JP2006282458A - Hydrogen generating device and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generating device that suppresses decrease in emission and to provide a fuel cell system using the device. <P>SOLUTION: The hydrogen generating device 110 is equipped a catalyst and a controlling means functioning in such a manner that: when gasoline and a cathode-off gas are supplied, a hydrogen-containing gas is generated by the reforming reaction on the heated catalyst; when an anode-off gas and combustion air are supplied, the catalyst is heated by the heat generating reaction; a fluid to be supplied to each reactor and a fluid to be discharged from the reforming reactor are switched so as to alternately perform the above reforming reaction and the heat generating reaction; and upon switching the reforming reaction to the heat generating reaction in each reactor, at least a part of the residual gasoline and the cathode-off gas in the reactor is first discharged through a port where the hydrogen-containing gas is discharged during the reforming reaction, and then the reforming reaction is switched to the heat generating reaction in the reactor. The fuel cell system 100 is equipped with the above hydrogen generating device 110. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydrogen generator that performs a fuel reforming reaction using a catalyst and a regeneration reaction for heating and regenerating the catalyst, and a fuel cell system including the same.

  A conventional electric vehicle is equipped with a fuel cell as a power source for driving the vehicle, and with hydrogen or a raw fuel for generating hydrogen, which is a fuel for causing the fuel cell to perform a power generation operation.

  When the hydrogen itself is mounted, the hydrogen gas is compressed and packed in a high-pressure cylinder or liquefied and filled into a tank, or mounted using a hydrogen storage alloy or a hydrogen adsorbing material. However, in the case of high pressure filling, although the container wall thickness is thick and large, the internal volume is limited and the hydrogen filling amount is small. Further, in the case of liquefaction filling with liquid hydrogen, vaporization loss is unavoidable and a great deal of energy is required for liquefaction. Further, hydrogen storage alloys and hydrogen adsorbing materials have insufficient hydrogen storage density required for electric vehicles and the like, and it is difficult to control hydrogen storage / adsorption.

  In addition, when the raw fuel is mounted, there is a method of obtaining hydrogen by steam reforming the fuel. However, since the reforming reaction is endothermic, a separate heat source is required. Therefore, a system using an electric heater or the like as the heat source cannot improve the overall energy efficiency. Furthermore, it is inevitable that the amount of hydrogen can be stably secured under all environmental conditions.

  The actual hydrogen supply method has not yet been established technically, but it is an urgent need to establish a hydrogen supply method in light of the anticipated increase in hydrogen utilization in various devices in the future. Has been.

  As a technology related to the above, a reformer that uses a catalyst to repeatedly switch a fuel reforming reaction that is an endothermic reaction and an exothermic reaction (regeneration reaction) that regenerates the catalyst temperature decreased by the reforming reaction. Has been proposed (see, for example, Patent Document 1).

  Moreover, a fuel cell using a hydrogen permeable material is disclosed as an example of a fuel cell that performs a power generation operation in a high temperature range (see, for example, Patent Document 2). In addition to the above, various techniques related to this are disclosed (for example, see Patent Documents 3 and 4).

In addition, when switching from the reforming reaction to the regeneration reaction, the heat at the outlet of the reforming reactor (during reforming) is improved by flowing a non-heating fluid such as steam in the direction opposite to the flow direction of the reforming raw material. A PSR type reforming reactor that has been transferred to the center of a quality reactor has been proposed (see, for example, Patent Document 5). However, when such a system is used, when switching from the reforming reaction to the regeneration reaction, the reforming raw material and the reforming gas generated in the reforming reaction remain in the reforming reactor. When the reforming raw material and the reforming gas remain in the reforming reactor, the reforming raw material and the reforming gas in the reforming reactor are discharged to the atmosphere together with the non-heated fluid during the regeneration reaction. Since the discharge of the reforming raw material and the reforming gas leads to a reduction in emissions, there is a demand for improvement.
U.S. Patent No. 2004-175326 JP 2004-146337 A U.S. Patent No. 2004-170558 US Patent No. 2004-170559 US 2003-235529

  As described above, although a fuel cell system using a reforming device that reforms and generates hydrogen by switching between a reforming reaction and a regeneration reaction (exothermic reaction) has been proposed, it suppresses emission reduction at the time of reaction switching. The technology is not yet proposed.

  An object of this invention is to provide the hydrogen generator which suppressed the emission fall, and a fuel cell system using the same.

  The present invention provides a steam reforming reaction between a reforming raw material and a reforming gas, which is an endothermic reaction, and recovers the catalyst temperature lowered by the steam reforming reaction to regenerate the reforming reactivity on the catalyst. The present invention relates to a hydrogen generating apparatus that repeatedly switches and repeats an exothermic reaction (hereinafter also referred to as “regeneration reaction”) of a raw material for heat generation, and a fuel cell using the same. The exothermic reaction includes a combustion reaction and the like.

  In order to achieve the above object, a hydrogen generator according to a first aspect of the present invention includes a catalyst, and when the reforming raw material and the reforming gas are supplied, the reforming raw material and the reforming raw material are heated on the catalyst. Hydrogen-containing gas is generated by the reforming reaction of the reforming gas, and when the exothermic raw material is supplied, the catalyst is heated by the exothermic reaction of the exothermic raw material, and the reforming reaction and the exothermic reaction can be switched. A reforming reactor, switching means for switching each flow path of the fluid supplied to the reforming reactor and the fluid discharged from the reforming reactor, and the reforming reaction of the reforming reactor, The fluid supplied to the reforming reactor and the fluid discharged from the reforming reactor are switched by the switching means so that the exothermic reaction is performed alternately, and the reforming reactor is reformed. When switching from regenerative reaction to The supply of quality raw material is stopped and at least part of the reforming raw material and / or reforming gas remaining in the reforming reactor is discharged from the side where the hydrogen-containing gas is discharged during the reforming reaction. And a control means for switching the reforming reactor from the reforming reaction to the exothermic reaction.

  Here, the “reforming reaction” in the present invention may include a “partial oxidation reaction” which is an exothermic reaction in addition to the “steam reforming reaction” which is the following endothermic reaction.

C _n H _{2n + 2} + nH ₂ O → (2n + 1) H ₂ + nCO (1)
C _n H _{2n + 2} + (n / 2) O ₂ → (n + 1) H ₂ + nCO (2)
CO + H ₂ O → CO ₂ + H ₂ (3)
CH ₄ + 3H ₂ → CH ₄ + H ₂ O (4)

  In the reforming reaction in the present invention, the steam reforming reaction (1) is mainly performed.

  According to the first aspect of the present invention, the control means switches at least one of the reforming raw material and / or the reforming gas remaining in the reforming reactor when switching from the reforming reaction to the exothermic reaction (regeneration reaction). After the portion is discharged from the side where the hydrogen-containing gas is discharged during the reforming reaction, the fluid supplied to the reforming reactor is switched by the switching means to switch from the reforming reaction to the exothermic reaction. It is possible to prevent the reforming material and / or the reforming gas from being discharged from the side from which the regeneration reaction off-gas is discharged during the regeneration reaction. Thereby, the fall of the emission of a hydrogen generator can be controlled.

