JP4800691B2 - Fuel cell reformer - Google Patents

Description

  The present invention relates to a fuel cell reforming apparatus.

  Conventionally, a reformed gas (anode gas) containing hydrogen is produced by reacting a fuel (for example, city gas mainly composed of methane) and water vapor with a reforming catalyst, and the reformed gas is used as a fuel cell. Various fuel cell reforming apparatuses have been proposed in which they are supplied to the anode electrode (fuel electrode).

By the way, when the temperature of the above-described reforming catalyst rises to a predetermined value (about 700 [° C.]), the reforming reaction is started. Therefore, it is desirable to quickly raise the temperature of the reforming catalyst when starting the reformer. Therefore, for example, in the technique described in Patent Document 1, a combustion burner is disposed in the vicinity of the reforming catalyst, and the temperature of the reforming catalyst is raised by the exhaust gas generated by the combustion of the combustion burner. In addition, when the temperature of the reforming catalyst is increased more quickly, a heater is attached in the vicinity of the reforming catalyst.
Japanese Patent Laid-Open No. 2002-20104 (paragraphs 0015, 0016, FIG. 1, etc.)

  However, as described above, when the combustion burner is attached to the reformer and the heater is attached, there is a problem that the configuration becomes complicated. Moreover, when heating with the exhaust gas of a combustion burner like the technique of patent document 1, since a reforming catalyst is heated from the outside, it will heat up gradually from the outer part of a reforming catalyst. Therefore, in the case of a reforming catalyst having a plurality of types of catalysts and exhibiting a complicated structure, it takes time for the temperature to be raised to a predetermined value, and in terms of improving the startability of the reforming apparatus. There was room for improvement.

  Therefore, the object of the present invention is to solve the above-mentioned problems and to quickly raise the temperature of the reforming catalyst to a predetermined temperature at which the reforming reaction can be performed, while improving the startability, while having a simple configuration without using a heater or the like. An object of the present invention is to provide a fuel cell reforming apparatus.

In order to solve the above-mentioned object, in claim 1, a reformed gas containing hydrogen is generated by reacting a fuel and water vapor with a reforming catalyst, and the generated reformed gas is used in a fuel cell. In a fuel cell reforming apparatus configured to supply a fuel electrode, a partial oxidation catalyst that is disposed upstream of the reforming catalyst to partially oxidize the fuel, a combustor that heats the reforming catalyst, and An exhaust pipe disposed near the reforming catalyst and exhausting exhaust gas flowing from the combustor, and supplying the gas generated by the partial oxidation to the reforming catalyst at the start, and then the combustion The exhaust gas was recirculated to a combustor and burned in the combustor, and exhaust gas generated by the combustion was allowed to flow into the exhaust gas pipe .

  Further, in the present invention, the temperature detection means for detecting the temperature of the reforming catalyst, and the gas generated by the partial oxidation when the detected temperature of the reforming catalyst exceeds a predetermined value. And a stopping means for stopping the supply of.

In the fuel cell reforming apparatus according to claim 1, the partial oxidation is performed on the upstream side of the reforming catalyst that reacts the fuel with water vapor to generate the reformed gas containing hydrogen and partially oxidizes the fuel. A catalyst , a combustor that heats the reforming catalyst, and an exhaust gas pipe that is disposed in the vicinity of the reforming catalyst and exhausts the exhaust gas flowing in from the combustor. after feeding to the reforming catalyst, the burning in the combustor refluxed to the combustor, the exhaust gas generated by combustion Ru to flow into the exhaust gas pipe, i.e., the prior art as, the combustion burner in the exhaust gas of the reforming catalyst Since it was configured not to heat from the outside but to heat by relatively supplying a relatively high temperature gas generated by partial oxidation, which is an exothermic reaction, directly to the reforming catalyst and passing through the reforming catalyst, Heater etc. Although it is a simple configuration that is not used, a reforming catalyst having a complicated structure can be quickly heated up to a predetermined value, more precisely, to a temperature at which the reforming reaction can be started, so that the reformer can be warmed up. Startability can be improved. Furthermore, although the reforming catalyst is oxidized when exposed to an oxidizing atmosphere, the gas generated by the partial oxidation is a reducing gas and is not oxidized.

