JP5487563B2 - Electronics - Google Patents

Description

The present invention relates to electronic devices.

  In recent years, fuel cells using hydrogen as fuel as a clean power source with high energy conversion efficiency have begun to be applied to automobiles and portable devices. A fuel cell is a device that converts chemical energy into electrical energy by electrochemically reacting fuel and oxygen in the atmosphere.

  An example of the fuel used in the fuel cell is hydrogen. However, hydrogen is a gas at room temperature and has problems in handling and storage. On the other hand, fuels that are liquid at room temperature, such as alcohols, are easy to handle and store, and are attracting attention as raw materials for hydrogen.

In the case of producing hydrogen from liquid fuel, a reformer, a carbon monoxide remover, etc. are required. The reformer takes out hydrogen necessary for power generation, for example, by reacting vaporized liquid fuel with water vapor. The carbon monoxide remover removes carbon monoxide which is a by-product of the reforming reaction.
A catalyst is used for the reaction in the reformer or the carbon monoxide remover. A catalyst is fixed as a catalyst layer on the inner wall of the reformer or carbon monoxide remover.

  Some catalysts used in reformers and carbon monoxide removers, such as Pd / ZnO catalysts, may oxidize themselves and degrade catalyst performance when exposed to an oxidizing atmosphere for a long time. . For this reason, it is necessary to stop the operation of the fuel cell device without placing the catalyst in an oxidizing atmosphere.

  In addition, after the operation of the fuel cell device is stopped, if a substance that becomes liquid fuel, water, or an oxidizer remains in the reformer or the carbon monoxide remover, the reforming is performed to start the operation of the fuel cell device. When the temperature of the reactor or carbon monoxide remover rises, the liquid fuel and water inside quickly evaporate and the internal pressure increases at once, or the catalyst is oxidized and deteriorated, or the reformer and carbon monoxide remover There are concerns about the adverse effects of

For example, in Patent Document 1, when the fuel cell device is stopped, exhaust gas obtained by burning the remaining fuel in the flow path with a combustor is used as the purge gas.
JP 2003-317772 A

However, in Patent Document 1, air is supplied to the combustor for combustion in the combustor at the time of stoppage. However, there is a problem if the exhaust gas contains hydrogen in the exhaust gas. In order to exhaust the exhaust gas, the amount of oxygen more than that for burning hydrogen is contained. As a result, the reformer or the like is purged with exhaust gas containing excess oxygen, which may oxidize the catalyst. was there.
The subject of this invention is providing the fuel cell apparatus and electronic device which prevent deterioration of catalysts, such as a reformer, and destruction of a catalyst layer.

In order to solve the above-described problems, the invention described in claim 1 is an electronic device that generates power using a reformer that reforms raw fuel and the fuel reformed by the reformer. Carbon dioxide containing a fuel cell, a heater, and a carbon dioxide absorbent that absorbs carbon dioxide in the off-gas discharged from the fuel cell and releases the absorbed carbon dioxide when heated by the heater An absorber, and a first catalytic combustor that is provided in a flow path connecting the fuel cell and the carbon dioxide absorber, and burns the remaining fuel in the reformer discharged from the fuel cell ; A carbon dioxide supply channel connecting the carbon dioxide absorber and the reformer, and a second channel branched from a channel between the reformer and the fuel cell. A catalytic combustor, and the fuel cell device An electronic device main body driven by electric power supplied from the battery device, and in the initial stage of the stop operation of the fuel cell device, the gas in the reformer is burned in the first catalytic combustor, In the middle stage of the stop operation of the fuel cell device, the carbon dioxide absorber is heated, and the carbon dioxide adsorbed on the carbon dioxide absorber is converted into the carbon dioxide supply channel, the reformer, and the second It is characterized by discharging to the outside through a catalytic combustor .

  According to the present invention, unreacted fuel gas in the reformer or carbon monoxide remover can be purged to prevent catalyst deterioration and catalyst layer destruction.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

[First Embodiment]
FIG. 1 is a block diagram showing an electronic device 100 according to the first embodiment of the present invention. The electronic device 100 is a portable electronic device such as a notebook personal computer, a PDA, an electronic notebook, a digital camera, a mobile phone, a wristwatch, or a game device.

  The electronic device 100 is roughly configured by a fuel cell device 130, an electronic device main body 101 driven by electric power supplied from the fuel cell device 130, and the like. The fuel cell device 130 generates electric power and supplies it to the electronic device main body 101 as will be described later.

  Next, the fuel cell device 130 will be described. The fuel cell device 130 generates electric power to be output to the electronic device main body 101, and the fuel cartridge 102, the liquid feed pump 103, the reaction device 110, the fuel cell 140, the DC / DC converter 131, and the secondary battery 132. And a control unit 133.

The fuel cartridge 102 stores liquid raw fuel (for example, methanol, ethanol, dimethyl ether) and water separately.
The raw fuel and water in the fuel cartridge 102 are respectively sucked by the liquid feed pump 103, mixed, and sent to the vaporizer 104 of the reactor 110.

The reactor 110 includes a vaporizer 104, a reformer 105, a carbon monoxide remover 106, a carbon dioxide absorber 107, a catalytic combustor (first catalytic combustor) 109, and the like. Contained.
The vaporizer 104 is heated to about 110 to 160 ° C. by heat transfer from the reformer 105 and the like, and vaporizes the liquid mixture sent from the fuel cartridge 102. The air-fuel mixture vaporized by the vaporizer 104 is sent to the reformer 105.