  In the present invention, the raw material for reforming is a hydrocarbon fuel (for example, methane gas, gasoline) generally used as a fuel for obtaining a synthesis gas (particularly hydrogen) of hydrogen and carbon monoxide by a reforming reaction such as steam reforming. Etc.) can be appropriately selected and used. As the reforming gas, steam containing water necessary for steam reforming can be used. Further, as the reforming gas, for example, a gas (hereinafter, also referred to as “cathode off-gas”) exhausted from the cathode (air electrode; hereinafter the same) of the fuel cell and containing water can also be used. .

  In addition, the exothermic raw material includes a mixture of exothermic fuel or the like and air, and the exothermic fuel can be appropriately selected from commonly used hydrocarbon fuels (eg, methane gas, gasoline, etc.). Furthermore, a gas containing hydrogen discharged from the anode (hydrogen electrode; hereinafter the same) (hereinafter sometimes referred to as “anode off gas”) may be used as the heat generating fuel.

  According to the first aspect of the present invention, when the control means switches the reforming reactor from a reforming reaction to an exothermic reaction, the supply of the reforming raw material is stopped and the reforming reactor is stopped. The purge gas may be supplied to the gas, and at least a part of the reforming raw material and / or the reforming gas remaining in the reforming reactor may be discharged by the purge gas. Thus, the reforming raw material is stopped by supplying the reforming raw material and / or the reforming gas remaining in the reforming reactor with the purge gas. At the time of the reaction, at least part of the reforming raw material and / or reforming gas remaining from the side from which the hydrogen-containing gas is discharged can be discharged, and the hydrogen-containing gas remaining in the reforming reactor can also be discharged. It can be discharged from the same side with purge gas. For this reason, emission efficiency can be suppressed and the utilization efficiency of the hydrogen-containing gas can be improved. Further, as the purge gas, water vapor or the like can be used, and further, the reforming gas may be used. Hereinafter, the side where the hydrogen-containing gas is discharged during the reforming reaction (that is, the side where the exothermic raw material is supplied during the exothermic reaction (regeneration reaction)) may be referred to as the “regeneration side”.

  According to the first aspect of the present invention, the control means maintains the supply of the reforming gas to the reforming reactor when switching the reforming reactor from the reforming reaction to the exothermic reaction, By stopping the supply of the reforming raw material to the reforming reactor, at least part of the reforming raw material and / or reforming gas remaining in the reforming reactor is removed from the reforming reactor. It can be configured to discharge from. In this way, the supply of the reforming raw material to the reforming reactor is stopped while maintaining the supply of the reforming gas to the reforming reactor, thereby mixing in the reforming reactor. The gas can be pushed out of the reactor with the reforming gas, and at least a part of the reforming raw material and / or the reforming gas remaining in the reforming reactor and the hydrogen-containing gas are supplied from the regeneration side of the reactor. Can be discharged.

  The hydrogen generator of the first aspect of the present invention comprises at least a pair of the reforming reactors, and the control means alternately switches the reforming reaction and the exothermic reaction of the pair of reforming reactors, The reforming reactor can perform a reforming reaction, and the other reforming reactor can perform an exothermic reaction. In this way, a reforming reactor (hereinafter referred to as “PSR (Pressure)” which can be performed by switching between a reforming reaction of fuel using heat storage and an exothermic reaction (regeneration reaction) for recovering the amount of heat storage reduced by the reforming reaction. By providing a pair of “swing reforming type reformers”), at least one unit can perform a fuel reforming reaction and at least one other unit can perform a regeneration reaction ( Hereinafter, this hydrogen generator is sometimes referred to as “PSR reformer”.)

  For example, when there are two reforming reactors, one of them undergoes a reforming reaction that is an endothermic reaction using heat storage in the chamber, and the other is a regeneration reaction that is an exothermic reaction. When the one heat storage amount decreases due to the progress of the reforming reaction, switching is performed by switching means for switching the reforming material flow path to the two reforming reactors and the combustion fuel flow path, and the other reforming is performed. It is possible to switch from the regeneration reaction to the reforming reaction so that the fuel reforming is performed with the heat stored by the regeneration reaction in the reactor. This eliminates the need for a separate heater and enables continuous hydrogen generation with high use efficiency of heat energy.

  A fuel cell system according to a second aspect of the present invention includes the above-described hydrogen generator of the present invention and a fuel cell that generates electric power by supplying the hydrogen-containing gas reformed and produced in the reforming reactor. be able to.

  According to the second aspect of the present invention, it is possible to prevent at least a part of the reforming raw material and / or reforming gas remaining in the reforming reactor from being discharged out of the system. Thereby, the fall of the emission of a fuel cell system can be suppressed.

  In the fuel cell system according to the second aspect of the present invention, the fuel cell includes a hydrogen permeable metal layer and an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer. it can.

  The fuel cell including the hydrogen permeable metal layer and the electrolyte layer has an operating temperature range of 300 to 600 ° C. Since this temperature range is substantially the same as the reaction temperature range in which the steam reforming reaction proceeds, it has the advantage that the hydrogen-containing gas produced by steam reforming is supplied in the operating temperature range of the fuel cell, and the anode offgas is reduced. It can be returned to the PSR reformer as it is and used for the regeneration reaction. This is particularly suitable in terms of system configuration and effective use of thermal energy.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrogen generator which suppressed the emission fall, and a fuel cell system using the same can be provided.

(First embodiment)
Hereinafter, embodiments of the fuel cell system of the present invention will be described in detail with reference to the drawings, and details of the hydrogen generator of the present invention will also be specifically described through the description.

  In the present embodiment, the present invention is applied to an electric vehicle equipped with a hydrogen separation membrane fuel cell (HMFC) in which a proton-permeable ceramic layer laminated on the surface of a hydrogen-permeable metal membrane is used as an electrolyte membrane. The hydrogen generation apparatus is mounted, and the hydrogen separation membrane fuel cell is configured to perform a power generation operation using hydrogen reformed and generated by the hydrogen generation apparatus.

  In the present embodiment, gasoline is used as the reforming material to be reformed by the steam reforming reaction, and cathode offgas containing moisture is used as the reforming gas. In the present embodiment, a combustion reaction is used as the exothermic reaction, and a mixed fuel of combustion fuel and combustion gas is used as the exothermic raw material used in the exothermic reaction. In the present embodiment, anode off-gas discharged from the hydrogen electrode side of the fuel cell is used as the combustion fuel, and combustion air (air) is used as the combustion gas. However, the present invention is not limited to such an embodiment.

  First, the basic configuration of the fuel cell system of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the configuration of the fuel cell system according to the first embodiment. In FIG. 1, a fuel cell system 100 of the present invention includes a hydrogen generator 110 including a reactor 112 (PSR1) and a reactor 114 (PSR2), and a hydrogen separation membrane fuel cell 120 (HMFC). The hydrogen generation device 110 is configured to perform the power generation operation by supplying the hydrogen produced by reforming to the fuel cell 120.

