JPH10302821A - Carbon monoxide reducing device for solid high polymer fuel cell and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon monoxide reducing device of solid polymer fuel cell capable of reducing carbon monoxide in efficient, simple constitution, and provide its operating method. SOLUTION: In a device for oxidizing and reducing carbon monoxide in a reformed gas in a solid polymer fuel cell containing a fuel reforming system for reforming hydrocarbon or alcohol fuel with a catalyst, a means 38 for introducing oxygen or air into a region where the temperature of the reformed gas is 100-150 deg.C is arranged, and a carbon monoxide oxidizing catalyst layer 30 is arranged in the downstream position than the oxygen or air introducing portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance apparatus for reducing carbon monoxide constituting a solid polymer fuel cell system using hydrocarbons or alcohols as a raw fuel and an operation method thereof.

[0002]

2. Description of the Related Art A polymer electrolyte fuel cell has a high current density even at a relatively low temperature. Recently, hydrocarbons or alcohols have been obtained by steam reforming as a hydrogen source for solid polymer fuel cells. The reformed gas is mainly composed of hydrogen, carbon dioxide,
Contains water vapor and traces of carbon monoxide (typically 1%).

[0003] Solid polymer fuel cells are also concerned with the heat resistance and durability of the polymer ion conversion membrane used as an electrolyte, and are relatively low in temperature (typically 60 ° C to 60 ° C) as compared with other fuel cells.
120 ° C.), but still easily obtain current densities over phosphoric acid fuel cells operated at higher temperatures,
Attention has been paid to the simplicity of operation and handling because no corrosive liquid electrolyte is used, and active research and development are being conducted.

[0004] In particular, for expanding applications, hydrocarbons, fuels such as natural gas, propane, etc., or methanol, etc., which are more generally available from conventional pure hydrogen fueled systems and are easy to handle. It is important to develop a system that uses alcohol fuel as raw fuel.

[0005] As one method of avoiding the influence of CO, attempts have been made to improve the resistance of the electrode catalyst to CO poisoning so that the anode of the polymer electrolyte fuel cell is not affected by CO. Operating temperature 9
It is required to reduce the CO concentration to 100 ppm or less even at about 0 ° C.

Another method for avoiding the influence of CO is to reduce the amount of CO generated by the reforming reaction. For this reason, adsorption purification, purification using a hydrogen selective permeable membrane, and the like are being studied. However, when applied to a small-scale fuel cell, economies of scale cannot be expected, and this is not a suitable method.

Therefore, a CO selective oxidation system in which carbon monoxide is oxidized and reduced to carbon dioxide with a small amount of oxygen in the presence of a catalyst has been attempted. Also, the catalyst is usually Pt, Ru
It is said that a catalyst in which a noble metal or the like is supported on a carrier is good.

FIG. 7 shows a conventional apparatus for removing carbon monoxide.
Oxidation reaction vessel 1 containing only oxidation catalyst 4 as shown in FIG.
There is a configuration in which oxygen is introduced into the reformed gas line 2 on the input side through the air introduction line 3. However, in such a device for removing carbon monoxide, the oxidation reaction of CO does not gradually occur, and a reaction that hinders the oxidation reaction of CO occurs simultaneously.
The O concentration could only be reduced to 200 ppm.

[0009] Recently, as a carbon monoxide removing device for reducing the CO concentration, there is a device as shown in JP-A-8-47621. As shown in FIG. 8, this carbon monoxide removing device includes a plurality of units each containing only an oxidation catalyst, in this case, air is supplied to the reformed gas pipe 2 on each input side of the first to third oxidation reaction vessels 7 to 9. Oxygen is respectively introduced through branch pipes 10a to 10c branched from the introduction pipe line 3, and CO 2 is introduced.
The CO is reduced by gradually causing the oxidation reaction of CO. In the figures, 5a to 5c are flow controllers provided in the branch pipes 10a to 10c, and 6a to 6c are first to third oxidation reaction vessels 7 to 5c.
Reference numeral 9 denotes a CO concentration sensor provided in the reformed gas pipe 2 on each input side.

In the carbon monoxide removing apparatus having such a configuration, not only the reaction between O ₂ and CO but also the O ₂ by the oxidation catalyst contained in the first to third oxidation reaction vessels 7 to 9.
And H ₂ also occur simultaneously. In addition, since the reaction between O ₂ and H ₂ is more active at higher temperatures, it is important to reduce the influence of the temperature rise due to the oxidation reaction between O ₂ and CO.

[0011]

As described above, in the polymer electrolyte fuel cell system, it is efficient if the concentration of carbon monoxide can be reduced to an extremely low level with a minimum amount of oxygen. Further, in order to be used in a system, it is important that the device is positioned in the temperature gradient of the entire system without difficulty, and a compact device is required.

The most important point to consider for compactness is not to simply make the carbon monoxide removing device compact, but to simplify the whole fuel treatment system of the polymer electrolyte fuel cell. For this purpose, it is important that the constituent devices are also positioned in the system.

However, in the carbon monoxide removing apparatus having the structure shown in FIG. 7, when oxygen is introduced from one point on the upstream side of the oxidation catalyst, the operation is easy but the CO at the outlet of the CO removing apparatus is easy. The concentration increases. This is because the selective oxidation reaction of CO is hindered by the temperature rise due to the rapid CO oxidation reaction near the inlet.

In the apparatus for removing carbon monoxide as shown in FIG. 8, oxygen is introduced from each input side of the first to third oxidation reaction vessels to reduce the influence of temperature rise due to heat of the oxidation reaction. Therefore, although the CO concentration at the outlet of the CO removing device is low, there is a problem that the structure becomes complicated and control becomes difficult.

The present invention has been made in view of the above circumstances, and has as its object to reduce carbon monoxide in a solid polymer fuel cell system capable of reducing carbon monoxide with an efficient, simple, and simple configuration. An object of the present invention is to provide an apparatus and an operation method thereof.

[0016]

According to the present invention, in order to achieve the above object, a carbon monoxide reducing device is constituted by the following means, and this device is operated. The invention corresponding to claim 1 is an apparatus for reducing oxidation of carbon monoxide in a reformed gas of a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel by using a catalyst. The temperature of the reformed gas is 100 to 15
Means for introducing oxygen or air into the 0 ° C. region and a carbon monoxide oxidation catalyst layer are provided downstream of the oxygen or air introduction site.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described configuration, oxygen or air is introduced when the temperature of the reformed gas is in the range of 100 to 150 ° C. Therefore, carbon monoxide can be selectively oxidized efficiently.

According to a second aspect of the present invention, there is provided the carbon monoxide reducing device for a polymer electrolyte fuel cell according to the first aspect of the present invention, wherein the device is provided between the means for introducing oxygen or air and the carbon monoxide oxidation catalyst layer. Mixing means is provided.

Therefore, in the carbon monoxide reducing device for a solid polymer fuel cell having the above-mentioned structure, the above-mentioned claim 1 is provided.
In addition to the operation and effect of the invention corresponding to the above, since a relatively small amount of oxygen or air and the reformed gas can be well mixed by the mixing means, the concentration of carbon monoxide can be made extremely low.

