JP2007290900A - Heat exchange-type reformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchange-type reformer having good heat exchange efficiency of a heating part and a reforming part. <P>SOLUTION: In the heat exchange-type reformer 10, a reforming passage 18 carrying a reforming catalyst 22 for reforming reaction is adjacent to a combustion passage 20 carrying an oxidation catalyst 24 for combustion through a plate part 52. The reforming passage 18 performs reforming reaction including steam reforming reaction for forming hydrogen from a reforming raw material supplied. The combustion passage 20 supplies the heat generated in connection with the catalytic combustion of a fuel supplied to the reforming passage 18. The reforming passage 18 and the combustion passage 20 compose a parallel flow-type heat exchanger, wherein the directions of gases flowing through both the passages are adapted to the direction of the arrow F. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat exchange type reformer that performs a reforming reaction for obtaining a reformed gas containing hydrogen from a reforming raw material such as a hydrocarbon while receiving heat supply from a heating unit in the reforming unit.

A reforming channel for reforming a hydrocarbon raw material to generate a hydrogen-containing gas between a plurality of stacked plates, and a fuel gas for supplying heat for reforming reaction to the reforming channel A cross flow heat exchange type fuel reformer having a combustion flow path for combustion is known (see, for example, Patent Document 1). Patent Document 1 describes a technique for setting a non-supported region of a catalyst between plates so that an exothermic distribution of a combustion reaction and an endothermic distribution of a reforming reaction at each part between the plates are adjusted.
Japanese Patent Application Laid-Open No. 2004-244230

  In the conventional cross-flow heat exchange type fuel reformer described above, a device has been devised to make the high heat generation part due to the combustion reaction coincide with the high heat absorption part due to the reforming reaction. There was room for improvement in terms of improving exchange efficiency.

  In a parallel flow heat exchange type fuel reformer, when the supported range of the reforming catalyst and the supported range of the oxidation catalyst are the same, the reaction rate of the combustion reaction becomes the reaction rate of the reforming reaction. On the other hand, since it is remarkably fast, the exothermic peak of the reforming reaction tends to shift downstream in the gas flow direction with respect to the exothermic peak of the combustion reaction. For this reason, in the parallel flow heat exchange type fuel reformer, there is a concern that the amount of heat generated locally may be excessive with respect to the amount of heat absorbed in the vicinity of the upstream end of the oxidation catalyst, and a local high temperature region may be generated. Is done. In particular, when the supporting range of the oxidation catalyst is widened upstream in the gas flow direction from the supporting range of the reforming catalyst due to lack of catalyst supporting accuracy, local catalyst peeling, etc. (In a wide range).

  In view of the above facts, an object of the present invention is to obtain a heat exchange type reformer having good heat exchange efficiency between the heating section and the reforming section.

  In order to achieve the above object, a heat exchange type reformer according to the invention described in claim 1 carries a reforming catalyst for reforming reaction and is supplied by a reforming reaction including a steam reforming reaction. An oxidation catalyst for catalytic combustion that is adjacent to the reforming section via a partition so as to generate a reforming section for generating hydrogen from the raw material and a gas flow in the same direction as the gas flow of the reforming section And a heating unit for supplying heat generated by catalytic combustion of the supplied fuel to the reforming unit.

  In the heat exchange type reformer according to claim 1, while the reforming unit receives heat supply from the heating unit through combustion, the supplied reformed gas is brought into contact with the reforming catalyst to cause a reforming reaction (acceleration). And hydrogen (containing gas) is obtained. The reforming reaction generates a high endothermic site in the vicinity of the upstream end (reforming raw material supply side) in the reforming catalyst support range, and the combustion reaction is the upstream side (fuel supply side) in the oxidation catalyst support range. A highly exothermic part is generated in the vicinity of the end of the plate.

  Here, since the flow direction of the reforming raw material (reformed gas) in the reforming section and the flow direction of the fuel or combustion gas in the heating section are the same, in other words, in the heating section and the reforming section. Since a parallel flow heat exchange type reformer is configured, a high heat generation site due to a combustion reaction in the heating unit and a high heat absorption site due to the reforming reaction in the reforming unit are arranged in the direction of gas flow in each catalyst support range. It can occur on the same side (upstream side). That is, it is possible to bring a portion where heat generation is large close to a portion where the endothermic demand is large (matching the distribution tendency of heat absorption and heat generation). Therefore, by minimizing the heat conduction path inside the reformer, the heat exchange type reformer according to claim 1 has good heat exchange efficiency between the heating section and the reforming section.

  A heat exchange type reformer according to a second aspect of the present invention is the heat exchange type reformer according to the first aspect, wherein the end of the reforming raw material supply side in the supported range of the reforming catalyst in the reforming unit. The position was set on the upstream side in the gas flow direction from the end position on the fuel supply side in the supporting range of the oxidation catalyst in the heating section.

  3. The heat exchange type reformer according to claim 2, wherein the position where the reforming material first contacts the reforming catalyst in the reforming section is more gas flow direction than the position where the fuel first contacts the oxidation catalyst in the heating section. Therefore, the endothermic peak in the reforming section can be shifted upstream. Thereby, the high exothermic part by combustion reaction and the high endothermic part by reforming reaction can be matched more favorably.

  For example, when the main reaction of the reforming reaction is a steam reforming reaction that is an endothermic reaction, an endothermic reaction occurs from the upstream end side of the reforming catalyst in the reforming section. The endothermic peak slightly shifts downstream from the exothermic peak due to the slow speed, but slow endothermic reaction is achieved by extending the upstream end of the reforming catalyst slightly upstream from the upstream end of the oxidation catalyst. The speed is complemented, and the high exothermic part due to the combustion reaction and the high endothermic part due to the reforming reaction agree well. Thereby, generation | occurrence | production of the local high temperature site | part by the imbalance of heat-absorption amount and the emitted-heat amount is prevented.

