JP2006318870A - Fuel cell system and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of stably supplying electric power and to provide a fuel cell used for it. <P>SOLUTION: The fuel cell system 100 is equipped with a hydrogen generation device 110 comprising reactors 112, 114 having a catalyst and capable of switching reforming reaction and exothermic reaction, three-way valves SV1-SV7 for switching the passage of fluid supplied to the reactors 112, 114 and the passage of fluid exhausted from the reactors, and a control means 170 switching the three-way valves SV1-SV7 to cause reforming reaction in one reactor out of the reactors 112, 114 and the exothermic reaction in the other reactor, and the reforming reaction and the exothermic reaction alternately in the reactors; a hydrogen tank 125 housing hydrogen-containing gas reformed and produced in the hydrogen generation device 110; and a fuel cell 120 generating electric power with hydrogen-containing gas supplied from the hydrogen tank 125. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system including a reforming reactor and a fuel cell which are switched between a fuel reforming reaction using a catalyst and a regeneration reaction for heating and regenerating the catalyst, and a fuel cell used therefor.

  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 between an endothermic fuel reforming 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).

  When such a fuel cell system is used, a reforming reaction and an exothermic reaction are alternately performed using a pair of reactors, and hydrogen gas is continuously supplied. However, in such a system, when the reforming / exothermic reaction of the reactor is switched, the hydrogen concentration of the hydrogen gas supplied to the fuel cell decreases or the air used for the exothermic reaction is supplied to the fuel cell. There are various problems such as being mixed in the generated hydrogen gas and sudden pressure fluctuations.

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 to 5).
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 reformer that reforms and generates hydrogen by switching between a reforming reaction and a regeneration reaction (exothermic reaction) has been proposed, the above-described problems at the time of reaction switching are not solved. At present, no technology to solve has been proposed.

  An object of this invention is to provide the fuel cell system which can supply electric power stably, and the fuel cell used for this.

  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 generation apparatus that repeatedly switches and repeats an exothermic reaction between an exothermic raw material and an exothermic gas (hereinafter also referred to as “regeneration reaction”) 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 fuel cell system according to a first aspect of the present invention includes a catalyst, and when the reforming material and the reforming gas are supplied, the reforming material and the reforming material are heated on the heated catalyst. A hydrogen-containing gas is generated by a reforming reaction of the reforming gas. When the exothermic raw material and the exothermic gas are supplied, the catalyst is heated by the exothermic reaction of the exothermic raw material and the exothermic gas, and the reforming is performed. At least a pair of reforming reactors capable of switching between a quality reaction and the exothermic reaction, a flow path of fluid supplied to the reforming reactor, and a flow path of fluid discharged from the reforming reactor Switching means for switching, a reforming reaction is performed in one of the reforming reactors and an exothermic reaction is performed in the other reforming reactor, and the reforming reaction and the exothermic reaction of the reforming reactor And so that is done alternately A hydrogen generation unit comprising: a control unit that switches the switching unit; a hydrogen buffer unit that contains a hydrogen-containing gas reformed and generated by the hydrogen generation unit; and a hydrogen-containing gas supplied from the hydrogen buffer unit to generate electric power A power generation unit.

  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)
CO + 3H ₂ ＣＨCH ₄ + H ₂ O (4)

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

  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 heat generating material, it can be appropriately selected and used from commonly used hydrocarbon fuels (for example, methane gas, gasoline, etc.), and similarly, as the heat generating gas, air or the like is used. it can.

  In addition, 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 be used. . 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 material.

  In addition, the fuel cell system of the present invention can perform a reforming reactor (hereinafter referred to as “PSR”) that can switch between a fuel reforming reaction using heat storage and an exothermic reaction that recovers the amount of heat storage that has decreased due to the reforming reaction. By providing a pair of (Pressure swing reforming type reformers)), at least one fuel reforming reaction can be performed, and at least one other fuel regeneration reaction can be performed. (Hereinafter, this hydrogen generator may be referred to as “PSR reformer”.)

  Therefore, according to the first aspect of the present invention, the control means of the hydrogen generator performs the reforming reaction in one reforming reactor and the exothermic reaction in the other reforming reactor, and The switching means is switched so that the reforming reaction and the exothermic reaction of the reforming reactor are alternately performed.