  The reformer 105 has a flow path formed therein, and a reforming catalyst is supported on the wall surface of the flow path. As the reforming catalyst, a Cu / ZnO-based catalyst, a Pd / ZnO-based catalyst, or the like is used. The reformer 105 heats the air-fuel mixture sent from the vaporizer 104 to about 300 to 400 ° C. by heat transfer from a heater / temperature sensor 105a included in the catalytic combustor 109 and the reformer 105, which will be described later, The reforming reaction is caused by the catalyst. That is, a mixed gas (reformed gas) such as hydrogen, carbon dioxide as a fuel, and a minute amount of carbon monoxide as a by-product is generated by a catalytic reaction between raw fuel and water.

Here, when the raw fuel is methanol, the reformer 105 mainly undergoes a steam reforming reaction, which is a main reaction as shown in the following chemical reaction formula (1).
CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (1)
In addition, a small amount (about 1%) of carbon monoxide is generated as a by-product by a side reaction such as the following chemical reaction formula (2) that occurs sequentially after the chemical reaction formula (1).
H ₂ + CO ₂ → H ₂ O + CO (2)
The product (reformed gas) resulting from the reactions of the chemical reaction formulas (1) and (2) is sent to the carbon monoxide remover 106.

A flow path is formed inside the carbon monoxide remover 106, and a selective oxidation catalyst for selectively oxidizing carbon monoxide is supported on the wall surface of the flow path. As the selective oxidation catalyst, for example, Pt / Al ₂ O ₃ or the like can be used.

The reformed gas generated by the reformer 105 and the external air are sent to the carbon monoxide remover 106. The reformed gas is mixed with air and flows through the flow path of the carbon monoxide remover 106, and is heated to about 110 to 160 ° C. by heat transfer from the reformer 105 and the catalytic combustor 109. Carbon monoxide in the reformed gas is preferentially oxidized by the main reaction as shown in the following chemical reaction formula (3) by the catalyst. As a result, carbon dioxide is generated as the main product, and the concentration of carbon monoxide in the reformed gas can be reduced to about 10 ppm at which the fuel cell 140 can be supplied.
2CO + O ₂ → 2CO ₂ (3)
Since the reaction of the chemical reaction formula (19) is an exothermic reaction, it is disposed adjacent to the vaporizer 104 where the endothermic reaction (vaporization of the mixed solution) is performed.
The reformed gas that has passed through the carbon monoxide remover 106 is sent to the fuel cell 140.

  The reformed gas (off-gas) and air that have passed through the fuel supply channel 144a of the fuel cell 140 are sent to the catalytic combustor 109, and the hydrogen remaining in the reformed gas is combusted by oxygen in the air. A heat exchanger (not shown) is disposed adjacent to the carbon monoxide remover 106, and in the process of passing off-gas and air supplied from the fuel cell 140 to the catalytic combustor 109, the heat of the carbon monoxide remover 106 is passed. Heat off-gas and air.

  The carbon dioxide absorber 107 includes a carbon dioxide absorbent. As a carbon dioxide absorbent, for example, carbon dioxide is absorbed at a temperature lower than a certain temperature x ° C., and carbon dioxide is released at a temperature higher than a certain temperature y (> x) ° C. As the carbon dioxide absorbent, for example, a carbon dioxide adsorbent such as monoethanolamine, calcium oxide, and magnesium oxide can be used.

  Alternatively, a carbon dioxide adsorbent in which the lumen of a porous zeolite having pores with nanometer sizes is modified with an amino group may be used. As such a carbon dioxide adsorbent, for example, molecular sieve 4A (manufactured by Sakai Kogyo Co., Ltd.) can be used.

During normal operation, the carbon dioxide absorber 107 absorbs carbon dioxide in the exhaust gas of the catalytic combustor 109 because it is less than x ° C.
The carbon dioxide absorber 107 is provided with a heater / temperature sensor 107a. As will be described later, the heater and temperature sensor 107a heats the carbon dioxide absorbent to a temperature higher than y ° C. after the reforming of the reformer 105 for power generation, that is, during the stop operation of the fuel cell device 130. Carbon dioxide absorbed by the carbon absorbent is released. The released carbon dioxide is used for purging in the reactor 110. The purged carbon dioxide having a concentration of almost 100% pushes out the gas containing the oxide containing water and oxygen in the reactor 110 to the outside of the reactor 110.

Here, the required amount when using the molecular sieve 4A as the carbon dioxide adsorbent is calculated.
The partial pressure of carbon dioxide in the exhaust gas discharged from the catalytic combustor 109 is about 38 kPa. When the carbon dioxide partial pressure is about 38 kPa at a temperature of 25 ° C., the amount of carbon dioxide absorbed by the molecular sieve 4A is about 18 g per 100 g.
When the volume of the reactor 110 is 12 ml, carbon dioxide required for purging in the reactor 110 is about 24 mg. Therefore, the amount of molecular sieve 4A required is about 133 mg.
The adsorbed gas is released by heating the molecular sieve 4A to 200 to 250 ° C. by the heater / temperature sensor 107a.

  The fuel cell 140 converts chemical energy into electrical energy by an electrochemical reaction between the reformed gas and oxygen. Hereinafter, the case where the fuel cell 140 is a polymer electrolyte fuel cell will be described.

  The fuel cell 140 supplies the reformed gas to the solid polymer electrolyte membrane 141, the fuel electrode 142 (anode) and the oxygen electrode 143 (cathode) formed on both surfaces of the solid polymer electrolyte membrane 141, and the fuel electrode 142. A fuel electrode separator 144 provided with a fuel supply flow path 144a to be supplied and an oxygen electrode separator 145 provided with an oxygen supply flow path 145a for supplying oxygen to the oxygen electrode 143 are stacked.

