JPH11265725A - Carbon monoxide removing device and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove CO (carbon monoxide), while avoiding an occurrence of abrupt reaction in the vicinity of a gas inlet of a CO removing device and a lowering of reactivity in the vicinity of gas outlet, and excellently maintaining efficiency of selective oxidation reaction. SOLUTION: This CO removing device 5 produces reactive gas by mixing air with reformed hydrogen-rich gas containing CO, and removes CO in the reactive gas by catalyst in a reactor. It is composed of a selective oxidation reactor 51 and an air humidifier 56, and air around a fuel cell system is humidified by cooling water A used for a cooling process in a fuel cell 6, and the humidified air is mixed with the reformed gas and introduced into the selective oxidation reactor 51 in order to remove CO.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for removing carbon monoxide in a fuel cell system and an improved technique for operating the apparatus.

[0002]

2. Description of the Related Art In a fuel cell system, an anode gas containing hydrogen is supplied to an anode side of a fuel cell, and a cathode gas containing oxygen is supplied to a cathode side, and hydrogen and oxygen are electrochemically reacted to generate power. Things. Normally, air is used as the cathode gas, but light hydrocarbons such as natural gas and naphtha or lower alcohols such as methanol are used as the anode gas, and these are reformed by steam reforming reaction or partial oxidation reaction. A hydrogen-rich reformed gas obtained by the reaction is used.

[0003] In the fuel reforming reaction, carbon monoxide (hereinafter referred to as CO) poisoning a platinum (Pt) -based catalyst used in a fuel cell system is produced by a side reaction. This CO is
The concentration is reduced to about 1% in the CO converter before reaching the fuel cell, but it can be reduced to about 100 ppm (0.01%) or less by adding a CO removal device. (Japanese Unexamined Patent Publication No. 3-276577)
No. Gazette).

[0004]

By the way, the reformed gas introduced into the CO removing device needs to be mixed in advance with a gas containing oxygen (air or the like) as an oxidizing agent in order to carry out a CO removing reaction (selective oxidation reaction). There is. Here, the reaction tends to react rapidly near the gas inlet of the CO removal device where the oxygen concentration becomes relatively high. If the heat of the reaction increases the temperature of the catalyst layer beyond the appropriate temperature range, the CO selectivity decreases. As the fuel cell system decreases, a side reaction such as a harmful hydrogen combustion reaction proceeds. Further, in the vicinity of the gas exhaust port of the CO removing device, the progress of the selective oxidation reaction, which should be originally performed, is hindered due to lack of oxygen, contrary to the gas inlet port.

On the other hand, for example, Japanese Patent Application Laid-Open No. 8-47621
And JP-A-8-133702 disclose a technique in which the amount of air supplied to a CO removing device is adjusted in accordance with the degree of progress of a selective oxidation reaction to prevent a rapid progress of the reaction. However, if the amount of oxygen is reduced by adjusting the amount of air, the amount of oxygen for oxidizing and removing CO may be insufficient, which may have a side effect of suppressing the selective oxidation reaction in the entire CO removing device. Can be

At present, further expectations have been placed on the development of technology for improving the reaction efficiency of such a CO removal device. The present invention has been made in view of the above problems, and an object of the present invention is to solve a problem related to temperature control such as a rapid reaction near a gas inlet of a CO removing device and a decrease in reactivity near a gas outlet. Avoid,
It is an object of the present invention to provide a CO removal apparatus for a fuel cell system capable of removing CO while maintaining the efficiency of the selective oxidation reaction, and an operation method thereof.

[0007]

In order to solve the above-mentioned problems, the present invention provides a method for producing a reaction gas by mixing air with a hydrogen-rich reformed gas containing carbon monoxide and generating the reaction gas by a catalyst in a reactor. The carbon monoxide removing apparatus for removing carbon monoxide therein is provided with a reaction gas diluting means for diluting carbon monoxide and oxygen in the reaction gas while increasing the heat capacity of the reaction gas before removing carbon monoxide. A carbon oxide removing device was used.