According to a third aspect of the present invention, there is provided the carbon monoxide reducing device for a polymer electrolyte fuel cell according to the first or second aspect, wherein the outer surface or the inside of the carbon monoxide oxidation catalyst layer container is provided. A cooling means is provided.

Therefore, in the carbon monoxide reduction device for a solid polymer fuel cell having the above-described structure, in addition to the operation and effect of the invention according to claim 1 or 2, the cooling means directly reduces the temperature. Since the temperature rise of the carbon oxide oxidation catalyst layer is suppressed, the effect of reducing carbon monoxide can be increased.

According to a fourth aspect of the present invention, there is provided a polymer electrolyte fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol-based fuel, in which oxidation is reduced by using carbon monoxide in a reformed gas as a catalyst. In this apparatus, two catalyst layers are provided, a Pt catalyst is provided in the first stage, a Ru catalyst is stored in the second stage, and oxygen or air introducing means is provided for each oxidation catalyst layer.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described structure, a Pt catalyst tank is provided in the front stage and a Pt catalyst layer is provided in the rear stage in series, and oxygen is added to each catalyst layer. Alternatively, since air is introduced, carbon monoxide can be reduced to an extremely low concentration.

According to a fifth aspect of the present invention, there is provided the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the fourth aspect of the present invention, wherein the first catalyst or the air introducing means and the first carbon monoxide oxidation catalyst are provided. Mixing means is provided between the layers.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described structure, in addition to the function and effect of the invention according to claim 4, a stabilizing device provided downstream of the mixing means is provided. Mixing means such as a tick mixer improves the mixing with the reformed gas, and can efficiently reduce carbon monoxide.

According to a sixth aspect of the present invention, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the fourth or fifth aspect, the first carbon monoxide oxidation catalyst layer and the second Cooling means is provided between the carbon monoxide oxidation catalyst layer.

Therefore, in the carbon monoxide reducing device for a polymer electrolyte fuel cell having the above-described structure, in addition to the function and effect of the invention according to claim 4 or 5, the cooling means significantly reduces The concentration of carbon oxide can be reduced.

According to a seventh aspect of the present invention, there is provided the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the invention according to any one of the fourth to sixth aspects, wherein the temperature of the reformed gas at the inlet is reduced. To 100-150 ° C.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described structure, the function and effect of the invention corresponding to any one of claims 4 to 6 are added. By setting the temperature of the reformed gas at the inlet to 100 to 150 ° C., the concentration of carbon monoxide can be effectively reduced.

The invention according to claim 8 is a catalyst layer for oxidizing and reducing carbon monoxide in a reformed gas of a polymer electrolyte fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel. Two carbon monoxide oxidation catalyst layers are provided, a Pt catalyst is accommodated in a first carbon monoxide oxidation catalyst layer in a former stage, and a Ru catalyst is accommodated in a second carbon monoxide oxidation catalyst layer in a latter stage. In an operation method of a carbon monoxide reduction device for a polymer electrolyte fuel cell, wherein an oxygen or air introduction means is provided corresponding to a layer, the O ₂ / CO ratio in the introduced oxygen amount or the introduced air amount is determined by the first stage. It is small for the carbon monoxide oxidation catalyst layer and large for the second carbon monoxide oxidation catalyst layer so that the total O ₂ / CO is small.

Therefore, in the operation method of the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above configuration,
As the introduction amount of oxygen or air, the introduction amount ratio O ₂ / CO in the former stage is made smaller, the introduction amount ratio O ₂ / CO in the latter stage is made larger, and the total amount of O ₂ / CO is made smaller to obtain the maximum carbon monoxide. A reduction effect can be exhibited.

According to a ninth aspect of the present invention, there is provided a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol-based fuel, in which the carbon monoxide in the reformed gas is oxidized using a catalyst. In the apparatus, an oxidation reaction vessel is provided in which an oxidation catalyst for selectively oxidizing carbon monoxide in the reformed gas in the presence of oxygen and a substance having no oxidation activity are mixed and accommodated.

Therefore, in the apparatus for reducing carbon monoxide for a polymer electrolyte fuel cell having the above structure, the reformed gas and oxygen are mixed in the reaction layer in which the oxidation catalyst and the substance having no oxidation activity are mixed. By supplying the gas, the oxidation reaction of CO gradually occurs in the entire oxidation reaction vessel, and C
O reduction efficiency is improved.

According to a tenth aspect of the present invention, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the ninth aspect, a Pt catalyst or a Ru catalyst is used as an oxidation catalyst for selectively oxidizing carbon monoxide. Alternatively, a Pt-Ru alloy catalyst is used.

Therefore, in the carbon monoxide reduction device for a solid polymer fuel cell having the above-described structure, in addition to the effect of the invention according to claim 9, the activity as an oxidation catalyst is high and CO is reduced. Since a noble metal based material having excellent selective oxidation properties is used, it is excellent in making the apparatus compact.

According to an eleventh aspect of the present invention, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the ninth or tenth aspect, alumina, silica, or stainless steel is used as the substance having no oxidizing activity. .

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above structure, the substance having no oxidizing activity is obtained in addition to the function and effect of the invention according to claim 9 or 10. By using alumina, silica, and stainless steel, the CO oxidation reaction gradually occurs, oxidation of hydrogen is suppressed, and CO can be reduced to an extremely low concentration.

The invention corresponding to claim 12 is the invention according to claim 11
In the apparatus for reducing carbon monoxide for a polymer electrolyte fuel cell according to the present invention, the shape of the substance having no oxidizing activity is granulated particles.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described structure, in addition to the function and effect of the invention according to claim 10, the shape of a substance having no oxidation activity is formed. By using the granulated particles, the reformed gas can be supplied to the fuel cell without causing a pressure loss as compared with the related art.

According to a thirteenth aspect of the present invention, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the ninth aspect, the volume ratio between the oxidation catalyst and the substance having no oxidation activity is 2: 1 to 1: 1. : 10.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described structure, the CO 2 is mixed by mixing the oxidation catalyst and the substance having no oxidation activity in a ratio of 2: 1 to 1:10. Oxidation reaction occurs gradually, and CO2
Reduction efficiency is improved.

According to a fourteenth aspect, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the ninth aspect, one oxygen or air introduction system is provided upstream of the oxidation reaction vessel.

Therefore, in the carbon monoxide reduction device for a polymer electrolyte fuel cell having the above-described configuration, in addition to the function and effect of the invention corresponding to claim 9, there is a place where oxygen or air is introduced. Since CO can be reduced in one place,
The structure can be simpler than the conventional structure.

According to a fifteenth aspect of the present invention, in the carbon monoxide reduction device for a polymer electrolyte fuel cell according to the ninth aspect, an oxidation catalyst and a substance having no oxidation activity are mixed inside or outside the oxidation reaction vessel. Cooling means for cooling the reaction layer is provided.

