JP2002193602A - Device for decreasing co for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smaller reactor with better performance as well as improved vibration resistance of the reactor body. SOLUTION: The reactor body 1 comprises an inlet 2 for introducing reformed gas, catalyst layers 3 for converting CO in reformed gas into CO2, and an outlet 4 for emitting the reformed gas in which the CO is decreased. It has means 6 and 7 for adjusting the temperature of the reactor body 1. At least a portion of catalyst support in the catalyst layers 3 is formed of porous body 8 made from both or either of ceramic or metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon monoxide reducing device for a fuel cell applied to a solid polymer fuel cell system using a hydrocarbon or alcohol as a raw fuel.

[0002]

2. Description of the Related Art Generally, a fuel cell generates electricity from hydrogen obtained by reforming various fuels and oxygen in the air. As the fuel for the fuel cell, hydrocarbons such as methane, ethane, and propane, or alcohols such as methanol are steam reformed to produce hydrogen. The reformed gas obtained here contains hydrogen as a main component, and contains carbon dioxide, water vapor and carbon monoxide (generally about 6 to 8%) as other components.

The polymer electrolyte fuel cell can be operated at a relatively low temperature (60 to 120 ° C.) as compared with other fuel cells, and the electrolyte is not corrosive and easy to handle. Has advantages. In addition, since the polymer electrolyte fuel cell can be operated at a much higher current density than a phosphoric acid type fuel cell or the like, it is expected to be used as a mobile power supply mounted on an automobile or the like.

However, in a polymer electrolyte fuel cell, when operating at a low temperature, the catalyst of the fuel electrode of the cell is easily affected by poisoning by carbon monoxide. Need to be kept low. For example, when the operating temperature of the polymer electrolyte fuel cell is set to about 90 ° C., the carbon monoxide concentration of the reformed gas supplied to the cell is set to 10 p.
If it is not reduced below pm, the characteristics of the battery will deteriorate over time.

[0005] Therefore, in a polymer electrolyte fuel cell, a reactor for effectively reducing the concentration of carbon monoxide in the reformed gas supplied to the cell is required. In particular, when constructing an in-vehicle fuel cell system, it is necessary to reduce the size of the reactor in order to make effective use of the limited space and to have a strong structure that can withstand vibration during operation. Can be

Hereinafter, a conventional example of a carbon monoxide reducing device for a fuel cell will be described with reference to FIG.

As shown in FIG. 7, the conventional apparatus for reducing carbon monoxide for a fuel cell comprises a reaction vessel main body 1, an inlet 2 for introducing a reformed gas into the reaction vessel main body 1, and a reforming gas inlet. A catalyst layer 3 for converting carbon monoxide in the gas into carbon dioxide;
And an outlet 4 for discharging the reformed gas with reduced carbon monoxide.

The catalyst layer 3 is generally formed by filling a granular catalyst 5 formed into a tablet, a sphere or a granule. A heating unit 6 is provided around the reaction vessel main body 1, and the heating section 6 is provided on the basis of a detection signal from a temperature detection unit 7 such as a thermocouple for detecting the temperature of the catalyst layer 3. Adjust the temperature of 1 properly.

In the carbon monoxide reducing device for a fuel cell configured as described above, carbon monoxide in the reformed gas comes into contact with the particulate catalyst 5 in the catalyst layer 3 when passing through the reaction vessel main body 1. After being converted to carbon dioxide by a chemical reaction
It is discharged from the discharge port 4.

[0010]

However, in the above-described conventional carbon monoxide reducing device for a fuel cell, the device is not operated due to fluidization of the particulate catalyst 5 accompanying gas flow during operation of the device or vibration applied to the system. The charged granular catalyst 5 gradually powdered due to internal friction, and the differential pressure increased, which sometimes hindered the operation of the system.