  In addition, for example, when the reforming reaction includes an exothermic reaction such as a partial oxidation reaction in addition to the steam reforming reaction, such an exothermic reaction mainly occurs on the upstream side of the reforming catalyst support range. Subject to reaction. Here, by positioning the upstream end position of the oxidation catalyst on the downstream side with respect to the upstream end position of the reforming catalyst, after the exothermic reaction in the reforming section is converged, the heat supply from the heating section is received and the endothermic reaction is performed. It is possible to optimize (optimize) the heat balance of the system by adopting a structure for performing the reaction.

  A heat exchange type reformer according to a third aspect of the present invention is the heat exchange type reformer according to the first or second aspect, wherein the reforming raw material is supplied in the supporting range of the reforming catalyst in the reforming section. The catalyst loading concentration in a predetermined range from the end on the side was set higher than the catalyst loading concentration in other portions in the reforming catalyst loading range.

  In the heat exchange type reformer according to claim 3, the reforming catalyst loading concentration is higher in the predetermined range (part) from the upstream end in the reforming catalyst loading range than in other portions. The endothermic reaction is promoted at a part of the upstream end side of the supporting range. In other words, the endothermic peak in the reforming section is shifted upstream. For this reason, it complements the slow endothermic reaction rate in the reforming part to make the high exothermic part due to the combustion reaction well coincide with the high endothermic part due to the reforming reaction, It is possible to increase the amount of heat supplied to the reforming section.

  A heat exchange type reformer according to a fourth aspect of the present invention is the heat exchange type reformer according to any one of the first to third aspects, wherein the fuel in the range where the oxidation catalyst is supported in the heating section. The catalyst loading concentration in a predetermined range from the supply side end was set to be lower than the catalyst loading concentration in other portions in the oxidation catalyst loading range.

  In the heat exchange type reformer according to claim 4, since the supported concentration of the oxidation catalyst is lower than the other portion in a predetermined range (part) from the upstream end side in the supported range of the oxidation catalyst, the supported range of the oxidation catalyst. The exothermic reaction in a part of the upstream side is relaxed (suppressed). In other words, the peak of heat generation in the heating unit is shifted downstream. As a result, the fast combustion reaction in the heating unit is suppressed to make the highly exothermic part due to the combustion reaction well coincide with the high endothermic part due to the reforming reaction, or the amount of heat supplied to the reforming part after convergence of the exothermic reaction in the reforming part It becomes possible to make it the structure which increases.

  As described above, the heat exchange type reformer according to the present invention has good heat exchange efficiency between the heating section and the reforming section.

  A heat exchange reformer 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, the overall system configuration of the fuel cell system 11 to which the heat exchange reformer 10 is applied will be described, and then the detailed structure of the heat exchange reformer 10 will be described.

(Overall configuration of fuel cell system)
FIG. 4 shows a system configuration diagram (process flow sheet) of the fuel cell system 11. As shown in this figure, the fuel cell system 11 includes a fuel cell 12 that generates power by consuming hydrogen, and a heat exchange reforming process for generating hydrogen-containing reformed gas to be supplied to the fuel cell 12. The reactor (reformer) 10 is a main component.

  The fuel cell 12 is configured by sandwiching an electrolyte (not shown) between an anode electrode (fuel electrode) 14 and a cathode electrode (air electrode) 16. The fuel cell 12 mainly includes hydrogen supplied to the anode electrode and the cathode electrode 16. It is configured to generate electricity by electrochemical reaction with supplied oxygen. Although various types of fuel cells 12 can be employed, in this embodiment, the fuel cell 12 is operated in an intermediate temperature range (about 300 ° C. to 600 ° C.) and water is generated at the cathode electrode 16 along with power generation. A fuel cell (for example, a solid polymer type or a hydrogen separation membrane type fuel cell) having a produced proton-conducting electrolyte is employed.

  As shown in FIG. 4, the heat exchange type reformer 10 includes a reforming flow path 18 as a reforming section that generates a hydrogen-containing reformed gas to be supplied to the anode electrode 14 of the fuel cell 12, and a reformer. The mass flow path 18 includes a combustion flow path 20 as a heating unit for supplying heat for performing the reforming reaction. A reforming catalyst 22 is supported in the reforming channel 18, and hydrogen gas is produced by catalytic reaction of the supplied hydrocarbon gas (gasoline, methanol, natural gas, etc.) and reforming gas (steam). Is generated (reforming reaction is performed).

The reforming reaction in the reforming channel 18 includes each reaction including the steam reforming reaction represented by the formula (1) as represented by the following formulas (1) to (4). Therefore, the reformed gas obtained in the reforming process includes hydrogen (H ₂ ), carbon monoxide (CO), methane (CH ₄ ), cracked hydrocarbons, unreacted raw material hydrocarbons (C _x H _y ), etc. Combustible gas and carbon dioxide (CO ₂ ), water (H ₂ O), and other non-flammable gases.

_{C n H m + nH 2 O} → nCO + (n + m / 2) H 2 ... (1)
_{C n H m + n / 2O} 2 → nCO + m / 2H 2 ... (2)
CO + H ₂ O⇔CO ₂ + H ₂ (3)
CO + 3H ₂ ＣＨCH ₄ + H ₂ O (4)
The main steam reforming reaction of the formula (1) in this reforming reaction is an endothermic reaction, and the reforming flow path 18 is set at a temperature environment sufficient for the reaction and at a medium temperature or a high temperature as described above. In order to supply the reformed gas to the fuel cell 12 to be operated, the fuel cell 12 is operated at a temperature higher than a predetermined temperature. The combustion channel 20 is configured to supply heat for maintaining the reforming reaction and operating temperature in the reforming channel 18. The combustion flow path 20 is provided adjacent to the reforming flow path 18 carrying the oxidation catalyst 24, and is configured to cause catalytic combustion by bringing the supplied fuel into contact with the oxidation catalyst 24 together with oxygen. . Further, the partial oxidation reaction of the formula (2) is an exothermic reaction, and the heat generated by this partial oxidation reaction is used for the steam reforming reaction together with the heat from the combustion channel 20.