The solid polymer electrolyte membrane 141 transmits hydrogen ions, but has a property of not passing oxygen molecules, hydrogen molecules, carbon dioxide, and electrons.
The reformed gas is sent to the fuel electrode 142 via the fuel supply channel 144a. At the fuel electrode 142, the reaction shown in the following electrochemical reaction formula (4) by hydrogen in the reformed gas occurs.
H ₂ → 2H ⁺ + 2e ⁻ (4)
The generated hydrogen ions permeate the solid polymer electrolyte membrane 141 and reach the oxygen electrode 143. The generated electrons are supplied to the anode output electrode 146.

Air is sent to the oxygen electrode 143 through the oxygen supply channel 145a. In the oxygen electrode 143, water is generated by hydrogen ions that have passed through the solid polymer electrolyte membrane 141, oxygen in the air, and electrons supplied from the cathode output electrode 147 as shown in the following electrochemical reaction formula (5). Is done.
2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O (5)
Note that a catalyst (not shown) that promotes the reactions of the electrochemical reaction formulas (4) and (5) is provided on both surfaces of the solid polymer electrolyte membrane 141.

  The anode output electrode 146 and the cathode output electrode 147 are connected to a DC / DC converter 131 that is an external circuit, and electrons that have reached the anode output electrode 146 are supplied to the cathode output electrode 147 through the DC / DC converter 131. .

  The DC / DC converter 131 converts the power generated by the fuel battery cell 140 into an appropriate voltage, and then supplies the power to the electronic device main body 101 and charges the secondary battery 132 with the power. The control unit 133 controls the entire fuel cell device 130.

  A three-way valve 161 is provided in a flow path 151 that connects the vaporizer 104 and the reformer 105. A carbon dioxide supply channel 157 is connected to the three-way valve 161. The three-way valve 161 includes a connection between the flow channel 151 a on the vaporizer 104 side and the flow channel 151 b on the reformer 105 side of the flow channel 151, and a connection between the flow channel 151 b and the carbon dioxide supply flow channel 157. Do one selectively.

  A three-way valve 162 is provided in the flow path 152 that connects the reformer 105 and the carbon monoxide remover 106. The three-way valve 162 is connected to an air supply flow path 152 b that supplies air (oxygen) to the carbon monoxide remover 106. The three-way valve 162 switches on / off the connection between the flow path 152 and the air supply flow path 152b.

  A three-way valve 163 is provided in the flow path 153 connecting the carbon monoxide remover 106 and the fuel battery cell 140. A bypass channel 158 is connected to the three-way valve 163. The three-way valve 163 includes a connection between the flow path 153a on the carbon monoxide remover 106 side and the flow path 153b on the fuel cell 140 side of the flow path 153, and a connection between the flow path 153a and the bypass flow path 158. Do one selectively.

  A four-way valve 164 is provided in the flow path 154 connecting the fuel battery cell 140 and the catalytic combustor 109. A bypass flow path 158 is connected to the four-way valve 164, and an air supply flow path 154c is connected. The four-way valve 164 includes, among the channels 154, a channel 154a on the fuel cell 140 side, a channel 154b on the catalyst combustor 109 side and an air supply channel 154c, a channel 154b, an air supply channel 154c and a bypass. The channel 158 is selectively connected.

  A three-way valve 165 is provided in the flow path 155 that connects the catalytic combustor 109 and the carbon dioxide absorber 107. An exhaust passage 155 c is connected to the three-way valve 165. The three-way valve 165 selectively connects the flow path 155 to the flow path 155a on the catalyst combustor 109 side and the flow path 155b on the carbon dioxide absorber 107 side, and connects the flow path 155a and the exhaust flow path 155c. .

A three-way valve 166 is provided in the exhaust passage 156 that exhausts the exhaust gas that has passed through the carbon dioxide absorber 107. A carbon dioxide supply channel 157 is connected to the three-way valve 166. The three-way valve 166 selectively connects the flow path 156a on the carbon dioxide absorber 107 side to the other flow path 156b and the connection between the flow path 156a and the carbon dioxide supply flow path 157 in the exhaust flow path 156.
Connections in the three-way valves 161, 162, 163, 165, 166 and the four-way valve 164 are controlled by the control unit 133.

  Here, the operation of the three-way valves 161, 162, 163, 165, 166 and the four-way valve 164 will be described.

  During normal operation of the fuel cell device 130, as shown in FIG. 1, the three-way valve 161 connects the flow channel 151a and the flow channel 151b. The three-way valve 162 connects the flow path 152 and the air supply flow path 152b. The three-way valve 163 connects the flow path 153a and the flow path 153b. The four-way valve 164 connects the flow path 154a, the flow path 154b, and the air supply flow path 154c. The three-way valve 165 connects the flow path 155a and the flow path 155b on the carbon dioxide absorber 107 side. A three-way valve 166 connects the flow paths 156a and 156b. At this time, the fuel flows from the vaporizer 104 to the reformer 105, the reformed gas generated in the reformer 105 flows to the fuel cell 140 through the carbon monoxide remover 106, and off-gas flows from the fuel cell 140. The exhaust gas flows to the catalytic combustor 109 and is discharged from the catalytic combustor 109 through the carbon dioxide absorber 107 and the exhaust passage 156. At this time, carbon dioxide generated by the reformer 105, the carbon monoxide remover 106, and the catalytic combustor 109 is absorbed by the carbon dioxide absorber 107 having a temperature lower than x ° C.

