JP5634729B2 - 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, a reformer that generates a reformed gas containing hydrogen by reforming a raw fuel using a burner and a reformed gas generated in the reformer are subjected to a shift reaction. A shift reaction unit that lowers the carbon monoxide concentration of the reformed gas, and a selective oxidation reaction unit that further reduces the carbon monoxide concentration of the reformed gas by selectively oxidizing the reformed gas that has undergone the shift reaction in the shift reaction unit. The thing equipped with these is known. In such a hydrogen production apparatus, the temperature of the shift reaction section and the selective oxidation reaction section is increased by heating at the time of start-up (see, for example, Patent Documents 1 and 2).

  In addition, such a conventional hydrogen production apparatus further includes an evaporation unit that generates steam using ambient heat. For example, in the hydrogen production apparatus described in Patent Document 3, the heat generation portion has a spiral shape. The water pipe is wound as an evaporation part.

JP 2007-335224 A JP 2006-248864 A JP 2005-162583 A

  By the way, in recent hydrogen production apparatuses, with the spread of household fuel cell systems, there is a strong demand for improved performance.

  Then, this invention makes it a subject to provide the hydrogen production apparatus and fuel cell system which can improve performance.

In order to solve the above-described problems, a hydrogen production apparatus according to the present invention is provided in a cylindrical shape with a reforming unit that generates a reformed gas containing hydrogen by reforming raw fuel and steam using a burner. A shift reaction unit that lowers the carbon monoxide concentration of the reformed gas by a shift reaction of the reformed gas generated in the reforming unit, and a reformed gas that is provided in a cylindrical shape and undergoes a shift reaction in the shift reaction unit A selective oxidation reaction section for further reducing the carbon monoxide concentration of the shift reaction section, a shift catalyst section provided in a cylindrical shape along the axis of the shift reaction section, and reforming generated in the reforming section A first reformed gas channel for flowing gas from one side to the other side in the axial direction at the outer periphery of the shift reaction unit; and a reformed gas that has been circulated through the first reformed gas channel Second reformed gas flow path that circulates from the outer periphery side to the inner periphery side, and the second reforming A third reformed gas that is circulated from the other side in the axial direction to one side in the inner periphery of the shift reaction section and is introduced to one side in the axial direction of the shift catalyst section. A cooling unit for cooling the reformed gas flowing through the first reformed gas channel is adjacent to the first reformed gas channel of the shift reaction unit . The shift reaction unit is provided in a cylindrical shape surrounding the shift reaction unit and includes an evaporation unit that generates water vapor by heating the water stored therein using ambient heat. The selective oxidation reaction unit is a selective oxidation reaction. A selective oxidation catalyst unit provided in a cylindrical shape along the axis of the unit, and further includes a control unit that adjusts the position of the water surface of the water stored in the evaporation unit, and the control unit is configured so that the position of the water surface is a selective oxidation catalyst. The position of the water surface is adjusted so as to be above the upper end of the part .

In the hydrogen production apparatus according to the present invention, the shift reaction section (the shift catalyst and the reformed gas supplied to the shift catalyst) can be suitably cooled by the cooling section, and the temperature of the shift reaction section can be controlled with high accuracy. Can do. Further, the heat generated in the shift reaction section can be recovered by the reformed gas flowing through the first reformed gas flow path and the cooling section, and the efficiency can be improved. Therefore, according to the present invention, it is possible to improve the performance of the hydrogen production apparatus. In addition, since the position of the water surface in the evaporation unit is higher than the upper end of the selective oxidation catalyst unit, it is possible to prevent the cooling near the upper end of the selective oxidation catalyst unit from being insufficient, and the temperature of the selective oxidation catalyst unit is rapidly increased. It can be surely prevented.

