JP2009096706A - Reforming apparatus for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reforming apparatus for a fuel cell with a simple constitution. <P>SOLUTION: In a reforming apparatus, for use in a fuel cell, for reforming a raw fuel into a hydrogen-rich reformed gas, a reformer 12 generates the reformed gas from the raw fuel. A shift reactor 14 reduces carbon monoxide contained in the reformed gas through a shift reaction. A selective oxidation unit 16 reduces the carbon monoxide contained in the reformed gas that has passed through the shift reactor 14 by performing selective oxidation on the carbon monoxide. A reforming reaction tube 18 houses linearly the reformer 12, the shift reactor 14 and the selective oxidation unit 16 in this order, and further houses a desulfurization unit 160. A combustion means produces combustion exhaust gas by combusting the raw fuel. An outer casing 22 is placed around the reforming reaction tube 18, and the outer casing 22 has a large diameter than that of the reforming reaction tube 18. A heated flow passage 32 through which the combustion exhaust gas passed to heat the reforming reaction tube 18 is formed between the reforming reaction tube 18 and the outer casing 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reformer for a fuel cell that reforms raw fuel into a reformed gas used in a fuel cell system.

  A polymer electrolyte fuel cell generates electric power by converting chemical energy of hydrogen into electric energy. Practically, hydrogen used as a fuel for a polymer electrolyte fuel cell is a natural gas, a hydrocarbon gas such as naphtha, or a raw fuel gas of alcohols such as methanol and water vapor, which can be obtained relatively easily and inexpensively. Are mixed and reformed by a reformer. Hydrogen gas obtained by reforming is supplied to the fuel electrode of the fuel cell and used for power generation.

  Generally, the reformer includes a burner for supplying heat necessary for the reforming reaction of the raw fuel gas with steam. The combustion gas generated by burning the fuel with the burner is guided from the combustion cylinder to a path provided in the vicinity of the reforming reaction section, whereby the thermal energy of the combustion gas is used for the reforming reaction (for example, Patent Documents). 1 and 2).

In addition, an organic sulfur component is added as an odorant to city gas and propane gas used as raw fuel gas so that gas leakage can be easily detected. If city gas or propane gas containing organic sulfur components is supplied to the reformer as it is, organic sulfur components adhere to the reformer catalyst, and the reforming performance of the reformer decreases due to sulfur poisoning. It will be. Therefore, a reformer equipped with a desulfurizer has been devised (see, for example, Patent Documents 3 and 4).
JP 2007-15911 A International Publication No. 03/078311 Pamphlet JP 2003-12302 A JP 2002-356308 A

  However, the reformers described in Patent Documents 1 and 2 flow the combustion exhaust gas generated by burning the fuel with a burner inside the reforming section, thereby generating the thermal energy of the combustion exhaust gas and generating or reforming high-temperature steam. Therefore, the reforming section must be arranged outside the combustion exhaust gas passage. In addition, a carbon monoxide shifter and a carbon monoxide remover for reducing carbon monoxide contained in the reformed gas generated by the reformer are further outside the flow path including the reformer. Therefore, the flow path is complicated. As a result, the diameter of the reforming part is increased, and this is a cause of increasing the complexity and size of the entire reformer. Moreover, when it is going to add a desulfurization function to such a reformer, the structure becomes further complicated.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel cell reforming device having a simple configuration.

  In order to solve the above problems, a reformer for a fuel cell according to an aspect of the present invention is a reformer for a fuel cell that reforms a raw fuel into a hydrogen-rich reformed gas. A desulfurization section that removes sulfur, a reforming section that generates reformed gas from raw fuel from which sulfur components have been removed in the desulfurizing section, a shift shift section that reduces carbon monoxide contained in the reformed gas by a shift reaction, The selective oxidation unit that selectively oxidizes and reduces carbon monoxide contained in the reformed gas that has passed through the shift conversion unit, and the reforming unit, the shift conversion unit, and the selective oxidation unit are linearly stored in this order, Furthermore, a reforming reaction cylinder that houses the desulfurization section, a combustion means that burns raw fuel to generate combustion exhaust gas, an outer cylinder that is disposed on the outer periphery of the reforming reaction cylinder, and has a larger diameter than the reforming reaction cylinder, Formed between the reforming reaction cylinder and the outer cylinder to heat the reforming reaction cylinder And a heating channel which flue gas passes.