[0008] By such a reaction gas diluting means, oxygen
The reaction temperature can be prevented from rising excessively without significantly changing the / carbon monoxide (O ₂ / CO) ratio,
An efficient CO selective oxidation reaction can be performed. Further, if the reaction gas diluting means is realized by humidifying means for humidifying the air, the reaction gas can be safely diluted by relatively inert water vapor added to the air by the humidifying means, and The overall heat capacity can be increased, and the effect of suppressing the temperature rise can be enhanced.

Further, in the case where the carbon monoxide removing device is for a fuel cell system and the humidifying means is for humidifying the air with the cooling water of the fuel cell, the resources in the system are used to enable the external use. There is no need to newly provide a device, which contributes to downsizing of the fuel cell system and is advantageous in cost. Further, if the carbon monoxide removing device is for a fuel cell system, and the reaction gas diluting device is provided with a cathode exhaust gas supplying device for supplying a cathode exhaust gas of the fuel cell to the reformed gas side, the operation of the fuel cell is increased. Since the amount of oxygen is reduced and the air is in a humidified state, together with the above-described effect of controlling the heat capacity of the reaction gas by water, when O ₂ / CO is made equal to that when using normal air, more water vapor and The fuel cell system can be diluted with N ₂ , perform a favorable selective oxidation reaction, and efficiently obtain electric power.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) (Description of Overall Configuration of Fuel Cell System) FIG. 1 is a configuration diagram of a polymer electrolyte fuel cell system according to a first embodiment of the present invention.

The fuel cell system generates power by using a fuel gas such as natural gas, city gas, and naphtha. The fuel cell system mainly includes a desulfurizer 1 for removing a sulfur component in the fuel gas. An ejector 2 for mixing fuel gas with high-temperature steam, a reformer 3 for reforming the fuel gas by steam to generate a hydrogen-rich reformed gas, and oxidizing CO in the reformed gas to CO ₂ by steam. CO shift device 4 that removes and removes (shift reaction), CO removal device 5 that selectively oxidizes and removes CO in the reformed gas, and the reformed gas from CO removal device 5 as a fuel electrode (anode electrode). The solid polymer fuel cell 6 generates electricity by taking in air serving as an oxygen source into an air electrode (cathode electrode) 62.

The desulfurizer 1 is filled with a cobalt-molybdenum (Co-Mo) -based or zinc oxide (ZnO) -based catalyst or the like for desulfurization, and is heated to about 200 ° C. by a heater (not shown).
By heating to about 300 ° C., various sulfur components such as hydrogen sulfide (H ₂ S) and alkyl sulfide (R-SH) contained in the fuel gas are adsorbed and removed. In the present embodiment, the reformer 3 employs a reforming method using a steam reforming reaction, and includes a cylindrical reformer 31 in which a nickel (Ni) -based catalyst is filled as a reforming catalyst; And a burner 32 that heats the reformer 31 to a high temperature by burning fuel gas.

The CO converter 4 has a cylindrical vessel filled with a copper-zinc catalyst or the like as a catalyst for CO conversion. While circulating in the direction, CO is oxidized to CO ₂ at an operating temperature of about 180 ° C. to 250 ° C. (shift reaction),
The CO concentration of the reformed gas is reduced to about 1% (10,000 ppm).

The CO removing device 5 comprises a selective oxidation reactor 51 and an air humidifier 56 in the present embodiment. The selective oxidation reactor 51 and the air humidifier 56 are connected to a pipe 5 described later.
2, 105 are connected to each other. Among them, the cylindrical buffer tank 561 that forms the main body of the air humidifier 56 is filled with cooling water A up to the middle in the vertical direction of the cylinder length. 55 is inserted through a buffer tank lid 562. The humidified air flow pipe 54 is further inserted into the buffer tank lid 562, and the humidified air in the air portion B above the cooling water A is sent out to the humidified air flow pipe 52 by suction of the air pump 53. The humidified air flowing through the humidified air flow pipe 52 is sent to a pipe 105 for feeding the reformed gas to the selective oxidation reactor 51, and is mixed with the reformed gas to be used for generating a reaction gas.