FIG. 2 is a block diagram showing the flow path in the reaction apparatus 110 after reforming of the reformer 105 for power generation, that is, in the initial stage of the stop operation of the fuel cell apparatus 130. Here, the initial stage is when the temperature of the reformer 105 and the carbon monoxide remover 106 is 100 ° C. or higher.
In the stop operation of the fuel cell device 130, first, as shown in FIG. 2, the connection between the reformer 105 and the carbon monoxide remover 106 is maintained, and the flow path 152 and the air supply flow path 152b are connected. The three-way valve 162 is switched so that the connection is turned off. Further, the three-way valve 163 is switched so as to connect the flow path 153a and the bypass flow path 158. Further, the four-way valve 164 is switched so as to connect the flow path 154b, the air supply flow path 154c, and the bypass flow path 158.

Then, a small amount of raw fuel is supplied to the vaporizer 104 by the liquid feed pump 103. Water is not supplied. At this time, the reformed gas and fuel gas in the reformer 105 and the carbon monoxide remover 106 do not flow to the fuel cell 140 but flow to the catalytic combustor 109 via the bypass channel 158, and the exhaust gas flows to the catalytic combustor 109. From the carbon dioxide absorber 107 and the exhaust passage 156. Thereby, the reformed gas in the reformer 105 and the carbon monoxide remover 106 is purged by the fuel gas.
In this state, it waits until the temperature of the reformer 105 and the carbon monoxide remover 106 becomes lower than 100 ° C.

FIG. 3 is a block diagram showing the flow path in the reactor 110 in the middle and late stages of the stopping operation of the fuel cell device 130. Here, the mid-late stage is a period from when the temperature of the reformer 105 and the carbon monoxide remover 106 becomes lower than 100 ° C. until it completely stops.
When the temperatures of the reformer 105 and the carbon monoxide remover 106 are lower than 100 ° C., the supply of fuel by the liquid feed pump 103 is completely stopped. Further, the three-way valve 161 is switched so as to connect the channel 151b and the carbon dioxide supply channel 157, and the three-way valve 165 is switched so as to connect the channel 155a and the exhaust channel 155c. Further, the three-way valve 166 is switched so as to connect the flow path 156a and the carbon dioxide supply flow path 157.

Then, the carbon dioxide absorbent is heated to a temperature higher than y ° C. by the heater / temperature sensor 107a, and the carbon dioxide absorbed by the carbon dioxide absorbent is released. At this time, carbon dioxide released from the carbon dioxide absorbent passes through the reformer 105, the carbon monoxide remover 106, the bypass passage 158, and the catalytic combustor 109 from the carbon dioxide supply passage 157 and from the exhaust passage 155c. Discharged. As a result, the fuel gas in the reformer 105 and the carbon monoxide remover 106 is purged with carbon dioxide, and the fuel gas is combusted by the catalytic combustor 109 and discharged from the exhaust passage 155c.
When the purge is completed, heating by the heater / temperature sensor 107a is stopped. Thereafter, in order to prevent the outside air from flowing back from the exhaust passage 155c, the connection between the passage 155a and the exhaust passage 155c is turned off, and the connection between the passage 154b and the air supply passage 154c is turned off in three directions. The valve 165 and the four-way valve 164 are switched.
Thus, the stopping operation of the fuel cell device 130 is completed.

  Thus, according to the present embodiment, water and carbon monoxide can be removed by purging the reformer 105 and the carbon monoxide remover 106 with the fuel gas of raw fuel not containing water. . Further, the unreacted fuel gas is removed by purging with carbon dioxide, and the fuel cell device 130 is stopped in a state in which the reformer 105 and the carbon monoxide remover 106 are filled with carbon dioxide. Deterioration and destruction of the catalyst layer can be prevented.

<Modification 1>
4 to 6 are block diagrams showing flow paths in the reactor 110 according to the first modification of the present embodiment. FIG. 4 is a normal operation, and FIG. 5 is an initial stage of a stop operation of the fuel cell device 130. FIG. 6 is a block diagram in the mid-late stage. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is omitted.

In this modification, a second catalytic combustor 108 is provided. Further, a four-way valve 163B is provided instead of the three-way valve 163, and a flow path 159 that continues to the second catalytic combustor 108 is connected to the four-way valve 163B. A check valve 169 is provided in the flow path 159 to prevent the fluid from flowing back from the flow path 159b on the catalytic combustor 108 side to the flow path 159a on the four-way valve 163B side.
In addition, an air supply channel 159c that supplies air to the second catalytic combustor 108 is connected to the channel 159b. The exhaust gas of the second catalytic combustor 108 is discharged to the outside from the exhaust passage 160.

  As shown in FIG. 4, in the normal operation, the flow path 153a and the flow path 153b are connected by a four-way valve 163B, and the fuel is sent from the vaporizer 104 to the reformer 105 as in the first embodiment. The reformed gas flows from the reformer 105 to the fuel cell 140 through the carbon monoxide remover 106, the off-gas flows from the fuel cell 140 to the catalytic combustor 109, and the exhaust gas flows from the catalytic combustor 109 to carbon dioxide. It is discharged through the absorber 107 and the exhaust passage 156. At this time, carbon dioxide generated by the reformer 105, the carbon monoxide remover 106, and the catalytic combustor 109 is absorbed by the carbon dioxide absorber 107 having a temperature lower than x ° C.

  In the present modification, the operation of the fuel cell device 130 in the initial stage and the middle / late stage of the stop operation are different. In this modification, at the initial stage of the stop operation of the fuel cell device 130, the four-way valve 163B is switched so as to connect the flow path 153a and the flow path 158 as shown in FIG. Further, the three-way valve 162 is switched so that the connection between the flow path 152 and the air supply flow path 152b is turned off, and the four directions are set so as to connect the flow path 154b, the air supply flow path 154c, and the bypass flow path 158. The valve 164 is switched.