  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. In addition, when the amount of heat stored in one of the two has decreased due to the progress of the reforming reaction, an exothermic reaction is caused by switching means for switching the reforming raw material flow path and the exothermic raw material flow path to the two reforming reactors. At the same time, the other is switched from the exothermic reaction to the reforming reaction so that the fuel reforming is performed with the heat stored by the exothermic reaction. This eliminates the need for a separate heater and enables continuous hydrogen generation with high use efficiency of heat energy.

  According to the first aspect of the present invention, the hydrogen buffer unit is provided in the supply path for supplying the hydrogen-containing gas generated in the hydrogen generation unit to the power generation unit. For this reason, the hydrogen-containing gas generated in the hydrogen generation unit is temporarily stored in the hydrogen buffer unit before being supplied to the power generation unit, and the hydrogen-containing gas stored in the hydrogen buffer unit is supplied to the power generation unit. As a result, even if the amount of hydrogen gas generated in the hydrogen generator decreases due to the switching of the exothermic / reforming reaction, the hydrogen concentration in the hydrogen-containing gas supplied to the power generator in the hydrogen buffer is reduced. Variation (decrease) can be mitigated. Further, even if the air used for the exothermic reaction is mixed in the hydrogen-containing gas generated in the hydrogen generating part by switching between the exothermic / reforming reaction, the hydrogen already contained in the hydrogen buffer part By mixing with the containing gas, the concentration of the air in the hydrogen-containing gas can be reduced, and the concentration fluctuation of the hydrogen-containing gas can be mitigated. Furthermore, even when the flow rate of the hydrogen-containing gas is reduced when the heat generation / reforming reaction is switched, flow rate fluctuations and pressure fluctuations can be reduced in the hydrogen buffer.

  In addition, the “hydrogen buffer part” is not particularly limited as long as it has a function capable of temporarily storing a hydrogen-containing gas. For example, a hydrogen buffer part having a certain volume or more compared to a normal supply pipe, A hydrogen storage alloy or the like can be used.

  The fuel cell system of the first aspect of the present invention can continuously and stably supply electric power by these actions.

  The fuel cell system according to the first aspect of the present invention includes a hydrogen generation device including the hydrogen generation unit, a hydrogen tank including the hydrogen buffer unit, and a fuel cell including the power generation unit. (Hereinafter, referred to as “first configuration” in some cases). In the first configuration, the hydrogen-containing gas generated by the hydrogen generator is supplied to a hydrogen tank serving as a hydrogen buffer, and the hydrogen-containing gas in the hydrogen tank is supplied to the fuel cell, thereby achieving the above-described effects. Can do.

  In the first configuration, as the hydrogen tank, an ordinary tank-shaped tank having a hollow interior or a tank provided with a hydrogen storage alloy can be used. In particular, a hydrogen tank provided with a hydrogen storage alloy can be designed compactly, and the fuel cell system can be miniaturized.

  Furthermore, in the first configuration, the fuel cell can be provided with a hydrogen permeable metal layer and an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer.

  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 exothermic reaction. This is particularly suitable in terms of system configuration and effective use of thermal energy.

  Further, the fuel cell system of the present invention may be configured to include a hydrogen generation device including the hydrogen generation unit, and a fuel cell including the hydrogen buffer unit and the power generation unit (hereinafter referred to as `` No. 2 ”). In the second configuration, the hydrogen-containing gas generated by the hydrogen generator is directly supplied to the fuel cell. However, since the hydrogen buffer unit is provided in the fuel cell itself, the function of the hydrogen buffer unit described above is achieved. It can be demonstrated in a fuel cell.

  In the second configuration, the fuel cell is sandwiched between a hydrogen permeable metal layer, an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer, the hydrogen permeable metal layer, and the electrolyte layer. And a hydrogen storage alloy layer can be used. According to such a fuel cell, the hydrogen gas accommodated in the hydrogen storage alloy layer having the function of a hydrogen buffer is supplied to the electrolyte layer that is the power generation unit. Thereby, while being able to show the above-mentioned effect, a fuel cell system can be reduced in size.