  According to this aspect, the reforming section, the shift shift conversion section, and the selective oxidation section are housed in this order in one reforming reaction cylinder, and the desulfurization section is also housed. The carbon monoxide contained in the reformed gas can be reduced and the sulfur component can also be removed without forming.

  According to the present invention, the configuration of the fuel cell reforming apparatus can be simplified.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. Further, for convenience of explanation, the positional relationship between the respective members will be described in correspondence with the upper, lower, left, and right sides of the drawing, but it is a relative positional relationship to the last and is not limited thereto. For example, it is also possible to have an aspect that is upside down.

(First embodiment)
FIG. 1 is a cross-sectional view showing a configuration of a fuel cell reforming apparatus 10 according to a first embodiment. The fuel cell reformer 10 generates a hydrogen-rich reformed gas by steam reforming methane, propane, butane, or the like, which is a raw fuel.

  The fuel cell reformer 10 includes a reforming unit 12 that generates reformed gas from raw fuel, a shift shifter 14 that reduces carbon monoxide contained in the reformed gas by a shift reaction, and a shift shifter 14. The selective oxidation unit 16 that selectively oxidizes and reduces carbon monoxide contained in the reformed gas that has passed through, and the reforming unit 12, the shift shift conversion unit 14, and the selective oxidation unit 16 are linearly stored in this order. In addition, the reforming reaction cylinder 18 that accommodates the desulfurization section 160, the burner 20 as combustion means for combusting raw fuel to generate combustion exhaust gas, and the outer periphery of the reforming reaction cylinder 18 are coaxially disposed and modified. An outer cylinder 22 having a larger diameter than the quality reaction cylinder 18. The periphery of the outer cylinder 22 is covered with a heat insulating material 24 except for a place where a plurality of pipes communicate with the outside.

  The burner 20 mixes and burns the air taken in from the air intake 26 and the raw fuel off-gas taken in from the fuel intake 28. When the raw fuel gas burns in the burner 20, a high-temperature combustion exhaust gas of 1200 to 1300 ° C. is generated. The burner 20 is disposed in the combustion chamber 30 formed at the end of the reforming reaction cylinder 18 on the reforming section 12 side, and is fixed to the lower portion of the outer cylinder 22. As a result, the heat of the combustion exhaust gas generated by the burner 20 can be immediately used for the reforming reaction in the reforming section 12, so that the thermal efficiency can be improved.

  Between the reforming reaction cylinder 18 and the outer cylinder 22, a heating flow path 32 through which the above-described combustion exhaust gas passes is formed in order to heat the reforming reaction cylinder 18.

  The reforming unit 12 is made of a case 34 having a smaller outer diameter than the reforming reaction tube 18 provided at the bottom of the reforming reaction tube 18, and metal particles such as nickel and ruthenium housed under the case 34 are made of alumina. And a catalyst layer 36 containing a reforming catalyst supported on the catalyst. On the upper surface of the case 34, an opening 38 is formed through which raw fuel and water vapor are mixed. The case 34 is provided with a vent on the side surface so that the reformed gas can pass from the side surface of the catalyst layer 36.

  The raw fuel is supplied to the catalyst layer 36 of the reforming unit 12 from the outside of the fuel cell reforming apparatus 10 via the raw fuel supply path 40 that penetrates the reforming reaction cylinder 18, the outer cylinder 22, and the heat insulating material 24. Is done. At this time, the raw fuel is heated by the fuel exhaust gas flowing through the heating flow path 32 or the reformed gas inside the reforming reaction cylinder 18 and the temperature of the reformed gas is lowered.