In order to improve the reforming characteristics, it is effective to increase the surface area per unit volume of the catalyst layer 3 to increase the contact area with the reaction gas. In order to increase the particle size, it is necessary to reduce the particle size, and the resulting increase in pressure loss has been a factor limiting the improvement of the characteristics of the reaction vessel body 1.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and aims at improving the vibration resistance of a reaction vessel main body and improving the performance of the reaction vessel main body so as to reduce the size of a fuel cell. It is an object to provide a carbon monoxide reduction device.

[0013]

To achieve the above object, according to the first aspect of the present invention, there is provided an inlet for a reformed gas containing at least carbon monoxide, and an inlet for the reformed gas introduced from the inlet. A reaction vessel body having a catalyst layer for converting carbon monoxide to carbon dioxide, an outlet for discharging the reformed gas having reduced carbon monoxide by the catalyst layer, and adjusting the temperature of the reaction vessel body. A carbon monoxide reducing device for a fuel cell comprising a temperature adjusting means, wherein at least a part of a catalyst support of the catalyst layer is formed of at least one of a porous body of ceramics and metal. is there.

The porous body according to the first aspect of the present invention is a structure having a large number of pores, such as a honeycomb or a foam.

According to the first aspect of the present invention, at least a part of the catalyst support of the catalyst layer is formed of at least one of a porous body of ceramics and metal.
The catalyst support has a strong structure and has a large surface area. By applying a catalyst to the support, the vibration resistance of the reaction vessel body is improved, and the surface area per unit volume of the catalyst layer is increased. be able to. as a result,
The reforming characteristics of the reaction vessel main body can be improved, and the size can be easily reduced.

According to a second aspect of the present invention, in the carbon monoxide reducing device for a fuel cell according to the first aspect, at least a part of the catalyst support of the catalyst layer is made to react with carbon monoxide and water vapor to produce carbon dioxide. And a shift catalyst for converting to hydrogen.

According to the second aspect of the present invention, by applying a shift catalyst to a catalyst support having a strong structure and a large surface area, the vibration resistance of the reaction vessel main body is improved, and the catalyst layer is formed. Surface area per unit volume can be increased. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

According to a third aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to the second aspect, a noble metal such as platinum, gold, or ruthenium is used as an active species of the shift catalyst. It is assumed that.

According to the third aspect of the invention, the use of a noble metal as the active species of the shift catalyst allows the shift catalyst to have oxidation resistance. This makes it possible to stabilize the characteristics of the reaction vessel main body and reduce the size of the fuel cell reforming system.

According to a fourth aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to the second aspect, the applied shift catalyst is selected from cerium, lanthanum, ruthenium, silicon, calcium, strontium, magnesium, and bismuth. At least one element to be added is added.

According to the fourth aspect of the present invention, by adding the above elements to the shift catalyst, the time characteristics of the shift catalyst can be stabilized and the catalyst activity can be improved. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

According to a fifth aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to the first aspect, a flow path for flowing a cooling medium is formed in at least a part of the catalyst support of the catalyst layer. It is characterized by having done.

According to the fifth aspect of the present invention, at least a part of the catalyst support is provided with a flow path for flowing a cooling medium, so that at least a part of the reaction vessel main body is kept at a temperature suitable for the reaction. Can be cooled down. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

According to a sixth aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to the first or fifth aspect, a flow path for a reformed gas and a flow path for flowing a cooling medium in the reaction vessel main body. Are formed in a meandering shape.

According to the sixth aspect of the present invention, the reformed gas flow path and the flow path for circulating the cooling medium are formed in a meandering shape, so that the reformed gas and the cooling medium are efficiently contacted. be able to. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

According to a seventh aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to any one of the first to sixth aspects, the applied catalyst differs depending on the position of the catalyst layer. Things.