  A fuel cell according to a second aspect of the present invention includes a hydrogen permeable metal layer, an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer, and sandwiched between the hydrogen permeable metal layer and the electrolyte layer. And a hydrogen storage alloy layer formed. In the fuel cell according to the second aspect of the present invention, the hydrogen permeable metal layer functions as a hydrogen buffer, and can suppress fluctuations in flow rate, concentration fluctuation, pressure fluctuation, and the like of the hydrogen-containing gas supplied from the outside.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can supply electric power stably, and the fuel cell used for this 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 a reforming material to be reformed by a steam reforming reaction, cathode offgas containing moisture as a reforming gas, and a hydrogen electrode side of a fuel cell as a heat generating material to be burned during a regeneration reaction. The anode off-gas exhausted from the air is used as the exothermic 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 according to the present invention includes a hydrogen generator 110 having a reactor 112 (PSR1) and a reactor 114 (PSR2), a hydrogen tank 125, and a hydrogen separation membrane fuel cell 120 (HMFC). ), And is configured to perform a power generation operation by supplying hydrogen reformed and generated by the hydrogen generator 110 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 to be able to switch between a reforming reaction and an exothermic reaction. Switching between the reforming reaction and the exothermic reaction is performed by supplying gasoline (reforming raw material) and cathode offgas (reforming gas) supply channels, anode offgas (heating raw material), and combustion air (heating gas). A plurality of valves (valves V1 to V8 and three-way valves SV1 to SV7) are connected to the flow path, the discharge flow path of the reformed and generated hydrogen-containing gas, and the flow path of the regenerated off gas discharged from the regenerated reactor. ) Can be performed by controlling. Here, the valves V <b> 1 to V <b> 8 are valves that can be switched between gas passage and cutoff by opening and closing thereof. Further, three pipes are connected to the three-way valves SV1 to SV7, and any two pipes of the three pipes communicate 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 By switching the fuel supplied to the fuel, each reforming / regeneration reaction is reversed. That is, in a reactor that has undergone a reforming reaction, a reforming reaction is switched to an exothermic reaction by supplying an exothermic raw material and a exothermic gas instead of a reforming raw material and a reforming gas, and an exothermic reaction is performed. In the reactor in which the reaction was performed, the reforming raw material and the reforming gas are supplied instead of the exothermic raw material and the exothermic gas, thereby shifting from the exothermic reaction to the reforming reaction. At this time, the supply of the reforming raw material and the reforming gas and the exothermic raw material and the exothermic gas are configured to be performed from opposite sides in consideration of the temperature gradient in the reactor.

  In the present embodiment, a hydrogen tank 125 is provided between the hydrogen generator 110 and the fuel cell 120, and the hydrogen-containing gas generated in the hydrogen generator 110 passes through the hydrogen tank 125 and the fuel cell. It is comprised so that 120 may be supplied. At this time, the hydrogen tank 125 functions as a buffer for the hydrogen-containing gas, and can suppress fluctuations in the amount of hydrogen-containing gas produced, concentration fluctuations, and pressure fluctuations when the reforming / exothermic reaction is switched in the hydrogen generator 110. .

  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 also 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 of the reactor 112 and the reactor 114 (hereinafter also referred to as “regeneration side”). The other ends of the hydrogen-containing gas discharge pipe 134A and the hydrogen-containing gas discharge pipe 134B are connected to the three-way valve SV2, respectively. Further, 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 valve. .

  The other end of the anode supply pipe 136 is connected to the hydrogen tank 125, and the hydrogen-containing gas that has passed through the anode supply pipe 136 is temporarily stored in the hydrogen tank 125. One end of an anode supply pipe 137 is connected to the outlet side of the hydrogen tank 125, and a hydrogen-containing gas is supplied to the anode via the pipe. The anode of the fuel cell 120 is connected to the other end of the anode supply pipe 137 on the inlet side, and one end of the anode exhaust pipe 138A is connected to 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 anode off-gas and the like 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. A three-way valve SV7 is connected to the other end of the combustion air supply pipe 140B, and is connected to a combustion air supply pipe 140A provided with a pump P2 through the three-way valve SV7. Further, the three-way valve SV7 is connected with a combustion air supply pipe 140C connected to the mixer 141 at the other end, and the combustion air supply pipe 140A and any one of the combustion air supply pipes 140B and 140C are communicated by driving the valve. It is configured to be able to. The three-way valve SV7 is controlled so as to connect the combustion air supply pipe 140A and the supply pipe communicating with the reactor that performs the regeneration reaction out of any of the combustion air supply pipes 140B and 140C.