Therefore, in the carbon monoxide reduction device for a solid polymer fuel cell having the above-described structure, in addition to the effect of the invention according to claim 9, the heat generated by the oxidation and reduction of CO is added. Since the temperature rise is directly suppressed by the cooling means, the CO reduction effect can be increased.

According to a sixteenth aspect of the present invention, there is provided a polymer electrolyte fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel, in which carbon monoxide in the reformed gas is oxidized using a catalyst. In the operation method of the apparatus, when the carbon monoxide contained in the reformed gas is reduced by using an oxidation catalyst, the temperature of the oxidation reaction layer formed by mixing the oxidation catalyst and the substance having no oxidation activity is reduced by the oxidation of CO. Reaction 1
Cool so as to keep the temperature between 00C and 160C.

Therefore, in the above-described operation method of the oxidation reducing apparatus, the temperature of the oxidation catalyst in the oxidation reaction layer is set to CO 2
CO is further reduced by maintaining the temperature at 100 ° C. to 160 ° C. in which the oxidation reaction of
O reduction efficiency can be greatly improved.

[0048]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a solid polymer fuel cell system to which a carbon monoxide reduction device according to the present invention is applied.

For example, in a solid polymer fuel cell system using methanol as a fuel, as shown in FIG. 1, a reformer 1 for reforming methanol by steam to generate a hydrogen-rich reformed gas is provided.
2, a solid polymer fuel cell 14 using hydrogen gas and oxygen gas as fuel and a solid polymer membrane as electrolyte, and a monoxide for oxidizing and removing carbon monoxide (hereinafter referred to as CO) in the reformed gas in the presence of oxygen. A carbon reduction device (hereinafter referred to as a CO reduction device) 16.

The reformer 12 includes a reforming reaction section 1 containing a methanol reforming catalyst (eg, a Cu—ZnO-based catalyst).
8 and a heating section 20 for heating the methanol reforming catalyst in the reforming reaction section 18 to an appropriate temperature. Then, the reformer 12 receives the supply of water and methanol to the reforming reaction section 18, and proceeds with the following two-stage chemical reaction by the methanol reforming catalyst of the reforming reaction section 18 to produce a hydrogen-rich reformed gas. (Dry gas H ₂ ; about 75%) is generated and sent downstream.

CH 3 OH → 2H ₂ + CO CO + H ₂ O → H ₂ + CO ₂ Therefore, the reformed gas sent out from the reformer 12 is a mixed gas that occupies a large part of hydrogen and carbon dioxide.
It contains about 0.2 to 2% of CO which is an intermediate product of the above reaction. In the above-mentioned chemical reaction, the methanol reforming catalyst in the reforming reaction section 18 has an appropriate temperature (for example, 220 to 300).
C).

Therefore, the reformer 12 receives supply of methanol and hydrogen gas to the heating section 20 as an exothermic energy source,
Each is burned, and the heat of combustion heats the reforming reaction section 18. The surplus hydrogen gas from the fuel cell 14 is used as the hydrogen gas.

Further, the CO reduction device 16 receives the supply of the reformed gas and the air from the reformer 12, oxidizes the CO in the reformed gas to convert it into CO _2, and supplies the fuel cell 14 with a hydrogen-rich reforming gas. Pump out quality gas. The details of the CO removing device 16 will be described later.

Further, the solid polymer fuel cell 14 is constituted by sandwiching a solid polymer electrolyte membrane 22 which selectively transmits hydrogen ions between an anode 24 and a cathode 26, and a fuel gas supplied to the anode and the cathode. Electromotive force is generated by the electrochemical reaction, and power is generated. If the reformed gas supplied to the anode 24 contains CO, the electrode catalyst constituting the anode 24 is poisoned, and sufficient performance cannot be exhibited. Of course, this depends on the operating temperature of the cell and the CO concentration, but for polymer electrolyte fuel cells, it is usually 80 ° C.
Operating at ~ 100 ° C, CO concentration is 100ppm
Beyond this, there will be a noticeable effect on performance.

Next, surplus reformed gas is sent from the anode 24 to the heating section 20 of the reformer 12, part of the surplus air is sent from the cathode 26 to the heating section 20, and the rest is released to the atmosphere. . The heating unit 20 also supplies methanol, which is a fuel, as necessary. However, the unused hydrogen in the reformed gas sent from the cathode 24 around the unused hydrogen in the reformed gas sent from the anode 24 is removed. Cathode 2 in the center
It is mixed and burned with the excess air from 6 and becomes a heat source of the heating unit.

Although the above-mentioned solid polymer fuel cell system 10 is provided with a check valve, a flow meter, a pump and the like in each supply pipe, the description is omitted because it is not directly related to the present invention. I do.

Next, the detailed configuration of the CO removing device 16 will be described with reference to FIG. FIG. 2 is a configuration diagram showing a first embodiment of the CO reduction device according to the present invention. As shown in FIG. 2, the reformed gas from the reformer 12 has an operation temperature of 2
Since the temperature is in the range of 00 to 300 ° C., the temperature of the reformed gas is also substantially equal to the temperature and is sent out. Further, if the amount of the reforming catalyst is sufficiently charged, the CO concentration can be reduced by the reformer 12.
Is delivered as the equilibrium concentration of the outlet temperature.

In this case, if the outlet temperature is low, the CO concentration is low. However, if the temperature is lower than 200 ° C., the reaction speed is remarkably slowed down, and the amount of catalyst becomes enormous. The CO concentration at that time is about 0.2%, which is a minimum, and is actually 230 ° C.
This is an example in which a CO concentration of about 0.5% is usually used.

The temperature of the reformed gas is measured by a temperature sensor 27a through a pipe 36, and air is introduced at an appropriate flow rate by a flow regulator 40 through an air introduction pipe 38 in an appropriate temperature range. After being mixed with the gas and mixed by the mixing means 28, the CO enters the CO oxidation catalyst layer 30, where the CO is oxidized and flows out, and is sent to the fuel cell 14 after confirming that the temperature is appropriate by a temperature sensor (not shown). Can be

In the present invention, the temperature of the reformed gas entering the CO oxidation catalyst layer 30 must be in the range of 100 to 150 ° C.
This is the key to effective removal. Here, the effects of the CO reduction device 16 will be described using specific numerical values.

The CO oxidation catalyst layer 30 is a tubular body having a cross-sectional area of 15 cm ² and a length of 5 cm, and carries and stores a Pt catalyst (catalyst carrying amount 0.25%). Then, from the reformer 12, the reformed gas (H ₂ ; 75.5%, CO 2
₂ ; 24%, CO; 0.5%) at a flow rate of 13 L / min.

The air was introduced through the air line 38 by the flow controller 40 so that the flow rate was adjusted so that O ₂ /CO=1.5. At the same time, a CO concentration meter was installed downstream of the CO oxidation catalyst layer 30 to measure the CO concentration.