The cooling water A is supplied to the inside of a cooling section 63 provided as a cooling control section in the fuel cell 6 by an annular pipe 11.
The refrigerant circulated through 1 stays in the buffer tank 561. The cooling water (about 80 ° C.) supplied to the cooling process inside the fuel cell 6 is replenished by a replenishing tank (not shown) for the loss due to evaporation or the like while temporarily staying in the buffer tank 561 as described above. Meanwhile, it is used for generating the humidified air. The cooling water A is introduced into the heat exchanger 112 from the annular pipe 111 after a certain period of time by the driving of the pump 113, cooled to an appropriate temperature here, and then sent again to the cooling unit 63.

The selective oxidation reactor 51 is a cylindrical vessel filled with a platinum-alumina (Pt—Al ₂ O ₃ ) -based catalyst or the like as a selective oxidation catalyst. Temperature range (approximately 100 ° C for the above catalyst)
(In the range of 250 ° C. to 250 ° C.) to reduce the CO concentration to about 0.01% (100 ppm) or less by performing a selective oxidation reaction.

The fuel cell 6 is a polymer electrolyte fuel cell, and includes an anode (negative electrode) portion 61, a cathode (positive electrode) portion 62 opposed thereto, and an electrolyte portion disposed between the opposed electrode portions 61 and 62. (Not shown), and a cooling portion 63 having the annular pipe 111 inserted into the fuel cell 6 housing. (Description of Piping) As shown in FIG. 1, a piping 10 for feeding a fuel gas from a fuel gas supply source (not shown) such as a city gas to the desulfurizer 1 as shown in FIG.
0, piping 1 for sending fuel gas from desulfurizer 1 to ejector 2
01, the burner 32 of the reformer 3 from the fuel gas supply source
A pipe 102 for sending a fuel gas to the reformer 3, and a pipe 10 for sending a mixed gas of a fuel gas and hot steam from the ejector 2 to the reformer 3.
3. A pipe 104 for sending reformed gas from the reformer 3 to the CO converter 4, a pipe 105 for sending reformed gas from the CO converter 4 to the selective oxidation reactor 51, and a three-way valve 1 from the selective oxidation reactor 51.
Pipes 106 and 108 for sending the reformed gas to the anode section 61 of the fuel cell 6 via the line 07 and a pipe 109 for sending unreacted anode exhaust gas from the anode section 61 to the burner 32 are provided.

As the water-based pipe, there is provided an annular pipe 111 for circulating cooling water to the cooling section 63, the air humidifier 56, and the heat exchanger 112 of the fuel cell 6 sequentially. For a mixed gas of steam and air (humidified air), there are humidified air circulation pipes 54 and 52. In addition, the piping 114 for sending air to the burner 32 and the gas sent from the selective oxidation reactor 51 when the system is started are sent to the burner 32 by bypassing the fuel cell 6. A pipe 110 is provided.

Although not shown for the sake of simplicity, valves (not shown) for adjusting the flow rate are inserted into these pipes so that they can be adjusted according to the operating condition of the fuel cell system. . (Explanation of Operation Method) In the initial stage of starting the fuel cell system having the above-described configuration, first, the reformer 31 of the reforming apparatus 3 starts the reforming reaction of the fuel gas.
Temperature rise is important. Therefore, first, the valve is operated so that all the fuel gas flows through the pipe 102 and is directly sent to the burner 32.

Next, air and fuel gas are sent from the pipes 114 and 102 to the burner 32, respectively, and the burner 32 is ignited to burn the fuel gas, and the reformer 31 is heated and heated. At this time, the three-way valve 107 is set so that the gas flows to the bypass pipe 110 side. At the same time, the CO converter 4, the selective oxidation reactor 51 and the fuel cell 6
Is also heated and heated by external heat such as a heater (not shown).

After the reformer 31 is heated to about 400 ° C. and the CO shift converter 4 and the selective oxidation reactor 51 are heated above the dew point of steam, the fuel gas is supplied to the desulfurizer 1 by operating a valve. And desulfurization treatment is performed. Next, the desulfurized fuel gas is introduced into the ejector 2 through the pipe 101, where the fuel gas and high-temperature steam are mixed and introduced into the reformer 31 through the pipe 103.