  When the exothermic reaction is performed in the reactor 114, the anode off gas is supplied in the mixer 139 by driving the pump P2 provided in the combustion air supply pipe 140A and opening and closing the valve V2 provided in the combustion air supply pipe 140B. It is configured to be mixed with combustion air and supplied to the reactor 114. The anode exhaust pipe 138C is provided with a valve V3.

  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 a mixer 141, and is connected to the regeneration side of the reactor 112 at the other end. When the regeneration reaction is performed in the reactor 112, the anode off gas discharged from the fuel cell 120 via the anode exhaust pipe 138 </ b> B is mixed with the combustion air in the mixer 141 and then supplied to the reactor 112. At this time, the three-way valve SV7 is controlled so that the combustion air supply pipes 140A and 140C communicate with each other. The combustion air supply pipe 140C is provided with a valve V8.

  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, a cooling pipe 150 for inserting cooling air sucked from the atmosphere is provided so that the inside of the cell can be cooled by heat exchange. .

  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 a direction opposite to the discharge direction of the hydrogen-containing gas. The exothermic raw material is preheated in the catalyst non-supporting portion and then supplied to the catalyst 162. 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 and a gas supply pipe 146C 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. 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 catalyst 162 built in the cylindrical body 160 is supplied by supplying anode off-gas (and gasoline or hydrogen-containing gas if necessary). An anode off gas can be supplied to perform an oxidation reaction.

  Next, the hydrogen tank 125 will be described with reference to FIG. FIG. 3 is a schematic view for explaining the hydrogen tank in the first embodiment. As shown in FIG. 3, the hydrogen tank 125 in the present embodiment is a tank in which a space of a certain capacity is secured. In this space, the hydrogen-containing elementary gas is accommodated and serves as a hydrogen buffer. The hydrogen tank 125 is a cylindrical body having a circular cross section with a diameter of 20 cm made of SUS316, and is a hollow body in which 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.

Next, the fuel cell 120 will be described with reference to FIG. FIG. 4 is a cross-sectional view for explaining the fuel cell in the present embodiment. As shown in FIG. 4, the hydrogen separation membrane fuel cell (HMFC) 120 includes a battery membrane 174 having a dense hydrogen permeable membrane using a hydrogen permeable metal, and an oxygen electrode (O ₂ 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 has become so.

  Between the oxygen electrode 176 and the battery film 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 battery film 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 composed of platinum and other metals) or an electrolyte solution (for example, Nafion Solution manufactured by Aldrich Chemical). Can be formed.

The battery film 174 has a four-layer structure including a dense substrate (dense hydrogen permeable film 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. 4, a sandwich structure film composed of three layers of Pd layer 186 / base material 184 / Pd layer 188, that is, a laminated structure of two or more layers composed of different metals (dense film composed of a 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 battery membrane 174 includes 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, so that the electrolyte membrane can be made thin. 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. Electricity is supplied to the outside by causing an electrochemical reaction (battery reaction) represented by the formulas (1) to (3). Equations (1) and (2) represent reactions on the anode side and 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)

  The switching of each valve will be described with reference to FIG. FIG. 5 is a configuration diagram for explaining the valve control. As shown in FIG. 5, the valves V <b> 1 to V <b> 8, the three-way valves SV <b> 1 to SV <b> 7, and the pumps P <b> 1 to P <b> 3 are connected to a control unit (CPU) 170, and their opening / closing and switching are controlled by the control unit 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 (exothermic reaction). Further, the control unit 170 can control the supply amount of gasoline (reforming raw material), cathode gas, and combustion air (heating gas) by controlling the pumps P1 to P3.

  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 that is used when a reforming reaction is performed in the reactor 112 and a regeneration reaction (exothermic reaction) is performed in the reactor 114, and is shown in white. The drainage pipe indicates a pipe that is not used in such a case. In addition, among the valves V1 to V8 shown in FIG. 1, a valve shown in white means that the valve is open, and a 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 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 hydrogen tank 125 through the hydrogen-containing gas discharge pipe 134A and the anode supply pipe 136.