  The raw fuel supply path 40 passes through the interior of the reforming reaction cylinder 18 and is connected to the desulfurization section 160 in the middle. The desulfurization unit 160 is a so-called hydrodesulfurization system (also referred to as hydrodesulfurization system) that removes sulfur components by reacting raw fuel containing impurities such as sulfur with hydrogen in the presence of a catalyst. A return line (not shown) for returning a part of the hydrogen-rich gas or reformed gas that has not been used in the fuel cell to the desulfurization unit 160 is connected to the raw fuel supply path 40 upstream of the desulfurization unit 160. ing.

  The desulfurization unit 160 desulfurizes a combined gas of the supplied raw fuel gas and a recycle gas containing H2 gas in an amount of 10 vol% of the raw fuel gas. As the hydrodesulfurization catalyst, a Co—Mo type or Ni—Mo type is used, and as the adsorbent, a zinc oxide type catalyst is used. By this hydrogenation / adsorption desulfurization reaction (RCH2SH + H2 → RCH3 + H2SZnO + H2S → ZnS + H2O), the raw fuel gas is desulfurized to a concentration of the contained sulfur component of about 20 to 50 ppb.

  Further, among organic sulfur, RSH and COS are adsorbed by a zinc oxide-based catalyst depending on conditions (for example, 250 to 400 ° C.), but in general, once on a Co—Mo or Ni—Mo based hydrodesulfurization catalyst. Usually it is adsorbed with ZnO after changing to H2S. As the catalyst, for example, a Cu—Zn-based catalyst, a Ni—Zn-based catalyst, or the like may be appropriately selected in consideration of its operating temperature, cost, and the like. The desulfurization reaction temperature in the desulfurization unit 160 according to the present embodiment is 350 ° C. to 400 ° C.

  Further, the steam necessary for the reforming reaction in the reforming unit 12 is generated from the reformed water supplied from the outside of the fuel cell reforming apparatus 10 via the steam supply path 42. The reformed water, which is a liquid supplied from the outside, is vaporized by the combustion exhaust gas or the reformed gas whose temperature is raised inside the reforming reaction cylinder 18 and is supplied to the catalyst layer 36 as water vapor, and the shift shift section. 14 and the temperature of the selective oxidation unit 16 are lowered.

  In the reformer 10 for a fuel cell according to the present embodiment, the raw fuel supply path 40 joins at the steam supply path 42 and the junction 44 on the downstream side of the location where water passing through the steam supply path 42 is vaporized. is doing. In other words, the raw fuel supply path 40 and the water vapor supply path 42 merge at the downstream side of the desulfurization unit 160. Thereby, it is prevented that the water and water vapor | steam which pass the water vapor | steam supply path 42 mix in the desulfurization part 160, and the fall of the desulfurization performance of the desulfurization part 160 is suppressed. The steam supply path 42 has a coil shape in which a part of the steam supply path 42 is spirally wound inside the outer cylinder 22 and the reforming reaction cylinder 18, and water is easily vaporized by increasing the surface area. Therefore, water vapor is generated at least at the lower end of the coil on the upstream side of the junction 44.

  As in the fuel cell reforming apparatus 10 according to the present embodiment, after the temperature rise of the raw fuel and the vaporization of water by heating of the combustion exhaust gas are performed in the separate raw fuel supply path 40 and the water vapor supply path 42. By combining the raw fuel and water vapor, it becomes easy to control the supply of water vapor by raising the temperature of the raw fuel or vaporizing water in each supply channel.

  The shift shifter 14 includes, for example, a catalyst layer 46 made of copper oxide or zinc oxide pellets, and a partition plate 48 that supports the catalyst layer 46 and has holes formed so that the reformed gas permeates from below to above. And have. The shift shifter 14 can reduce carbon monoxide by a shift reaction using water vapor contained in the reformed gas by the action of the catalyst layer 46.

  For example, the selective oxidation unit 16 has a catalyst layer 50 made of a carbon monoxide selective oxidation catalyst supported by alumina, and a hole formed so as to support the catalyst layer 50 and allow the reformed gas to permeate from below to above. And a partition plate 52. In the selective oxidation unit 16, the concentration of carbon monoxide is further reduced by oxidizing the carbon monoxide with oxygen by the action of the catalyst layer 50 to carbon dioxide.