  The heat exchange reformer 10 supplies combustion heat obtained by catalytic combustion of fuel in the combustion channel 20 to the reforming channel 18 via a plate portion 52 described later. For this reason, the amount of heat is directly applied to the reforming channel 18 without converting the amount of heat into temperature as in the configuration in which the reforming channel 18 is heated via a heat medium (fluid) such as combustion gas. It can be configured.

  The fuel cell system 11 includes a raw material pump 26 for supplying a hydrocarbon raw material to the reforming flow path 18, and a discharge portion of the raw material pump 26 is connected to the reforming flow path 18 via a raw material supply line 28. It is connected to the raw material inlet 18A. The hydrocarbon raw material slightly contains a sulfur component (sulfur compound) that does not contribute to the above reforming reaction. This hydrocarbon raw material is supplied to the reforming flow path 18 in a gas phase or atomized state, for example, by a vaporizing means (not shown) such as an evaporator or an injection.

  The reformed gas outlet 18 </ b> B of the reforming channel 18 is connected to the upstream end of the reformed gas supply line 30 whose downstream end is connected to the fuel inlet 14 </ b> A of the anode electrode 14. Thereby, the reformed gas generated in the reforming channel 18 is supplied to the anode electrode 14 of the fuel cell 12. On the other hand, the upstream end of the anode offgas line 32 is connected to the offgas outlet 14 </ b> B of the anode electrode 14, and the downstream end of the anode offgas line 32 is connected to the fuel inlet 20 </ b> A of the combustion channel 20.

As described above, in the fuel cell system 11, the hydrogen in the reformed gas generated in the reforming channel 18 is consumed in the fuel cell 12, and the remaining components other than the consumed hydrogen are supplied to the combustion channel 20 as anode offgas. Combustible components (hydrogen (H ₂ ), carbon monoxide (CO), hydrocarbon (HC), methane (CH ₄ ), carbon dioxide (CO ₂ )) are consumed as fuel in the combustion channel 20. It has become so. An exhaust gas line 34 for discharging combustion exhaust gas to the outside of the system is connected to the exhaust gas outlet 20B of the combustion flow path 20.

  The fuel cell system 11 also includes a cathode air pump 36 for supplying cathode air to the cathode electrode 16, and the discharge portion of the cathode air pump 36 has an air inlet 16 </ b> A at the downstream end of the cathode electrode 16. The upstream end of the cathode air supply line 38 connected to is connected. Further, the upstream end of the steam supply line 40 is connected to the off-gas outlet 16B of the cathode electrode 16, and the downstream end of the steam supply line 40 is connected to the steam inlet 18C of the reforming flow path 18. As a result, the cathode off gas containing water vapor generated at the cathode electrode 16 and oxygen not consumed at the cathode electrode 16 is supplied to the reforming channel 18. Then, water vapor in the cathode off-gas is used for the steam reforming reaction of the formula (1), and oxygen is used for the partial oxidation reaction of the formula (2). That is, the heat exchange type reformer 10 according to the present embodiment supplies the cathode offgas containing oxygen to the reforming flow path 18, so that the ratio of the supplied oxygen amount to the carbon amount in the hydrocarbon weight loss is O /. It is said that it is an offensive that is operated under conditions where the C ratio is high.

  Further, the fuel cell system 11 includes a cooling air pump 42 for supplying cooling air to the fuel cell 12, and the discharge part of the cooling air pump 42 has a refrigerant flow path ( It is connected to the upstream end of the cooling air line 44 connected to the inlet 12A (not shown). The refrigerant flow path outlet 12 </ b> B is connected to the upstream end of the combustion support gas supply line 46. The combustion support gas supply line 46 is connected to the combustion support gas inlet 20 </ b> C in the combustion flow path 20, and supplies a cooling off gas containing oxygen as the combustion support gas to the combustion flow path 20. Thereby, in the combustion flow path 20, the anode off gas from the anode off gas line 32 and the cooling off gas from the combustion support gas supply line 46 are brought into contact with the built-in oxidation catalyst 24 to cause catalytic combustion. .

  In the fuel cell system 11, for example, a separation membrane (a porous material separation membrane such as polyimide or ceramic) that selectively transmits only water vapor in the cathode offgas is provided in the water vapor supply line 40, or reforming water vapor is supplied. By introducing it from outside the system, a configuration in which oxygen is not supplied to the reforming flow path 18 or a configuration in which the amount of oxygen supplied (O / C ratio) to carbon in the hydrocarbon raw material is reduced can be achieved. In these configurations, the main reaction of the reforming reaction in the heat exchange reformer 10 is a steam reforming reaction, and the partial oxidation reaction is not performed or the heat generation amount due to the partial oxidation reaction becomes extremely small.

(Configuration of heat exchange type reformer)
FIG. 2 shows the heat exchange type reformer 10 in an exploded perspective view. As shown in this figure, the heat exchange type reformer 10 has a reforming channel 18 as a reforming unit and a combustion channel 20 as a heating unit between a plurality of unit plate members 50 and 51 stacked. The unit plate members 50 and 51 are formed as independent gas flow paths separated by the plate portions 52 as partition walls. In this embodiment, the reforming flow path 18 and the combustion flow path 20 are alternately arranged in the stacking direction (thickness direction of the plate portion 52), and are adjacent to each other via the plate portion 52. This will be specifically described below.

