8 by a certain distance, a heat loss may occur while the reformed gas RG flows to the heat exchanger HEX. On the other hand, in the present embodiment, the water evaporation channel 33 can recover heat without loss from the reformed gas RG immediately after flowing out from the selective oxidation reaction unit 8. Thus, by efficiently supplying the steam that has recovered the heat of the reformed gas RG to the reforming unit 6, the reforming efficiency of the entire hydrogen production apparatus 1 can be improved. In the hydrogen production apparatus 1 according to this embodiment, the selective oxidation reaction unit 8 has a simple configuration in which the selective oxidation reaction outlet gas channel 34 is formed between the selective oxidation reaction unit 8 and the water evaporation channel 33. The heat of the reformed gas RG as the outlet gas can be used effectively. As a result, it is possible to prevent the apparatus from becoming large and the structure from becoming complicated as compared with the case where a separate heat exchanger HEX is provided.

  Further, the selective oxidation reaction unit 8 is in direct contact with the water evaporation channel 33 through which the water W flows by the configuration in which the selective oxidation reaction outlet gas channel 34 is disposed between the selective oxidation reaction unit 8 and the water evaporation channel 33. Without this, the selective oxidation reaction outlet gas channel 34 can function as a heat medium. As a result, the temperature of the selective oxidation catalyst 8x of the selective oxidation reaction unit 8 can be prevented from becoming too low, and the reaction efficiency of the selective oxidation reaction unit 8 can be improved. In addition, deterioration of the selective oxidation catalyst 8x can be prevented. As described above, according to the hydrogen production apparatus 1 according to the present embodiment, the reforming efficiency of the hydrogen production apparatus 1 as a whole can be improved with a simple structure.

  Further, in the hydrogen production apparatus 1 according to the present embodiment, the exhaust gas flow channel 32 is disposed at a position adjacent to the water evaporation flow channel 33 on the opposite side of the selective oxidation reaction outlet gas flow channel 34. Since the exhaust gas flow path 32 is disposed at a position adjacent to the water evaporation flow path 33, the water in the water evaporation flow path 33 can be efficiently evaporated by receiving heat from the high temperature exhaust gas EG.

  Moreover, in the hydrogen production apparatus 1 according to the present embodiment, the low temperature shift reaction unit 13 has an outlet 52 through which the reformed gas RG after the shift reaction passes. In addition, the air pipe 15 can supply air to the reformed gas RG passing through the outlet 52 from the direction facing the flow of the reformed gas RG. The reformed gas RG is collected at the outlet 52 when it flows out of the low temperature shift reaction unit 13. At this time, the air pipe 15 can supply air to the reformed gas RG collected at the outlet 52. Thereby, air and the reformed gas RG can be mixed efficiently. Furthermore, since the air pipe 15 can supply air from the direction opposite to the flow of the reformed gas RG, the reformed gas RG and the air collide and are mixed more efficiently.

  In addition, since the fuel cell system 100 according to the present invention includes the hydrogen production apparatus 1, the above-described effect that the reforming efficiency of the hydrogen production apparatus 1 as a whole can be improved with a simple structure is achieved. .

  The preferred embodiment of the present invention has been described above. However, the hydrogen production apparatus and the fuel cell system according to the present invention are not limited to the hydrogen production apparatus 1 and the fuel cell system 100 according to the embodiment. The gist described in the claims may be modified within a range not changing, or applied to other things. For example, one having a different structure of the reforming part may be adopted, and the desulfurization part 2 may not be provided.

  For example, the configuration of the hydrogen production apparatus shown in the above embodiment is an example, and the configuration of the portion excluding the positional relationship of the selective oxidation reaction unit 8, the selective oxidation reaction outlet gas channel 34, and the water evaporation channel 33 is as follows. There is no particular limitation, and the positional relationship and configuration of each flow path, pipe, and component may be changed as appropriate.

  Moreover, although the said embodiment is equipped with the high temperature shift reaction part 12 and the low temperature shift reaction part 13 as what carries out the shift reaction of the carbon monoxide in reformed gas, as shown in FIG. You may have only.

  Incidentally, the above “tubular shape” includes not only a substantially cylindrical shape but also a substantially polygonal tubular shape. In addition, the substantially cylindrical shape and the substantially polygonal cylindrical shape mean a cylindrical shape and a polygonal cylindrical shape in a broad sense such as those substantially equal to the cylindrical shape and the polygonal cylindrical shape, and those including at least a cylindrical shape and a polygonal cylindrical shape. ing.

  DESCRIPTION OF SYMBOLS 1 ... Hydrogen production apparatus, 10 ... Burner, 20 ... Cell stack (fuel cell stack), 8 ... Selective oxidation reaction part, 13 ... Shift reaction part, 15 ... Air piping (air supply part), 32 ... Exhaust gas flow path, 33 ... water evaporation channel (evaporation channel), 34 ... selective oxidation reaction outlet gas channel (gas channel), 52 ... outlet, 100 ... fuel cell system, G ... axis.

Claims (5)

A selective oxidation reaction part for selectively oxidizing carbon monoxide in the reformed gas containing hydrogen;
An evaporating flow path for generating water vapor by circulating water;
A gas flow path through which the reformed gas flows,
The gas flow path is disposed between the selective oxidation reaction portion and the evaporation flow path,
The reformed gas flows out of the selective oxidation reaction section and then flows through the gas flow path.
The portion through which the reformed gas flows before flowing into the selective oxidation reaction section is disposed outside the gas flow path, along the evaporation flow path via the gas flow path,
The selective oxidation reaction unit is disposed along the evaporation channel via the gas channel,
The hydrogen production apparatus , wherein the gas flow path is disposed adjacent to the evaporation flow path . It further comprises an exhaust gas passage through which the burner exhaust gas used for generating the reformed gas flows.
The hydrogen production apparatus according to claim 1, wherein the exhaust gas flow channel is disposed at a position adjacent to the evaporation flow channel on the opposite side of the gas flow channel. A shift reaction section for removing carbon monoxide in the reformed gas by a shift reaction;
An air supply unit for supplying air to the reformed gas from the shift reaction unit toward the selective oxidation reaction unit,
The shift reaction unit has an outlet through which the reformed gas after the shift reaction flows out,
The hydrogen production apparatus according to claim 1, wherein the air supply unit supplies the air to the reformed gas flowing out from the outlet from a direction opposite to the flow of the reformed gas. . The hydrogen production apparatus according to any one of claims 1 to 3,
A fuel cell system comprising: a fuel cell stack that generates electric power using the reformed gas generated by the hydrogen production apparatus. A selective oxidation reaction part for selectively oxidizing carbon monoxide in the reformed gas containing hydrogen;
An evaporating flow path for generating water vapor by circulating water;
A gas flow path through which the reformed gas flows,
The gas flow path is disposed between the selective oxidation reaction portion and the evaporation flow path,
The reformed gas flows out of the selective oxidation reaction section and then flows through the gas flow path.
It further comprises an exhaust gas passage through which the burner exhaust gas used for generating the reformed gas flows.
2. The hydrogen production apparatus according to claim 1, wherein the exhaust gas passage is disposed at a position adjacent to the evaporation passage on the opposite side of the gas passage.

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