Next, the mixed gas is passed through the inside of the reformer 31 to start a reforming reaction. Generated reformed gas is C
It is sequentially sent to the O-transformer 4 and the selective oxidation reactor 51 side, and flows from the pipe 106 to the pipe 110 to be supplied to the burner 32. This allows the reformer 31 to operate in the operating temperature range of 700
The temperature of the CO shift converter 4 and the selective oxidation reactor 51 are also heated and raised by the CO shift reaction and the high-temperature reformed gas.

When the reformer 31, the CO shift converter 4, the selective oxidation reactor 51, and the fuel cell 6 are heated to the operating temperature range, the three-way valve 107 is switched to the fuel cell 6 side for normal operation. enter. As a result, the hydrogen-rich reformed gas is introduced into the anode section 61 of the fuel cell 6, and air is introduced into the cathode section 62 through the air pump 64 and the air introduction pipe 65, so that the electrochemical reaction proceeds and power is generated. .

The operating temperature range of each component in the fuel cell system is as follows.
O-transformer 4 is about 180-300 ° C., selective oxidation reactor 51
Is about 100-250 ° C., and the fuel cell 6 is about 70-80 ° C. In this operating temperature range, the fuel cell system supplies power from the fuel cell 6 to an external load.

The air humidifier 56 in the fuel cell system during normal operation includes an air pump 53 having a humidified air flow pipe 52.
When driven to discharge in the direction, the buffer tank 561
The pressure inside the fuel cell system is reduced, and the air around the fuel cell system is taken into the cooling water A in the buffer tank 561 from the air introduction pipe 55. This air is humidified with the temperature of the cooling water A (about 80 ° C.) as a dew point, then moves to the air section B, and is connected to the piping 10 by the air pump 53 through the humidified air circulation pipes 54 and 52.
5 is sent. As a result, a reaction gas obtained by mixing the reformed gas from the CO converter 4 and the humidified air mixed gas is sent into the selective oxidation reactor 51.

With the above structure, during the selective oxidation reaction,
The reaction gas component air to avoid excessive temperature rise
Humidify, but the specific effect that can be obtained
The following two main effects are obtained. That is, water
CO or O using the volume of steam _TwoConcentration of reaction gas components such as
The reaction gas using the heat capacity of water vapor
The temperature rise can be increased by significantly increasing the overall heat capacity.
Increase the suppression effect.

This water vapor is also used for the purpose of preventing the electrolyte membrane (solid polymer electrolyte membrane) of the fuel cell from drying out and wetting the electrolyte membrane for good power generation. In this embodiment, control is performed by a known gas flow controller such as a valve so as to maintain the ratio of CO in the reformed gas to O ₂ in the humidified air. The settings relating to this control can be adjusted as appropriate according to the composition of the fuel gas used and the like.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 2 is a schematic diagram illustrating a main configuration of the fuel cell system according to the present embodiment. Most of the system configuration is the same as that of the first embodiment, except that the humidified air generated by the air humidifier 56 is used in the fuel cell 6 and the cathode exhaust gas is used as the selective oxidation reactor 51 of the CO removal device 5. The point to introduce is different.

Generally, in a fuel cell, air is used as an oxygen source. In acidic electrolyte fuel cells,
Since oxygen and hydrogen ions react near the cathode to produce water, when the air supplied to the fuel cell is discharged, the amount of oxygen is reduced by several percent from the beginning, and the amount of nitrogen is increased with respect to the amount of oxygen. It becomes exhaust gas (cathode exhaust gas). Particularly in a polymer electrolyte fuel cell, since humidified air is supplied to the cathode side to maintain the electrolyte membrane in a wet state, the cathode exhaust gas contains relatively large amounts of nitrogen and water vapor relative to oxygen in the cathode exhaust gas. Become. Since both of these can increase the heat capacity of the reaction gas, this embodiment utilizes the cathode exhaust gas as a reaction gas component.