When the temperature of the reformed gas measured by the temperature sensor 27a is 120 ° C., the CO concentration is 60 ppm,
95 ppm at ℃, 350 ppm at 170 ℃
And the temperature rises, the CO concentration rises and 100pp
m or less, it was necessary to reduce the temperature to 150 ° C. or less. On the low temperature side, 20-30% of steam is contained in the reformed gas.
Considering the existence and the battery operating temperature of 80 to 100 ° C., the temperature is preferably set to 100 ° C. or more.

FIG. 3 is a block diagram showing a second embodiment of the CO reduction apparatus according to the present invention. C of the second embodiment
The O removing device 16 is different from the first embodiment in that a CO oxidation catalyst layer, a configuration for introducing air, and a cooling unit are provided. Therefore, in the following description, the description of members having the same functions as those of the first embodiment will be omitted.

As shown in FIG. 3, the CO reduction device 16 of the second embodiment includes two CO oxidation catalyst layers 30a and 30b in the middle of the reforming pipe 36, and the first CO oxidation catalyst layer 30a. Contains a granular Pt catalyst (supported amount 0.25%) 31a supported on a carrier, and a similar Ru catalyst (supported amount 1%) 31b in the second CO oxidation catalyst layer 30b.
Is stored. Correspondingly, the air is branched into branch pipes 38a and 38b through the air introduction pipe 38 so that air can be introduced into each catalyst layer.

The first CO oxidation catalyst layer 30a and the second
The cooling means 32 is provided between the CO oxidation catalyst layers 30b. The reformed gas merges with an appropriate amount of air introduced from the branch pipe 38a from the middle through the reforming pipe 36, and the mixing means 2
8a mixed in the first CO oxidation catalyst layer 30a.
O is oxidized and reduced and delivered.

Next, the air merges with the air introduced from the branch pipe 38b, is cooled to an appropriate temperature by the cooling means 32, and then enters the second CO oxidation catalyst layer 30b, where C reaches a very low concentration.
After being oxidized and reduced, O is sent to the fuel cell 14.

The first and second CO oxidation catalyst layers 30a, 30
The catalysts 31a and 31b contained in b are preferably Pt and Ru catalysts supported on a carrier having a large surface area, and the medium is preferably, for example, γ-Al ₂ O ₃ , silica / alumina, or the like.

In this case, if the supported amount can be reduced, a less expensive catalyst can be obtained. However, if it is adjusted by an immersion method usually used in consideration of the oxidation activity, Pt is 0.20 to 0.20.
0.5% and about 0.8 to 1.5% of Ru are required.
Further, the first CO oxidation catalyst layer 30a is preferably a Pt catalyst, and the second CO oxidation catalyst layer 30b is preferably a Ru catalyst.

By the way, the Pt catalyst has excellent oxidation activity at a low temperature and efficiently oxidizes a relatively high concentration of CO. Further, the Ru catalyst has an oxidation activity at a higher temperature than the Pt catalyst and also has a methanation reaction activity shown below.

CO + 3H ₂ → CH ₄ + H ₂ O Therefore, the CO concentration can be reduced by this methanation reaction, so that the CO concentration can be reduced to an extremely low concentration. The cooling means 32 may be any one of air cooling and water cooling. This cooling means 32 is effective in the following cases.

When the CO concentration at the outlet of the reformer 12 is high, the temperature rise of 100 ° C. or more causes the first CO oxidation catalyst layer 30 a
Therefore, if the temperature of the reformed gas at the inlet of the first CO oxidation catalyst layer 30a is 120 ° C., the temperature at the outlet becomes 220 ° C. or more.

If the reformed gas flows into the second CO oxidation catalyst layer 30b in such a state, the following CO ₂ methanation reaction also occurs in the second CO oxidation catalyst layer 30b.

CO ₂ + 4H ₂ → CH ₄ + 2H ₂ O This is a large exothermic reaction, the temperature runs away, and a favorable result cannot be obtained. Naturally, the CO concentration cannot be reduced to an extremely low concentration. In such a case, the reformed gas may be cooled, detected by the temperature sensor 27b, and introduced into the second CO oxidation catalyst layer 30b at about 120 to 180 ° C.

The upper limit temperature of 180 ° C. is a temperature at which the temperature of the second CO oxidation catalyst layer 30b does not exceed 200 ° C. Here, the effect of the CO reduction device 16 in the second embodiment will be described using specific numerical values.

The first and second CO oxidation catalyst layers 30a, 30
“b” is a tubular body having a cross-sectional area of 15 cm ₂ and a length of 5 cm, and contains a supported granular Pt catalyst (catalyst carrying amount 0.25%) and a supported granular Ru catalyst (catalyst carrying amount 1%), respectively. Then, from the reformer 12, the reformed gas (H ₂ ;
5.5 L, CO ₂ ; 24%, CO; 0.5%) in 25 L
/ Min at a flow rate of / min. In addition, air is supplied to the air introduction line 3
After passing through 8, the flow rate was adjusted by the flow rate regulators 40a and 40b so that the flow rate became O ₂ /CO=1.5, and each flow rate was adjusted to 9: 1 and introduced. At the same time, the second CO oxidation catalyst layer 30
A CO concentration meter was installed downstream of b, and the CO concentration was measured.
The temperature of the reformed gas measured by the temperature sensor 27a is 150
° C, and the CO concentration at the outlet of the second CO oxidation catalyst layer 30b at this time was 20 ppm.

Further, the cooling means 32 is operated under the same conditions, and when the temperature detected by the temperature sensor 27b is 140 ° C., the CO concentration at the outlet of the second CO oxidation catalyst layer 30b becomes 1
It was significantly reduced to 0 ppm or less.

Next, a method of operating the CO reduction device will be described as a third embodiment. In order to reduce the CO concentration to a very low concentration, the amount of air introduced is also an important factor. As described above, since the amount of air introduced naturally depends on the CO concentration in the reformed gas, it is convenient to specify O ₂ / CO.
If O ₂ / CO can be made as small as possible to make the CO concentration extremely low, the power generation efficiency of the fuel cell is improved.

As shown in the second embodiment, the first C
In the CO reduction device composed of the O oxidation catalyst layer 30a and the second CO oxidation catalyst layer 30b, the second CO oxidation catalyst layer 3
It is sufficient if the CO concentration can be made extremely low at the outlet of 0b.
If the CO oxidation catalyst layer 30a can be reduced by about 90%, the function has been sufficiently performed. That is, the O ₂ / CO ratio introduced into the first CO oxidation catalyst layer 30a and the second CO oxidation catalyst layer 30b is changed, and the total O ₂ / CO
What is necessary is just to make a ratio small and to exhibit the maximum CO reduction effect. For this purpose, the O ₂ / CO ratio of the air sent to the first CO oxidation catalyst layer 30a is reduced to reduce the second CO oxidation catalyst layer 3a.
It has been found that the above object can be achieved by increasing the O ₂ / CO ratio of the air sent to Ob.