  The reactor 112 and the reactor 114 shown in FIG. 1 are each provided with a catalyst and an injection device, and are configured so that the reforming reaction and the regeneration reaction can be switched. Switching between the reforming reaction and the regeneration reaction is performed by supplying gasoline (reforming raw material) and cathode offgas (reforming gas) supply flow path, anode offgas (combustion fuel), and combustion air (combustion gas) supply flow. A plurality of valves (valves V1 to V10 and three-way valves SV1 to SV8), a discharge passage for the hydrogen-containing gas produced by reforming, and a passage for the regeneration off gas discharged from the reactor subjected to the regeneration reaction. It is configured so that it can be done by controlling. Here, the valves V <b> 1 to V <b> 10 are valves that are switched between passing and blocking of gas by opening and closing thereof. Further, three pipes are connected to the three-way valves SV1 to SV8, and any two pipes of the three pipes are communicated with each other by driving the valves.

  The fuel cell system 100 of the present invention is configured to perform a steam reforming reaction in one reactor and to perform a regeneration reaction in the other reactor. In addition, since the steam reforming reaction is an endothermic reaction, the temperature of the reactor performing the steam reforming reaction is monitored, and when the temperature inside the reactor falls below a certain temperature, two reactors The fuel supplied to is switched to reverse the reforming and regeneration reactions. In other words, in a reactor that has undergone a reforming reaction, a heat generating raw material is supplied instead of the reforming raw material and the reforming gas, the reforming reaction is switched to the regeneration reaction, and the regeneration reaction is performed. In this reactor, the reforming raw material and the reforming gas are supplied instead of the exothermic raw material to shift from the regeneration reaction to the reforming reaction. At this time, the supply of the reforming raw material and the reforming gas and the supply of the exothermic raw material are performed from the opposite sides in consideration of the temperature gradient in the reactor.

  In the present embodiment, when switching from the reforming reaction to the regeneration reaction (combustion reaction), the supply of the gasoline for reforming and the cathode off-gas for reforming gas are stopped, and then the purge gas is reacted for a certain period of time. After supplying the reactor to the reactor and discharging the mixed gas containing gasoline from the regeneration side to the outside of the reactor, the valves are switched to change the raw materials and gases supplied to each reactor, and the reforming reaction / regeneration reaction It is comprised so that it may switch.

  In the operation of the fuel cell system 100 of the present invention, the reforming / regeneration reaction of each reactor is repeatedly switched. In this embodiment, for the sake of convenience, the reforming reaction is performed in the reactor 112. A case where the regeneration reaction is performed in the reactor 114 will be described.

  The basic structure of the fuel cell system of the present invention will be described. As shown in FIG. 1, a fuel supply connected to one side of the reactor 112 and the reactor 114 (hereinafter sometimes referred to as “reforming side”) via a fuel supply pipe 130A and a three-way valve SV1. The pipe 130B and the fuel supply pipe 130C are connected to each other, and the raw material for reforming is supplied through them. The fuel supply pipe 130A is provided with a pump P1, and gasoline that is a reforming raw material is supplied to the reactor 112 by driving the pump P1. The fuel supply pipes 130B and 130C are provided with valves V1 and V5, respectively. Furthermore, each of the reactor 112 and the reactor 114 is provided with a temperature sensor 116 and a temperature sensor 118 for detecting the temperature in each reactor.

  One end of a hydrogen-containing gas discharge pipe 134A and one end of a hydrogen-containing gas discharge pipe 134B are connected to the other side (regeneration side) of the reactor 112 and the reactor 114, respectively. The other ends of the hydrogen-containing gas discharge pipe 134B are connected to the three-way valve SV2, respectively. One end of an anode supply pipe 136 is further connected to the three-way valve SV2, and the anode supply pipe 136 and one of the hydrogen-containing gas discharge pipes 134A and 134B can be communicated with each other by switching the three-way valve SV2. ing.

  The other end of the anode supply pipe 136 is connected to the anode of the fuel cell 120, and a hydrogen-containing gas is supplied to the anode through the pipe. The anode of the fuel cell 120 is connected to the other end of the anode supply pipe 136 on the inlet side and to one end of the anode exhaust pipe 138A on the outlet side. All the gas supplied to the anode of the fuel cell 120 is discharged through the anode exhaust pipe 138A. A three-way valve SV3 is connected to the other end of the anode exhaust pipe 138A, and is configured to communicate with either the anode exhaust pipe 138B or the anode exhaust pipe 138C by switching the three-way valve SV3.

  The anode exhaust pipe 138C is connected to the regeneration side of the reactor 114 at the other end, and is configured to be able to supply the anode off-gas discharged from the fuel cell 120. Further, the anode exhaust pipe 138C is provided with a mixer 139 connected to the combustion air supply pipe 140B. The combustion air supply pipe 140B is communicated with the combustion air supply pipe 140A via a three-way valve SV8. The combustion air is supplied to the mixer 139 by opening / closing the valve V2 provided in the combustion air supply pipe 140B and driving the pump P2. It is configured so that it can be supplied. The anode off gas discharged from the fuel cell 120 is mixed with the combustion air supplied from the combustion air supply pipe 140 </ b> B in the mixer 139 and supplied to the reactor 114. The anode exhaust pipe 138C is provided with a valve V3. Further, the three-way valve SV8 is provided with one end of a combustion air supply pipe 140C.

  A discharge pipe 142A is connected to the reforming side of the reactor 114, and the gas after the oxidation reaction can be discharged out of the system via the three-way valve SV4 and the discharge pipe 142B. Further, the discharge pipe 142A and the fuel supply pipe 130C connected to the reforming side of the reactor 114 are provided with valves V4 and V5, respectively.

  The discharge pipe 142A is configured to be able to communicate with the discharge pipe 142B or 142C via the three-way valve SV4. The other end of the discharge pipe 142C is connected to the three-way valve SV5.

  The anode exhaust pipe 138B is provided with a valve V6, and is connected to the regeneration side of the reactor 112 at the other end. Further, the anode pipe 138B is provided with a mixer 154 to which the other end of the combustion air supply pipe 140C is connected. Further, the combustion air supply pipe 140C is provided with a valve V10.

  One end of a cathode supply pipe 144 provided with a pump P3 is connected to the inlet side of the cathode (oxygen electrode; hereinafter the same) of the fuel cell 120, and air supplied from the cathode supply pipe 144 can be supplied to the cathode. It is configured as follows. Further, one end of a gas supply pipe 146A is connected to the cathode outlet side of the fuel cell 120 so that the cathode off-gas can be discharged.

  The other end of the gas supply pipe 146A is provided with a three-way valve SV5, and communicates with the gas supply pipe 146B via the three-way valve SV5. Further, the other end of the discharge pipe 142C is connected to the three-way valve SV5, and is configured to be able to communicate with either the discharge pipe 142C or the gas supply pipe 146B.

A three-way valve SV6 is connected to the other end of the gas supply pipe 146B, and one end of a gas supply pipe 146C having a valve V7 and a discharge pipe 148 are further connected to the three-way valve SV6. The other end of the gas supply pipe 146C is connected to the reforming side of the reactor 112, and is configured so that a cathode off-gas containing H ₂ O can be inserted into the reactor 112. The discharge pipe 148 is used to discharge the gas supplied from the gas supply pipe 146B to the outside of the system by switching the three-way valve SV6.