  Further, in the fuel cell reforming apparatus according to claim 2, the temperature detecting means for detecting the temperature of the reforming catalyst, and the detected temperature of the reforming catalyst are set to a predetermined value (more accurately, the reforming catalyst). A stop means for stopping the supply of the gas generated by the partial oxidation when the temperature exceeds the reforming catalyst. When the reforming reaction is started when the temperature of the catalyst is increased, the supply of the gas generated by the partial oxidation is stopped, which affects the reforming reaction in the reforming catalyst in addition to the effects described above. Without this, the temperature of the reforming catalyst can be raised.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel cell reforming apparatus according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic view for explaining a fuel cell reforming apparatus according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 10 denotes a fuel cell (stack). The fuel cell 10 includes an electrolyte membrane (solid polymer membrane), a cathode electrode (air electrode) and an anode electrode (fuel electrode) that sandwich the membrane, and a separator (none of which is shown) disposed outside each electrode. This is a known solid polymer fuel cell formed by stacking a plurality of unit cells composed of

  Connected to the fuel cell 10 is a cathode gas supply system 12 that supplies cathode gas (reaction air) to the cathode electrode. The cathode gas supply system 12 includes an air cleaner 14 that removes atmospheric (air) dust, a cathode gas pump 16 that is disposed downstream of the air cleaner 14 and that pumps air that has passed through the air cleaner 14 to the fuel cell 10 as cathode gas, And a cathode gas flow path 18 that connects the cathode gas pump 16 to an inlet (not shown) of the cathode electrode of the fuel cell 10. The cathode gas pump 16 has a suction port (not shown) communicating with the atmosphere via the air cleaner 14 and a discharge port (not shown) connected to the cathode electrode of the fuel cell 10 via the cathode gas flow path 18. Connected to.

  The fuel cell 10 is connected to an anode gas supply system 20 that supplies an anode gas (hydrogen gas) to the anode electrode. The anode gas supply system 20 includes a reformer 22 and an anode gas flow path 24 that connects the reformer 22 to an inlet (not shown) of the anode electrode of the fuel cell 10.

  The reformer 22 includes a desulfurizer 28 that removes an odorant of fuel (for example, city gas), specifically, an organic sulfur compound such as mercaptan, and a fuel that has passed through the desulfurizer 28 flows into the apparatus. A reformer 30 for generating the contained reformed gas (that is, anode gas) and a fuel flow path 32 for connecting the desulfurizer 28 to the reformer 30 are provided.

  As shown in FIG. 1, the fuel flow path 32 is composed of a first fuel flow path 32a and a second fuel flow path 32b branched therefrom. The first fuel flow path 32a is connected to a warm-up fuel pipe (described later, not shown in FIG. 1) of the reformer 30, and a first electromagnetic valve 34a is disposed in the middle thereof. The second fuel flow path 32b is connected to a reforming fuel pipe (described later, not shown in FIG. 1) of the reformer 30, and a second electromagnetic valve 34b is disposed in the middle thereof. The Each of the first and second electromagnetic valves 34a and 34b is a normal / close type electromagnetic valve (an electromagnetic valve that closes when not energized and opens when energized), and when the fuel cell 10 is not in operation. Are all closed.

  The reformer 22 further includes a water feed pump 36 that pumps water used for reforming (hereinafter referred to as “water for reforming”) to the reformer 30, and the water feed pump 36 is connected to a reforming water pipe ( The reforming water flow path 38 connected to a not-shown FIG. 1, the air cleaner 40 for removing atmospheric (air) dust, and the air disposed on the downstream side of the air cleaner 40 and passing through the air cleaner 40 is used as a warming fuel. A warm-up air pump 42 that pumps air to the reformer 30 as air for burning (described later) (hereinafter, referred to as “warm-up air”), and a warm-up air pump 42 that serves as a warm-up air pipe (described later) of the reformer 30. 1 is connected to an air flow path for warming 44 connected to a not-shown in FIG. 1 and an exhaust gas pipe (described later, not shown in FIG. 1) of the reformer 30, and exhaust gas generated by combustion is introduced into the atmosphere. And an exhaust gas passage 46 for discharging.

  The fuel cell 10 also includes an output terminal 50 that outputs power generated by the fuel cell 10, and a power control system 52 that controls the power is connected to the output terminal 50. The power control system 52 includes an electronic control unit (hereinafter referred to as “ECU”) 54 formed of a microcomputer, and an inverter 56 that converts electric power (DC current) generated by the fuel cell 10 into AC current having a predetermined frequency. It consists of.

  The ECU 54 is connected to the cathode gas pump 16, the water supply pump 36, the warm air pump 42, the inverter 56, and the like through the signal line 58 and controls their operations. Further, the ECU 54 is connected to a drive circuit (not shown) of the first and second electromagnetic valves 34a and 34b via a signal line 58, and excites / non-energizes the first and second electromagnetic valves 34a and 34b. The valve opens and closes when excited, and controls its operation. The ECU 54 is connected to a power storage device 60 such as a battery as an operation power source before the fuel cell 10 generates electric power.