  Further, the cooling unit is provided in a cylindrical shape surrounding the shift reaction unit, and an exhaust gas passage for circulating the exhaust gas of the burner, and an evaporation unit provided in a cylindrical shape surrounding the exhaust gas channel and generating water vapor, It is preferable that it is comprised including. In this case, at the time of start-up, the shift reaction unit can be heated and heated by burning the burner and causing the exhaust gas to flow through the exhaust gas passage. Therefore, the heater used at the time of starting becomes unnecessary, and it becomes possible to reduce the number of parts. In addition, the exhaust gas can be cooled (the heat of the exhaust gas is moved to the evaporation unit) at the evaporation unit, and the exhaust gas can be cooled to improve efficiency. On the other hand, the evaporation unit can utilize the heat from the exhaust gas and the shift reaction unit, and can stabilize the vaporized state of water vapor. Therefore, further performance improvement of the hydrogen production apparatus can be realized.

  Further, the exhaust gas flow channel allows exhaust gas to flow from one side in the axial direction to the other side, and the evaporation unit can introduce water from the other side in the axial direction and lead water vapor from one side in the axial direction. preferable. In this case, in the evaporation section, water is introduced from the outlet side (downstream side) of the exhaust gas flow path, so that the exhaust gas can be lowered particularly on the outlet side, so that the efficiency can be further improved.

The shift reaction unit has a high temperature shift reaction unit that performs a high temperature shift reaction and a low temperature shift reaction unit that performs a low temperature shift reaction, and the upper end of the evaporation unit is the lower end of the high temperature shift catalyst unit of the high temperature shift reaction unit. It is preferable that the evaporator is configured to cover at least the lower end of the high temperature shift catalyst.

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

  This fuel cell system also has the above-described effect that the number of parts can be reduced and the performance can be improved because the hydrogen production apparatus is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the performance improvement in a hydrogen production apparatus and a fuel cell system is attained.

It is a block diagram showing a part of fuel cell system concerning one embodiment. It is a schematic front end view which shows the hydrogen production apparatus of FIG. It is a flowchart which shows the time of starting of the hydrogen production apparatus of FIG. It is a schematic front end view which shows the modification 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 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 FIG. 2, the hydrogen production apparatus 1 includes a desulfurization unit 2 (see FIG. 1) and a cylindrical main body 3 having a central axis as an axis G. 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 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 feed unit 5 combines and mixes the raw fuel and steam (steam) desulfurized in the desulfurization unit 2 to generate a mixed gas (mixed fluid), and supplies the generated mixed gas to the reforming unit 6 while diffusing. . A reforming section (SR: Steam Reforming) 6 generates a reformed gas by steam reforming the mixed gas supplied from the feed section 5 with the reforming catalyst 6x, and supplies the reformed gas to the shift reaction section 7. To do.

  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. In addition, since the steam reforming reaction is an endothermic reaction, the reforming unit 6 uses the burner 10 as a heat source for heating the reforming catalyst 6x of the reforming unit 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 section 2 (see FIG. 1) may be supplied as burner fuel and burned.

  The shift reaction unit 7 lowers the carbon monoxide concentration (CO concentration) of the reformed gas supplied from the reforming unit 6, and causes the carbon monoxide in the reformed gas to undergo a shift reaction that is an exothermic reaction. Convert to hydrogen and carbon dioxide. The shift reaction unit 7 here performs the shift reaction in two stages, and performs a high temperature shift reaction (HTS: a shift reaction at a high temperature (for example, 400 ° C. to 600 ° C.)). 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.), Have.

  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 (low temperature shift catalyst unit) 13x, thereby reducing the CO concentration of the reformed gas. Reduce. 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.

  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 causes the carbon monoxide in the reformed gas and air introduced from the outside to undergo a selective oxidation reaction that is an exothermic reaction by a selective oxidation catalyst (selective oxidation catalyst unit) 8x. To selectively oxidize and convert 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. ing. This selective oxidation reaction unit 8 leads out the reformed gas with the CO concentration further reduced.

  The evaporating unit 9 is for generating water vapor by using the surrounding heat. The evaporation unit 9 has a jacket structure and has a cylindrical outer shape with the central axis as the axis G. The evaporating unit 9 is disposed so as to be 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. The evaporation unit 9 supplies the generated water vapor to the feed unit 5.