  The unit plate member 50 includes a plate portion 52 formed in a flat plate shape. The plate part 52 is configured such that flow direction conversion parts 52B and 52C are connected to both sides in the longitudinal direction of a parallel flow part 52A that is rectangular in a plan view. In this embodiment, the flow direction conversion parts 52B and 52C are each formed in a triangular shape such that the bottom side coincides with the short side of the parallel flow part 52A (rectangular shape). It is formed into a shape. Each unit plate member 50 includes an outer wall 54 erected from the periphery of the plate portion 52 on the side where the reforming flow path 18 is formed.

  The outer wall 54 is a spacer that forms the reforming flow path 18 between the stacked unit plate members 50 and 51 by being erected from the entire circumference of the plate portion 52 except for each side portion of the direction changing portions 52B and 52C. In addition to fulfilling the function and the outer wall function of preventing gas outflow from the reforming flow path 18, the gas inlet 50A on the flow direction changing portion 52B side and the gas outlet 50B on the flow direction changing portion 52C side are formed. The gas inlet 50 </ b> A and the gas outlet 50 </ b> B are formed symmetrically with respect to the centroid of the plate portion 52.

  A plurality of standing walls (partition walls) 56 that divide the reforming channel 18 into a plurality of parallel channels are provided upright from the side of the plate portion 52 of the unit plate member 50 where the reforming channel 18 is formed. Each standing wall 56 is substantially parallel to the outer wall 54 from the gas inlet 50 </ b> A to the gas outlet 50 </ b> B, and is configured to partition the reforming channel 18 into a plurality of divided channels (microchannels) 58. Each divided flow path 58 is formed in a crank shape in which the flow path length from the gas inlet 50A to the gas outlet 50B is substantially constant by the symmetrical arrangement of the gas inlet 50A and the gas outlet 50B. Moreover, in the parallel flow part 52A in each divided flow path 58, a portion along the longitudinal direction of the parallel flow part 52A is a heat exchange flow path 58A.

  The unit plate member 51 includes a plate portion 52 having the same shape as the plate portion 52 constituting the unit plate member 50, and an outer wall 60 standing on the formation side of the combustion flow path 20 from the periphery of the plate portion 52. I have. The outer wall 60 is erected from the entire circumference of the plate portion 52 except for each one side portion in the direction changing portions 52B and 52C, thereby forming a combustion channel 20 between the stacked unit plate members 51 and 50. In addition to fulfilling the outer wall function of preventing gas outflow from the combustion flow path 20, a gas inlet 51A on the flow direction changing portion 52B side and a gas outlet 51B on the flow direction changing portion 52C side are formed.

  The gas inlet 51A is formed so as to open in a different direction with respect to the parallel flow portion 52A on the same side in the longitudinal direction as the gas inlet 50A of the unit plate member 50 (arrow A side in FIG. 2). Further, the gas outlet 51B is formed to open in a different direction with respect to the parallel flow portion 52A on the same side in the longitudinal direction as the gas outlet 50B of the unit plate member 50 (arrow B side in FIG. 2). .

  A plurality of standing walls (partition walls) 62 that divide the combustion channel 20 into a plurality of parallel channels are provided upright from the side of the plate portion 52 of the unit plate member 51 where the reforming channel 18 is formed. Each standing wall 62 is substantially parallel to the outer wall 60 from the gas inlet 51 </ b> A to the gas outlet 51 </ b> B, and is configured to partition the combustion channel 20 into a plurality of divided channels (microchannels) 64. Each divided flow path 64 is formed in a crank shape in which the flow path length from the gas inlet 51A to the gas outlet 51B is substantially constant due to the symmetrical arrangement of the gas inlet 51A and the gas outlet 51B. Moreover, in the parallel flow part 52A in each divided flow path 64, a portion along the longitudinal direction of the parallel flow part 52A is a heat exchange flow path 64A.

  In the heat exchange type reformer 10 described above, the gas inlets 50A and 51A are located on the same side (arrow A side) with respect to the parallel flow part 52A (heat exchange flow paths 58A and 64A) as described above, and the gas outlet 50B. , 51B are located on the same side (arrow B side) with respect to the parallel flow portion 52A, the gas flow directions in the heat exchange flow path 58A and the heat exchange flow path 64A of each layer are the same direction (arrow F direction). ing.

  The unit plate member 50 and the unit plate member 51 described above are made of, for example, a metal material such as stainless steel or a solid (not porous) ceramic material, and each part (plate portion 52, outer wall 54, standing wall 56, Alternatively, the plate portion 52, the outer wall 60, and the standing wall 62) are integrally formed. In addition, the unit plate member 50 and the unit plate member 51 are configured such that the plate portion 52 and the outer wall 54 or the outer wall 60 (respective standing walls 56 and 62) are, for example, brazed using a brazing material, diffusion bonding, or adhesion using a ceramic bond. Are airtightly joined.

  In the heat exchange type reformer 10, the raw material inlet 18A and the steam inlet 18C into which the reforming raw material (hydrocarbon) and water vapor (cathode off-gas) are introduced are formed in the opening portions of the gas inlets 50A of the respective layers. A quality inlet manifold is connected. A reforming outlet manifold (not shown) in which a reforming gas outlet 18B for releasing a hydrogen-containing gas is formed is connected to the opening portion of the gas outlet 50B of each layer in the heat exchange type reformer 10. On the other hand, in the opening portion of the gas inlet 51A of each layer in the heat exchange reformer 10, the fuel (anode off gas) and the combustion support gas (cooling off gas) are formed with the fuel inlet 20A and the combustion support gas inlet 20C (not shown). A combustion inlet manifold is connected. An exhaust gas outlet manifold (not shown) in which an exhaust gas outlet 20B of the combustion flow path 20 for discharging the combustion exhaust gas is formed is connected to an opening portion of the outlet 51B of each gas layer in the heat exchange reformer 10.