Then, only a small amount of raw fuel not containing water is supplied to the vaporizer 104 by the liquid feed pump 103. At this time, the reformed gas and fuel gas in the reformer 105 and the carbon monoxide remover 106 flow into the flow path 158 and are mixed with the air supplied from the air supply flow path 154c to be mixed with the first catalytic combustor 109. And is discharged from the exhaust passage 156 to the outside. Thereby, the reformed gas in the reformer 105 and the carbon monoxide remover 106 is purged by the fuel gas.

  When the temperatures of the reformer 105 and the carbon monoxide remover 106 are lower than 100 ° C. (the middle and late stages of the stop operation of the fuel cell device 130), as shown in FIG. The three-way valve 161 is switched to connect the path 157. Further, the three-way valve 166 is switched so as to connect the flow channel 156a and the carbon dioxide supply flow channel 157, the connection between the flow channel 153a and the flow channel 158 is turned off, and the flow channel 153a and the flow channel 159a are connected. Then, the four-way valve 163B is switched.

As in the first embodiment, the carbon dioxide absorbent is heated to a temperature higher than y ° C. by the heater / temperature sensor 107a, and the carbon dioxide absorbed by the carbon dioxide absorbent is released. At this time, the carbon dioxide released from the carbon dioxide absorbent passes through the reformer 105, the carbon monoxide remover 106, the flow path 159, and the second catalytic combustor 108 from the carbon dioxide supply flow path 157, and the exhaust flow path. It is discharged from 160 to the outside. Thereby, the fuel gas in the reformer 105 and the carbon monoxide remover 106 is purged with carbon dioxide. At this time, when the unreacted fuel gas is combusted by the second catalytic combustor 108 and discharged from the exhaust passage 160, the heating by the heater / temperature sensor 107a is stopped. Thus, the stopping operation of the fuel cell device 130 is completed.

  Thus, also in this modification, water and carbon monoxide can be removed by purging the reformer 105 and the carbon monoxide remover 106 with the fuel gas of the raw fuel not containing water. Further, the unreacted fuel gas is removed by purging with carbon dioxide, and the fuel cell device 130 is stopped in a state in which the reformer 105 and the carbon monoxide remover 106 are filled with carbon dioxide. Deterioration and destruction of the catalyst layer can be prevented. Further, since the check valve 169 is provided, exhaust gas and air can be prevented from flowing back to the carbon monoxide remover 106 and the reformer 105.

[Second Embodiment]
FIG. 7 is a block diagram showing an electronic device 200 according to the second embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same sign is attached | subjected to the last 2 digits, and description is omitted.

In the present embodiment, the fuel battery cell 240 is of a solid oxide type, and is changed into an electrolyte 241, a fuel electrode 242 (anode) and an oxygen electrode 243 (cathode) formed on both surfaces of the electrolyte 241, and a fuel electrode 242. A fuel electrode separator 244 provided with a fuel supply channel 244a for supplying a gaseous gas and an oxygen electrode separator 245 provided with an oxygen supply channel 245a for supplying oxygen to the oxygen electrode 243 are stacked.
As will be described later, in the solid oxide fuel cell 240, carbon monoxide can also be used for the reaction. For this reason, those corresponding to the flow path 152, the air supply flow path 152b, the carbon monoxide remover 106, and the three-way valve 162 are omitted.

The electrolyte 241 transmits oxygen ions but does not pass oxygen molecules, hydrogen molecules, carbon monoxide, carbon dioxide, and electrons.
The reformed gas is sent to the fuel electrode 242 via the fuel supply channel 244a. At the fuel electrode 242, the reactions shown in the following electrochemical reaction formulas (6) and (7) occur due to hydrogen in the reformed gas, carbon monoxide, and oxygen ions that have passed through the electrolyte 241.
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (6)
CO + O ²⁻ → CO ₂ + 2e ⁻ (7)
The generated electrons are supplied to the anode output electrode 246. Unreacted reformed gas (off-gas) is supplied to the catalytic combustor 209.

Oxygen (air) is supplied to the oxygen electrode 243 via the oxygen supply channel 245a. In the oxygen electrode 243, the reaction shown in the following electrochemical reaction formula (8) occurs by oxygen and electrons supplied from the cathode output electrode 247.
1 / 2O ₂ + 2e ⁻ → O ²⁻ (8)
The generated oxygen ions pass through the electrolyte 241 and are supplied to the fuel electrode 242. Unreacted oxygen (air) is supplied to the catalytic combustor 209.

  The operating temperature of the solid oxide fuel cell 240 is as high as about 700-1000 ° C. Further, in the present embodiment, the fuel cell 240 is accommodated in the heat insulating container 211 together with the vaporizer 204, the reformer 205, the catalytic combustor 209, and the carbon dioxide absorber 207. For this reason, the heat of the fuel cell 240 is used for the reaction in the reformer 205 and the fuel vaporization in the vaporizer 204.

  In this embodiment, after reforming the reformer 205 for power generation, that is, during the stop operation of the fuel cell device 230, instead of using the heater / temperature sensor 207a, the heat of the fuel cell 240 is changed to carbon dioxide. Conducted by the absorber 207, the carbon dioxide absorbent may be heated above y ° C and used to release carbon dioxide. In this case, the fuel cell 240 and the carbon dioxide absorber 207 are adjacent to each other at a predetermined interval, and the thermally conductive member that is electrically operated by the output of the secondary battery 232 during the stop operation is used as the fuel cell 240 and the carbon dioxide absorber. The carbon dioxide absorber 207 may be heated in contact with 207.