  In this 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 the combustion is improved by such combustion. The quality catalyst 6x is heated. And the exhaust gas (exhaust gas) of the burner 10 distribute | circulates the exhaust gas flow path L1, 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 feed unit 5 to generate a mixed gas. This mixed gas is supplied to the reforming unit 6 and subjected to steam reforming by the reforming catalyst 6x, whereby a reformed gas is generated. The generated reformed gas is selected by the shift reaction unit 7 after its carbon monoxide concentration is reduced to, for example, about 1% or less and mixed with air introduced from the outside (hereinafter referred to as “PROX air”). The carbon monoxide concentration is reduced to 10 ppm or less by the oxidation reaction unit 8 and is led to the cell stack 20 at 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 of the present embodiment will be described in more detail.

  In the hydrogen production apparatus 1 of the present embodiment, the low temperature shift reaction unit 13, the exhaust gas flow channel (cooling unit) L1, the evaporation unit (cooling unit) 9 and the selection in the portion from the center in the axis G direction to the lower end of the main body unit 3 The oxidation reaction part 8 is arrange | positioned in this order from the radial direction inner side to the outer side.

  The exhaust gas flow path L1 has a cylindrical outer shape with the central axis as the axis G. The exhaust gas flow path L <b> 1 is provided so as to surround the low temperature shift reaction unit 13, and is disposed adjacent to the radially outer side of the low temperature shift reaction unit 13. The exhaust gas passage L1 circulates the exhaust gas from above to below (from one side to the other side in the direction of the axis G).

  The evaporating section 9 is provided so as to surround the exhaust gas passage L1, and is disposed adjacent to the radially outer side of the exhaust gas passage L1. The evaporation unit 9 stores water introduced from the outside, and vaporizes the stored water using ambient heat (that is, by heat moved from the surroundings) to generate water vapor. The evaporation unit 9 supplies the generated water vapor to the feed unit 5.

  An introductory part 9a for introducing (inflowing) water from the outside is provided at the lower end part of the evaporation part 9, and a deriving part 9b for inducing (outflowing) water to the feed part 5 is provided at the upper end part. It has been. Further, the evaporator 9 has an upper end located above the lower end of the high temperature shift catalyst 12x in order to recover the heat generated by the high temperature shift reaction unit 12, and the evaporator 9 has at least the lower end of the high temperature shift catalyst 12x. It is configured to cover. The selective oxidation reaction unit 8 is provided so as to surround the evaporation unit 9, and is arranged adjacent to the radially outer side of the evaporation unit 9.

  Here, in the low temperature shift reaction unit 13 of the present embodiment, the reformed gas supplied from above the outer peripheral part is circulated to the lower part in the outer peripheral part, and then returned to the upper part so as to go around through the inner peripheral part. The low temperature shift catalyst unit 13x is introduced. Specifically, the configuration is as follows.

  That is, the low temperature shift reaction unit 13 includes a low temperature shift catalyst 13x, an outer peripheral channel (first reformed gas channel) S1, a lower channel (second reformed gas channel) S2, and an inner peripheral channel ( The third reformed gas flow path) S3 is included. The low temperature shift catalyst 13x has a cylindrical outer shape with the central axis as the axis G, and has an introduction portion 31 into which the reformed gas is introduced at the upper end portion thereof, and a derivation portion 32 for deriving the reformed gas at the lower end portion thereof. have. The low temperature shift catalyst 13x is closed by an annular plate-like punching plate (not shown) provided on each of the upper and lower ends thereof.

  The outer peripheral flow path S1 has a cylindrical outer shape with the central axis as the axis G, is provided on the outer peripheral portion of the low temperature shift reaction unit 13, and is disposed adjacent to the radially outer side of the low temperature shift catalyst 13x. The outer peripheral flow path S1 communicates with the high temperature shift reaction unit 12 on the upper side, and allows the reformed gas supplied from the high temperature shift reaction unit 12 to flow from the upper side to the lower side. Further, the evaporating section 9 and the exhaust gas flow path L1 are close to the outer peripheral flow path S1.