Here, this effect will be described with specific numerical values. As a comparative example, when air was introduced at O ₂ /CO=1.5 under the condition of no cooling in the second embodiment and distributed at a ratio of 9: 1, it was 20 ppm as described above. However, the other conditions are the same, and the first CO oxidation catalyst layer 30a is introduced with O ₂ /CO=1.0, and the second CO oxidation catalyst layer 30b is charged with the first CO oxidation catalyst. Layer 30a
Assuming that 90% of CO could be reduced by O ₂ /CO=2.0
As a result, the same CO concentration as the result of introducing air at 22 ppm could be obtained.

At this time, total O ₂ /CO=1.2
Which was smaller than 1.5 of the comparative example. Of course CO
It is more accurate to install a densitometer and determine O ₂ / CO based on the indicated value of the densitometer based on the above-mentioned concept to determine the amount of air to be introduced. However, it becomes complicated and expensive, and is adopted according to cost performance. It does not matter what the gist of the present invention is.

FIG. 4 is a block diagram showing a fourth embodiment of the CO reduction apparatus according to the present invention. The fourth embodiment differs from the first embodiment shown in FIG. 2 in that a cooling means is provided outside the container of the CO oxidation catalyst layer 50 so that cooling can be performed. CO oxidation catalyst layer 5
That is, a temperature sensor 45b is provided in the vicinity of the outlet of 0, so that the effect of cooling can be detected.

In this way, the CO oxidation catalyst layer 50 directly suppresses the temperature rise due to the heat generated by the reduction of CO oxidation, thereby increasing the CO reduction effect.

Here, the effect of the CO reduction device of the fourth embodiment will be described with specific numerical values. Temperature sensor 45
b, the outlet temperature of the CO oxidation catalyst layer 50 is detected, and
Except that air is supplied to the cooling means 51 provided on the outside of the container of the CO oxidation catalyst layer 50 so that the temperature of the reformed gas inlet is 12 ° C.
At 0 ° C. only), the CO concentration at the outlet of the CO oxidation catalyst layer 50 was 40 ppm, which was lower than 60 ppm of the comparative example.

FIG. 5 is a block diagram showing a fifth embodiment of the CO reduction apparatus according to the present invention. The reformer 12 shown in FIG.
After passing through the CO reduction device 16, the reformed gas is sent to the polymer electrolyte fuel cell 14. In this case, the temperature of the reformed gas from the reformer 12 is 200C to 300C. If the amount of the reforming catalyst is sufficiently charged, the CO concentration is sent out as an equilibrium concentration of the outlet temperature of the reformer 12. If the outlet temperature is low, the CO concentration is low. However, if the temperature is lower than 200 ° C., the reaction rate is remarkably slowed down, and the amount of catalyst becomes enormous. At this time, the CO concentration is about 0.2%, but this is the minimum value.
The concentration is usually about 0.5%.

When such a reformed gas flows into the oxidation reaction vessel 55 through the reformed gas pipe 36 as shown in FIG. 5, the CO concentration is measured by the CO concentration sensor 51.
In addition, oxygen for oxidizing CO is introduced into the reformed gas pipe 36 through the air introduction pipe 38 at an appropriate flow rate by the flow rate regulator 40, merges with the reformed gas, and is mixed with the reformed gas by the mixing means 28. After the oxygen is mixed and the inlet gas temperature is measured by the temperature sensor 52, the oxygen enters the oxidation reaction vessel 55 in which the oxidation catalyst 53 and the substance 54 having no oxidation activity are mixed.
CO is oxidized and reduced and sent to the fuel cell 14.

Here, C in the fifth embodiment is used.
The effect of the O reduction device 16 will be described using specific numerical values. A Pt catalyst (catalyst carrying amount 0.25%) was used as an oxidation catalyst 53 for selectively oxidizing CO, and an alumina ball (3 mm sphere) was used as a substance 54 having no oxidation activity. Also, the reformed gas (H ₂ / H ₂₎ from the reformer 12 of FIG.
(CO / CO ₂ = 75 / 24.5 / 0.5) to 20 L / mi
It was delivered at a flow rate of n.

The air was introduced through the air introduction pipe 38 by adjusting the flow rate at the flow regulator 40 so that the flow rate became O ₂ /CO=1.5. At the same time, the CO concentration in the reformed gas in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was measured.

As a result, by mixing the oxidation catalyst 53 for selectively oxidizing CO with the substance 54 having no oxidation activity, the oxidation reaction of CO gradually occurs in the entire oxidation reaction vessel 55.

The oxidation reaction vessel 55 contains a Pt catalyst: 10
When 0 cc was charged and the inlet gas temperature measured by the temperature sensor 52 was 120 ° C., the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 400 ppm.
On the other hand, the Pt catalyst: 100 c
When c and alumina balls: 100 cc were mixed, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 80 ppm.

From this, it can be seen that the CO reduction device improves the CO reduction efficiency as compared with the related art. Next, a sixth embodiment of the CO reduction device according to the present invention will be described with reference to FIG.

The CO reduction device 16 of the sixth embodiment
Differs from the fifth embodiment only in the type of the oxidation catalyst 53 that selectively oxidizes CO, and the other members perform the same function as the fifth embodiment.
Here, the description thereof is omitted.

In the sixth embodiment, as the oxidation catalyst 53, for example, Pt, Ru, Pd and their alloys Pt-R
Noble metals such as u and oxides such as Mn ₂ O ₃ are used. In this case, a noble metal system having high activity and excellent selectivity of CO is excellent in making the apparatus compact, and is preferable in achieving the object of the present invention. Further, among the noble metal materials, Pt, Ru and the like are preferable. The oxidation catalyst 53 is preferably supported on a carrier having a large surface area, such as γ-alumina and silica-alumina. If the supported amount can be reduced, a less expensive catalyst can be obtained. However, if it is adjusted by a commonly used impregnation method in consideration of oxidation activity, for example, Pt is 0.2 to 0.5%, and Ru is 0.8 to 0.8%.
About 1.5% is required.

By using the oxidation catalyst 53 for selectively oxidizing CO, CO can be efficiently reduced.
Here, the CO reduction device 1 according to the sixth embodiment is described.
6 will be described using specific numerical values.

P is added to the oxidation catalyst 53 for selectively oxidizing CO.
t / γ alumina catalyst (catalyst loading 0.25%), Ru /
γ-alumina catalyst (catalyst loading 1%), Pt-Ru / γ-alumina catalyst (catalyst loading Pt: 0.2%, Ru: 0.8
%), Using a LaMn ₂ O ₃ catalyst (catalyst carrying amount 5%),
Alumina balls (3 mm spheres) were used for the substance 54 having no oxidation activity.

The reformed gas (H ₂ / CO ₂ = 75 / 24.5) from the reformer 12 shown in FIG.
/0.5) at a flow rate of 20 L / min. In addition, the flow rate of the air is set to O
_{2 /} CO was adjusted to 1.5 and introduced. At the same time, the CO concentration in the reformed gas in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was measured.

As a result, 100 cc of Pt / γ alumina and 100 cc of alumina balls were mixed in the oxidation reaction vessel 55 and the inlet gas temperature measured by the temperature sensor 52 was 120.
° C, the reformed gas line 36 downstream of the oxidation reaction vessel 55
Was 80 ppm.