As a specific means, as shown in FIG. 2, a cathode exhaust gas supply pipe 69 connected to the pipe 105 side is provided on the exhaust pipe 68 of the cathode section 62. An air pump 70 is arranged in the cathode exhaust gas supply pipe 69. Further, the air introduction pipe 65 of the cathode section 62 and the exhaust pipe 68
Is provided, and a three-way valve 67 is provided at a connection portion between the bypass pipe 66 and the air introduction pipe 65.

In this fuel cell system, the fuel cell 6
The air humidified by the air humidifier 56 is introduced into the cathode portion 62 in order to wet the electrolyte membrane. (Operating Method of Fuel Cell System) The operating method of the fuel cell system having the above configuration is performed as follows together with the operation of the system. A part of the description that overlaps with the above-described embodiment will be omitted.

The operation of the fuel cell system at the initial startup is almost the same as that of the above-described system. First, the fuel gas is sent from the pipe 102 to the burner 32, which burns the fuel gas and heats and raises the temperature of the reformer 31 to about 400 ° C. Subsequently, the fuel gas is sent to the desulfurizer 1 and the reformer 31 side, and the CO
The pipe 11 is made to flow sequentially through the inside of the selective oxidation reactor 51.
The three-way valve 107 is adjusted so that it is introduced into the burner 32 from zero. In parallel with this, the three-way valve 67 is adjusted so that ordinary humidified air is fed into the pipe 105 by the air pumps 64 and 70. After a certain time, the CO transformer 4
After the selective oxidation reactor 51 reaches the level at which each reaction can be started, the three-way valve 107 is operated to allow the reformed gas from the selective oxidation reactor 51 to flow to the anode section 61 side of the fuel cell 6, The three-way valve 67 is set on the cathode section 62 side to introduce humidified air into the cathode section 62. Thereby, power generation is started in the fuel cell 6, and the cathode exhaust gas is introduced into the reaction gas to the selective oxidation reactor 51. With the above operation, the CO removal device 5 and the fuel cell system can be shifted to the normal operation.

(Explanation of Reaction Gas Composition Ratio and Reaction Efficiency) Next, the composition of the reaction gas introduced into the CO removal apparatus of the first and second embodiments and the reaction efficiency of the CO removal apparatus will be described. (FIG. 3) and the temperature distribution of the catalyst layer in the selective oxidation reactor 51 (FIG. 4). As the fuel gas introduced into the fuel cell system, city gas 13A (composition: 88% methane, 6% ethane, 4% propane, 2% butane) was used. The molar ratio (water / carbon ratio) between water molecules of steam introduced into the reformer in the reformer and carbon atoms in the fuel gas is about 2.5. In addition, the reforming reaction temperature in the reformer is about 700 ° C., and the reforming reaction temperature in the CO
Each was set around 0 ° C.

FIG. 3 shows a gas (conventional example) 302 in which various gases are mixed with a reformed gas 301 sent from the CO converter 4 to form a reaction gas, and ordinary air is mixed therein.
(Embodiment 1) 303 mixed with air (dew point 80 ° C.) humidified by the cooling water and gas mixed with cathode exhaust gas (air utilization 50%, dew point 80 ° C.) of fuel cell 6 Mode 2) The components of the reaction gas of 304 were shown. The O ₂ / CO ratio is set to 3 in each case. The reaction gas composition is H ₂ , CO, CO ₂ , CH ₄ , H ₂ O,
It is composed of components such as N ₂ and O _2, of which the components mainly involved in the selective oxidation reaction of CO are the CO and O 2 components (selective oxidation reaction; CO + / O ₂ → CO ₂ ).

In each embodiment and the conventional example, the battery output is 1k.
The gas flow rate per W is as follows (hydrogen utilization rate 7
0%, average cell voltage 0.6V). Conventional example; 28.7 L / min Embodiment 1; 31.0 L / min Embodiment 2; 35.3 L / min As is clear from this figure, the conventional air mixed gas 302
While H ₂ O is contained at about 10.9%, the humidified air mixed gas 303 reaches 17.5% and the cathode exhaust mixed gas 304 reaches 20.6%. in this way,
The reaction gas in the above-described embodiment contains H ₂ O at a composition ratio nearly twice that of the conventional case. The O ₂ / CO ratio is C
Oxidation reaction of other components occurs to some extent along with the selective oxidation reaction of O, so the O ₂ amount is set to be larger than the theoretical amount (O ₂ / C
It is preferable to set the O ratio to about 3).