  Further, inside the fuel cell 120, there is provided a cooling pipe 150 through which cooling air sucked from the atmosphere is inserted, so that the inside of the cell can be cooled by heat exchange. .

  Further, in the present embodiment, a purge gas supply pipe 152A provided with a pump P4, a purge gas supply pipe 152B and a purge gas supply pipe 152C connected to the purge gas supply pipe 152A via a three-way valve SV7 are provided. The other ends of the purge gas supply pipes 152B and 152C are connected to the reforming side of the reactors 112 and 114, respectively, so that steam supplied as purge gas can be supplied to any reactor from the reforming side. It is configured. Further, the purge gas supply pipes 152B and 152C are provided with valves V8 and V9, respectively. In the present embodiment, when switching from the reforming reaction to the regeneration reaction, after the supply of gasoline and cathode offgas is stopped, water vapor is supplied as purge gas from the reforming side into the reactor, thereby remaining in the reactor. The remaining gasoline as the reforming raw material, the cathode offgas as the reforming gas, and the residual hydrogen-containing gas can be discharged from the regeneration side of the reactor. As a result, it is possible to prevent the residual gasoline and residual cathode off gas in the reactor from being discharged from the reforming side of the reactor to the outside of the system and the like, and the emission is reduced, and the residual hydrogen-containing gas is sent to the fuel cell. As a result, the efficiency of hydrogen use can be increased.

  Next, the configuration of the reactor 112 and the reactor 114 will be described using the reactor 112 as an example. FIG. 2 is a schematic view for explaining the configuration of the reactor. As shown in FIG. 2, the reactor 112 includes a cylindrical body 160 having a circular cross section whose both ends are closed, and a catalyst (catalyst supporting part) 162 supported on the inner wall surface of the cylindrical body 160. The cylindrical body 160 forms a space for carrying out the reaction and functions as a catalyst carrier.

  The cylindrical body 160 is a hollow body that is formed into a cylindrical shape having a circular cross section with a diameter of 10 cm using a ceramic honeycomb, and both ends in the longitudinal direction of the cylinder are closed. As the cross-sectional shape and size, an arbitrary shape and size such as a rectangle other than a circle and an ellipse can be selected according to the purpose and the like.

  The catalyst 162 carries the catalyst in a region of a predetermined distance A from the both ends of the cylindrical body toward the in-cylinder direction, that is, from the both ends in the length direction, of the curved surface of the cylindrical body wall. It is left as a non-catalyst-supported portion and is supported on the entire surface excluding the non-catalyst-supported portion. For the catalyst 162, metals such as Pd, Ni, Pt, Rh, Ag, Ce, Cu, La, Mo, Mg, Sn, Ti, Y, and Zn can be used.

  When the reforming reaction is performed by the catalyst 162, the reformed and produced hydrogen-containing gas is cooled by the catalyst non-supporting portion downstream in the gas discharge direction, and the hydrogen-containing gas is supplied close to the operating temperature of the fuel cell 120. it can. On the other hand, when the reforming reaction is switched to the regeneration reaction, the catalyst non-supporting part is heated by heat exchange with the hydrogen-containing gas, and is supplied in the direction opposite to the discharge direction of the hydrogen-containing gas. The anode off-gas, which is the combustion fuel, is supplied to the catalyst 162 after being preheated in the catalyst non-supporting portion. Thereby, a temperature distribution in which the amount of heat storage becomes higher is formed near the center of the cylindrical body 160 on which the catalyst 162 is supported, and this temperature distribution is advantageous in terms of reactivity. The tubular body 160 is attached with a temperature sensor 116 for measuring the temperature of the catalyst.

  A fuel supply pipe 130B, a gas supply pipe 146C, and a purge gas supply pipe 152B are connected to the reforming side wall surface of the cylindrical body 160, and an injection device 164 is provided at the tip of the fuel supply pipe 130B. Yes. Further, a hydrogen-containing gas discharge pipe 134A and an anode discharge pipe 138B are connected to the wall surface on the regeneration side of the cylindrical body 160.

  When performing a steam reforming reaction in the reactor 112 during normal operation, the injector 164 injects gasoline (reforming raw material) at a wide angle and is housed in the cylindrical body 160 together with moisture contained in the cathode offgas. The supply onto the catalyst 162 and the reaction can be performed. In this case, the hydrogen-containing gas generated by the steam reforming reaction is exhausted from the hydrogen-containing gas discharge pipe 134A and supplied to the fuel cell 120.

  Further, when the regeneration reaction is performed in the reactor 112 after switching from the reforming reaction, the tubular body 160 is supplied by supplying an anode off-gas (and gasoline or hydrogen-containing gas if necessary) after supplying the purge gas. The anode off-gas can be supplied onto the catalyst 162 built in the chamber to perform a combustion reaction.

Next, the fuel cell 120 will be described with reference to FIG. FIG. 3 is a cross-sectional view for explaining the fuel cell in the present embodiment. As shown in FIG. 3, the hydrogen separation membrane fuel cell (HMFC) 120 includes an electrolyte membrane 174 having a dense hydrogen permeable membrane using a hydrogen permeable metal, and an oxygen electrode (O ₂₎ sandwiching the electrolyte membrane 174. Electrode) 176 and a hydrogen electrode (H ₂ electrode) 178. When the hydrogen-containing gas reformed and generated by the hydrogen generator 110 is supplied, hydrogen can be selectively permeated to perform power generation operation. It is like that.

  Between the oxygen electrode 176 and the electrolyte membrane 174, an air flow path 180 for passing, that is, supplying and exhausting air (Air) as an oxidant gas is formed between the hydrogen electrode 178 and the electrolyte membrane 174. A fuel flow path 182 for passing, that is, supplying and discharging hydrogen-rich fuel gas (here, reformed and produced hydrogen-containing gas) is formed. The oxygen electrode 176 and the hydrogen electrode 178 are made of various materials such as carbon (for example, carbon powder carrying platinum or an alloy made of platinum and another metal) or an electrolyte solution (for example, Nafion Solution manufactured by Aldrich Chemical). Can be formed.

The electrolyte membrane 174 has a four-layer structure including a dense substrate (dense hydrogen permeable membrane made of hydrogen permeable metal) 184 formed of vanadium (V). Palladium (Pd) layers (dense hydrogen permeable membranes made of a hydrogen permeable material) 186 and 188 are arranged so as to sandwich the base material 184 from both sides, and are opposite to the side in contact with the base material 184 of one Pd layer 186. On the side surface, an electrolyte layer 190 made of BaCeO ₃ (solid oxide) is further provided in a thin film shape.

  The base material 184 can be suitably formed using niobium, tantalum, and an alloy containing at least one of these in addition to vanadium (V). These have high hydrogen permeability and are relatively inexpensive, which is advantageous in terms of cost.

Electrolyte layer (BaCeO ₃ film) 190 may be configured by using a SrCeO ₃ based ceramic proton conductor other than BaCeO _3.

  Examples of the hydrogen permeable metal include, in addition to palladium, vanadium, niobium, tantalum, an alloy containing at least one of these, and a palladium alloy. The electrolyte layer can be protected by providing a dense film using these.