When 100 cc of Ru / γ alumina and 100 cc of alumina balls were mixed in the oxidation reaction vessel 55, the CO concentration in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was 70 ppm.

Similarly, the Pt-Ru / γ is placed in the oxidation reaction vessel 55.
When 100 cc of alumina and 100 cc of alumina balls were mixed, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 75 ppm.

Further, when 100 cc of Pd / γ alumina and 100 cc of alumina balls are mixed in the oxidation reaction vessel 55, the reformed gas pipe 36 is provided downstream of the oxidation reaction vessel 55.
Was 230 ppm.

Similarly, La / Mn ₂ O is added to the oxidation reaction vessel 55.
₃ : When 100 cc and alumina balls: 100 cc were mixed, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 500 ppm.

Therefore, a Pt catalyst was used as the oxidation catalyst 53,
Alternatively, it has been found that the CO reduction device 16 in which the Ru catalyst or the Pt-Ru catalyst and the substance 54 having no oxidation activity are mixed improves the CO reduction efficiency as compared with the gunshot.

Next, a seventh embodiment of the CO reduction apparatus according to the present invention will be described with reference to FIG. The CO reduction device 16 of the seventh embodiment is different from the fifth embodiment in that the inactive substance is different from that of the fifth embodiment.
Since the same function as that of the embodiment is performed, the description thereof is omitted here.

In the seventh embodiment, it is preferable that the substance 54 having no oxidation activity has no oxidation activity so that oxygen for oxidizing CO is not consumed by hydrogen. For example, alumina, silica, and stainless steel are used. Things.

As described above, by mixing the oxidation catalyst 53 with the substance 54 having no oxidation activity, the CO oxidation reaction gradually occurs, the oxidation of hydrogen is suppressed, and the CO concentration can be reduced to an extremely low concentration.

Here, C in the seventh embodiment is used.
The effect of the O reduction device 16 will be described using specific numerical values. The material 54 having no oxidation activity is Fe ₂ O ₃ / alumina, silica, stainless steel, and the above oxidation catalyst 5 for comparison.
The Pt / γ alumina used in 3 was used. The reformed gas was delivered at a flow rate of 20 L / min through the reformed gas line 36.

Further, the inlet gas temperature is maintained at 150 ° C., and the air flows through the air introduction pipe 38 to the flow controller 40 where the flow rate becomes H.
It was introduced so as to be adjusted to ₂ / O ₂ = 99 / l. At the same time, the O ₂ concentration in the hydrogen gas in the reformed gas pipe 36 was measured downstream of the oxidation reaction vessel 55.

As a result, when the oxidation reaction vessel 55 is filled with 100 cc of Pt / γ alumina:
Downstream, the O ₂ concentration in the reformed gas line 36 was 0%.

If the oxidation reaction vessel 55 is filled with 100 cc of Fe ₂ O ₃ / alumina, the oxidation reaction vessel 55
The O ₂ concentration in the reformed gas line 36 downstream of the 0.1%
Met.

Further, the alumina: 1 was placed in the oxidation reaction vessel 55.
When filled with 00 cc, the O ₂ concentration in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was 1%. Silica and stainless steel also had an O ₂ concentration of 1%.

Therefore, the CO reduction apparatus 1 using alumina, silica, and stainless steel as the substance 54 having no oxidizing activity was used.
6 suppresses the consumption of oxygen due to the reaction between hydrogen and oxygen,
O reduction efficiency can be improved.

Next, an eighth embodiment of the CO reduction apparatus according to the present invention will be described with reference to FIG. The CO reducing device 16 according to the eighth embodiment is different from the fifth embodiment in that the shape of the inactive substance is different, and the other members perform the same function as the fifth embodiment. Therefore, the description is omitted here.

In the eighth embodiment, as the substance 54 having no oxidizing activity, the reformed gas is supplied to the fuel cell 14 without causing a pressure loss in the oxidation reaction vessel 55 by using granulated particles. You.

Here, C in the eighth embodiment is used.
The effect of the O reduction device 16 will be described using specific numerical values. Alumina powder having an average particle diameter of 100 μm was used as the material 54 having no oxidizing activity, and 1 mm spherical alumina balls and 6 mm spherical alumina balls were used. The reformed gas was delivered at a flow rate of 20 L / min through the reformed gas line 36.

Further, the temperature of the inlet gas is maintained at 150 ° C., and the air flows through the air introduction line 38 at the flow controller 40 so that the flow rate becomes O.
_{2 /} CO was adjusted to 1.5 and introduced. At the same time, the pressure loss in the oxidation reaction vessel 55 was measured in the reformed gas pipe 36 upstream and downstream of the oxidation reaction vessel 55.

As a result, 100c having an average particle diameter of 100 μm
c, the pressure loss in the oxidation reaction vessel 55 is 0.3
kgf / cm ² . In addition, 1mm ball alumina ball
The pressure loss of the oxidation reaction vessel 55 when filling with 00 cc was 0.1 kgf / cm ² .

Further, 100 mm of 3 mm spherical alumina balls were
The pressure loss of the oxidation reaction vessel 55 when filling cc is 0 kg
f / cm ² . Similarly, one alumina ball of 6 mm sphere
The pressure loss of the oxidation reaction vessel 55 when filling with 00 cc was 0 kgf / cm ² .

Thus, by using particles obtained by granulating the shape of the substance 54 having no oxidizing activity, the CO reducing device 16 can supply the reformed gas to the fuel cell 14 without generating a pressure loss as compared with the prior art. Supplied.

Next, a ninth embodiment of the CO reduction device according to the present invention will be described with reference to FIG. The CO reduction device 16 of the ninth embodiment is different from the CO reduction device 16 of the fifth embodiment described above.
Oxidation catalyst 53 for selectively oxidizing O and inactive substance 5
Since the volume ratio of 4 is different, the other members perform the same functions as in the fifth embodiment, and therefore, description thereof will be omitted here.

In the ninth embodiment, the substance 54 having no oxidizing activity preferably has no oxidizing activity in order to prevent oxygen for oxidizing CO from being consumed by hydrogen. In this way, the CO oxidation reaction gradually occurs by mixing the oxidation catalyst 53 with the substance 54 having no oxidation activity.

Here, C in the ninth embodiment is used.
The effect of the O reduction device 16 will be described using specific numerical values. Alumina balls (3 mm
Sphere). Also, from the reformer through a reformed gas line 36 reformed gas _{(H 2 / CO / CO 2} = 75 / 24.5 /
0.5) was delivered at a flow rate of 20 L / min.

The air was introduced through the air introduction pipe 38 by adjusting the flow rate at the flow regulator 40 so that the flow rate became O ₂ /CO=1.5. At the same time, the CO concentration in the reformed gas placed in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was measured.

As a result, when 100 cc of Pt / γ alumina and 50 cc of alumina balls were mixed in the oxidation reaction vessel 55, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 100 ppm.