  Connected to the fuel cell 10 is an exhaust system 62 that exhausts the cathode gas discharged from the fuel cell 10 (hereinafter referred to as “cathode off-gas”). The exhaust system 62 includes an exhaust passage 64, and a muffler (not shown) or the like is connected to the exhaust passage 64. One end of the exhaust passage 64 is connected to a cathode gas discharge port (not shown) of the fuel cell 10, while the other end is opened to the atmosphere. Therefore, the cathode off gas discharged from the fuel cell 10 is discharged into the atmosphere through the exhaust passage 64.

  The fuel cell 10 is connected to a reflux system 68 that recirculates anode gas (unreacted gas; hereinafter referred to as “anode off gas”) discharged from the fuel cell 10 to the fuel cell 10 and the reformer 22. The recirculation system 68 includes a first anode offgas passage 70 that connects an anode gas discharge port (not shown) of the fuel cell 10 to the anode gas passage 24 described above, and a middle portion of the first anode offgas passage 70. A second anode off gas that is connected and connects the first anode off gas flow path 70 to a reformer (more precisely, an inlet (not shown in FIG. 1)) of the reformer 22 described later. And a flow path 72. Further, the reflux system 68 is connected in the middle of the anode gas flow path 24, and the anode gas reflux that connects the anode gas flow path 24 to the reformer of the reformer 22 (more precisely, the inlet of the reformer). A path 74 is provided.

  In addition to the components such as the cathode gas supply system 12 described above, the fuel cell 10 is connected to a cooling system for cooling the fuel cell 10 and a humidifier for humidifying the cathode gas. Since there is no direct relationship with the gist, neither illustration nor description is given.

  Next, the operation of the fuel cell 10 will be outlined.

  Dust is removed from the cathode gas (atmosphere) sucked by the cathode gas pump 16 by the air cleaner 14. The cathode gas from which the dust has been removed is supplied to the cathode electrode of the fuel cell 10 via the cathode gas flow path 18. Further, the reformed gas (anode gas) generated by the reformer 30 of the reformer 22 is supplied to the anode electrode via the anode gas flow path 24.

Thus, the cathode gas supplied to the cathode electrode of the fuel cell 10 causes an electrochemical reaction with the anode gas supplied to the anode electrode. Specifically, the electrode reaction occurring at the cathode and anode is as follows.
Anode electrode: H ₂ → 2H ⁺ + 2e ⁻
Cathode electrode: 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O
Therefore, the overall reaction is:
Overall: H ₂ + 1 / 2O ₂ → H ₂ O

  The electric power (DC current) generated by the fuel cell 10 by the above reaction is taken out from the output terminal 50, a part of which is used as a power source for auxiliary equipment such as the ECU 54 and the cathode gas pump 16, and the remainder is the inverter 56. Is converted to an alternating current having a predetermined frequency by the electric load (for example, an alternating current electric device such as a lighting fixture) 76.

  The cathode off gas discharged from the fuel cell 10 is discharged into the atmosphere through the exhaust passage 64. Further, the anode off-gas (unreacted gas) discharged from the fuel cell 10 is recirculated to the anode gas channel 24 via the first anode off-gas channel 70 and is supplied to the fuel cell 10 again. Of the anode off gas, the anode off gas that has not been supplied to the fuel cell 10 is supplied to the reformer 30 of the reformer 22 via the second anode off gas flow path 72.

  Next, the reformer 30 of the reformer 22 which is a characteristic part of the present invention will be described in detail.

  FIG. 2 is a schematic cross-sectional view schematically showing a cross section of the reformer 30 of the reformer 22.

  The reformer 30 includes a case portion 80 having a substantially cylindrical shape in appearance. The case portion 80 includes a reforming portion 82 for reforming and reacting reforming fuel and reforming water with a reforming catalyst, and reforming. A heating unit 84 for heating the catalyst is accommodated.

  The reforming unit 82 is connected to the second fuel flow path 32b described above, and the reforming fuel pipe 86 to which the fuel is supplied as the reforming fuel, and the reforming water pipe 38 connected to the reforming water flow path 38. A water pipe 88, a reforming catalyst 90 composed of a plurality of types of catalysts and exhibiting a porous shape, a reforming reactor 92 filled with the reforming catalyst 90, and a reformed gas pipe connected to the reforming reactor 92 94 and a CO removal unit 98 that is disposed in the middle of the reformed gas pipe 94 and is filled with a carbon monoxide removal catalyst (hereinafter referred to as “CO removal catalyst”) 96 that removes carbon monoxide (CO) by reaction. It consists of.