  The lower flow path S2 has an annular outer shape with the central axis as the axis G, is provided below the low temperature shift reaction unit 13, and is disposed adjacent to the lower side of the low temperature shift catalyst 13x. The lower flow path S2 has a radially outer side communicating with the outer peripheral flow path S1, and the reformed gas that has flowed through the outer peripheral flow path S1 is moved from the radially outer side (outer peripheral side) to the inner side (inner peripheral side). ).

  The inner peripheral channel S3 has a cylindrical outer shape, is provided in the inner peripheral portion of the low temperature shift reaction unit 13, and is disposed adjacent to the radially inner side of the low temperature shift catalyst 13x. The lower part of the inner peripheral channel S3 communicates with the lower channel S2, and the reformed gas that has circulated through the lower channel S2 is circulated from below to above. Further, the inner peripheral flow path S3 communicates with the introduction portion 31 at the upper end portion of the low temperature shift catalyst 13x, and introduces the circulated reformed gas into the upper end portion of the low temperature shift catalyst 13x.

  Such a low temperature shift reaction part 13 comprises the outer cylinder 33 which comprises an outer peripheral wall, the inner cylinder 34 which comprises an inner peripheral wall, the upper end board 35 which comprises an upper end wall, and a lower end wall as a concrete structure. A lower end plate 36, an outer partition tube 37 between the outer tube 33 and the inner tube 34, and an inner partition tube 38 between the inner tube 34 and the outer partition tube 37 are provided. The lower ends of the partition tubes 37 and 38 are closed by a partition plate 39. The partition plate 39 is provided with a lead-out pipe 40 for leading out the reformed gas subjected to the low temperature shift reaction from the low temperature shift reaction section 13.

  An outer peripheral channel S1 is defined by the outer cylinder 33 and the outer partition cylinder 37, a lower channel S2 is defined by the lower end plate 36 and the partition plate 39, and an inner peripheral part is defined by the inner cylinder 24 and the inner partition cylinder 38. A flow path S3 is provided. Further, the low temperature shift catalyst 13x is disposed in the upper end plate 35, the partition cylinders 37 and 38, and the partition plate 39.

  In the hydrogen production apparatus 1 of the present embodiment configured as described above, at the time of start-up, as shown in FIG. 3, first, burner fuel and air are supplied to the burner 10, and the burner 10 is ignited and burned. The exhaust gas from the burner 10 is circulated in the exhaust gas flow path L1 (S101). As a result, the evaporation section 9, the reforming catalyst 6x, the high temperature shift catalyst 12x, the low temperature shift catalyst 13x, and the selective oxidation catalyst 8x are heated by the circulated exhaust gas and the sensible heat transfer and radiant heat generated by the combustion of the burner 10. The temperature is raised.

  Subsequently, the temperature T at the lower part of the hydrogen production apparatus 1 (for example, the lower part of the low temperature shift reaction part 13 far from the burner 10 and the lower part of the selective oxidation reaction part 8) is the temperature Ta at which condensed water does not accumulate in the lower part of the reforming part 6. Is reached, water is introduced from the introduction part 9a into the evaporation part 9 so that the water level in the evaporation part 9 does not fall below a predetermined water level (for example, the upper end of the selective oxidation catalyst 8x) (S102, S103). Thereby, while producing | generating water vapor | steam, the hydrogen production apparatus 1 is further heated by superheated water vapor | steam.

  Subsequently, when more than a necessary amount of water vapor is generated, raw fuel is supplied to the reforming unit 6 to generate reformed gas. When the reformed gas reaches the selective oxidation reaction unit 8, PROX air is introduced (S104 to S106). Thereby, the CO concentration of the reformed gas led out to the cell stack 20 is set to 10 ppm or less, and power generation is started (S107).

  As described above, in the present embodiment, as described above, the temperature of the evaporation section 9 and all the catalysts 6x, 12x, 13x, and 8x can be heated by the exhaust gas at the time of startup, and it is not necessary to use a heater. Therefore, according to this embodiment, the number of parts can be reduced, and the cost can be reduced. Furthermore, power consumption at startup can be reduced.