According to the seventh aspect of the present invention, the applied catalyst is made different depending on the position of the catalyst layer.
Regarding the temperature distribution inside the reaction vessel body or the composition of the reformed gas, the most appropriate catalyst can be used to promote the carbon monoxide reduction reaction. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

[0028] In the invention according to claim 8, in the carbon monoxide reduction device for a fuel cell according to any one of claims 1 to 7, the amount of catalyst per unit volume of the catalyst layer and the catalyst are determined by the position of the catalyst layer. It is characterized in that any one of the amounts of the added additives is different.

According to the present invention, either the amount of the catalyst per unit volume of the catalyst layer or the amount of the additive added to the catalyst differs depending on the position of the catalyst layer. Regarding the internal temperature distribution or the composition of the reformed gas, the reduction reaction of carbon monoxide can be promoted by using a catalyst to which an additive is added in the most appropriate ratio.
Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

According to a ninth aspect of the present invention, in the carbon monoxide reduction device for a fuel cell according to any one of the first to eighth aspects, at least one of ceramics and metal supporting a catalyst depending on the position of the catalyst layer. The number of cells per unit cross-sectional area of the material is different.

According to the ninth aspect of the present invention, the number of cells per unit cross-sectional area of at least one of the ceramic and metal porous bodies supporting the catalyst varies depending on the position of the catalyst layer. According to the internal temperature distribution or the composition distribution of the reformed gas, the porosity of the porous body that is the support of the catalyst layer is controlled, and the surface area per unit volume of the catalyst along the reformed gas flow direction in the catalyst layer is controlled. After optimizing the change in carbon monoxide, the reduction reaction of carbon monoxide can be promoted. This improves the reforming characteristics of the reaction vessel body,
The size of the reaction vessel body can be reduced.

According to a tenth aspect of the present invention, in the carbon monoxide reducing device for a fuel cell according to any one of the first to eighth aspects, at least one of ceramics and metal supporting a catalyst depending on the position of the catalyst layer. The porosity of the body is different.

According to the tenth aspect of the present invention, the porosity of at least one of the ceramic and metal porous bodies supporting the catalyst is made different depending on the position of the catalyst layer. According to the composition distribution of the reformed gas, the porosity of the porous body which is the support of the catalyst layer is controlled to change the surface area per unit volume of the catalyst along the direction of the reformed gas flow in the catalyst layer, and The reaction for reducing carbon monoxide can be promoted after optimizing the pressure loss of the bed. Thereby, the reforming characteristics of the reaction vessel main body can be improved, and the size of the reaction vessel main body can be reduced.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a carbon monoxide reduction device for a fuel cell according to the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a cross-sectional view showing a first embodiment of a carbon monoxide reduction device for a fuel cell according to the present invention. Parts that are the same as or correspond to the conventional configuration will be described using the same reference numerals as in FIG.

As shown in FIG. 1, this embodiment comprises a reaction vessel main body (reactor) 1 and an inlet 2 for introducing a reformed gas containing carbon monoxide into the reaction vessel main body 1. ,
A catalyst layer 3 for converting carbon monoxide in the reformed gas introduced from the inlet 2 into carbon dioxide, and an outlet 4 for discharging a reformed gas having reduced carbon monoxide by the action of the catalyst layer 3; And a heating unit 6 and a temperature detecting unit 7 as temperature adjusting means for appropriately adjusting the temperature of the catalyst layer 3.

As the catalyst support of the catalyst layer 3, a ceramic (cordierite) honeycomb 8, which is a porous body having a strong and large surface area, is used. The catalyst is wash-coated on the ceramic honeycomb 8 to form a catalyst layer. Form 3 Here, the dimensions of the ceramic honeycomb 8 were cylindrical having a diameter of 3 cm and a length of 10 cm, and the number of cells per 1 cm ^{2 of} cross-sectional area was 400 cells. A filler 9 such as glass wool is inserted between the reaction vessel main body 1 and the ceramic honeycomb 8 in order to prevent the reformed gas from slipping through.

Next, the operation of the present embodiment will be described.