  In the heat exchange type reformer 10 described above, the reforming catalyst 22 is carried on the inner surface of the divided flow path 58 in the unit plate member 50, and the oxidation catalyst is formed on the inner surface of the divided flow path 64 in the unit plate member 51. 24 is carried. As shown in FIG. 1 which is an exploded plan view in which the standing walls 56 and 62 are not shown, the reforming catalyst 22 is a predetermined excluding a part on the gas inlet 50A side in the divided flow path 58 (reforming flow path 18). The oxidation catalyst 24 is supported over a predetermined range excluding a part of the divided flow path 64 (combustion flow path 20) on the gas inlet 51A side.

  More specifically, in the reforming catalyst 22, the upstream carrying end 22 </ b> A that is the end on the upstream side (arrow A side) in the gas flow direction to which the reforming raw material is supplied is heat exchanged in each divided flow path 58. It is offset upstream from the upstream end of the flow path 58A. On the other hand, in the oxidation catalyst 24, the upstream carrying end 24A, which is the upstream end (arrow A side) in the gas flow direction to which fuel is supplied, is located at the upstream end of the heat exchange flow path 64A in each divided flow path 64. It is almost coincident. Therefore, in the parallel AC heat exchange type reformer 10, the supporting range of the reforming catalyst 22 in the reforming channel 18 is upstream of the supporting range of the oxidation catalyst 24 in the combustion channel 20 in the gas flow direction. It has a wide configuration.

  In the heat exchange type reformer 10, the slurry-like catalyst carrier introduced from the gas outlet 50B and the gas outlet 51B is sucked independently from the gas inlet 50A and the gas inlet 51A, so that the divided flow path of the reforming flow path 18 is obtained. 58 and the divided flow path 64 of the combustion flow path 20 are made different in the installation range of the catalyst carrier, and then the reforming catalyst 22 and the oxidation catalyst 24 are supported on the catalyst carrier installed in the respective divided flow paths 58 and 64. As described above, the reforming catalyst 22 and the oxidation catalyst 24 have different catalyst carrying ranges. In order to stop the suction of the catalyst carrier at the upstream carrier end 22A and the upstream carrier end 24A (control line), for example, the catalyst carrier is detected in a representative part or all of each of the divided flow paths 58 and 64. The detection signal of the catalyst sensor can be used.

  Next, the operation of the first embodiment will be described.

  In the fuel cell system 11 having the above-described configuration, the hydrocarbon raw material, water vapor (cathode offgas) is supplied from the raw material supply line 28 to the reforming passage 18 of the heat exchange reformer 10 by the operation of the raw material pump 26 and the cathode air pump 36. Is introduced. In the reforming flow path 18 of the heat exchange type reformer 10, the hydrocarbon raw material introduced while receiving heat supply from the combustion flow path 20 is brought into contact with the reforming catalyst 22 together with water vapor to satisfy the equation (1). A reforming reaction (see the above formulas (1) to (4)) including a steam reforming reaction and a partial oxidation reaction of the formula (2) is performed, and a reformed gas containing hydrogen at a high concentration is generated.

  The reformed gas generated in the reforming channel 18 is supplied to the anode electrode 14 from the fuel inlet 14 </ b> A of the anode electrode 14. In the fuel cell 12, hydrogen in the reformed gas supplied to the anode electrode 14 is protonated, and this proton moves to the cathode electrode 16 through the electrolyte and is introduced into the cathode electrode 16. React with. As the protons move, electrons flow from the anode electrode 14 toward the cathode electrode through the external conductor, and power generation is performed.

  With this power generation, in the fuel cell 12, hydrogen in the reformed gas supplied to the anode electrode 14 and oxygen in the cathode air supplied to the cathode electrode 16 are consumed according to the power generation amount (load power consumption). The cathode electrode 16 generates water (water vapor at the operating temperature). The gas containing water vapor is pushed out from the cathode electrode 16 to the water vapor supply line 40 as the cathode off gas as described above, and is introduced into the reforming flow path 18 from the water vapor inlet 18C.

  On the other hand, the gas after the hydrogen in the reformed gas is consumed according to the amount of power generated along with the power generation is discharged from the anode electrode 14 as the anode off, and this anode off gas passes through the anode off gas line 32, It is supplied to the combustion flow path 20 of the heat exchange type reformer 10. The combustion flow path 20 is supplied with the cooling off gas after cooling the fuel cell 12 from the combustion support gas supply line 46. In the combustion flow path 20, catalytic combustion occurs when the combustible component in the anode off-gas, which is fuel, is brought into contact with the oxidation catalyst 24 together with the oxygen in the cooling off-gas together with the combustion support gas. The heat generated by this catalytic combustion is supplied to the reforming flow path 18 via the plate portion 52. With this heat, the reforming flow path 18 maintains the reforming reaction, which is an endothermic reaction, and maintains the operating temperature (reformed gas temperature) at a temperature necessary for the reforming reaction.

  As described above, in the fuel cell system 11, the hydrocarbon raw material is supplied to the heat exchange type reformer 10, and each exhaust gas of the fuel cell 12 (cathode off-gas containing water vapor, anode off-gas containing combustible components, cooling containing oxygen). The operation of the heat exchange reformer 10 that generates hydrogen to be supplied to the fuel cell 12 is maintained by effectively using off gas).

  By the way, the reforming reaction in the reforming channel 18 generates an endothermic peak on the reforming raw material inlet side, that is, on the upstream supporting end 22A side of the reforming catalyst 22 supporting range. In addition, the combustion reaction of the combustion channel 20 causes a peak of heat generation on the fuel inlet side, that is, on the upstream carrying end 24A side of the oxidation catalyst 24 carrying range. For this reason, for example, in the cross-flow type heat exchange type reformer, the gas flow direction intersects between the reforming section and the heating section, so that there is a problem that a local high temperature section is generated due to the structure. Further, for example, in the counter flow type heat exchange type reformer, since the peak of the endothermic heat generation between the reforming part and the heating part occurs at the end of the heat exchange part opposite to the gas flow direction, the heat exchange in the reformer It is unsuitable as a vessel.