When the reaction gas having the above composition is introduced into the selective oxidation reactor of the CO removing device, the temperature distribution of the oxidation catalyst layer becomes as shown in the temperature distribution table of FIG. In this figure, a curve (i) represents a conventional air mixed gas 302 and a curve (i).
i) shows each temperature curve of the humidified air mixed gas 303, and curve (iii) shows each temperature curve of the cathode exhaust mixed gas 304. First, when the air-mixed gas 302 at about 100 to 150 ° C. is introduced into the selective oxidation reactor 51, the reaction rapidly proceeds near the gas inlet soon after the introduction, and the temperature of the catalyst layer rises to a high temperature state (about 200 to 250 ° C). Since the upper limit of the appropriate temperature range for the selective oxidation reaction is around 200 ° C., the removal of CO after the gas is introduced into the reactor is limited to the time when the catalyst layer reaches this high temperature range. . However, as shown by the curve (i), the actual area of the catalyst layer where the selective oxidation reaction can be performed was limited to the vicinity of the gas inlet.

On the other hand, when the humidified air mixed gas 303 (curve ii) is introduced into the selective oxidation reactor (51), even if the reaction gas comes into contact with the selective oxidation catalyst, O
Since the two components are diluted, the reaction is suppressed, and the reaction starts gently. Further, since the heat capacity of the reaction gas is increased due to the increase in water vapor, a sharp rise in the reaction temperature is also avoided, so that the rise curve of the catalyst temperature becomes gentle as shown in FIG. The area of the catalyst layer contributing to the reaction increases from the gas inlet to the gas outlet. Thereby, the CO removal efficiency is improved.

When the cathode exhaust gas 304 (curve iii) is used, the humidified air mixed gas 303 (curve i) is used.
There are the following effects in addition to the effects of i). That is, since a lower than normal air by operation of the oxygen concentration fuel cell cathode exhaust 304, when in the same manner as the dew point and O ₂ / CO ratio humidified air mixed gas 303 is N ₂ and the amount of water vapor in the gas This further increases the effect of suppressing the oxidation reaction. Further, since the heat capacity also increases, more effective control can be performed with respect to the increase in the reaction temperature.

The effect of such water vapor is generally proportional to the amount of water vapor added to the reaction gas, and the effect is that the maximum amount of water vapor saturation of the reaction gas is used to reduce the amount of water vapor in the air around the carbon monoxide removal device. It is obtained in the range when the minimum value is set. In this range, the effect of increasing the efficiency of the selective oxidation reaction by diluting the concentrations of carbon monoxide and oxygen while increasing the heat capacity of the reaction gas increases as the amount of water vapor increases. However, when a large amount of steam is added, since a heat source for generating steam is required, it is needless to say that the addition amount needs to be adjusted in consideration of the heat balance of the system. Although the effect is small even if the amount of water vapor is small, it is better to use the exhaust heat of the fuel cell 6 and set the amount of addition using the temperature of the cooling water or the cathode exhaust gas (about 80 ° C.) as a dew point. It is desirable because it is possible to obtain an effective result without having to newly provide a facility for humidification.

It should be noted in the embodiment, an example of mixing the water vapor into the reaction gas, since it is sufficient relatively inert ingredient for CO selective oxidation reaction, even N ₂ in the other Good. However when using N ₂ or the like must be separately provided equipment for supplying this. Further, in the above embodiment, the example in which the reactor 51 has a cylindrical shape has been described, but the reactor 51 may have a rectangular tube shape or the like.

[0041]

As is apparent from the above description, according to the present invention, a reaction gas is generated by mixing air with a hydrogen-rich reformed gas containing CO, and the CO in the reaction gas is generated by a catalyst in a reactor. The apparatus for removing carbon monoxide is provided with a reaction gas dilution means for diluting CO and oxygen in the reaction gas while increasing the heat capacity of the reaction gas before removing CO, so that the gas in the It is possible to avoid that the selective oxidation reaction rapidly progresses near the introduction port to lower the reaction efficiency, and it is possible to remove CO while maintaining the efficiency of the selective oxidation reaction satisfactorily.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a main configuration of a fuel cell system (Embodiment 1) which is an application example of the present invention.