  The dense film (coating film) made of the hydrogen permeable metal is generally made of vanadium (vanadium simple substance and vanadium-nickel alloy, etc.) on the oxygen electrode 176 side because it is generally high in hydrogen permeability and relatively inexpensive. ), Niobium, tantalum, and alloys containing at least one of these are preferably used. Although these can be applied on the hydrogen electrode side, it is desirable to use them on the oxygen electrode 176 side in order to avoid hydrogen embrittlement. On the hydrogen electrode 178 side, for example, palladium or a palladium alloy is preferably used because hydrogen permeability is relatively high and hydrogen embrittlement is difficult.

  As shown in FIG. 3, a sandwich structure film consisting of three layers of Pd layer 186 / base material 184 / Pd layer 188, that is, a laminated structure of two or more layers made of different metals (dense film made of hydrogen permeable material). In this case, a metal diffusion suppression layer that suppresses diffusion of the different metals may be provided on at least a part of the contact interface of the different metals (for example, see FIGS. 10 and 11 described later). The metal diffusion suppressing layer is described in paragraph numbers [0015] to [0016] of JP-A No. 2004-146337.

  As the layer structure of the above sandwich structure film, in addition to the structure of palladium (Pd) / vanadium (V) / Pd, a five-layer structure such as Pd / tantalum (Ta) / V / Ta / Pd may be used. Is possible. As described above, V has a faster proton or hydrogen atom permeation rate than Pd and is inexpensive, but has a lower ability to dissociate hydrogen molecules into protons and the like. For this reason, hydrogen permeation performance can be improved by providing a Pd membrane having a high ability to protonate hydrogen molecules on one or both sides of the V membrane. In this case, by providing a metal diffusion suppression layer between the metal films, it is possible to suppress mutual diffusion between different kinds of metals and to suppress a decrease in hydrogen permeation performance, and thus a decrease in electromotive force of the fuel cell.

  The electrolyte layer 190 is made of a solid oxide, and a reaction suppression layer that suppresses the reaction between oxygen atoms in the electrolyte layer 190 and Pd may be provided at a part of the interface with the Pd layer 186 (for example, described later). Reaction suppression layer 210 in FIG. This reaction suppression layer is described in paragraphs [0024] to [0025] of JP-A No. 2004-146337.

  The electrolyte membrane 174 is composed of a vanadium base material, which is a dense hydrogen-permeable material, and an inorganic electrolyte layer formed on the cathode side of the fuel cell 120, which makes it possible to reduce the thickness of the electrolyte membrane. When applied to a high-temperature solid oxide fuel cell (SOFC) used, the operating temperature can be lowered to a temperature range of 300 to 600 ° C. As a result, the fuel cell system of the present invention that supplies the cathode off-gas discharged from the fuel cell directly to the PSR reformer that undergoes the reforming reaction can be suitably configured.

When a hydrogen-containing gas having a high hydrogen (H ₂ ) density is supplied to the fuel flow path 182 and air containing oxygen (O ₂ ) is supplied to the air flow path 180, the hydrogen separation membrane type fuel cell 120 will be described below. The electrochemical reaction (battery reaction) represented by the formulas (1) to (3) is caused to supply electric power to the outside. Equations (1) and (2) represent reactions on the anode side and the cathode side, respectively, and Equation (3) represents the total reaction in the fuel cell.

H ₂ → 2H ⁺ + 2e ⁻ (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
H ₂ + (1/2) O ₂ → H ₂ O (3)

  Switching of each valve will be described with reference to FIG. FIG. 4 is a configuration diagram for explaining the valve control. As shown in FIG. 4, the valves V <b> 1 to V <b> 10, the three-way valves SV <b> 1 to SV <b> 8, and the pumps P <b> 1 to P <b> 4 are connected to a control unit (CPU) 170. . The control unit 170 is connected to the temperature sensor 116 and the temperature sensor 118, and can monitor the temperature in the reactor 112 and the reactor 114. The controller 170 controls the valves and pumps according to the temperatures in the reactor 112 and the reactor 114, and can shift from the reforming reaction of each reactor to the regeneration reaction (combustion reaction). Furthermore, the control unit 170 can control the supply amount of gasoline (reforming raw material), cathode gas, and the like by controlling each pump.

  Next, the gas flow and control of the fuel cell system 100 in the present embodiment will be described with reference to FIG. In FIG. 1, the exhaust pipe indicated by a thick line indicates a pipe used when a reforming reaction is performed in the reactor 112 and a regeneration reaction (combustion reaction) is performed in the reactor 114, and is indicated by white lines. The drainage pipe indicates a pipe that is not used in such a case. In addition, among the valves V1 to V10 shown in FIG. 1, the valve shown in white means that the valve is open, and the valve shown in black means that the valve is closed.

  In FIG. 1, when gasoline is first supplied from the fuel supply pipe 130A by driving the pump P1, it is supplied to the reactor 112 through the fuel supply pipe 130B connected to the fuel supply pipe 130A by the three-way valve SV1. Here, in the present embodiment, the water used for the reforming reaction is a circulation type that supplies the cathode off-gas from the fuel cell 120, but if necessary, the water is supplied from outside the system together with the gasoline or separately from the gasoline. Can be configured to be supplied into the system.

  In the reactor 112 to which gasoline and moisture contained in the cathode off gas are supplied, hydrogen is generated by the steam reforming reaction, and the hydrogen-containing gas is discharged to the hydrogen-containing gas discharge pipe 134A. At this time, the three-way valve SV2 is adjusted so that the hydrogen-containing gas discharge pipe 134A and the anode supply pipe 136 communicate with each other. The hydrogen-containing gas discharged from the reactor 112 is supplied to the anode of the fuel cell 120 through the hydrogen-containing gas discharge pipe 134A and the anode supply pipe 136, and is used for power generation of the fuel cell 120.

  The anode off gas containing surplus hydrogen that has not been protonated at the anode of the fuel cell 120 is discharged from the anode exhaust pipe 138A. At this time, the three-way valve SV3 is adjusted so that the anode exhaust pipe 138A and the anode exhaust pipe 138C communicate with each other, and the anode off-gas discharged to the anode exhaust pipe 138A is sent to the anode exhaust pipe 138C. Has been. The anode off gas sent to the anode exhaust pipe 138C is first supplied to the mixer 139 through this.

  At this time, the three-way valve SV8 is adjusted so that the combustion air supply pipes 140A and 140B communicate with each other, and the combustion air can be supplied to the mixer 139. Further, the valve V2 is controlled to be open.

  The anode off gas supplied to the mixer 139 is mixed with the combustion air supplied through the combustion air supply pipes 140A and 140B, and then supplied to the reactor 114. At this time, the valve V3 is controlled to be in an open state. In the present invention, a separate auxiliary fuel pipe may be provided so as to supply auxiliary combustion such as gasoline for assisting the regeneration reaction together with the anode off gas.

  The anode off gas supplied to the reactor 114 is used for heat generation by the regeneration reaction, and is then discharged out of the system through the discharge pipes 142A and 142B. At this time, the valve V4 provided in the discharge pipe 142 is controlled to be opened, and the valves V5 and V9 provided in the fuel supply pipe 130C and the purge gas supply pipe 152C are controlled to be closed. ing.