  Here, in the heat exchange type reformer 10, a parallel flow type heat exchanger having the same gas flow direction in the heat exchange channel 58A of the reforming channel 18 and the heat exchange channel 64A of the combustion channel 20 is used. In other words, in other words, the endothermic peak generated on the gas inlet 50A side where the reforming raw material is supplied in the reforming reaction, and the exothermic peak generated on the gas inlet 51A side where the fuel is supplied in the combustion reaction. Therefore, the heat exchange efficiency between the reforming flow path 18 and the combustion flow path 20 is improved. Thereby, in the heat exchange type reformer 10, it is possible to efficiently generate hydrogen by reforming by effectively using the heat generated in the combustion flow path 20.

  Thus, in the heat exchange type reformer 10 according to the first embodiment, the heat exchange efficiency between the combustion channel 20 and the reforming channel 18 is good.

  Further, in the heat exchange type reformer 10, since the supported range of the reforming catalyst 22 is wide on the upstream side with respect to the supported range of the oxidation catalyst 24, local reformation due to the reaction rate difference between the reforming reaction and the combustion reaction is caused. Generation of a high temperature part is prevented. Hereinafter, a description will be given in comparison with the comparative example shown in FIG. In the heat exchange type reformer 200 according to the first comparative example shown in FIG. 8A, the supporting range of the reforming catalyst 22 and the supporting range of the oxidation catalyst 24 are the same. In such a heat exchange type reformer 200, since the reaction rate of the combustion reaction is remarkably faster than the reaction rate of the reforming reaction, reforming is performed on the exothermic peak Pc of the combustion reaction as shown in FIG. The exothermic peak Pr of the reaction tends to shift downstream. For this reason, in the heat exchange type reformer 200, the heat generation amount becomes excessive with respect to the heat absorption amount in a local region in the vicinity of the upstream support end 22A of the reforming catalyst 22 and the upstream support end 24A of the oxidation catalyst 24, There is concern that a local high-temperature site H (local high-temperature state) as shown in FIG. In particular, like the heat exchange type reformer 210 according to the second comparative example shown in FIG. 9A, the supporting range of the oxidation catalyst 24 on the gas inlet 51A side due to insufficient catalyst supporting accuracy, local catalyst peeling, or the like. Is wider than the supporting range of the reforming catalyst 22, local high-temperature sites H as shown in FIG. 9B are more likely to be generated (over a wide range).

  On the other hand, in the heat exchange type reformer 10, since the support range of the reforming catalyst 22 is wide on the upstream side with respect to the support range of the oxidation catalyst 24 as described above, as shown in FIG. Compared to exchangeable reformer 200 (see imaginary line), exothermic peak Pr of the reforming reaction approaches the exothermic peak Pc of the combustion reaction (shifts upstream), in other words, the reaction rate of the reforming reaction is increased. Slowness is complemented and the occurrence of local high temperature conditions can be avoided. Further, by setting the upstream carrying end 22A of the reforming catalyst 22 on the upstream side of the upstream carrying end 24A of the oxidation catalyst 24, the lack of catalyst carrying accuracy (error) is absorbed and local peeling is prevented. Since the allowance is formed, the probability that the unsupported region of the reforming catalyst 22 is formed in the supporting range of the oxidation catalyst 24 can be significantly reduced. That is, it is possible to greatly reduce the risk of occurrence of local high temperature parts.

  Further, in the heat exchange type reformer 10, since the reforming reaction includes the partial oxidation reaction represented by the formula (2) as described above (operated under a condition where the O / C ratio is high), Generates heat associated with the partial oxidation reaction in the reforming channel 18 (part of the upstream side of the heat exchange channel 58A). For this reason, as shown by a broken line in FIG. 3A, there is a region where the endothermic amount is small in the initial stage of the reforming reaction as compared with the reaction not involving the partial oxidation reaction. Here, in the heat exchange type reformer 10, since the upstream carrying end 22A of the reforming catalyst 22 is located upstream from the upstream carrying end 24A of the oxidation catalyst 24 as described above, Initially, the heat generated by the partial oxidation reaction is used for the steam reforming reaction, and the steam reforming reaction is maintained by supplying heat from the combustion channel 20 after the partial oxidation reaction is converged. As a result, the heat absorption and heat generation at each part in the gas flow direction are balanced (the distribution of the heat absorption and heat generation (the tendency) coincides), and the heat balance of the heat exchange reformer 10 as a whole (system) is optimized. The

  In the condition where oxygen is not supplied to the reforming channel 18 or the condition of the low O / C ratio where the amount of oxygen supplied to the hydrocarbon raw material is small, partial reforming reaction does not occur in the reforming channel 18 or due to partial oxidation reaction. Fever is extremely small. Even in this case, it goes without saying that the effect as the above-described parallel flow heat exchange type heat exchange reformer 10 and the effect of suppressing the occurrence of a local high temperature state can be obtained. In this case, the amount of offset in the gas flow direction between the upstream carrying end 22A of the reforming catalyst 22 and the upstream carrying end 24A of the oxidation catalyst 24 is operated under conditions involving partial oxidation reaction or high O / C ratio. It can be set smaller than the configuration.

  Next, another embodiment of the present invention will be described. Parts and portions that are basically the same as those in the first embodiment or the previous configuration are denoted by the same reference numerals as those in the first embodiment or the previous configuration, and the description thereof is omitted. Sometimes omitted.