  The hydrogen-containing gas supplied into the hydrogen tank 125 is temporarily stored in the hydrogen tank 125, and then supplied to the anode of the fuel cell 120 through the anode supply pipe 137 and 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 SV7 is controlled so that the combustion air supply pipes 140A and 140B communicate with each other. 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 addition, 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 142A is controlled to be opened, and the valve V5 provided in the fuel supply pipe 130C is controlled to be closed.

  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.

  When the reforming reaction is performed in the reactor 112, the hydrogen-containing gas generated in the hydrogen generator 110 as described above is supplied to the fuel cell 120 via the hydrogen tank 125.

  Next, conversion control of reforming / exothermic reaction in the reactor 112 and the reactor 114 will be described with reference to FIG. 6 is a flowchart showing the reforming / exothermic reaction conversion control in the first embodiment, FIG. 6A is a flowchart showing the reforming control of PSR1, and FIG. 6B is a flowchart showing the reforming control of PSR2. It is. In FIG. 6A (PSR1 reforming control), the control means 170 first supplies gasoline and cathode off-gas to the reactor 112 to perform the reforming reaction in the reactor 112 (PSR1), and the reactor 114 (PSR2). ), An anode off gas and combustion air are supplied to the reactor 114 (step S101). The control means 170 monitors the temperature in the reactor 112 in which the reforming reaction is performed while supplying the raw material gas to each reactor by the temperature sensor 116, and detects the temperature T1 in the reactor 112 (step). S102).

  Next, the control means 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 control means 170 determines that the temperature T1 is equal to or higher than the threshold value T0 (No at Step S103), the control unit 170 continues to return to Step S101 and continues to supply the raw material gas to each reactor as it is.

  On the other hand, when the control means 170 determines that the temperature T1 is less than the threshold (Yes at Step S103), the supply of the raw material gas to each reactor is stopped (Step S104). After stopping the supply of the raw material gas, the control means 170 switches each valve in order to switch the reforming / exothermic reaction of each reactor (step S105).

  Next, the control means 170 supplies anode off gas and combustion gas to the reactor 112 to switch the reaction in the reactor 112 to exothermic reaction, and supplies gasoline and cathode off gas to the reactor 114 to supply the reactor 114. The internal reaction is switched to the reforming reaction, the hydrogen-containing gas generated in the reactor 114 is supplied to the fuel cell 120 (step S106), and the process proceeds to PSR2 reforming control.

  Similarly, in the PSR2 reforming control as shown in FIG. 6B, first, the control means 170 supplies gasoline and cathode off-gas to the reactor 114 in order to perform the reforming reaction in the reactor 114 (PSR2), In order to perform a regeneration reaction in the reactor 112 (PSR1), anode offgas and combustion air are supplied to the reactor 112 (step S111). The control means 170 monitors the temperature in the reactor 114 in which the reforming reaction is performed while supplying the raw material gas to each reactor by the temperature sensor 118, and detects the temperature T2 in the reactor 114 (step). S112).

  Next, the control means 170 compares the temperature T2 detected by the temperature sensor 118 with a threshold T0 (for example, about 600 ° C.), and determines whether or not the temperature T2 is lower than the threshold T0 (step S113). When the control means 170 determines that the temperature T2 is equal to or higher than the threshold T0 (No at Step S113), the control unit 170 continues to return to Step S111 and continues to supply the raw material gas to each reactor as it is.

  On the other hand, when the control means 170 determines that the temperature T2 is lower than the threshold (Yes at Step S113), the supply of the raw material gas to each reactor is stopped (Step S114). After stopping the supply of the raw material gas, the control means 170 switches each valve in order to switch the reforming / exothermic reaction of each reactor (step S115).

  Next, the control means 170 supplies anode off gas and combustion gas to the reactor 114 to switch the reaction in the reactor 114 to exothermic reaction, and supplies gasoline and cathode off gas to the reactor 112, The internal reaction is switched to the reforming reaction, and the hydrogen-containing gas generated in the reactor 112 is supplied to the fuel cell 120 (step S116), and the process shifts to PSR1 reforming control.