  An air supply path 54 that communicates with the outside of the fuel cell reforming apparatus 10 to supply oxygen consumed by the selective oxidation unit 16 to a region between the shift shift unit 14 and the selective oxidation unit 16. The distal end portion 56 is disposed. As a result, the air flowing from the tip 56 rises together with the reformed gas from which carbon monoxide has been reduced in the shift shift unit 14 and contributes to the reaction in the selective oxidation unit 16.

  An opening 58 is formed on the upper surface of the reforming reaction cylinder 18 above the selective oxidation unit 16. Connected to the opening 58 is a reformed gas delivery pipe 60 for delivering a reformed gas with sufficiently reduced carbon monoxide to the fuel electrode of a fuel cell (not shown).

  Next, the operation of the fuel cell reforming apparatus 10 according to the present embodiment will be described. The combustion exhaust gas generated by the burner 20 heats the reforming reaction cylinder 18 from the side while ascending the heating channel 32 after heating the lower surface of the reforming reaction cylinder 18. At this time, the catalyst layer 36 is heated through the reforming reaction cylinder 18 to a temperature necessary for the reforming reaction, for example, in the range of 600 to 700 ° C. Further, the water vapor supply path 42 is heated directly or indirectly by the fuel exhaust gas via the reforming reaction cylinder 18, and the reformed water passing through the inside is vaporized. On the other hand, the fuel exhaust gas is cooled by the water vapor supply passage 42 as the heating passage 32 is raised, and the temperature gradually decreases. The combustion exhaust gas that has passed through the heating flow path 32 is discharged to the outside from a discharge port 62 formed in the upper portion of the outer cylinder 22.

  The water vapor evaporated in the water vapor supply path 42 and the raw fuel heated in the raw fuel supply path 40 are mixed in the junction 44 and sent out downward in the case 34. The raw fuel gas containing water vapor is gradually heated by the heat of the combustion exhaust gas when passing through the inside of the catalyst layer 36, and changes to a hydrogen-rich reformed gas by the reforming reaction.

  The reformed gas obtained by reforming the raw fuel gas rises inside the reforming reaction cylinder 18 by the flow of the supplied raw fuel gas and reaches the shift shift unit 14. Here, since the reforming reaction in the reforming unit 12 is an endothermic reaction, the reformed gas whose temperature has decreased due to the heat recovery of the steam supply path 42 reaches the shift shift unit 14. The shift reaction in the shift shift unit 14 is performed, for example, in the range of 200 to 300 ° C., and heat balance is achieved by the heat recovery of the water vapor supply path 42, so an appropriate temperature can be maintained without special temperature control. It is possible to maintain. As a result, the reformed gas is reduced in carbon monoxide at the shift shift section 14.

  In the case of an apparatus in which the temperature at the shift shift section 14 does not reach an appropriate temperature, the amount of raw fuel in the burner 20 is adjusted, or the number of turns of the coil of the water vapor supply path 42 near the shift shift section 14 is increased or decreased. Can be adjusted.

  The reformed gas whose carbon monoxide has been reduced in the shift shift unit 14 further rises while the flow is regulated by the flow straightening plate 64 inside the reforming reaction cylinder 18 by the flow of the supplied raw fuel gas, and the selective oxidation unit 16 is reached. At that time, the air supplied from the air supply path 54 also rises in the reforming reaction cylinder 18 and reaches the selective oxidation unit 16.

  Since the selective oxidation unit 16 is disposed in the vicinity of the inlet 66 of the water vapor supply path 42, the temperature of the reformed gas is lower than the temperature of the reformed gas in the shift shift unit 14 by cooling with the reformed water. . The selective oxidation reaction in the selective oxidation unit 16 is performed at a lower temperature than the shift reaction in the shift shift unit 14, for example, in the range of 70 to 200 ° C., and heat balance is achieved by heat recovery of the steam supply path 42. It is possible to maintain the reformed gas at an appropriate temperature without controlling the temperature. As a result, the reformed gas is further reduced in carbon monoxide in the selective oxidation unit 16.