Here, the case where calcium oxide is used as the carbon dioxide absorbent will be described.
The adsorption of carbon dioxide by calcium oxide is an exothermic reaction shown in the thermochemical equation (9). For this reason, carbon dioxide is released from calcium carbonate at high temperatures.
CaO (s) + CO ₂ (g) = CaCO ₃ (s) +178.32 kJ · mol ⁻¹ (9)

FIG. 8 is a graph showing the relationship between the temperature T [K] and the equilibrium pressure of carbon dioxide in the equation (9). In FIG. 8, the horizontal axis is 1 / T × 1000.
At a temperature of 900 ° C. (T = 1173K), the equilibrium pressure of carbon dioxide is 107 kPa. Therefore, carbon dioxide is released until the partial pressure of carbon dioxide in the atmosphere where the carbon dioxide absorbent is placed reaches the equilibrium pressure.

FIG. 9 is a graph showing the change over time in the decarboxylation rate when the partial pressure of carbon dioxide in the atmosphere is changed at 900 ° C. (T = 1173K). Here, P carbon dioxide partial pressure in the atmosphere, the carbon dioxide equilibrium pressure and P _e, white triangles in FIG. 9 _{(P e -P) / P e} = 0.83, open squares (P _e -P) / P _e = 0.75, a white circle is _{(P e -P) / P e} = 0.66. In any condition, the decarboxylation reaction rate curve is a sigmoid type, and the reaction is classified into three periods of an induction period, a chemical reaction rate limiting period, and a diffusion rate limiting period based on its shape.

When (P _e −P) / P _e = 0.66 (white circle), it takes 5 minutes to complete the induction period. When (P _e −P) / P _e = 0.75 (white square), the chemical reaction rate-limiting period is reached within 1 minute. When (P _e −P) / P _e = 0.83 (white triangle), the chemical reaction rate-limiting period is reached in a shorter time, and almost all carbon dioxide is released in about 3 minutes.

Here, when the equilibrium pressure of carbon dioxide is 107 kPa, P at which (P _e −P) / P _e = 0.83 is about 18.3 kPa. On the other hand, the partial pressure of carbon dioxide in the atmosphere is about 30 Pa. Therefore, when the carbon dioxide absorber 207 is filled with air, almost all of the carbon dioxide is released in a shorter time. In the initial stage of stoppage, the exhaust gas is filled with exhaust gas discharged from the catalytic combustor 209, and the partial pressure of carbon dioxide at that time may be different from the partial pressure in the atmosphere. Since the inside air is supplied, it quickly becomes the same as the concentration in the atmosphere.

  Also in this modification, water and carbon monoxide can be removed by purging the inside of the reformer 205 with the raw fuel gas that does not contain water, as in the first embodiment. Further, the unreacted fuel gas is removed by purging with carbon dioxide, and the fuel cell device 230 is stopped in a state where the reformer 205 is filled with carbon dioxide, so that the catalyst is deteriorated or the catalyst layer is destroyed. In addition to being able to prevent, the fuel gas is burned by the catalytic combustor 209 and then exhausted. Furthermore, since the carbon dioxide is released using the heat of the fuel cell 240, an electric heater / temperature sensor is not required, and power consumption can be reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 10 is a block diagram showing a fuel cell apparatus 330 according to the third embodiment of the present invention. In addition, illustration is abbreviate | omitted about a DC / DC converter, a secondary battery, a control part, and an electronic device main body. In addition, regarding the same configuration as that of the first embodiment, the same reference numerals are given to the last two digits and the description is omitted.

  In the present embodiment, three-way valves 361 and 362 are provided in a flow path 351 between the vaporizer 304 and the reformer 305. An opening / closing valve 363 is provided in the flow path 353 between the carbon monoxide remover 306 and the fuel battery cell 340, and a three-way valve is provided in the flow path 354 between the fuel battery cell 340 and the catalytic combustor 309. 364 is provided.

  A bypass channel 358 is provided between the three-way valve 361 and the three-way valve 364. An exhaust passage 351d is connected to the three-way valve 362. An air supply channel 352 b that supplies air (oxygen) to the carbon monoxide remover 306 is connected to the channel 352 between the reformer 305 and the carbon monoxide remover 306. An air supply channel 354 c that supplies air (oxygen) to the catalytic combustor 309 is connected to the channel 354 b between the three-way valve 364 and the catalytic combustor 309.

The three-way valve 361 has a connection between the flow path 351a between the vaporizer 304 and the three-way valve 361, a flow path 351b between the three-way valves 361 and 362, and a connection between the flow path 351a and the bypass flow path 358. Selectively.
The three-way valve 362 selectively connects the flow path 351c between the three-way valve 362 and the reformer 305 and the flow path 351b, and connects the flow path 351c and the exhaust flow path 351d.
The opening / closing valve 363 opens and closes the flow path 353.
The three-way valve 364 selectively connects the flow path 354a between the fuel battery cell 340 and the three-way valve 364 and the flow path 354b, and connects the bypass flow path 358 and the flow path 354b.

  Here, the operation of the three-way valves 361, 362, 364 and the opening / closing valve 363 during normal operation and stop operation will be described.

  During normal operation, as shown in FIG. 10, the three-way valve 361 connects the flow path 351a and the flow path 351b. The three-way valve 362 connects the flow path 351b and the flow path 351c. The on-off valve 363 is open. The three-way valve 364 connects the flow channel 354a and the flow channel 354b.

  At this time, the fuel flows from the vaporizer 304 to the reformer 305, the reformed gas from the reformer 305 flows to the fuel cell 340 through the carbon monoxide remover 306, and the off-gas is catalytically combusted from the fuel cell 340. The exhaust gas is discharged from the catalytic combustor 309 through the exhaust passage 356.