The heating unit 84 is connected to the first fuel flow path 32 a described above, and the warm-up fuel pipe 100 to which fuel is supplied as the warm-up fuel, and the warm-up air pipe 102 connected to the warm-up air flow path 44. A partial oxidation catalyst 104 disposed upstream of the reforming reactor 92 filled with the reforming catalyst 90 to partially oxidize the warm-up fuel, a partial oxidation reactor 106 filled with the partial oxidation catalyst 104, The reforming catalyst temperature sensor 108 is disposed near the carbon catalyst 90 and outputs a signal corresponding to the temperature of the reforming catalyst 90 to the ECU 54. The reforming catalyst temperature sensor 108 is disposed near the CO removal catalyst 96. And a CO removal catalyst temperature sensor 110 for outputting the obtained signal to the ECU 54. For example, platinum palladium alumina (Pt—Pd / Al ₂ O ₃ ) is used as the partial oxidation catalyst 104.

  As shown in the drawing, the reforming catalyst temperature sensor 108 includes a first reforming catalyst temperature sensor 108a disposed upstream of the reforming catalyst 90 (in other words, near the upper portion of the reforming reactor 92), The second reforming catalyst temperature sensor 108b is disposed downstream (near the lower portion of the reforming reactor 92). The CO removal catalyst temperature sensor 110 includes a first CO removal catalyst temperature sensor 110a disposed on the upstream side of the CO removal catalyst 96 (in other words, near the lower portion of the CO removal unit 98), a downstream side thereof, More precisely, it includes a second CO removal catalyst temperature sensor 110b disposed in the vicinity of the substantially central portion of the CO removal unit 98. Note that in this specification, the descriptions indicating the upper and lower relationships such as the upper portion, the lower portion, the upper end and the lower end all represent the upper and lower relationships in the direction of gravity.

  The heating unit 84 is further disposed in the vicinity of the upper end 80a of the case unit 80, and further includes a catalytic combustor 112 having a combustion catalyst described later, a combustion chamber 114 connected to the catalytic combustor 112, and a connection to the combustion chamber 114. And an exhaust gas pipe 116 that exhausts exhaust gas generated by combustion in the combustion chamber 114.

  As shown in FIG. 2, the combustion chamber 114 is disposed at a position below the catalytic combustor 112. The combustion chamber 114 is disposed such that the upper portion 114 a protrudes from the upper end 80 a of the case portion 80 and the lower portion 114 b is near the lower end 80 b of the case portion 80. The combustion chamber 114 communicates with the exhaust gas pipe 116 at the lower portion 114b. The exhaust gas pipe 116 extends upward along the outer wall 114c of the combustion chamber 114, and then bends in the vicinity of the upper end 80a of the case portion 80. Then, it is connected to the exhaust gas flow path 46 described above.

  The reforming water pipe 88 of the reforming section 82 is disposed so as to circulate a plurality of times around the outer periphery 98a of the ring-shaped CO removing section 98 disposed so as to surround the combustion chamber 114, the exhaust gas pipe 116, and the like. Thereafter, it is disposed in the interior 116 a of the exhaust gas pipe 116. The reforming water pipe 88 arranged in the interior 116a of the exhaust gas pipe 116 is arranged so as to circulate a plurality of times around the circumference while contacting the outer wall 114c of the combustion chamber 114.

  Next, a reforming fuel pipe 86 is connected to the reforming water pipe 88 via a connection portion 118. Hereinafter, the reforming water pipe 88 on the downstream side of the connection portion 118 in the reforming water flow of the reforming water pipe 88 is referred to as a “reforming fuel / water pipe” and denoted by reference numeral 120. The reforming fuel / water pipe 120 is further arranged around the outer wall 114 c of the combustion chamber 114 a plurality of times, and then connected to the reforming reactor 92.

  The outer wall 92 a of the reforming reactor 92 extends downward while being in contact with the exhaust gas pipe 116 disposed along the outer wall 114 c of the combustion chamber 114. The reforming reactor 92 communicates with the reformed gas pipe 94 at the lower end 92b.

  The reformed gas pipe 94 extends upward along the outer wall 92a of the reforming reactor 92, then bends near the upper end 80a of the case portion 80, and is then connected to the anode gas flow path 24 described above. The Further, a CO removal unit 98 for removing CO remaining in the reformed gas generated in the reforming reactor 92 is disposed in the middle of the reformed gas pipe 94. In the interior of the case portion 80 of the reformer 30, a heat insulating material 122 is disposed (filled) in a space other than each component such as the combustion chamber 114 and the reforming reactor 92 described above. That is, the combustion chamber 114 and the reforming reactor 92 are covered with the heat insulating material 122.