  As described above, in the fuel cell reforming apparatus 10, the reforming unit 12, the shift shift conversion unit 14, and the selective oxidation unit 16 are accommodated in one reforming reaction cylinder 18 in this order, and further, the desulfurization unit. Since 160 is also housed, carbon monoxide contained in the reformed gas can be reduced and a sulfur component can be removed without forming a complicated flow path. In addition, the entire apparatus can be made compact by providing a desulfurizer inside the reforming reaction tube as compared with the case where the desulfurization part is provided outside the apparatus. Further, since the combustion exhaust gas passes through the heating flow path 32 between the reforming reaction cylinder 18 and the outer cylinder 22, heat necessary for the reforming reaction in the reforming section 12 inside the reforming reaction cylinder 18 is supplied. Therefore, no heating means such as a heater is required. Further, by forming the heating flow path 32 between the reforming reaction cylinder 18 and the outer cylinder 22, the fuel cell reforming apparatus 10 can be configured with a simple configuration without requiring a flow path that requires folding or many cylinders. Can be realized.

  In other words, the fuel cell reforming apparatus 10 according to the present embodiment is not provided with a flow path that requires folding or many cylinders, so that the cost is reduced by reducing the number of parts and simplifying the manufacturing process. The Moreover, since the heat insulation of the whole apparatus is easily securable by covering the outer peripheral part of the outer cylinder 22 with the heat insulating material 24, the process at the time of mounting | wearing with the heat insulating material 24 can be simplified.

  In addition, the heating flow path 32 is formed so that the combustion exhaust gas passes from the reforming unit 12 side toward the selective oxidation unit 16 side, so that the combustion exhaust gas is connected to the reforming reaction cylinder 18 and the steam supply path 42. The temperature gradually decreases while performing heat exchange. Therefore, the combustion exhaust gas passes through the inside of the heating channel 32 while the temperature is appropriately lowered from the reforming section having a high reaction temperature to the selective oxidation section having a low reaction temperature. Therefore, it is possible to form the heating flow path 32 linearly without providing the return of the flow path or new heating means.

  Further, the fuel cell reforming apparatus 10 is supplied with heat necessary for the desulfurization reaction in the desulfurization section 160 when the combustion exhaust gas passes through the heating passage 32 between the reforming reaction cylinder 18 and the outer cylinder 22. Therefore, compared with the case where the desulfurization part 160 is provided outside the apparatus, a heating means such as a heater is not necessary, and the thermal efficiency of the entire apparatus is improved. Moreover, the flow path of the raw fuel supply path 40 can be shortened compared with the case where the desulfurization part 160 is provided outside the apparatus.

  Further, as shown in FIG. 1, the desulfurization unit 160 is provided between the reforming unit 12 and the shift shift conversion unit 14. Thereby, the heat required for desulfurization reaction is supplied by the combustion exhaust gas which heated the reforming part 12, or reformed gas. Therefore, the fuel cell reforming apparatus 10 according to the present embodiment can efficiently raise the temperature of the desulfurization section up to a steady temperature during operation of the apparatus.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing the configuration of the fuel cell reforming apparatus 110 according to the second embodiment. In the fuel cell reforming apparatus 110 according to the present embodiment, the desulfurization section 162 is disposed at a position where the axial position of the reforming reaction cylinder 18 overlaps the shift shift section 164. Thereby, the vertical direction of the reforming reaction cylinder 18 becomes compact, and the fuel cell reforming apparatus 110 can be miniaturized. Further, the shift transformation section 164 is formed in an annular shape, and the desulfurization section 162 is provided on the inner periphery of the shift transformation section 164. Thereby, the fuel cell reformer 110 can efficiently raise the temperature of the shift shift section 164 at the time of startup.

  Moreover, the desulfurization part 162 which concerns on this Embodiment is good to set so that desulfurization reaction temperature may be about 200 degreeC-300 degreeC. Generally, the shift reaction temperature in the shift shift unit 164 is about 200 ° C to 300 ° C. Moreover, since the sulfur component in the desulfurization part 162 is about several ppm, the heat_generation | fever by a desulfurization reaction is also slight. Therefore, the desulfurization unit 162 is configured to be in contact with the shift reaction temperature by configuring the shift shift unit 164 and the desulfurization unit 162 that are in heat balance while cooling the catalyst layer 46 that generates heat by the shift reaction with water. It becomes easy to maintain the temperature at 200 ° C to 300 ° C.