  On the other hand, on the cathode side of the fuel cell 120, air serving as an oxidant is supplied to the cathode of the fuel cell 120 through the cathode supply pipe 144 by driving the pump P3. Oxygen in the air supplied to the cathode reacts with protons that have passed through the electrolyte membrane and electrons that have passed through an external circuit (not shown) to produce water. The cathode off gas containing water is discharged to the gas supply pipe 146A.

  The three-way valves SV5 and SV6 are controlled so that the gas supply pipe 146A, the gas supply pipe 146B, and the gas supply pipe 146C communicate with each other, and the cathode off-gas sent from the cathode of the fuel cell 120 is the gas supply pipe 146A. To reactor 112 through ~ 146C. Thus, by sending the cathode offgas from the fuel cell 120 to the reactor 112 that performs the reforming reaction, the water contained in the cathode offgas can be used for the steam reforming reaction in the reactor 112. Thereby, for example, the amount of moisture supplied from outside the system can be reduced, and an efficient system can be configured.

  Further, during normal operation, cooling air is supplied to the cooling pipe 150, and the inside of the fuel cell 120 is cooled by heat exchange through the cooling pipe 150.

  Next, control of each valve and pump when switching the reaction in the reactor 112 from the reforming reaction to the regeneration reaction (combustion reaction) will be described with reference to FIGS. 5 and 6. First, referring to FIG. 5, anode off-gas (combustion fuel), combustion air (combustion gas), water vapor (purge gas), gasoline (reforming raw material), cathode off-gas (reforming gas) in reactor 112. A relationship between the supply timing and the supply amount will be described. FIG. 5 is an explanatory diagram showing the relationship between the supply timing and supply amount of anode off gas, combustion air, water vapor, gasoline, and cathode off gas in the first embodiment.

  In FIG. 5, the direction indicated by the arrow from the right side to the left side of the paper indicates the passage of time, and the direction indicated by the arrow extending upward from the reference axis indicates the supply amount of each raw material and gas. FIG. 5 shows the relationship between the supply timing and supply amount of each raw material and gas in the reactor 112, and the reforming reaction is performed in the reactor 112 in the first period and the third period. In the second period and the fourth period, the regeneration (combustion) reaction is performed. In the fuel cell system of the present invention, this reforming / regeneration reaction is repeatedly performed.

  As shown in FIG. 5, in the first period, gasoline and cathode off-gas are supplied to the reactor 112, and the reforming reaction is performed.

  During the first period in FIG. 5, the control unit 170 monitors the temperature in the reactor 112 that is performing the reforming reaction by the temperature sensor 116, and determines that the detected temperature has decreased below a predetermined temperature. First, the supply of gasoline and cathode off-gas to the reactor 112 is stopped (point A in FIG. 5). Next, the controller 170 supplies water vapor (purge gas) into the reactor 112, extrudes gasoline, cathode offgas, and hydrogen-containing gas remaining in the reactor 112 with the purge gas, and discharges them from the regeneration side of the reactor 112. Thereby, it is possible to prevent the remaining gasoline, cathode offgas, and hydrogen-containing gas from being discharged from the reforming side of the reactor 112 due to the anode offgas supplied from the regeneration side of the reactor 112 during the regeneration reaction. .

  Thereafter, the supply of water vapor (purge gas) is stopped (point B in FIG. 5), and the valves and pumps are switched so as to supply the anode off-gas and combustion air to the reactor 112. By this switching, the reaction in the reactor 112 is switched from the reforming reaction to the regeneration reaction, and is shifted from the first period shown in FIG. 5 to the second period.

  In the second period in FIG. 5, the regeneration reaction is performed in the reactor 112 until the temperature in the reactor 114 becomes equal to or lower than a predetermined temperature. When the controller 170 determines that the temperature in the reactor 114 is equal to or lower than the predetermined temperature, the valves are switched again to switch the reaction in the reactor 112 to the reforming reaction. Then, the period of the reforming / regeneration reaction is continued to the third period, the fourth period,..., The nth period. At this time, in the third cycle in which the reforming reaction is performed, the same processing as that in the first cycle is performed, and after the remaining gasoline in the reactor 112 is discharged, the shift to the next cycle is performed.

  Next, transition control from the reforming reaction to the regeneration reaction in the reactor 112 will be described with reference to FIG. FIG. 6 is a flowchart showing the transition control from the reforming reaction to the regeneration reaction of the reactor 112 in the first embodiment. In FIG. 6, the controller 170 first supplies gasoline and cathode offgas to the reactor 112 in order to perform the reforming reaction in the reactor 112 (PSR1) (step S101). The controller 170 monitors the temperature in the reactor 112 in which the reforming reaction is performed while supplying gasoline and cathode off-gas to the reactor 112, and detects the temperature T1 in the reactor 112. (Step S102).

  Next, the controller 170 compares the temperature T1 detected by the temperature sensor 116 with a threshold T0 (for example, about 600 ° C.), and determines whether or not the temperature T1 is less than the threshold T0 (step S103). When the controller 170 determines that the temperature T1 is equal to or higher than the threshold T0 (No at Step S103), the control unit 170 returns to Step S101 and supplies gasoline and cathode offgas to the reactor 112.

  On the other hand, when the controller 170 determines that the temperature T1 is less than the threshold (Yes at Step S103), the supply of gasoline and cathode offgas to the reactor 112 is stopped (Step S104).

  Next, the control unit 170 supplies a certain amount of water vapor as a purge gas to the reactor 112, and discharges the gasoline, cathode offgas, and hydrogen-containing gas remaining in the reactor 112 from the regeneration side of the reactor 112 (step S105). . In the present embodiment, the supply of the water vapor (purge gas) can suppress the remaining gasoline from being discharged from the reforming side and reducing the system emission. Furthermore, the fuel cell system 100 of the present invention can use the remaining hydrogen in the reactor in the fuel cell by discharging the residual hydrogen-containing gas from the regeneration side of the reactor 112. Thereby, the use efficiency of hydrogen produced | generated by reforming reaction can be made high.

  After supplying the purge gas, the control unit 170 switches the reforming / regeneration reaction of each reactor, supplies anode off gas and combustion air to the reactor 112, switches the reaction in the reactor 112 to the regeneration reaction, and decreases the reaction. The temperature in the chamber is regenerated by a regeneration reaction (exothermic reaction) (step S106).

  In the above description, only the switching control from the reforming reaction to the regeneration reaction in the reactor 112 has been described, but the same control is performed when the reactor 114 switches from the reforming reaction to the regeneration reaction.