  Further, as shown in FIG. 2, an ejector 126 is disposed in the middle of the warm air fuel pipe 100 of the heating unit 84, and the warm air air pipe 102 is connected to the ejector 126. As a result, the warm-up fuel flowing through the warm-up fuel pipe 100 and the warm-up air flowing through the warm-up air pipe 102 are mixed by the ejector 126.

  A partial oxidation reactor 106 is connected to the downstream side of the ejector 126 in the warm-up fuel pipe 100 in the warm-up fuel flow. As described above, the partial oxidation reactor 106 is disposed on the upstream side of the reforming reactor 92, and a diffusion ring 128 is interposed between the partial oxidation reactor 106 and the reforming reactor 92. The diffusion ring 128 includes a circular tube 128a, and a plurality of holes 128b are formed in the circular tube 128a. That is, the partial oxidation reactor 106 and the reforming reactor 92 are communicated with each other through the hole 128 b of the diffusion ring 128.

  The catalytic combustor 112 is formed on the combustion burner 130 and the upper portion of the combustion burner 130, and the above-described second anode off-gas flow path 72 and anode gas recirculation path 74 are connected so that an anode off-gas etc. flows in. 132, and a combustion catalyst 134 that is disposed downstream of the combustion burner 130 and combusts by reaction a mixed gas (to be described later) burned by the combustion burner 130. The combustion catalyst 134 has a substantially cylindrical shape and is disposed near the upper portion 114 a of the combustion chamber 114. For example, a platinum (Pt) -based catalyst is used as the combustion catalyst 134.

  Further, in the catalytic combustor 112, an exhaust gas treatment catalyst 136 is disposed between the combustion burner 130 and the combustion catalyst 134. The exhaust gas treatment catalyst 136 is a catalyst that treats harmful substances contained in the exhaust gas generated by the combustion in the combustion burner 130 by reaction.

  Next, on the premise of the reforming device 22 configured as described above, control of warming-up and reforming operations of the reforming device 22 executed by the ECU 54 when the fuel cell 10 is started will be described with reference to FIG. To do.

  FIG. 3 is a flowchart showing the processing.

  First, in S10, it is determined whether or not a start instruction for the fuel cell 10 has been made, specifically, whether or not a start switch (not shown) has been turned on by the operator. When the result in S10 is negative, the subsequent processing is skipped, while when the result in S10 is positive, the process proceeds to S12 to excite and open the first electromagnetic valve 34a disposed in the first fuel flow path 32a. .

  When the first electromagnetic valve 34a is opened, the city gas supplied from a city gas supply source (not shown) is freed of organic sulfur compounds such as odorants by the desulfurizer 28 shown in FIG. The Thereby, it is possible to prevent the reforming catalyst 90 and the like disposed downstream in the city gas flow from being poisoned by sulfur. Next, the city gas (fuel) from which the organic sulfur compound has been removed is supplied as a warm-up fuel to the warm-up fuel pipe 100 of the reformer 30 via the first fuel flow path 32a.

  As shown by arrows in FIG. 2, the warm-up fuel supplied to the warm-up fuel pipe 100 is ejected by an ejector 126, a partial oxidation reactor 106, a diffusion ring 128, a reforming reactor 92, a reformed gas pipe 94, and CO removal. It flows into the anode gas flow path 24 through the portion 98. The warm-up fuel flowing into the anode gas passage 24 is supplied to the inlet 132 of the combustion burner 130 of the catalytic combustor 112 via the anode gas recirculation passage 74. The warm-up fuel is burned by the combustion burner 130, and thus exhaust gas is generated. The exhaust gas is supplied to the exhaust gas treatment catalyst 136, and harmful substances contained in the exhaust gas are processed by reaction.

  The exhaust gas treated with harmful substances flows toward the combustion catalyst 134 and passes through the combustion chamber 114 and flows into the exhaust gas pipe 116 while raising the temperature of the combustion catalyst 134. The exhaust gas flows upward in FIG. 2 while raising the temperature of the interior 116 a and the wall surface of the exhaust gas pipe 116. At this time, as described above, the reforming reactor 92 and the CO removing unit 98 are arranged so that the outer wall 92a and the inner periphery 98b thereof are in contact with the exhaust gas pipe 116, so that the heat of the exhaust gas pipe 116 is transmitted. Thus, the reforming catalyst 90 filled in the reforming reactor 92 and the CO removal catalyst 96 of the CO removal unit 98 are also heated and raised in temperature. The exhaust gas in the exhaust gas pipe 116 then flows to the exhaust gas flow path 46 and is discharged into the atmosphere.