(Third embodiment)
In the fuel cell reforming apparatus according to each of the above-described embodiments, the steam supply path 42 passes through the interior of the reforming reaction cylinder 18 and the catalyst layer 46 of the shift shift unit 14 and the catalyst layer 50 of the selective oxidation unit 16 are provided. It is provided to penetrate. For this reason, in the portion where the water vapor supply path 42 is in direct contact with the catalyst layer 50, the catalyst temperature is unnecessarily lowered, and the reaction may not be sufficiently performed. Therefore, in the present embodiment, the temperature of the catalyst layer is prevented from lowering more than necessary by devising the arrangement of the water vapor supply path.

  FIG. 3 is a cross-sectional view showing the configuration of the fuel cell reforming apparatus 210 according to the third embodiment. The fuel cell reforming apparatus 210 is significantly different from the fuel cell reforming apparatus 10 according to the first embodiment in that a water vapor supply path 142 is provided inside the heating flow path 32. With such a configuration, the catalyst layer 46 of the shift shift unit 14 and the catalyst layer 50 of the selective oxidation unit 16 are indirectly cooled by the water vapor supply path 142 via the reforming reaction cylinder 18. It is suppressed that a part of temperature falls extremely. As a result, for example, carbon monoxide does not sufficiently react in the selective oxidation unit 16 and unreacted carbon monoxide is suppressed from being sent to the fuel electrode of the fuel cell. Further, the steam supply path 142 may be provided so as to contact the reforming reaction cylinder 18. As a result, not only heat recovery from the combustion exhaust gas but also more heat of reaction in the catalyst layers 46 and 50 can be recovered, and the catalyst layers 46 and 50 can be further cooled. Further, the reformed gas inside the reforming reaction cylinder 18 can be further cooled.

  Further, when the catalyst layer 50 of the selective oxidation unit 16 is cylindrical as in the fuel cell reforming apparatus according to each of the above-described embodiments, when the diameter of the catalyst layer 50 increases, the central portion of the catalyst layer There is a possibility that the heat removal is not performed sufficiently. In such a case, the central portion of the catalyst layer 50 becomes high temperature, and normal and efficient reaction becomes difficult. In particular, when the water vapor supply path 142 is disposed outside the reforming reaction cylinder 18 as in the fuel cell reforming apparatus 210 according to the present embodiment, the heat removal tends to be insufficient. Therefore, for example, if the temperature of the catalyst layer 50 of the selective oxidation unit 16 exceeds an appropriate temperature range, a side reaction that oxidizes hydrogen in the reformed gas may occur.

  Therefore, in the fuel cell reforming apparatus 210 according to the present embodiment, the catalyst layer 150 of the selective oxidation unit 16 is formed in a ring shape. As a result, the catalyst layer 50 has a hollow central portion that is difficult to control in an appropriate temperature range, and therefore, undesirable side reactions are suppressed.

(Fourth embodiment)
FIG. 4 is a cross-sectional view showing a configuration of a fuel cell reforming apparatus 310 according to the fourth embodiment. As described above, the catalytic reaction in the selective oxidation section needs to be performed within an appropriate temperature range. Usually, in the catalyst layer of the selective oxidation portion, the reaction occurs most on the inlet side where the reformed gas flows, so that the temperature of the catalyst layer also tends to be higher on the inlet side and lower on the outlet side. Therefore, if the temperature of the reformed gas flowing into the catalyst layer of the selective oxidation unit is too high, the reaction temperature in the vicinity of the inlet of the catalyst layer may become higher than the appropriate temperature range.