(Second Embodiment)
FIG. 5 shows an exploded plan view of a heat exchange type reformer 70 according to the second embodiment of the present invention corresponding to FIG. As shown in this figure, the heat exchange type reformer 70 is different from the heat exchange type reformer 70 according to the first embodiment in that the supporting range of the reforming catalyst 22 is wider upstream than the supporting range of the oxidation catalyst 24. In common with the mass device 10, it differs from the heat exchange type reformer 10 in that the upstream carrying end 22 </ b> A of the reforming catalyst 22 substantially coincides with the upstream end of the heat exchange flow path 58 </ b> A. Therefore, in the heat exchange type reformer 70, a part of the upstream end side of the heat exchange flow path 64A is set as a non-supporting region of the oxidation catalyst 24. Other configurations of the heat exchange reformer 70 are the same as the corresponding configurations of the heat exchange reformer 10.

  As described above, in the heat exchange type reformer 70 according to the second embodiment, the supporting range of the reforming catalyst 22 is wide on the upstream side with respect to the supporting range of the oxidation catalyst 24 as described above. Therefore, the heat exchange reformer 70 can obtain the same effect by the same operation as the heat exchange reformer 10. That is, in the heat exchange type reformer 70, the high heat generation site due to the combustion reaction and the high heat absorption site due to the reforming reaction can be matched well.

  The present invention is limited to the fact that the upstream carrying ends 22A and 24A in the carrying range of the reforming catalyst 22 and the oxidation catalyst 24 are based on the upstream end of the parallel flow portion 52A (heat exchange flow paths 58A and 64A). Never happen. However, it is desirable to effectively use the volumes of the heat exchange channels 58A and 64A in order to obtain good heat exchange performance (to achieve downsizing).

(Third embodiment)
FIG. 6 shows an exploded plan view corresponding to FIG. 1 of a heat exchange type reformer 80 according to a third embodiment of the present invention. As shown in this figure, the heat exchange type reformer 80 carries the reforming catalyst 22 and the oxidation catalyst 24 in each reforming channel 18 (divided channel 58) and combustion channel 20 (divided channel 64). The range is equivalent to the supported range of the reforming catalyst 22 and the oxidation catalyst 24 in the heat exchange type reformer 70, except that a part of the reforming catalyst 22 has a higher supporting concentration than the other parts. This is different from the heat exchange type reformer 70 according to the second embodiment.

  Specifically, the supported concentration of the reforming catalyst 22 in the range from the upstream supporting end 22 </ b> A of the reforming catalyst 22 to the predetermined distance L <b> 1 along the gas flow direction is higher than the other portions in the supporting range of the reforming catalyst 22. Is a high (dense) high-concentration carrying region 22B. In this embodiment, the downstream end of the high concentration carrying region 22B is located slightly downstream from the upstream carrying end 24A of the oxidation catalyst 24. In other words, the upstream carrying end 24 </ b> A (combustion start position) of the oxidation catalyst 24 is located in the middle (intermediate) portion of the high concentration carrying region 22 </ b> B of the reforming catalyst 22 in the gas flow direction. Other configurations of the heat exchange reformer 80 are the same as the corresponding configurations of the heat exchange reformers 70 and 10.

  Therefore, the effect similar to that of the heat exchange reformer 10 or 70 according to the first or second embodiment can be obtained by the 80 according to the third embodiment. Further, in the heat exchange type reformer 80, since the predetermined range on the inlet side end portion side of the reforming raw material is the high concentration supporting region 22B, the reforming reaction in the high concentration supporting region 22B of the reforming catalyst 22 is performed. As a result, the endothermic amount increases, and the endothermic peak Pc accompanying the reforming reaction in the reforming channel 18 shifts to the upstream side so as to be closer to the peak of combustion exotherm in the combustion channel 20. For this reason, in the heat exchange type reformer 80, the heat generation in the combustion flow path 20 can be more effectively used to efficiently generate hydrogen by reforming, and the generation of a local high temperature state is more effective. Is avoided. Further, even when the reforming reaction involves a partial oxidation reaction, the heat exchange type reformer 80 in which the endothermic amount on the inlet side end side of the reforming raw material, that is, the high concentration supporting region 22B becomes large, is partially oxidized. The reaction (heat generation) converges early, and the heat absorption and heat generation at each part in the gas flow direction is well balanced, and the heat balance of the heat exchange reformer 80 as a whole (system) is optimized.

  In the third embodiment, an example is shown in which the upstream support end 22A of the reforming catalyst 22 (high concentration support region 22B) is positioned upstream of the upstream support end 24A of the oxidation catalyst 24. The invention is not limited to this. For example, the upstream carrying end 22A of the high concentration carrying region 22B may be substantially coincident with the upstream carrying end 24A of the oxidation catalyst 24. Even in this case, since the endothermic peak shifts to the upstream side by the high concentration carrying region 22B, the same effect as the heat exchange type reformer 10 according to the first embodiment can be obtained.

(Fourth embodiment)
FIG. 7 shows an exploded plan view of a heat exchange type reformer 90 according to the fourth embodiment of the present invention corresponding to FIG. As shown in this figure, the heat exchange type reformer 90 is a heat exchange type reformer according to each of the above embodiments in that a part of the oxidation catalyst 24 has a lower supported concentration than the other parts. Is different from 10, 70, 80.

  Specifically, the supported concentration of the oxidation catalyst 24 in the range from the upstream support end 24A of the oxidation catalyst 24 to the predetermined distance L2 along the gas flow direction is lower than the other portions in the support range of the oxidation catalyst 24 ( It is a thin) low-concentration carrying region 24B. In this embodiment, the upstream carrying end 24 </ b> A that is the upstream end of the low concentration carrying region 24 </ b> B substantially coincides with the upstream carrying end 22 </ b> A of the reforming catalyst 22. In other words, the reforming catalyst 22 and the oxidation catalyst 24 including the low concentration supporting region 24B have at least approximately the same catalyst supporting range on the upstream side. Other configurations of the heat exchange reformer 90 are the same as the corresponding configurations of the heat exchange reformers 70 and 10.