  Returning to the description of FIG. 3, the process then proceeds to S14, where the outputs of the first and second reforming catalyst temperature sensors 108a and 108b and the first and second CO removal catalyst temperature sensors 110a and 110b are read and reformed. Temperatures upstream and downstream of the catalyst 90 and upstream and downstream of the CO removal catalyst 96 are detected. Next, in S16, it is determined whether or not the detected temperatures of the reforming catalyst 90 and the CO removal catalyst 96 have all exceeded a predetermined value (specifically, about 400 [° C.]). When the result in S16 is negative, the processes of S14 and S16 are executed again, while when the result in S16 is positive, the process proceeds to S18 to drive the warm-up air pump 42.

  When the warm air pump 42 is driven, the atmosphere (air) is sucked by the warm air pump 42 and flows into the air cleaner 40 where dust is removed. The air from which the dust has been removed, that is, the warm air, is supplied to the warm air tube 102 via the warm air channel 44.

The warm air supplied to the warm air tube 102 is mixed with warm fuel flowing through the warm fuel tube 100 by the ejector 126 shown in FIG. The mixed warming fuel and warming air are supplied to the partial oxidation reactor 106, and the partial oxidation catalyst 104 causes a reaction to generate (generate) a mixed gas (gas). The reaction is specifically as follows.
CH ₄ + 1 / 2O ₂ → CO + 2H ₂

  Since the partial oxidation reaction described above is an exothermic reaction, the generated mixed gas has a relatively high temperature. The high-temperature mixed gas is directly supplied to the reforming catalyst 90 while being diffused by passing through the holes 128 b of the diffusion ring 128. The mixed gas passes through the porous reforming catalyst 90 to further raise the temperature of the reforming catalyst 90, and then passes through the reforming gas pipe 94 and flows into the CO removing section 98, where CO is removed. The temperature of the catalyst 96 is also raised. This mixed gas is a reducing gas composed of carbon monoxide, hydrogen, and nitrogen contained in the warm air, so that the reforming catalyst 90 and the CO removal catalyst 96 are not oxidized.

  Next, the mixed gas flows into the anode gas passage 24 from the reformed gas pipe 94 and is then supplied to the inlet 132 of the combustion burner 130 of the catalytic combustor 112 via the anode gas recirculation passage 74. The mixed gas is burned by the combustion burner 130 and then supplied to the exhaust gas treatment catalyst 136, where harmful substances contained in the mixed gas are processed by reaction.

  The mixed gas that has been treated with harmful substances flows toward the combustion catalyst 134. Since the combustion catalyst 134 is heated to a temperature at which the combustion reaction can be started by the exhaust gas described above, the mixed gas is brought into contact with the combustion catalyst 134 and burned. Thereafter, the mixed gas flows while raising the temperature of the combustion chamber 114 and the exhaust gas pipe 116, and is discharged to the atmosphere via the exhaust gas flow path 46.

  Returning to the description of FIG. 3, the process then proceeds to S20, in which the outputs of the first and second reforming catalyst temperature sensors 108a and 108b and the first and second CO removal catalyst temperature sensors 110a and 110b are read again and revised. Temperatures on the upstream side and downstream side of the catalyst 90 and on the upstream side and downstream side of the CO removal catalyst 96 are detected. Next, in S22, whether or not the detected temperatures of the reforming catalyst 90 and the CO removal catalyst 96 have all exceeded a predetermined value (specifically, about 700 [° C.]), in other words, the reforming catalyst 90. It is determined whether or not the temperature at which the reforming reaction can start is reached and the temperature at which the carbon removal catalyst 96 can start the carbon monoxide removal reaction is reached.

  When the result in S22 is negative, the processes of S20 and S22 are executed again. When the result in S22 is affirmative, the program proceeds to S24, in which the first electromagnetic valve 34a is de-energized and closed, while the second electromagnetic valve 34b disposed in the second fuel flow path 32b is excited to open. To do.

  As a result, the fuel is not supplied to the warm-up fuel pipe 100 and is supplied as the reforming fuel to the reforming fuel pipe 86 of the reformer 30 via the second fuel flow path 32b. Next, in S26, the drive of the warm air pump 42 is stopped, and the supply of the warm air to the warm air tube 102 is also stopped.

  As described above, when the reforming catalyst 90 reaches a predetermined temperature and is in a state capable of the reforming reaction, the supply of the mixed gas generated by the partial oxidation of the partial oxidation catalyst 104 to the reforming catalyst 90 is stopped. did. In this specification, the time when the warming-up operation (warming-up operation) for bringing the reforming device 22 into a reformable state as described above is performed is referred to as “when the reforming device is started”, and will be described later. The time when the reforming operation is performed in the reformer 22 is referred to as “during normal operation of the reformer”.