When 100 cc of Pt / γ alumina and 100 cc of alumina balls were mixed in the oxidation reaction vessel 55, the CO concentration in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was 50 ppm.

Further, when 1000 cc of Pt / γ alumina and 500 cc of alumina balls are mixed in the oxidation reaction vessel 55, the reformed gas pipe 36 is provided downstream of the oxidation reaction vessel 55.
Was 10 ppm.

When the amount of alumina balls was further increased, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 tended to increase. From this, the CO reduction device 16 mixes the oxidation catalyst 53 and the substance 54 having no oxidation activity in a ratio of 2: 1 to 1:10 to reduce the C.
It was found that the O oxidation reaction occurred gradually, and the CO reduction efficiency was improved as compared with the conventional case.

Next, a tenth embodiment of the CO reduction apparatus according to the present invention will be described with reference to FIG. In the CO reduction device 16 of the tenth embodiment, the reformed gas line 36 in which the air introduction line 38 for introducing oxygen or air of the fifth embodiment is located upstream of the oxidation reaction vessel 55 is used. The connection is made only at one point, and the other members perform the same functions as those of the fifth embodiment. Therefore, description thereof is omitted here.

By mixing the oxidation catalyst 53 and the substance 54 having no oxidation activity as in the tenth embodiment, the CO oxidation reaction occurs gradually, so that CO can be reduced even if introduced from one place.

Here, the above effects of the CO reduction device 16 in the tenth embodiment will be described using specific numerical values. 100 cc of the Pt catalyst was used as the oxidation catalyst 53, and 500 cc of alumina balls were used as the substance 54 having no oxidation activity.
The reformed gas (H ₂ / H ₂₎ passes through the reformed gas line 36 from the reformer.
(CO / CO ₂ = 75 / 24.5 / 0.5) to 20 L / mi
It was delivered at a flow rate of n.

The air was introduced through the air introduction pipe 38 by adjusting the flow rate at the flow regulator 40 so that the flow rate became O ₂ /CO=1.5. At the same time, the CO concentration in the reformed gas in the reformed gas line 36 downstream of the oxidation reaction vessel 55 was measured.

As a result, the CO concentration in the reformed gas pipe 36 downstream of the oxidation reaction vessel 55 was 50 ppm.
Here, a comparison with the conventional configuration shown in FIG. 8 is as follows. In FIG. 8, an oxidation catalyst 5 is placed in a first oxidation reaction vessel 7.
As No. 3, 100/3 cc of a Pt catalyst and 500/3 cc of alumina balls as a substance 54 having no oxidation activity were mixed and filled, and the second and third oxidation reaction vessels 8 and 9 were similarly mixed and charged.

Further, the reformed gas (H
₂ / CO / CO ₂ = 75 / 24.5 / 0.5) to 20 L
/ Min at a flow rate of / min. Further, the air passes through the air introduction line 3 and has an air volume L equivalent to O ₂ / CO / CO 2 = 1.5.
Was adjusted by the flow controller 5a so that L / 3 was supplied to the first oxidation reaction vessel 7. Similarly, the second oxidation reaction vessel 8,
The flow rate was adjusted by the flow regulators 5b and 5c so that L / 3 was supplied to the third reaction vessel 9. At the same time, the CO concentration in the reformed gas in the reformed gas line 2 was measured downstream of the third reaction vessel 9.

As a result, the CO concentration in the reformed gas line 2 downstream of the third oxidation reaction vessel 9 was 50 ppm. From this, it was found that the CO reduction device 16 can reduce CO even in one place where oxygen or air is introduced, and can reduce CO with a simpler structure than in the related art.

Next, an eleventh embodiment of the CO reduction device according to the present invention will be described with reference to FIG. The CO reducing device 16 according to the eleventh embodiment is provided with a cooling means 56 for cooling the oxidation catalyst 53 and the inactive substance 54 filled in the oxidation reaction vessel 55 according to the fifth embodiment. Since the other members have the same functions as those of the fifth embodiment, description thereof will be omitted here.

As shown in FIG. 6, the temperature rise in the oxidation reaction vessel 55 due to the heat generated by the oxidation and reduction of CO
By directly suppressing the amount of CO by using No. 6, the CO reduction effect can be increased.

Here, the effects of the CO reduction device 16 in the eleventh embodiment will be described using specific numerical values. A Pt catalyst was used as the oxidation catalyst 53, and an alumina ball (3 mm ball) was used as the substance 54 having no oxidation activity. The reformed gas (H ₂ / H ₂ ) from the reformer 12 of FIG.
(CO / CO ₂ = 75 / 24.5 / 0.5) to 20 L / mi
It was delivered at a flow rate of n. The air was introduced through the air introduction line 36 by adjusting the flow rate at the flow regulator 40 so that the flow rate became O ₂ /CO=1.5. At the same time, CO in the reformed gas in the reformed gas line 36 downstream of the oxidation reaction vessel 55
The concentration was measured.

As a result, when 100 cc of Pt / γ alumina and 500 cc of alumina balls were mixed in the oxidation reaction vessel 55, the reformed gas pipe 3 was located downstream of the oxidation reaction vessel 55.
The CO concentration at 6 was 50 ppm.

Further, the temperature of the oxidation catalyst 53 in the oxidation reaction vessel 55 is increased by the cooling means 56 so that the oxidation reaction of CO proceeds.
By cooling to 00 ° C. to 160 ° C., the CO concentration in the reformed gas line 36 downstream of the oxidation reaction vessel 55 becomes 10%.
ppm.

From this, it was found that the CO reduction device 16 further reduced CO by cooling the inside of the oxidation reaction vessel 55, and the CO reduction efficiency was improved as compared with the conventional case.

The present invention is not limited to the above-described embodiments, but can be implemented with various modifications without departing from the scope of the invention. For example, in the eighth embodiment, the shape of the inactive substance 54 is described as a sphere. However, the present invention is not limited to this. Even when the shape is a column, ring, three leaf, or four leaf, By selecting an appropriate size, the oxidation reaction vessel 5
The reformed gas is supplied to the fuel cell without causing a pressure loss of 5.

In the CO reducing apparatus of the eleventh embodiment, the cooling means 56 for cooling is provided inside the oxidation reaction vessel 55, but is not limited to this. The structure installed outside the container 55 may be sufficient. Further, a fin may be provided inside or outside the oxidation reaction vessel 55.

Even with such a configuration, the influence of heat generation due to the CO oxidation reaction can be reduced, and the CO reduction efficiency can be improved. Further, the mixing ratio of the oxidation catalyst 53 and the substance 54 having no oxidation activity and the installation of the cooling means 56 depend on the size and cost of the CO reduction device 16,
May be determined depending on the CO concentration at the outlet of the present invention, and the gist of the present invention is not changed at all.

[0143]

As described above, according to the present invention, an apparatus for reducing carbon monoxide in a solid polymer fuel cell system capable of reducing carbon monoxide with an efficient, simple and simple structure, and its operation We can provide a method.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a polymer electrolyte fuel cell system to which the present invention is applied.