  FIG. 11 is a block diagram showing the fuel cell device 330 during the stop operation. In the stop operation, as shown in FIG. 11, the three-way valve 361 switches so as to connect the flow path 351a and the bypass flow path 358. The three-way valve 362 switches so as to connect the flow path 351c and the exhaust flow path 351d. The on-off valve 363 is closed. The three-way valve 364 switches so as to connect the flow path 354b and the bypass flow path 358.

At this time, the air supplied from the air supply channel 352b passes through the reformer 305 and is discharged from the exhaust channel 351d. Thereby, the reformed gas in the reformer 305 is purged with air. At this time, the carbon deposited on the surface of the catalyst of the reformer 305 is oxidized and exhausted by oxygen in the air, so that the surface of the catalyst is exposed and the catalytic reaction is easily caused.
A small amount of fuel flows from the vaporizer 304 via the bypass flow path 358 to the catalytic combustor 309, and exhaust gas is discharged from the catalytic combustor 309 via the exhaust flow path 356. The combustion heat in the catalytic combustor 309 at this time is used to maintain a temperature necessary for promoting the elimination reaction of the carbon adhering to the catalyst of the reformer 305.
When the purge is completed, the fuel and air supply is stopped. Thus, the stop operation is completed.

  As described above, according to the present embodiment, water and carbon monoxide can be removed by purging the interior of the reformer 305 with air, and catalyst deterioration and catalyst layer destruction can be prevented. .

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. 12 to 14 are block diagrams showing a fuel cell device 430 according to a fourth embodiment of the present invention. FIG. 12 is a normal operation, FIG. 13 is a stop operation, and FIG. 14 is a fuel cell device after the stop. FIG.
In addition, illustration is abbreviate | omitted about a DC / DC converter, a secondary battery, a control part, and an electronic device main body. Further, regarding the same configuration as that of the third embodiment, the same reference numerals are given to the last two digits and description thereof is omitted.

In the present embodiment, one valve 460 is used instead of the three-way valves 361, 362, 364 and the open / close valve 363 in the third embodiment.
The valve 460 includes a valve box 460a and a valve body 460b accommodated in the valve box 460a.

  The valve box 460a has a cylindrical shape, and is provided with seven ports 461, 462, 463, 464, 465, 466, and 467 at intervals along the circumference. In FIG. 12, seven ports 461, 462, 463, 464, 465, 466, 467 are arranged in this order in the clockwise direction.

Here, the positional relationship between the seven ports 461, 462, 463, 464, 465, 466, and 467 will be described.
The distance along the inner circumference of the valve box 460a between the ports 461 and 462 is AB, the distance along the inner circumference of the valve box 460a between the ports 462 and 463 is BC, the inner circumference of the valve box 460a between the ports 463 and 464 The distance along the inner circumference of the valve box 460a between the ports 464 and 465 is DE, the distance along the inner circumference of the valve box 460a between the ports 465 and 466 is the distance along the inner circumference of the valve 460a, and between the ports 466 and 467. The distance along the inner periphery of the valve box 460a is FG, and the distance between the ports 467 and 461 along the inner periphery of the valve box 460a is GA. Then, AB = BC = DE = GA (= α). When CD = β, EF = γ, and FG = δ, α <γ and α <δ. Note that α, β, γ, and δ are all different values, and 4α + β + γ + δ = πR (R is the inner diameter of the valve box 460a) is established.

Channels 471, 472, 473, 474, 475, 476, 477 are connected to the ports 461, 462, 463, 464, 465, 466, 467, respectively.
The flow path 471 is connected to the machine 404. The flow path 472 is connected to the reformer 405. The channel 473 is connected to the carbon monoxide remover 406. The channel 474 is an exhaust channel. The flow paths 475 and 476 are each connected to the fuel battery cell 440. The flow path 477 is connected to the catalytic combustor 409.

  The valve body 460b has a cylindrical shape and is accommodated in the valve box 460a so as to be rotatable in the circumferential direction. The valve body 460 is provided with six holes 481, 482, 483, 485, 486, and 487 at intervals along the circumference. A channel 491 is formed between the holes 481 and 482, a channel 492 is formed between the holes 483 and 485, and a channel 493 is formed between the holes 486 and 487.

  Here, the positional relationship between the six holes 481, 482, 483, 485, 486, and 487 will be described. The distance along the outer periphery of the valve body 460b between the holes 481, 482 is ab, the distance along the outer periphery of the valve body 460b between the holes 482, 483 is bc, and the distance along the outer periphery of the valve body 460b between the holes 483, 485 is along. The distance along the outer periphery of the valve body 460b between the holes 485 and 486 is ef, the distance along the outer periphery of the valve body 460b between the holes 486 and 487 is fg, and the distance between the holes 487 and 481 is between the holes 487 and 481. Let ga be the distance along the outer periphery. Then, ab = bc = ga = α, ce = α + β, ef = γ, and fg = δ.

  Here, the operation of the valve 460 during normal operation and stop operation will be described.

During normal operation, the positions of the port 461 and the hole 481, the port 462 and the hole 482, the port 463 and the hole 483, the port 465 and the hole 485, the port 466 and the hole 486, and the port 467 and the hole 487 are the same as shown in FIG. I'm doing it. Accordingly, the flow channel 491 connects the flow channel 471 and the flow channel 472, the flow channel 492 connects the flow channel 473 and the flow channel 475, and the flow channel 493 connects the flow channel 476 and the flow channel 477. ing.
Note that the port 464 does not match the position of any hole.