  When the warming-up operation of the reformer 22 is completed by the processes of S24 and S26, the process proceeds to S28 and the water pump 36 is driven. When the water feed pump 36 is driven, a reforming operation is started in the reformer 22. Specifically, the reforming water from the water supply source (not shown) sucked by the water pump 36 passes through an ion filter (not shown) and the like, and then the reforming water pipe 88 through the reforming water flow path 38. Is flowed into.

  The reforming water pipe 88 is arranged so as to circulate around the outer periphery 98a of the CO removal section 98 that is relatively high in temperature, and is arranged in the interior 116a of the exhaust gas pipe 116 that has been heated by the exhaust gas or mixed gas. Therefore, it will be heated by them. As a result, the reforming water that has flowed into the reforming water pipe 88 evaporates into steam, and the steam flows into the reforming fuel pipe 86 at the connection portion 118 via the second fuel flow path 32b. It is mixed and mixed with the reforming fuel.

  The reformed fuel and water vapor that have been mixed pass through the reforming fuel / water pipe 120 and then flow into the reforming reactor 92. As described above, the reforming catalyst 90 of the reforming reactor 92 is heated to a reformable temperature (about 700 [° C.]), so that a steam reforming reaction occurs, that is, the mixed reforming is performed. A reformed gas containing hydrogen is generated from the quality fuel and water vapor.

The steam reforming reaction is specifically as follows.
CH ₄ + H ₂ O → CO + 3H ₂
Part of the carbon monoxide produced at this time further reacts with water vapor to produce hydrogen and carbon dioxide (that is, a shift reaction occurs). Specifically, it is as follows.
CO + H ₂ O → CO ₂ + H ₂

  Next, the reformed gas is supplied from the reforming reactor 92 to the reformed gas pipe 94 and then supplied to the CO removing unit 98. Here, since the reformed gas is heated to a temperature at which the CO removal catalyst 96 can remove carbon monoxide (about 700 [° C.]), the remaining CO is removed by the reaction, and then the anode gas flow path 24.

  As described above, the ECU 54 at the time of starting the fuel cell 10 controls the warming operation and the reforming operation of the reforming device 22 so that the reforming fuel and the steam react with the reforming catalyst 90 in the reformer 30. Thus, a reformed gas (anode gas) is generated.

  Further, when the control of the warming-up operation and the reforming operation of the reformer 22 is completed, the ECU 54 then drives the cathode gas pump 16 to start the operation control of the fuel cell 10 described above.

  In addition, since the steam reaction in the reforming catalyst 90 is an endothermic reaction, it is necessary to heat the reforming catalyst 90 continuously. Therefore, when the reformer 22 is in a normal operation and reformed gas is generated, the reformed gas (more specifically, the reformer is introduced into the inlet 132 of the combustion burner 130 of the catalytic combustor 112. 22, and the anode gas that flows in through the anode gas recirculation path 74 and the anode offgas that flows in through the second anode offgas flow path 72). As a result, the reformed gas is burned by the combustion burner 130 and then supplied to the exhaust gas treatment catalyst 136 to treat harmful substances contained in the reformed gas. Next, after the reformed gas is supplied to the combustion catalyst 134 and further burned, the reformed catalyst 90 continues to be heated by flowing through the exhaust pipe 116.

  Thus, the fuel cell reforming apparatus 22 according to the present invention is disposed upstream of the reforming catalyst 90 that generates reformed gas containing hydrogen by reacting reforming fuel and steam. And a partial oxidation catalyst 104 that partially oxidizes the fuel, and at the time of start-up, a mixed gas generated by partial oxidation is supplied to the reforming catalyst 90. In addition to heating from the above, a relatively high-temperature mixed gas generated by partial oxidation, which is an exothermic reaction, is directly supplied to the reforming catalyst 90 and heated by passing through the porous reforming catalyst 90 Therefore, the reforming catalyst 90 is set to a predetermined value, more precisely, to a temperature at which the reforming reaction can be started (specifically, about 700 [° C.]). Rapid temperature rise So that it is, therefore it is possible to improve the startability of the reformer 22. Furthermore, although the reforming catalyst 90 and the CO removal catalyst 96 are oxidized when exposed to an oxidizing atmosphere, the mixed gas generated by the partial oxidation is a reducing gas and is not oxidized.