In a reactor having the same dimensions, a diameter of 4 mm,
A reactor filled with a pellet-shaped catalyst having a height of 4 mm was prepared, and compared with a reactor using the ceramic honeycomb 8 according to the present embodiment as a catalyst support.

First, when a test in which vibration was applied to each reactor at a rate of 120 times per minute was performed for 10 hours, about 8% by weight of the catalyst was powdered in the reactor filled with the conventional granular catalyst. However, in the reactor using the ceramic honeycomb 8 according to the present embodiment as a catalyst support, powdering of the catalyst was not observed.

Further, when the catalyst surface area per unit volume in the catalyst layer of the reactor was compared, the catalyst surface area per unit volume of the honeycomb catalyst according to the present embodiment was about 1% of that of the conventional reactor packed with the granular catalyst. From 1.5 times to 1.8 times.

As described above, according to this embodiment, the catalyst is applied to the catalyst layer 3 of the reactor on a support formed of a porous body such as a honeycomb or a foam having excellent mechanical strength. Therefore, even if the device itself vibrates, it is not damaged, and the characteristics of the reactor can be maintained.

Further, the reaction area per unit volume can be increased as compared with a conventional reactor formed by filling a granular catalyst, so that the characteristics as a reactor can be improved. As a result, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size can be easily reduced.

In the present embodiment, the ceramic honeycomb 8 is used for the entire catalyst support of the catalyst layer 3, but a part thereof may be used, and a metal honeycomb, a ceramic foam,
The same effect can be obtained by using any one of the metal foams or a combination thereof. That is, the catalyst support of the catalyst layer 3 may be formed of at least one of a porous body of ceramics or metal. The same applies to the following embodiments.

[Second Embodiment] FIG. 2 is a cross-sectional view showing a second embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and described. The same applies to the following embodiments.

In this embodiment, the dimensions of the reaction vessel main body 1 in FIG. 2 are the same as those of the reaction vessel main body 1 described in the first embodiment, and the catalyst layer 3 is formed by washing a copper-zinc-aluminum oxide catalyst. It is composed of a coated ceramic honeycomb 10 and a filler 9 such as glass wool for preventing the reformed gas from slipping through.

Next, the operation of the present embodiment will be described.

In the present embodiment having the above-described structure, carbon monoxide in the reformed gas introduced into the reaction vessel main body 1 also contains a catalyst layer in the reaction vessel main body 1 together with water vapor in the reformed gas. The catalyst comes into contact with the catalyst supported on 3 and is converted into carbon dioxide and hydrogen by a chemical reaction represented by the following reaction formula, and is discharged from the outlet 4.

[0049]

## STR1 ## _{CO + H 2 O → CO 2} + H 2 In this case, if it has a sufficient amount of catalyst reaction vessel main body 1 with respect to the reformed gas flow rate, the fuel gas composition at the outlet 4 of the reformed gas, the reaction It becomes almost equal to the equilibrium condition at the operating temperature of the container body 1. For example, the composition of the introduced reforming gas is as follows: carbon monoxide 6%, steam 36%, carbon dioxide 10%.
% And hydrogen 29% (the rest is an inert component such as nitrogen), the equilibrium condition, that is, the theoretically lowest carbon monoxide concentration at the outlet of the reaction vessel main body 1 is as follows. About 0.5% at 200 ° C.
1%.

When the reactor temperature is set to 200 ° C. in the reaction vessel body 1 according to the present embodiment, the concentration of carbon monoxide at the outlet of the reaction vessel body 1 is 0.15%.
And a value almost equal to the equilibrium concentration was obtained.

As described above, according to the present embodiment, the catalyst layer 3
By applying a shift catalyst to a honeycomb catalyst or a porous body having a large surface area per unit volume, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced. Further, the mechanical strength of the reaction vessel main body 1 can be improved by applying the shift catalyst to a support having excellent vibration resistance.

[Third Embodiment] Next, a third embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention will be described with reference to FIG.