  As described above, in the present embodiment, the reforming / exothermic reaction is repeatedly switched in each reactor.

  Next, taking the fluctuation of the hydrogen flow rate as an example, the buffer action of the hydrogen tank 125 in the present embodiment will be described with reference to FIG. FIG. 7 is an explanatory diagram conceptually showing the fuel cell system of the first embodiment. As shown in graph A in FIG. 7, when the reforming / exothermic reaction is switched in each reactor, the flow rate of hydrogen supplied to the hydrogen tank 125 temporarily decreases (point X in FIG. 7). However, since a certain amount of hydrogen-containing gas is accommodated in the hydrogen tank 125, even if the flow rate of the hydrogen-containing gas supplied to the hydrogen tank 125 is temporarily reduced, the flow rate fluctuation is As shown in graph B in FIG. 7, fluctuations in the flow rate of the hydrogen-containing gas supplied to the fuel cell 120 can be reduced.

  As described above, according to the present embodiment, the flow rate variation, concentration variation, pressure variation and the like of the hydrogen-containing gas at the time of the reforming / exothermic reaction switching in each reactor are reduced by the buffer function of the hydrogen tank 125. Thereby, the fuel cell system which can supply electric power stably can be comprised.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the fuel cell system having the same configuration as that of the first embodiment, the second embodiment is configured using an MH tank 127 including a hydrogen storage alloy instead of the hydrogen tank 125.

  The fuel cell system 102 using the MH tank 127 in the second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the thing similar to the member in 1st Embodiment, and the description is abbreviate | omitted. FIG. 8 is a schematic diagram showing the configuration of the fuel cell system according to the second embodiment.

  As shown in FIG. 8, one end of an anode supply pipe 136 and one end of an anode supply pipe 137 are connected to the MH tank 127 to temporarily store a hydrogen-containing gas generated by the hydrogen generator 110. It is configured to be able to. Specifically, the hydrogen-containing gas discharged from the reactor 112 is first supplied to the MH tank 127 via the hydrogen-containing gas discharge pipe 134A and the anode supply pipe 136. Thereafter, the hydrogen-containing gas supplied into the MH tank 127 is temporarily stored in the MH tank 127, and then supplied to the anode of the fuel cell 120 via the anode supply pipe 137 and used for power generation of the fuel cell 120. Is done.

  Next, the MH tank 127 in the second embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram for explaining the MH tank in the second embodiment. As shown in FIG. 9, a hydrogen storage part 129 made of a hydrogen storage alloy is provided inside the MH tank 127, and by storing the hydrogen gas in the hydrogen-containing gas in the hydrogen storage part 129, the hydrogen buffer As a role. The hydrogen storage unit 129 is made of a hydrogen storage alloy capable of reversibly releasing hydrogen gas, and the hydrogen in the hydrogen-containing gas is a metal in the metal lattice in an atomic state or an ionic state in the hydrogen storage alloy. Occluded by binding or ionic bonding. Hydrogen gas in the hydrogen-containing gas is accommodated in the hydrogen storage unit 129 by pressurization by supplying the hydrogen-containing gas from the hydrogen generator 110, and from the hydrogen storage unit 129 by depressurization by supplying the hydrogen-containing gas to the fuel cell 120. Released. Note that hydrogen gas can be stored and released by heat.

  As the hydrogen storage alloy constituting the hydrogen storage portion 129, for example, a known material such as Mg—Ni system or V—Ti system can be appropriately selected.

  According to the present embodiment, flow rate fluctuation, concentration fluctuation, pressure fluctuation and the like of the hydrogen-containing gas at the time of reforming / exothermic reaction switching in each reactor are reduced by the buffer function of the MH tank 127. Thereby, the fuel cell system which can supply electric power stably can be comprised.

  Further, the hydrogen storage alloy constituting the hydrogen storage unit 129 can store hydrogen gas of about 1000 times its own volume at room temperature and 1 atm. For this reason, MH tank 127 itself can be designed compactly, and size reduction of fuel cell system 102 can be achieved.