  In view of this, in the fuel cell reforming apparatus 310, the selective oxidation unit 116 includes a folded flow path 118 and a ring-shaped catalyst layer 250 provided in the middle of the folded flow path 118. The return flow path 118 passes through the first flow path 120 and the first flow path 120 in which the reformed gas that has passed through the shift shift section 14 travels along the inner surface of the reforming reaction cylinder 18 toward the combustion chamber 30 side. The reformed gas comprises a second flow path 122 folded inward so that the reformed gas is directed to the combustion chamber 30 side. Further, the catalyst layer 250 is provided in the second flow path 122.

  Thus, before the reformed gas reaches the inlet side of the catalyst layer 250, heat is taken away by the low-temperature reformed water flowing through the steam supply path 142 disposed on the outer periphery of the first channel 120. Therefore, the reaction temperature on the inlet side of the catalyst layer 250 can be reduced to an appropriate temperature range. Further, the water vapor supply path 142 may be provided so as to contact the first flow path 120. Thereby, the temperature of the reformed gas flowing into the inlet side of the catalyst layer 250 can be further reduced.

  In addition, since the first flow path 120 and the second flow path 122 are arranged side by side, the reaction heat in the catalyst layer 250 can be recovered via the reformed gas. Further, since the reformed gas flows through the catalyst layer 250 toward the combustion chamber 30 in the second flow path, the reformed gas that flows into the first flow path 120 even when the reaction heat on the outlet side of the catalyst layer 250 is small. Thus, a decrease in temperature can be suppressed. As a result, a decrease in the reaction temperature on the outlet side that tends to be lower than the reaction temperature on the inlet side in the catalyst layer 250 is suppressed, and the entire catalyst layer 250 is maintained in a temperature range appropriate for the catalyst reaction.

  Here, the reaction temperature of the catalyst layer 250 is good to be maintained in the range of 100-200 degreeC. Preferably, it is good to maintain in the range of 120-180 degreeC. More preferably, it is good to maintain in the range of 130-170 degreeC. In the region where the temperature is too low, the reaction becomes insufficient. In addition, an unnecessary side reaction is preceded in a region where the temperature is too high.

  Note that, by providing the folded flow path 118 as in the present embodiment, the inlet side of the catalyst layer 250 of the selective oxidation unit 116 can be disposed on the side away from the shift shift unit 14 of the selective oxidation unit 116. It becomes. Therefore, the reforming that has substantially passed through the shift transformation unit 14 without increasing the distance between the shift transformation unit 14 and the selective oxidation unit 116, in other words, without extending the longitudinal direction of the reforming reaction cylinder 18. Since the distance until the gas reaches the catalyst layer 250 of the selective oxidation unit 116 becomes longer, the temperature of the reformed gas reaching the inlet side of the catalyst layer 250 can be lowered. As a result, the longitudinal direction of the fuel cell reforming apparatus 310 can be made compact.

  The present invention has been described with reference to each of the above-described embodiments. However, this is an exemplification, and the present invention is not limited to each of the above-described embodiments, and the configuration of each embodiment is appropriately set. Combinations and substitutions are also included in the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added are also included in the scope of the present invention. sell.

  In the fuel cell reforming apparatus described above, in the heat exchange section between gas and water, in order to promote heat transfer on the gas side, an object that increases heat transfer by diffusion of alumina balls, McMahon packing, etc. in the gas side passage. It may be filled. For example, combustion between the reforming unit 12 and the shift conversion unit 14, between the shift conversion unit 14 and the selective oxidation unit 16 (116), the upper part of the selective oxidation unit 16 (116), and the inlet side of the steam supply path 42. A heat exchange promoting material with the exhaust gas, etc. may be filled with a heat transfer promoting substance.

  In the fuel cell reforming apparatus 110 described above, the desulfurization section 162 is provided on the inner peripheral portion of the shift shift section 164, but the shift shift section 164 may be provided on the inner peripheral section of the desulfurization section 162. Thereby, the reformer 110 for fuel cells can efficiently raise the temperature of the desulfurization part 162 at the time of starting.

  The raw fuel used in the above-described fuel cell reforming apparatus is not limited to the exemplified methane, propane, butane and the like. For example, natural gas, hydrocarbons such as LPG mainly composed of propane / butane, naphtha and kerosene, alcohols such as methanol and ethanol, ethers such as dimethyl ether, and the like may be used as the raw fuel.