FIG. 2 is a schematic diagram showing a main configuration of a fuel cell system (Embodiment 2) which is an application example of the present invention.

FIG. 3 is a diagram showing a reaction gas composition ratio.

FIG. 4 is a diagram showing a temperature distribution of a catalyst layer of a selective oxidation reactor.

[Explanation of symbols]

 Reference Signs List 5 CO removal device 51 Selective oxidation reactor 52, 54 Humidified air flow tube 53, 64, 70 Air pump 55 Air introduction tube 56 Air humidifier 6 Polymer electrolyte fuel cell 61 Anode unit 62 Cathode unit 63 Cooling unit 67, 107 Three-way Valve 113 Pump 561 Buffer tank

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 8/04 H01M 8/04 J N 8/10 8/10

Claims (8)

[Claims] 1. A carbon monoxide removal apparatus for mixing a hydrogen-rich reformed gas containing carbon monoxide with air to generate a reaction gas and removing carbon monoxide in the reaction gas by a catalyst in a reactor. 2. The carbon monoxide removing apparatus according to claim 1, further comprising a reaction gas diluting means for diluting carbon monoxide and oxygen in the reaction gas while increasing the heat capacity of the reaction gas before removing carbon monoxide. 2. The apparatus for removing carbon monoxide according to claim 1, wherein said reactive gas diluting means is a humidifying means for humidifying air. 3. The fuel cell system according to claim 1, wherein the carbon monoxide removing device is a carbon monoxide removing device for a fuel cell system, and the humidifying unit humidifies air with cooling water of the fuel cell. Carbon monoxide removal equipment. 4. The carbon monoxide removing device is a carbon monoxide removing device for a fuel cell system, and the reactant gas diluting means supplies a cathode exhaust gas of a fuel cell to a reformed gas side. The apparatus for removing carbon monoxide according to claim 1, further comprising means. 5. The carbon monoxide removing device according to claim 3, wherein the fuel cell is a polymer electrolyte fuel cell. 6. A reaction gas generating step of generating a reaction gas by mixing air with a hydrogen-rich reformed gas containing carbon monoxide, and removing carbon monoxide in the reaction gas by a catalyst in a reactor. A method for operating a carbon monoxide removing apparatus comprising the steps of: removing carbon monoxide, mixing the reformed gas with the humidified air in the reactive gas generating step, and increasing the heat capacity of the reactive gas in advance to reduce the amount of monoxide in the reactive gas. A method for operating a carbon monoxide removing device, comprising a sub-step of diluting carbon and oxygen concentrations. 7. A method for operating a carbon monoxide removing device in a fuel cell system, comprising: a reaction gas generating step of mixing a hydrogen-rich reformed gas containing carbon monoxide with air to generate a reaction gas; A carbon monoxide removing step of removing carbon monoxide in the reaction gas by a catalyst in a reactor, wherein in the reaction gas generation step, cooling water of a fuel cell is mixed with air as water vapor, and the heat capacity of the reaction gas is previously determined. A sub-step of diluting the concentrations of carbon monoxide and oxygen in the reaction gas while increasing the concentration of carbon monoxide. 8. A method for operating a carbon monoxide removing apparatus in a fuel cell system, comprising: a reaction gas generating step of mixing a hydrogen-rich reformed gas containing carbon monoxide with air to generate a reaction gas; A carbon monoxide removal step of removing carbon monoxide in the reaction gas by a catalyst in a reactor, wherein in the reaction gas generation step, a cathode exhaust gas of a fuel cell is mixed with the reformed gas side as the air, A method for operating a carbon monoxide removing apparatus, comprising diluting the concentrations of carbon monoxide and oxygen in a reaction gas while increasing the heat capacity of the reaction gas with water vapor contained in a cathode exhaust gas.