  In the present embodiment, the following functions and effects are exhibited during operation (during the reforming reaction). That is, the exhaust gas flowing through the exhaust gas flow path L1 is cooled by the evaporation unit 9, and the exhaust gas is cooled. Therefore, the efficiency of the hydrogen production apparatus 1 can be improved.

  The low temperature shift reaction unit 13 (reformed gas supplied to the low temperature shift catalyst 13x and the low temperature shift reaction unit 13) is cooled by the evaporation unit 9. The selective oxidation reaction unit 8 (the reformed gas supplied to the selective oxidation catalyst 8x and the selective oxidation reaction unit 8) is cooled by the evaporation unit 9. In particular, the reformed gas supplied to the low temperature shift reaction unit 13 flows through the outer peripheral channel S1, the lower channel S2, and the inner peripheral channel S3 in this order, and then the introduction unit of the low temperature shift catalyst 13x. 31. Since the outer peripheral flow path S1 is adjacent to the exhaust gas flow path L1, the reformed gas is suitably cooled by the low temperature exhaust gas. Further, since the selective oxidation reaction unit 8 is adjacent to the evaporation unit 9, it is suitably cooled by the evaporation unit 9. Therefore, the temperatures of the low temperature shift reaction unit 13 and the selective oxidation reaction unit 8 can be accurately controlled.

  Furthermore, in this embodiment, the heat generated in the low temperature shift reaction unit 13 can be recovered by the reformed gas that flows through the outer peripheral channel S1, the exhaust gas that flows through the exhaust gas channel L1, and the evaporation unit 9. . As a result, the low temperature shift reaction unit 13 can be maintained at an appropriate temperature, and the efficiency can be further improved.

  On the other hand, in the evaporation section 9, the heat of the exhaust gas flowing through the exhaust gas flow path L1 and the heat generation of the low temperature shift reaction section 13 and the selective oxidation reaction section 8 are suitably utilized to heat water and generate water vapor. Therefore, water can be reliably vaporized to generate water vapor, and the vaporized state of water vapor can be stabilized.

  Therefore, according to the present embodiment, it is possible to improve the performance of the hydrogen production apparatus 1, and consequently improve the performance of the fuel cell system 100.

  Moreover, in the evaporation part 9 of this embodiment, since water is introduced from the lower introduction part 21a corresponding to the outlet side (downstream side) of the exhaust gas flow path L1, as described above, the temperature of the evaporation part 9 is reduced. A low part will be located in the exit side of exhaust gas flow path L1. Therefore, the exhaust gas can be lowered particularly at the outlet side, and the energy discharged to the outside can be further reduced, and as a result, the efficiency can be further improved.

  Further, in the low temperature shift catalyst 13x of the present embodiment, as described above, the reformed gas is introduced from the inlet 31 at the upper end and the reformed gas is led out from the outlet 32 at the lower end. . Therefore, the inlet side that is likely to become high temperature in the low temperature shift catalyst portion 13x is located on the opposite side to the outlet side of the exhaust gas passage L1. Therefore, the temperature rise on the outlet side in the exhaust gas can be suppressed, and the energy discharged to the outside can be further reduced.

  In the present embodiment, as described above, the evaporation section 9, the low temperature shift reaction section 13, and the selective oxidation reaction section 8 can be integrated as the main body section 3, and the hydrogen production apparatus 1 can be downsized. Further, the evaporation unit 9 has a function as a heat exchanger for cooling the low temperature shift reaction unit 13 and the selective oxidation reaction unit 8. Furthermore, the unevenness of the reformed gas supplied to the selective oxidation reaction unit 8 can be reduced, and a dispersion plate for dispersing PROX air can be eliminated.

  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, the arrangement configuration of the hydrogen production apparatus may be an arrangement arrangement in which the hydrogen production apparatus 1 is turned upside down (for example, a hydrogen production apparatus configured with the burner 10 installed in the lower part) and is limited. is not. Moreover, the hydrogen production apparatus 1 of the said embodiment may not be provided with the desulfurization part 2. The reforming unit 6 may be any unit that reforms raw fuel and water vapor.