  Further, a reforming catalyst temperature sensor 108 (first and second reforming catalyst temperature sensors 108a and 108b) that outputs a signal corresponding to the temperature of the reforming catalyst 90 is provided, and the temperature of the reforming catalyst 90 is a predetermined value ( Exactly, when the value at which the reforming reaction is started (about 700 [° C.]) is exceeded, the supply of the mixed gas generated by the partial oxidation is stopped, that is, when the temperature of the reforming catalyst 90 is raised. While the above-described mixed gas is supplied, the supply of the mixed gas is stopped when the reforming catalyst 90 is heated and the reforming reaction is started, so that the reforming reaction in the reforming catalyst 90 is affected. The temperature of the reforming catalyst 90 can be raised without giving any.

  Further, the mixed gas generated by partial oxidation is heated by the reforming catalyst 90 and the CO removal catalyst 96 and then burned by the combustion burner 130 and the combustion catalyst 134 of the catalytic combustor 112, and the combustion chamber 114 and the exhaust gas pipe 116. Therefore, the temperature of the reforming catalyst 90 and the CO removal catalyst 96 can be further increased, so that the fuel can be used efficiently.

As described above, in the first embodiment of the present invention, a reformed gas containing hydrogen is generated by reacting fuel and steam with the reforming catalyst (90), and the generated reformed gas is In the reformer (22) for a fuel cell that is supplied to the fuel electrode (anode electrode) of the fuel cell (10), a partial oxidation catalyst (22) that is disposed upstream of the reforming catalyst and partially oxidizes the fuel. 104) , a combustor (112) that heats the reforming catalyst, and an exhaust gas pipe (116) that is disposed in the vicinity of the reforming catalyst and exhausts exhaust gas flowing from the combustor , At start-up, after the gas (mixed gas) generated by the partial oxidation is supplied to the reforming catalyst, the gas is recirculated to the combustor and burned in the combustor, and the exhaust gas generated by the combustion is supplied to the exhaust pipe. so as to flow into Form was.

  Further, temperature detecting means (ECU 54. First and second reforming catalyst temperature sensors 108a and 108b; S20 in the flowchart of FIG. 3) for detecting the temperature of the reforming catalyst (90) and the detected reforming. Stop means (ECU 54. First electromagnetic valve 34a; S22, S24 in the flowchart of FIG. 3) for stopping supply of the gas generated by the partial oxidation when the temperature of the catalyst exceeds a predetermined value (about 700 [° C.]). , S26).

  In the above description, the material of the partial oxidation catalyst 104 and the temperature at which the reforming catalyst 90 can be reformed are specifically shown. However, these materials and numerical values are illustrative and are not limited.

  Further, although the fuel cell 10 is a solid polymer type, the present invention is not limited thereto, and other types may be used.

  In addition, although city gas is used as the reforming fuel, LP gas, kerosene, methanol, naphtha, biomass, gasoline, and the like may be used.

1 is a schematic diagram for explaining a fuel cell reforming apparatus according to a first embodiment of the present invention; FIG. It is a schematic cross section which shows typically the cross section of the reformer of the reformer shown in FIG. It is a flowchart showing the process of control of the warming-up operation | movement and reforming operation | movement of a reformer performed by the electronic control unit (ECU) shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell, 22 Reformer, 34a 1st electromagnetic valve (stop means), 54 Electronic control unit (ECU. Temperature detection means. Stop means), 90 Reform catalyst, 104 Partial oxidation catalyst, 108a 1st modification Catalyst temperature sensor (temperature detection means), 108b Second reforming catalyst temperature sensor (temperature detection means)

Claims (2)

In a fuel cell reforming apparatus, a fuel and water vapor are reacted with a reforming catalyst to generate a reformed gas containing hydrogen, and the generated reformed gas is supplied to a fuel electrode of a fuel cell. A partial oxidation catalyst that is disposed upstream of the reforming catalyst to partially oxidize the fuel, a combustor that heats the reforming catalyst, and is disposed adjacent to the reforming catalyst and flows from the combustor. An exhaust gas pipe for discharging exhaust gas, and at the start-up, the gas generated by the partial oxidation is supplied to the reforming catalyst, and then recirculated to the combustor and combusted in the combustor, and is generated by the combustion. An apparatus for reforming a fuel cell, wherein the exhaust gas is allowed to flow into the exhaust gas pipe .   Furthermore, temperature detection means for detecting the temperature of the reforming catalyst and stop means for stopping the supply of the gas generated by the partial oxidation when the detected temperature of the reforming catalyst exceeds a predetermined value. 2. The fuel cell reforming apparatus according to claim 1, wherein the reforming apparatus is configured as described above.

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