  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 in 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 a five-layered battery film 202 including a dense base material 212 formed of vanadium (V), an oxygen electrode (O ₂ electrode) 204 and a hydrogen electrode (H ₂ electrode) sandwiching the battery film 202. ) 206, and shows a hydrogen separation membrane fuel cell 200 having a metal diffusion suppression layer and a reaction suppression layer. The battery film 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 battery 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 a battery film 302 having a dense hydrogen permeable film using a hydrogen permeable metal, and an oxygen electrode (O ₂ electrode) 304 and a hydrogen electrode (H ₂ electrode) 306 that sandwich the battery film 302. The solid polymer type hydrogen separation membrane fuel cell 300 is shown. The battery membrane 302 has, for example, a multilayer structure in which the surfaces on both sides of the electrolyte layer 312 made of a solid polymer membrane such as a Nafion (registered trademark) membrane are sandwiched between dense hydrogen permeable metal membranes. A palladium (Pd) layer (dense film) 314 is provided on the surface on the hydrogen electrode (anode) 306 side of 312, and vanadium serving as a base material in order from the surface side on the oxygen electrode (cathode) 304 side surface of the electrolyte layer 312 -A nickel alloy (V-Ni) layer (dense film) 310 and a Pd layer (dense film) 308 are provided. Note that an air flow path 180 and a fuel flow path 182 are formed between the oxygen electrode 304 or the hydrogen electrode 306 and the battery 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 layer 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.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The third embodiment is configured by using a fuel cell 400 having a hydrogen buffer function instead of the fuel cell 120 without using the hydrogen tank 125 in the fuel cell system having the same configuration as that of the first embodiment. Is done.

  The fuel cell system 103 using the fuel cell 400 with a buffer function in the third embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the thing similar to the member in 1st Embodiment, and the description is abbreviate | omitted. FIG. 12 is a schematic diagram showing the configuration of the fuel cell system according to the third embodiment.

  As shown in FIG. 12, in the fuel cell system 103, the anode supply pipe 136 is directly connected to the anode of the fuel cell 400, and the hydrogen-containing gas generated by the hydrogen generator 110 passes through the anode supply pipe 136. 400.

A fuel cell 400 having a hydrogen buffer function will be described with reference to FIG. FIG. 13 is a cross-sectional view for explaining a fuel cell according to the third embodiment. As shown in FIG. 13, a hydrogen separation membrane type fuel cell (HMFC) 400 having a hydrogen buffer function includes a battery membrane 402 having a dense hydrogen permeable membrane using a hydrogen permeable metal, and a battery membrane 402. The oxygen electrode (O ₂ electrode) 404 and the hydrogen electrode (H ₂ electrode) 406 are configured to selectively transmit hydrogen gas when the hydrogen-containing gas reformed and generated by the hydrogen generator 110 is supplied. The power generation operation can be performed. For the oxygen electrode 404 and the hydrogen electrode 406, LaSrCoO ₃ or the like can be used.

  Between the oxygen electrode 404 and the battery film 402, an air flow path 180 for passing, that is, supplying and discharging air (Air) as an oxidant gas is formed. Is formed with a fuel flow path 182 for passing, that is, supplying and discharging the hydrogen-containing gas.

The battery film 402 has a five-layer structure including a dense base material (a dense hydrogen permeable film made of a hydrogen permeable metal) 408 formed of vanadium (V). The palladium (Pd) layers (dense hydrogen permeable membranes made of a hydrogen permeable material) 410 and 412 are disposed so as to sandwich the base material 408 from both sides, and are opposite to the side of the one Pd layer 410 in contact with the base material 408. A hydrogen storage alloy layer 414 is provided on the side surface. The hydrogen storage alloy layer 414 serves as a buffer for hydrogen gas that has passed through the hydrogen permeable membrane. Examples of the hydrogen storage alloy used for the hydrogen storage alloy layer 414 include the same ones as described above. Further, an electrolyte layer 416 made of BaCeO ₃ (solid oxide) is provided in a thin film on the surface opposite to the side in contact with the Pd layer 410 of the hydrogen storage alloy layer 414.

  In addition, as members other than the hydrogen storage alloy layer 414 constituting the fuel cell 400, the same members as those described in the first embodiment can be used.