  Moreover, although the said embodiment is provided 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, you may provide only the low temperature shift reaction part 13. FIG.

  In addition, as illustrated below, a control unit that adjusts the position of the water surface of the water stored in the evaporation unit 9 is provided, and this control unit is arranged such that the position of the water surface is above the upper end of the selective oxidation catalyst 8x. In addition, the position of the water surface may be adjusted.

  FIG. 4 is a schematic front end view showing a modification of the hydrogen production apparatus of FIG. As shown in FIG. 4, the hydrogen production apparatus 1 ′ according to the modification has a function of setting the position of the water surface WF of the water stored in the evaporation unit 9 above the upper end 8 a of the selective oxidation catalyst 8 x. is there. The hydrogen production apparatus 1 ′ includes a load detection sensor CE, a raw fuel supply pump 110, a water supply pump 120, a burner fuel supply pump 130, an air supply pump 140, temperature sensors C1 to C5 and a control unit 150 with respect to the above embodiment. It has more.

  The load detection sensor CE has a function of detecting the load of the cell stack 20 (the amount of power (W) required for the cell stack 20), and outputs the detection result to the control unit 150. The raw fuel supply pump 110 is a pump that supplies raw fuel to the reforming unit 6. The water supply pump 120 is a pump that supplies water to the evaporation unit 9. The burner fuel supply pump 130 is a pump that supplies burner fuel to the burner 10. The air supply pump 140 is a pump that supplies air to the burner 10. Each pump 110, 120, 130, 140 is electrically connected to the control unit 150 and driven based on a control signal input from the control unit 150.

  The temperature sensors C1 to C5 are sensors that detect the position of the water surface WF by detecting the temperature in the evaporator 9. The temperature sensor C <b> 1 detects the temperature of the water vapor derived from the evaporation unit 9. The temperature sensors C2 to C5 are provided in the evaporator 9 in this order from the upper side to the lower side. The temperature sensors C2 and C3 are disposed above the upper end 8a of the selective oxidation catalyst 8x, and the temperature sensors C4 and C5 are disposed between the upper end 8a and the lower end 8b of the selective oxidation catalyst 8x.

  The control unit 150 has a function of controlling the entire hydrogen production apparatus 1, and the position of the water surface WF is controlled by the selective oxidation catalyst of the selective oxidation reaction unit 8 by controlling the pumps 110, 120, 130, and 140. The position of the water surface WF is adjusted to be above the upper end 8a of 8x.

  In this hydrogen production apparatus 1 ′, the control unit 150 executes the following control to position the water surface WF above the upper end 8a of the selective oxidation catalyst 8x. That is, by using a predetermined control map according to the load fluctuation of the cell stack 20, by changing the set value of S / C to an optimum value, or by changing the set value of the burner air ratio to an optimum value, The position of WF is positioned above the upper end 8a of the selective oxidation catalyst 8x.

  Alternatively, the position of the water surface WF is detected using the temperature sensors C1, C2, C3, C4, and C5, and when the water surface WF rises or falls below a certain position, the set value of S / C is changed to an optimum value. Or by changing the set value of the burner air ratio to the optimum value, the position of the water surface WF is positioned above the upper end 8a of the selective oxidation catalyst 8x.

  Thus, according to the hydrogen production apparatus 1 ′, since the position of the water surface WF becomes higher than the upper end 8a of the selective oxidation catalyst 8x, it is possible to suppress the cooling near the upper end 8a from being insufficient, and the selective oxidation. A sudden increase in the temperature of the catalyst 8x can be reliably prevented.

  Here, the “water surface WF” is a boundary portion where the water in the evaporation section 9 becomes water vapor. “S / C” is the ratio of water vapor to carbon in the raw fuel supplied to the reforming unit 6. The “burner air ratio” is the ratio of the amount of air supplied to the burner 10 to the amount of air (theoretical air amount) that can completely burn all the burner fuel supplied to the burner 10.