  As described above, in the present embodiment, when switching from the reforming reaction to the regeneration reaction, the gasoline and cathode remaining in the reactor are supplied by supplying steam as purge air after stopping the supply of gasoline and cathode offgas. Off-gas and residual hydrogen-containing gas can be discharged from the regeneration side, and emission reduction due to residual gasoline being discharged outside the system can be suppressed. Moreover, the use efficiency of the hydrogen produced | generated by reforming reaction can be improved by discharging | emitting residual hydrogen in a reactor from the regeneration side. Thereby, the fuel consumption of a fuel cell system can also be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, when the reaction in the reforming reactor is switched from the reforming reaction to the regeneration reaction (exothermic reaction), the supply amount of gasoline as the reforming raw material is stopped while the reforming gas is used. By maintaining the supply of a certain cathode off-gas for a certain time, the gasoline and hydrogen-containing gas remaining in the reforming reactor can be discharged from the regeneration side of the reforming reactor.

  This embodiment is a mode in which cathode off-gas is used instead of supplying water vapor from outside the system as in the first embodiment. As shown in FIG. 7, the fuel cell system 102 in the present embodiment is the same as the fuel cell system 100 in FIG. 1 except for the purge gas supply pipes 140A to 140C, the pump P4, the valve V8, and the three-way valve SV7 in FIG. The same number is given to the same configuration, and the description is omitted.

  The control of each valve and pump when switching from the reforming reaction to the regeneration reaction (combustion reaction) in the second embodiment will be described with reference to FIGS. First, referring to FIG. 8, supply timing and supply amount of anode off-gas (combustion fuel), combustion air (combustion gas), gasoline (reforming raw material) and cathode off-gas (reforming gas) in the reactor 112. Will be described. FIG. 8 is an explanatory diagram showing the relationship between the supply timing and the supply amount of anode off gas, combustion air, gasoline, and cathode off gas in the second embodiment.

  In FIG. 8, the direction indicated by the arrow from the right side to the left side of the paper indicates the passage of time, and the direction indicated by the arrow extending upward from the respective reference axes indicates the supply amount of each raw material and gas. FIG. 8 shows the relationship between the supply timing and supply amount of each raw material and gas in the reactor 112, and the reforming reaction is performed in the reactor 112 in the first period and the third period. A regeneration reaction is performed in the second period and the fourth period. In the fuel cell system of the present invention, this reforming / regeneration reaction is repeatedly performed.

  During the first period in FIG. 8, the controller 170 monitors the temperature in the reactor 112 that is performing the reforming reaction by the temperature sensor 116, and determines that the detected temperature has decreased below a predetermined temperature. First, supply of gasoline to the reactor 112 is stopped (point C in FIG. 8). By stopping the supply of gasoline, the supply of the reforming raw material (gasoline) newly added to the reactor 112 is stopped. On the other hand, the cathode off gas is supplied to the reactor 112 for a certain period of time after the supply of gasoline is stopped, and the residual gasoline in the reactor 112 is pushed out together with the hydrogen-containing gas remaining in the reactor 112 to the cathode off gas, It is discharged from the regeneration side of the reactor 112. This prevents the remaining gasoline, cathode offgas, and residual hydrogen-containing gas from being discharged from the reforming side of the reactor 112 due to anode offgas or the like supplied from the regeneration side of the reactor 112 during the regeneration reaction. it can.

  Next, the controller 170 stops the supply of the cathode offgas to the reactor 112 (point D in FIG. 5), and switches each valve and pump so as to supply the anode offgas and combustion air to the reactor 112. By this switching, the reaction in the reactor 112 is switched from the reforming reaction to the regeneration reaction, and is shifted from the first period shown in FIG. 8 to the second period.

  In the second period in FIG. 8, the regeneration reaction (combustion reaction) is performed in the reactor 112 until the temperature in the reactor 114 becomes equal to or lower than a predetermined temperature. When the controller 170 determines that the temperature in the reactor 114 is equal to or lower than the predetermined temperature, the valves are switched again to switch the reaction in the reactor 112 to the reforming reaction. Then, the period of the reforming / regeneration reaction is continued to the third period, the fourth period,..., The nth period. At this time, in the third period in which the reforming reaction is performed, the same process as in the first period is performed, and after the residual gasoline and residual hydrogen-containing gas in the reactor 112 are discharged, the process shifts to the next period. .

  Next, transition control from the reforming reaction to the regeneration reaction in the reactor 112 will be described with reference to FIG. FIG. 9 is a flowchart showing the transition control from the reforming reaction to the regeneration reaction of the reactor 114 in the second embodiment. In FIG. 9, the controller 170 first supplies gasoline and cathode offgas to the reactor 112 in order to perform the reforming reaction in the reactor 112 (PSR1) (step S111). The controller 170 monitors the temperature in the reactor 112 in which the reforming reaction is performed while supplying gasoline and cathode off-gas to the reactor 112, and detects the temperature T1 in the reactor 112. (Step S112).

  Next, the controller 170 compares the temperature T1 detected by the temperature sensor 116 with a threshold T0 (for example, about 600 ° C.), and determines whether or not the temperature T1 is less than the threshold T0 (step S113). When the controller 170 determines that the temperature T1 is equal to or higher than the threshold T0 (No at Step S113), the control unit 170 returns to Step S111 and supplies gasoline and cathode off gas to the reactor 112.

  On the other hand, when the controller 170 determines that the temperature T1 is less than the threshold (Yes at Step S113), the supply of gasoline to the reactor 112 is stopped (Step S114). The controller 170 continues to supply the cathode off-gas to the reactor 112 after the gasoline supply is stopped, whereby residual gasoline and residual hydrogen-containing gas in the reactor 112 are discharged from the regeneration side of the reactor 112. .

  Next, the control unit 170 determines whether or not a certain time (for example, 2 seconds) has elapsed since the stop of gasoline supply (step S115). Continue (No at step S115).

  On the other hand, when the control unit 170 determines that a certain time has elapsed from the stop of gasoline supply (Yes in Step S115), the supply of the cathode offgas to the reactor 112 is stopped, and the reforming / regeneration reaction of each reactor is performed. In order to switch, each valve is switched (step S116).

  Next, the controller 170 supplies anode off gas and combustion air to the reactor 112 to switch the reaction in the reactor 112 to a regeneration reaction, and the reactor 112 reduces the temperature in the reactor to a regeneration reaction (combustion). (Reaction) to regenerate (step S117).

  In the above description, only the switching control from the reforming reaction to the regeneration reaction in the reactor 112 has been described, but the same control is performed when the reactor 114 switches from the regeneration reaction to the reforming reaction.

  As described above, in the present embodiment, when switching from the reforming reaction to the regeneration reaction, the gasoline supply is stopped before the cathode offgas supply is stopped, and only the cathode offgas is supplied for a certain period of time. By discharging the residual gasoline in the reactor from the regeneration side of the reactor, it is possible to suppress a reduction in emissions. At the same time, the residual hydrogen-containing gas in the reactor 112 is discharged from the regeneration side, so that the residual hydrogen gas can be used in the fuel cell 120, thereby improving the use efficiency of the hydrogen generated by the reforming reaction. be able to. Thereby, the fuel consumption of a fuel cell system can also be improved.

  In the above description, the case where gasoline is used as the reforming raw material has been described. However, the same configuration can be used when a hydrocarbon fuel other than gasoline is used.

  Next, another specific example of the hydrogen separation membrane fuel cell that can be diverted to the fuel cell 120 in the fuel cell system according to the first and second embodiments will be described with reference to FIGS. For details about other specific examples, reference can be made to the description in Japanese Patent Application Laid-Open No. 2004-146337.