  At this time, the fuel flows from the vaporizer 404 to the reformer 405, the reformed gas flows from the reformer 405 through the carbon monoxide remover 406 to the fuel cell 440, and the off-gas flows from the fuel cell 440 to the catalytic combustor. The exhaust gas is discharged from the catalytic combustor 409 through the exhaust passage 456.

During the stop operation, as shown in FIG. 13, the valve body 460b is rotated counterclockwise by α. Then, the positions of the port 461 and the hole 482, the port 462 and the hole 483, the port 464 and the hole 484, the port 463 and the hole 483, the port 465 and the hole 485, and the port 467 and the hole 481 coincide with each other. Accordingly, the flow path 491 connects the flow path 471 and the flow path 477, and the flow path 492 connects the flow path 472 and the flow path 474.
The flow path 493 of FIG. 13 rotates counterclockwise by α as compared with the state of FIG. 12, but since α <γ and α <δ, the hole 486 is formed between the port 465 and the port 466. The hole 487 is located between the port 466 and the port 467. For this reason, the ports 463, 465, and 466 do not coincide with any hole positions.

At this time, the air supplied from the air supply channel 452 b passes through the reformer 405 and is discharged from the exhaust channel 474. Thereby, the reformed gas in the reformer 405 is purged with air. At this time, since the carbon deposited on the surface of the catalyst of the reformer 405 is oxidized by oxygen in the air and exhausted, the surface of the catalyst is exposed and the catalytic reaction is easily caused.
Further, a small amount of fuel flows from the vaporizer 404 through the flow path 491 to the catalytic combustor 409, and exhaust gas is discharged from the catalytic combustor 409 through the exhaust flow path 456. The heat of combustion in the catalytic combustor 409 is used to maintain the temperature necessary to promote the desorption of carbon adhering to the catalyst of the reformer 405.

  When the purge is completed, the supply of fuel and air is stopped, and the ports 461, 462, 463, 464, 465, 466, 467 are connected to any holes 481, 482, 483, 485, 486, 487 as shown in FIG. The valve body 460b is rotated so as not to coincide with the position. Thus, the stop operation is completed.

Thus, according to this embodiment, water and carbon monoxide can be removed by purging the inside of the reformer 405 with air, and catalyst deterioration and catalyst layer destruction can be prevented. .
Further, since the flow path can be switched by one valve 460, the apparatus can be simplified and the switching can be easily performed in a short time.

1 is a block diagram showing an electronic device 100 according to a first embodiment of the present invention. 4 is a schematic diagram showing a flow path in the reaction apparatus 110 at an initial stage of a stop operation of the fuel cell device 130. FIG. FIG. 3 is a schematic diagram showing a flow path in the reaction apparatus 110 in a middle and late stage of a stop operation of the fuel cell device 130. It is a schematic diagram which shows the flow path in the reaction apparatus 110 which concerns on a 1st modification. It is a schematic diagram which shows the flow path in the reaction apparatus 110 which concerns on a 1st modification. It is a schematic diagram which shows the flow path in the reaction apparatus 110 which concerns on a 1st modification. It is a block diagram which shows the electronic device 200 which concerns on the 2nd Embodiment of this invention. It is a graph which shows the relationship between temperature T [K] and the equilibrium pressure of a carbon dioxide. It is a graph which shows the time change of the decarboxylation rate at the time of changing the carbon dioxide partial pressure in atmosphere. It is a block diagram which shows the fuel cell apparatus 330 which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the fuel cell apparatus 330 at the time of a stop operation | movement. It is a block diagram which shows the fuel cell apparatus 430 which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the fuel cell apparatus 330 at the time of a stop operation | movement. It is a block diagram which shows the fuel cell apparatus 430 after a stop.

Explanation of symbols

100, 200, 300, 400 Electronic device 104, 204, 304, 404 Vaporizer 105, 205, 305, 405 Reformer 106, 306, 406 Carbon monoxide remover 107, 207 Carbon dioxide absorber 107a, 207a, 307a , 407a Heater / temperature sensors 108, 109, 209, 309, 409 Catalytic combustors 130, 230, 330, 430 Fuel cell devices 140, 240, 340, 440 Fuel cell 157, 257 Carbon dioxide supply channels 152b, 352b, 452b Air supply flow path 156b, 256b, 351d, 474 Exhaust flow path 460a Valve box 460b Valve body 461-467 Port 471-477, 491-493 Flow path 481, 482, 483, 485, 486, 487 Hole

Claims (1)

A reformer for reforming raw fuel;
A fuel cell that generates power using the fuel reformed by the reformer;
A carbon dioxide absorber comprising: a heater; and a carbon dioxide absorbent that absorbs carbon dioxide in the off-gas discharged from the fuel cell and releases the absorbed carbon dioxide by being heated by the heater;
A first catalytic combustor which is provided in a flow path connecting between the fuel cell and the carbon dioxide absorber and burns the remaining fuel in the reformer discharged from the fuel cell ;
A carbon dioxide supply flow path connecting the carbon dioxide absorber and the reformer;
A second catalytic combustor provided via another flow path branched from the flow path between the reformer and the fuel cell;
A fuel cell device having
An electronic device body driven by electric power supplied from the fuel cell device;
With
In the initial stage of the stop operation of the fuel cell device, the gas in the reformer is burned in the first catalytic combustor,
In the middle stage of the stop operation of the fuel cell device, the carbon dioxide absorber is heated, and the carbon dioxide adsorbed on the carbon dioxide absorber is converted into the carbon dioxide supply channel, the reformer, and the second. Electronic device characterized by being discharged to the outside through a catalytic combustor.

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