  Therefore, also by 90 according to the fourth embodiment, the same effect can be obtained by the same operation as the heat exchange type reformers 10 and 70 according to the first or second embodiment. Further, in the heat exchange type reformer 90, since the predetermined range on the inlet side end portion side of the combustion fuel is the low concentration supporting region 24B, the combustion reaction in the low concentration supporting region 24B of the oxidation catalyst 24 is suppressed. As a result, the peak heat generation amount is reduced, the region where heat generation occurs (heat generation distribution) spreads downstream, and the peak of combustion heat generation in the combustion channel 20 becomes the endothermic peak accompanying the reforming reaction in the reforming channel 18. Proximity. Further, since the peak heat generation amount is kept low in the low-concentration support region 24B including the upstream support end 24A, a local high temperature is obtained in the configuration in which the upstream support ends 22A and 24A of the reforming catalysts 22 and 24 are substantially matched. The occurrence of the situation is more effectively avoided. Furthermore, even when the reforming reaction involves a partial oxidation reaction, the amount of electric heat from the combustion channel 20 to the reforming channel 18 can be kept low in the low concentration support region 24B. And the heat balance of the heat exchange reformer 90 as a whole (system) is optimized.

  In the fourth embodiment, an example is shown in which the upstream carrying end 22A of the reforming catalyst 22 and the upstream carrying end 24A of the oxidation catalyst 24 substantially coincide with each other. However, the present invention is not limited to this, for example, Similarly to the above embodiments, the upstream carrying end 22A of the reforming catalyst 22 may be set upstream of the upstream carrying end 24A of the oxidation catalyst 24. In the fourth embodiment, an example in which the high-concentration carrying region 22B is not set in the reforming catalyst 22 is shown. However, the present invention is not limited to this, and for example, the present embodiment in which the low-concentration carrying region 24B is set. In the embodiment, the high concentration support region 22B may be set in the reforming catalyst 22. As described above, by combining the configurations in which the peak of the endothermic heat is shifted to the opposite side, the endothermic distribution in the reforming flow path 18 and the distribution of the exothermic heat in the combustion flow path 20 are made to better match each other. It is also possible to balance heat generation well.

  Moreover, in each said embodiment, although the example which applied the heat exchange type | mold reformer 10 to the fuel cell system 11 was shown, this invention is not limited to this, For obtaining hydrogen-containing gas from a reforming raw material Various heat exchange type reformers are sufficient, and are not limited by the application.

  Further, in each of the above embodiments, the unit plate member 50 for forming the reforming flow path 18 and the unit plate member 51 for forming the combustion flow path 20 are alternately stacked to heat-reform the reformer 10. , 70, 80, and 90 are shown, but the present invention is not limited to this. For example, the unit in which the one-layer combustion flow path 20 is arranged with respect to the two-layer reforming flow path 18 is shown. The plate member 50 and the unit plate member 51 may be laminated.

It is a disassembled plan view which shows the principal part of the heat exchange type | mold reformer which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view which shows the principal part of the heat exchange type | mold reformer which concerns on the 1st Embodiment of this invention. (A) is a diagram showing the endothermic heat generation of the heat exchange reformer according to the first embodiment of the present invention, (B) is a diagram showing the endothermic heat generation of the heat exchange type reformer according to the comparative example. It is. 1 is a schematic system flow diagram of a fuel cell system to which a heat exchange type reformer according to a first embodiment of the present invention is applied. It is an exploded top view which shows the principal part of the heat exchange type | mold reformer which concerns on the 2nd Embodiment of this invention. It is an exploded top view which shows the principal part of the heat exchange type | mold reformer which concerns on the 3rd Embodiment of this invention. It is an exploded top view which shows the principal part of the heat exchange type | mold reformer which concerns on the 4th Embodiment of this invention. It is a figure which shows the heat exchange type | mold reformer which concerns on a 1st comparative example with embodiment of this invention, Comprising: (A) An exploded plan view, (B) is a top view which shows a local high temperature site | part. It is a figure which shows the heat exchange type | mold reformer which concerns on the 2nd comparative example with embodiment of this invention, Comprising: (A) An exploded plan view, (B) is a top view which shows a local high temperature site | part.

Explanation of symbols

10 Heat Exchange Type Reformer 18 Reforming Channel (Reforming Section)
20 Combustion flow path (heating part)
22 reforming catalyst 22A upstream carrying end (end position on reforming raw material supply side)
22B High concentration carrying region 24 Oxidation catalyst 24A Upstream carrying end (end position on fuel supply side)
24B Low concentration support area 52 Plate part (partition wall)
70/80/90 heat exchange reformer

Claims (4)

A reforming section for supporting a reforming catalyst for reforming reaction and generating hydrogen from a reforming raw material supplied by a reforming reaction including a steam reforming reaction;
An oxidation catalyst for catalytic combustion is supported while adjoining the reforming section through a partition so as to generate a gas flow in the same direction as the gas flow of the reforming section, and accompanying the catalytic combustion of the supplied fuel A heating unit for supplying the generated heat to the reforming unit,
A heat exchange type reformer equipped with   The end position of the reforming raw material supply side in the reforming catalyst support range in the reforming section is upstream of the fuel supply side end position in the heating catalyst support range of the oxidation catalyst in the gas flow direction. The heat exchange type | mold reformer of Claim 1 set.   The catalyst support concentration in a predetermined range from the end of the reforming raw material supply side in the reforming catalyst support range in the reforming section is set higher than the catalyst support concentration in other portions in the reforming catalyst support range. The heat exchange type reformer according to claim 1 or 2.   The catalyst carrying concentration in a predetermined range from the end portion on the fuel supply side in the carrying range of the oxidation catalyst in the heating unit is set lower than the catalyst carrying concentration in other portions in the carrying range of the oxidation catalyst. Item 4. The heat exchange type reformer according to any one of Items 3 to 3.

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