It is sectional drawing which shows the structure of the reformer for fuel cells which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the reformer for fuel cells which concerns on 2nd Embodiment. It is sectional drawing which shows the structure of the reformer for fuel cells which concerns on 3rd Embodiment. It is sectional drawing which shows the structure of the reformer for fuel cells which concerns on 4th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell reformer, 12 reformer, 14 shift shifter, 16 selective oxidation unit, 18 reforming reaction cylinder, 20 burner, 22 outer cylinder, 32 heating channel, 40 raw fuel supply channel, 42 steam supply Road, 110 Fuel cell reformer, 160 Desulfurization section, 162 Desulfurization section, 164 Shift shift section.

Claims (12)

A reformer for a fuel cell that reforms raw fuel into hydrogen-rich reformed gas,
A desulfurization section for removing sulfur components from raw fuel;
A reforming unit that generates reformed gas from raw fuel from which sulfur components have been removed in the desulfurization unit;
A shift shifter that reduces carbon monoxide contained in the reformed gas by a shift reaction;
A selective oxidation unit that selectively oxidizes and reduces carbon monoxide contained in the reformed gas that has passed through the shift transformation unit;
The reforming unit, the shift shift conversion unit, and the selective oxidation unit are stored linearly in this order, and a reforming reaction cylinder that further stores a desulfurization unit,
Combustion means for combusting raw fuel to produce combustion exhaust gas;
An outer cylinder disposed on the outer periphery of the reforming reaction cylinder and having a larger diameter than the reforming reaction cylinder;
A heating passage formed between the reforming reaction cylinder and the outer cylinder, through which the combustion exhaust gas passes to heat the reforming reaction cylinder;
A reformer for a fuel cell, comprising:   2. The reformer for a fuel cell according to claim 1, wherein the combustion means is disposed in a combustion chamber formed at an end portion of the reforming reaction cylinder on the reforming portion side.   3. The fuel cell reforming apparatus according to claim 1, wherein the heating passage is formed so that the combustion exhaust gas passes from the reforming unit side toward the selective oxidation unit side. 4. A water vapor supply path through which water is vaporized by heating with the flue gas to supply water vapor to the reforming section;
The desulfurization section is connected in the middle while passing through the inside of the reforming reaction cylinder, and the raw fuel is heated by heating with the combustion exhaust gas to supply the heated raw fuel to the reforming section. A raw fuel supply path
The desulfurization part has a hydrodesulfurization catalyst that removes sulfur by reaction with hydrogen,
The reformer for a fuel cell according to any one of claims 1 to 3, wherein the raw fuel supply path joins the water vapor supply path on the downstream side of the desulfurization section.   The reformer for a fuel cell according to claim 4, wherein the water vapor supply path is provided inside the heating flow path.   The reformer for a fuel cell according to claim 5, wherein the water vapor supply path is provided so as to contact the reforming reaction cylinder. The selective oxidation unit is
A first flow path in which the reformed gas that has passed through the shift shift section is directed along the inner surface of the reforming reaction tube toward the opposite side of the combustion chamber, and the reformed gas that has passed through the first flow path is on the combustion chamber side A folded flow path including a second flow path folded inwardly toward
A catalyst layer provided in the second flow path;
The fuel cell reformer according to any one of claims 4 to 6, characterized by comprising:   The reformer for a fuel cell according to claim 7, wherein the water vapor supply path is provided in contact with the first flow path.   The fuel cell reforming apparatus according to claim 1, wherein the desulfurization unit is provided between the reforming unit and the shift shift unit.   The fuel cell reforming apparatus according to any one of claims 1 to 8, wherein the desulfurization section has an axial position of the reforming reaction cylinder overlapping the shift shift section. The shift metamorphic part is formed in an annular shape,
The reformer for a fuel cell according to claim 10, wherein the desulfurization unit is provided on an inner periphery of the shift transformation unit. The desulfurization part is formed in an annular shape,
The reformer for a fuel cell according to claim 10, wherein the shift metamorphic section is provided in an inner peripheral portion of the desulfurization section.

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