FIG. 2 is a block diagram showing a schematic configuration for explaining a first embodiment of a CO reduction device according to the present invention.

FIG. 3 is a block diagram showing a schematic configuration for explaining second and third embodiments of the CO reduction device according to the present invention.

FIG. 4 is a block diagram showing a schematic configuration for explaining a fourth embodiment of a CO reduction device according to the present invention.

FIG. 5 is a block diagram showing a schematic configuration for describing fifth to tenth embodiments of a CO reduction device according to the present invention.

FIG. 6 is a block diagram showing a schematic configuration for explaining an eleventh embodiment of a CO reduction device according to the present invention.

FIG. 7 is a block diagram showing a schematic configuration of a conventional CO reduction device.

FIG. 8 is a block diagram showing a schematic configuration of a different conventional CO reduction device.

[Explanation of symbols]

 10 solid polymer fuel cell system 12 reformer 14 solid polymer fuel cell 16 CO reduction device 18 reforming unit 20 heating unit 22 solid polymer electrolyte membrane 24 ... Anode 26 ... Cathode 27a, 27b ... Temperature sensor 28,28a, 28b ... Mixing means 30a ... First CO oxidation catalyst layer 30b ... Second CO oxidation catalyst layer 31a ... Particulate Pt catalyst 31b ... ... Granular Ru catalyst 32 ... Cooling means 36 ... Reformed gas pipe 38 ... Air introduction pipe 38a, 38b ... Branch pipe 40, 40a, 40b ... Flow regulator 44 ... Reformed gas pipe 45a , 45b Temperature sensor 46 Mixing means 48 Air introduction conduit 49 Flow regulator 50 CO oxidation catalyst layer 51 CO concentration sensor 52 Temperature sensor 53 Oxidation catalyst 54 Activity without substance 55 ...... oxidation reaction vessel 56 ...... cooling means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Hizuka 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Inside Keihin Works, Toshiba Corporation

Claims (16)

[Claims] An apparatus for oxidizing and reducing carbon monoxide in a reformed gas of a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol-based fuel, comprising: A means for introducing oxygen or air into a region having a temperature of 100 to 150 ° C., and a carbon monoxide oxidation catalyst layer provided downstream of the introduction point of the oxygen or air. Carbon monoxide reduction device. 2. The carbon monoxide reducing device for a polymer electrolyte fuel cell according to claim 1, wherein a mixing means is provided between the means for introducing oxygen or air and the carbon monoxide oxidation catalyst layer. Carbon monoxide reduction device for polymer electrolyte fuel cells. 3. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 1, wherein a cooling means is provided on an outer surface or inside the carbon monoxide oxidation catalyst layer container. Carbon monoxide reduction device for polymer electrolyte fuel cells. 4. An apparatus for reducing oxidation of carbon monoxide in a reformed gas using a catalyst in a polymer electrolyte fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel, comprising: A carbon oxide oxidation catalyst layer is provided, and a Pt catalyst is stored in a first carbon monoxide oxidation catalyst layer in the first stage, and a Ru catalyst is stored in a second carbon monoxide oxidation catalyst layer in the second stage. And a means for introducing oxygen or air. 5. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 4, further comprising mixing means between the first catalyst or air introducing means and the first carbon monoxide oxidation catalyst layer. A carbon monoxide reduction device for a polymer electrolyte fuel cell, comprising: 6. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 4, wherein the first carbon monoxide oxidation catalyst layer and the second carbon monoxide oxidation catalyst layer are disposed between the first carbon monoxide oxidation catalyst layer and the second carbon monoxide oxidation catalyst layer. A carbon monoxide reducing device for a polymer electrolyte fuel cell, comprising a cooling means. 7. The apparatus for reducing carbon monoxide for a polymer electrolyte fuel cell according to claim 3, wherein the temperature of the reformed gas at the inlet is set to 100 to 150 ° C. Characteristic device for reducing carbon monoxide for polymer electrolyte fuel cells. 8. A catalyst layer for oxidizing and reducing carbon monoxide in a reformed gas of a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel.
One carbon monoxide oxidation catalyst layer is provided, a Pt catalyst is stored in a first first carbon monoxide oxidation catalyst layer, and a Ru catalyst is stored in a second second carbon monoxide oxidation catalyst layer. In a method for operating a carbon monoxide reduction device for a polymer electrolyte fuel cell comprising an oxygen or air introducing means corresponding to the above, the O ₂ / CO ratio in the introduced oxygen amount or the introduced air amount is changed to the first monoxide in the preceding stage. Small for carbon oxidation catalyst layer,
Larger for the second carbon monoxide oxidation catalyst layer,
A method of operating a carbon monoxide reduction device for a polymer electrolyte fuel cell, wherein O ₂ / CO is reduced as a whole. 9. An apparatus for oxidizing and reducing carbon monoxide in a reformed gas of a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol-based fuel, the method comprising: Carbon monoxide reduction for solid polymer fuel cells, characterized in that an oxidation reaction vessel containing an oxidation catalyst for selectively oxidizing carbon monoxide in the reformed gas and a substance having no oxidation activity is provided. apparatus. 10. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 9, wherein the oxidation catalyst for selectively oxidizing carbon monoxide is a Pt catalyst, a Ru catalyst, or a P catalyst.
A carbon monoxide reduction device for a polymer electrolyte fuel cell, which is a t-Ru alloy catalyst. 11. The solid polymer fuel cell according to claim 9, wherein the substance having no oxidizing activity is alumina, silica, or stainless steel. For carbon monoxide reduction equipment. 12. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 11, wherein the substance having no oxidizing activity is formed into granulated particles. Carbon oxide reduction device. 13. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 9, wherein the volume ratio between the oxidation catalyst and the substance having no oxidation activity is 2: 1 to 1:10. Carbon monoxide reduction device for polymer fuel cells. 14. The apparatus for reducing carbon monoxide for a polymer electrolyte fuel cell according to claim 9, wherein one oxygen or air introduction system is provided upstream of the oxidation reaction vessel. Carbon monoxide reduction device. 15. The carbon monoxide reduction device for a polymer electrolyte fuel cell according to claim 9, further comprising a cooling means for cooling a reaction layer in which an oxidation catalyst and a substance having no oxidation activity are mixed inside or outside the oxidation reaction vessel. A carbon monoxide reduction device for a polymer electrolyte fuel cell. 16. A method of operating an apparatus for reducing oxidation of carbon monoxide in a reformed gas of a solid polymer fuel cell system including a fuel reforming system for reforming a hydrocarbon or alcohol fuel by using a catalyst, the method comprising: When reducing the carbon monoxide contained in the reformed gas by using an oxidation catalyst, the temperature of the oxidation reaction layer formed by mixing the oxidation catalyst and the substance having no oxidation activity is 100 ° C. to 160 ° C. where the oxidation reaction of CO proceeds. A method for operating a carbon monoxide reduction device for a polymer electrolyte fuel cell, characterized in that the device is cooled so as to be maintained at a temperature.