In the fuel cell 400, 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 same electrochemical as described above. Electricity can be supplied to the outside by causing a reaction (battery reaction). Hydrogen gas supplied from the fuel flow path 182 and having passed through the palladium (Pd) layer 412, the base material 408 and the palladium (Pd) layer 412 is temporarily stored in the hydrogen storage alloy layer 414 in the hydrogen storage alloy layer 414. After that, it is discharged to the electrolyte layer 416. For this reason, even when a flow rate variation, a concentration variation, a pressure variation, or the like occurs in the hydrogen-containing gas supplied to the fuel cell 400 when the reforming / exothermic reaction of each reactor is switched, the hydrogen storage alloy layer Since 414 functions as a hydrogen buffer, each fluctuation of the hydrogen gas supplied to the electrolyte layer 416 can be reduced.

  As described above, also according to the present embodiment, the hydrogen storage metal incorporated in the fuel cell 400 causes the flow rate variation, concentration variation, pressure variation and the like of the hydrogen-containing gas when the reforming / exothermic reaction is switched in each reactor. Reduced by the buffer function of layer 414. Thereby, the fuel cell system which can supply electric power stably can be comprised.

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 the schematic for demonstrating the hydrogen tank in 1st Embodiment. It is sectional drawing for demonstrating the fuel cell in 1st Embodiment. It is a block diagram for demonstrating valve control. FIG. 6A is a flowchart showing reforming / exothermic reaction conversion control in the first embodiment, FIG. 6A is a flowchart showing reforming control of PSR1, and FIG. 6B is a flowchart showing reforming control of PSR2. It is explanatory drawing which shows notionally the fuel cell system of 1st Embodiment. It is the schematic which shows the structure of the fuel cell system of 2nd Embodiment. It is the schematic for demonstrating the MH tank in 2nd Embodiment. 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. It is the schematic which shows the structure of the fuel cell system of 3rd Embodiment. It is sectional drawing for demonstrating the fuel cell in 3rd Embodiment.

Explanation of symbols

100, 102, 103 Fuel cell system 110 Hydrogen generator 112, 114 Reactor 120, 200, 300, 400 Fuel cell 125 Hydrogen tank 127 MH tank 129 Hydrogen storage unit 170 Control units 184, 212, 408 Base materials 186, 188, 216, 314, 308, 410, 412 Palladium (Pd) layer 190, 208, 302, 416 Electrolyte layer 310 Vanadium-nickel alloy (V-Ni) layer 414 Hydrogen storage alloy layer P1-P4 Pump V1-V8 Valves SV1-SV7 3-way valve

Claims (7)

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 is used for heat generation. At least a pair of reforming reactors capable of switching the reforming reaction and the exothermic reaction by heating the catalyst by an exothermic reaction of the exothermic raw material and the exothermic gas when the raw material and the exothermic gas are supplied; A switching means for switching the flow path of the fluid supplied to the reforming reactor and the flow path of the fluid discharged from the reforming reactor, and the reforming reaction is performed in one of the reforming reactors. And a control means for switching the switching means so that the exothermic reaction is performed in the other reforming reactor and the reforming reaction and the exothermic reaction of the reforming reactor are alternately performed. A hydrogen generator,
A hydrogen buffer unit containing the hydrogen-containing gas reformed and generated by the hydrogen generation unit;
A power generation unit that generates power using the hydrogen-containing gas supplied from the hydrogen buffer unit;
A fuel cell system comprising:   2. The fuel cell system according to claim 1, comprising: a hydrogen generation device including the hydrogen generation unit; a hydrogen tank including the hydrogen buffer unit; and a fuel cell including the power generation unit.   The fuel cell system according to claim 2, wherein the hydrogen tank includes a hydrogen storage alloy.   The fuel cell system according to claim 2 or 3, 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.   The fuel cell system according to claim 1, further comprising: a hydrogen generation device including the hydrogen generation unit; and a fuel cell including the hydrogen buffer unit and the power generation unit.   The fuel cell includes a hydrogen permeable metal layer, an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer, a hydrogen storage alloy layer sandwiched between the hydrogen permeable metal layer and the electrolyte layer, The fuel cell system according to claim 5, comprising:   A hydrogen permeable metal layer, an electrolyte layer disposed on at least one side of the hydrogen permeable metal layer, and a hydrogen storage alloy layer sandwiched between the hydrogen permeable metal layer and the electrolyte layer. Fuel cell.

Images