FIG. 10 shows an electrolyte membrane 202 having a five-layer structure including a dense substrate 212 formed of vanadium (V), an oxygen electrode (O ₂ electrode) 204 and a hydrogen electrode (H ₂ electrode) sandwiching the electrolyte membrane 202. ) 206, and shows a hydrogen separation membrane fuel cell 200 having a metal diffusion suppression layer and a reaction suppression layer. The electrolyte membrane 202 includes a dense metal diffusion suppression layer 214 and a palladium (Pd) layer 216 in order from the surface side on the surface of the base 212 on the hydrogen electrode (anode) 206 side. Further, a dense reaction suppression layer (for example, a proton conductor, a mixed conductor, or an insulator layer) 210 and a solid oxide are formed on the oxygen electrode (cathode) 204 side surface of the base material 212 in this order from the surface side. A thin electrolyte layer (for example, a metal oxide SrCeO ₃ film which is one of perovskites) 208. The reaction suppression layer 210 has a function of suppressing the reaction between oxygen atoms in the electrolyte layer 208 and the base material (V) 212. Note that an air flow path 180 and a fuel flow path 182 are formed between the oxygen electrode 204 or the hydrogen electrode 206 and the electrolyte membrane 202 in the same manner as described above. Details of the metal diffusion suppression layer and the reaction suppression layer are as described above.

FIG. 11 includes an electrolyte membrane 302 having a dense hydrogen permeable membrane using a hydrogen permeable metal, and an oxygen electrode (O ₂ electrode) 304 and a hydrogen electrode (H ₂ electrode) 306 that sandwich the electrolyte membrane 302. The solid polymer type hydrogen separation membrane fuel cell 300 is shown. The electrolyte membrane 302 has a multilayer structure in which, for example, both surfaces of an electrolyte membrane 312 made of a solid polymer membrane such as a Nafion (registered trademark) membrane are sandwiched between hydrogen-permeable dense metal membranes. A palladium (Pd) layer (dense film) 314 is provided on the surface of the hydrogen electrode (anode) 306 side of 312, and the vanadium serving as a base material in order from the surface side of the surface of the electrolyte membrane 312 on the oxygen electrode (cathode) 304 side. -A nickel alloy (V-Ni) layer (dense film) 310 and a Pd layer (dense film) 308 are provided. Note that an air channel 180 and a fuel channel 182 are formed between the oxygen electrode 304 or the hydrogen electrode 306 and the electrolyte membrane 302 in the same manner as described above. Also in the fuel cell 120, a metal diffusion suppression layer can be provided between the V-Ni layer 310 and the Pd layer 308, and a reaction occurs between the V-Ni layer 310 or the Pd layer 314 and the electrolyte membrane 312. A suppression layer can be provided.

  In the polymer electrolyte fuel cell shown in FIG. 11, by forming a hydrogen permeable membrane using a hydrogen permeable metal so as to sandwich the hydrous electrolyte membrane, moisture evaporation and membrane resistance of the electrolyte membrane at a high temperature are achieved. It is possible to suppress the increase, and in general, the operating temperature of a low-temperature polymer electrolyte fuel cell (PEFC) can be improved to a temperature range of 300 to 600 ° C. This is suitable for the configuration of the fuel cell system of the present invention in which the cathode off-gas discharged from the fuel cell is directly supplied to the PSR reformer that undergoes the reforming reaction.

It is the schematic which shows the structure of the fuel cell system of 1st Embodiment. It is the schematic for demonstrating the structure of a reactor. It is sectional drawing for demonstrating the fuel cell in 1st Embodiment. It is a block diagram for demonstrating valve control. It is explanatory drawing which shows the relationship of the supply timing and supply amount of anode off gas, combustion air, gasoline, and cathode off gas in 1st Embodiment. It is a flowchart which shows the transition control from the reforming reaction of the reactor 112 in 1st Embodiment to regeneration reaction. It is explanatory drawing which shows the structure of the fuel cell system in 2nd Embodiment. It is explanatory drawing which shows the relationship of the supply timing and supply amount of anode off gas, water vapor | steam, gasoline, and cathode off gas in 2nd Embodiment. It is a flowchart which shows the transition control from the reforming reaction of the reactor 112 in 2nd Embodiment to regeneration reaction. It is sectional drawing for demonstrating the other example of the fuel cell in this invention. It is sectional drawing for demonstrating the other example of the fuel cell in this invention.

Explanation of symbols

100, 102 Fuel cell system 110 Hydrogen generator 112, 114 Reactor 120, 200, 300 Fuel cell 170 Controller 184, 212 Base material 186, 188, 216, 314, 308, 314 Palladium (Pd) layer 190, 208, 302 Electrolyte layer 310 Vanadium-nickel alloy (V-Ni) layer P1-P4 Pump V1-V10 Valve SV1-SV8 Three-way valve

Claims (6)

When a reforming raw material and a reforming gas are supplied, a hydrogen-containing gas is generated by a reforming reaction of the reforming raw material and the reforming gas on the heated catalyst, and a heat generating raw material is provided. A reforming reactor that heats the catalyst by an exothermic reaction of the exothermic raw material and can switch between the reforming reaction and the exothermic reaction;
Switching means for switching each flow path of the fluid supplied to the reforming reactor and the fluid discharged from the reforming reactor;
The switching means switches the fluid supplied to the reforming reactor and the fluid discharged from the reforming reactor so that the reforming reaction and the exothermic reaction of the reforming reactor are alternately performed, and When the reforming reactor is switched from the reforming reaction to the exothermic reaction, at least part of the reforming raw material and / or reforming gas remaining in the reforming reactor contains the hydrogen during the reforming reaction. Control means for switching the reforming reactor from the reforming reaction to the exothermic reaction after exhausting from the gas exhaust side;
A hydrogen generation apparatus comprising:   The control means, when switching the reforming reactor from a reforming reaction to an exothermic reaction, stops supplying the reforming raw material, supplies a purge gas to the reforming reactor, and uses the purge gas to improve the reforming reactor. The hydrogen generator according to claim 1, wherein at least part of the reforming raw material and / or reforming gas remaining in the quality reactor is discharged.   The control means maintains the supply of the reforming gas to the reforming reactor when the reforming reactor is switched from a reforming reaction to an exothermic reaction, while the reforming raw material is reformed. The at least part of the reforming raw material and / or reforming gas remaining in the reforming reactor is discharged from the reforming reactor by stopping the supply to the reactor. Hydrogen generator.   At least a pair of the reforming reactors are provided, and the control unit alternately switches between the reforming reaction and the exothermic reaction of the pair of reforming reactors, and one of the reforming reactors performs the reforming reaction. The hydrogen generator according to claim 1, wherein the other reforming reactor performs an exothermic reaction. The hydrogen generator according to any one of claims 1 to 4,
A fuel cell that generates electricity by supplying a hydrogen-containing gas reformed and produced in the reforming reactor;
A fuel cell system comprising:   6. The fuel cell system according to claim 5, wherein the fuel cell includes a hydrogen permeable metal layer and an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer.

Images