  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. Moreover, although the said embodiment is made into the coaxial structure which makes the center axis the axis | shaft G as a preferable, this invention may be set as the structure along the substantially coaxial structure or the axis | shaft G.

  DESCRIPTION OF SYMBOLS 1,1 '... Hydrogen production apparatus, 6 ... Reforming part, 7 ... Shift reaction part, 9 ... Evaporation part (cooling part), 10 ... Burner, 13 ... Low temperature shift reaction part (shift reaction part), 13x ... Low temperature shift Catalyst (shift catalyst unit), 20 ... cell stack (fuel cell stack), 100 ... fuel cell system, 150 ... control unit, G ... shaft, L1 ... exhaust gas flow channel (cooling unit), S1 ... outer peripheral channel (first) 1 reformed gas channel), S2 ... lower channel (second reformed gas channel), S3 ... inner peripheral channel (third reformed gas channel).

Claims (5)

A reforming unit that generates reformed gas containing hydrogen by reforming raw fuel and steam using a burner;
A shift reaction unit that is provided in a cylindrical shape and shifts the reformed gas generated in the reforming unit to reduce the carbon monoxide concentration of the reformed gas;
A selective oxidation reaction section that is provided in a cylindrical shape and further reduces the carbon monoxide concentration of the reformed gas that has undergone a shift reaction in the shift reaction section,
The shift reaction part is
A shift catalyst portion provided in a cylindrical shape along the axis of the shift reaction portion;
A first reformed gas flow path for causing the reformed gas generated in the reforming section to flow from one side in the axial direction to the other side in the outer peripheral portion of the shift reaction section;
A second reformed gas flow path for flowing the reformed gas that has flowed through the first reformed gas flow path from an outer peripheral side to an inner peripheral side of the shift reaction unit;
The reformed gas that has been circulated through the second reformed gas flow path is circulated from the other axial side to the one side at the inner peripheral portion of the shift reaction portion and one axial side of the shift catalyst portion. A third reformed gas flow path to be introduced into
A cooling unit for cooling the reformed gas flowing through the first reformed gas channel is in close proximity to the first reformed gas channel of the shift reaction unit,
The cooling unit is configured to include an evaporation unit that generates water vapor by heating the water stored in the cylinder surrounding the shift reaction unit using ambient heat,
The selective oxidation reaction section is provided so as to surround the evaporation section, and is disposed adjacent to the outside in the radial direction of the evaporation section, and is provided in a cylindrical shape along the axis of the selective oxidation reaction section. Part
A control unit for adjusting the position of the water surface of the water stored in the evaporation unit;
The said control part adjusts the position of the said water surface so that the position of the said water surface may become above the upper end of the said selective oxidation catalyst part, The hydrogen production apparatus characterized by the above-mentioned. The cooling part is
An exhaust gas flow path that is provided in a cylindrical shape surrounding the shift reaction unit and that circulates the exhaust gas of the burner;
The hydrogen production apparatus according to claim 1, further comprising: an evaporation unit that is provided in a cylindrical shape surrounding the exhaust gas flow path and generates the water vapor. The exhaust gas flow channel distributes the exhaust gas from one axial side to the other,
The hydrogen production apparatus according to claim 2, wherein the evaporating unit introduces water from the other side in the axial direction and derives the water vapor from one side in the axial direction. The shift reaction part is a low temperature shift reaction part that performs a low temperature shift reaction,
It further comprises a cylindrical high temperature shift reaction part for performing a high temperature shift reaction,
The evaporation unit is configured to cover at least the lower end of the high temperature shift catalyst unit of the high temperature shift reaction unit,
4. The hydrogen production apparatus according to claim 1 , wherein an upper end of the evaporation unit is located above a lower end of the high temperature shift catalyst unit . The hydrogen production apparatus according to any one of claims 1 to 4,
A fuel cell system comprising: a fuel cell stack that generates electric power using the reformed gas generated by the hydrogen production apparatus.

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