In this embodiment, the dimensions of the reaction vessel body 1 in FIG. 2 are the same as those of the reaction vessel body 1 described in the first embodiment, and the catalyst layer 3 is formed by wash-coating a platinum-titanium oxide catalyst. It is composed of a ceramic (cordierite) honeycomb 11 and a filler 9 such as glass wool for preventing the reformed gas from slipping through.

The amount of platinum carried on the catalyst layer 3 in this embodiment was 5 g per liter of the volume of the catalyst layer 3. The dimensions of the ceramic honeycomb 11 are 3 cm in diameter and 10 c in length.
m, the number of cells per one cross-sectional area was 400 cells.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, the temperature of the reaction vessel main body 1 is set to 300 ° C. by the temperature detecting section 7 and the heating section 6, and the reformed gas is reacted through the reformed gas inlet 2. When guided into the container body 1, the concentration of carbon monoxide at the outlet 4 of the reformed gas became about 0.6%.

Further, once the inlet 2 and outlet 4 of the reformed gas of the reaction vessel body 1 were disconnected from the pipe and opened to the atmosphere for 2 hours, the same test was conducted again by connecting the pipe. However, no change was observed in the carbon monoxide reduction characteristics before and after the opening to the atmosphere.

As described above, according to the present embodiment, since platinum is used as the active species of the shift catalyst, the shift catalyst used in the catalyst layer 3 has oxidation resistance. The catalyst characteristics are not affected by the leakage of air (oxygen), so that the reforming characteristics of the reaction vessel main body 1 can be obtained over a long period of time, and the reforming of the fuel cell can be performed without using a purge mechanism using an inert gas. Since the quality system can be configured, the reforming system can be downsized.

In this embodiment, platinum is used as the active species of the shift catalyst, but the same effect can be obtained by using a noble metal such as gold or ruthenium.

[Fourth Embodiment] Next, a fourth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention will be described with reference to FIG.

In this embodiment, the dimensions of the reaction vessel main body 1 in FIG. 2 are the same as those of the reaction vessel main body 1 described in the first embodiment, and the catalyst layer 3 is composed of a platinum-titanium oxide catalyst containing ruthenium and cerium. And a filler (eg, glass wool) that prevents the reformed gas from slipping through.

In this embodiment, the amount of platinum carried on the catalyst layer 3 was 5 g per liter of the volume of the catalyst layer 3, cerium was 10 g per liter of the catalyst layer, and ruthenium was 0.5 g per liter of the catalyst layer. The dimensions of the ceramic honeycomb 12 are a cylindrical shape having a diameter of 3 cm and a length of 10 cm, and a cross-sectional area of 1 c.
m ² per number of cells was 400 cells.

Next, the operation of the present embodiment will be described.

In the present embodiment configured as above, the temperature of the reaction vessel main body 1 is set to 250 ° C. by the temperature detecting section 7 and the heating section 6, and the reformed gas is reacted through the reformed gas inlet 2. When guided into the container body 1, the concentration of carbon monoxide at the outlet 4 of the reformed gas became about 0.3%. Under these conditions, continuous operation was performed for 100 hours, but after 100 hours, the concentration of carbon monoxide at the outlet 4 of the reformed gas was 0.4%, and there was almost no change over time. Almost the same effect was obtained when lanthanum, silicon, calcium, strontium, magnesium, bismuth or the like was added instead of cerium.

As described above, according to the present embodiment, deterioration of the characteristics over time can be prevented by adding at least one element selected from cerium, lanthanum, silicon, calcium, strontium, magnesium and bismuth to the shift catalyst. While being suppressed, the activity of the catalyst can be improved. Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

[Fifth Embodiment] FIG. 3 is a cross-sectional view showing a fifth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention.

In this embodiment, the dimensions of the reaction vessel main body 1 in FIG. 3 are basically the same as those of the reaction vessel main body 1 described in the first embodiment, and the catalyst layer 3 is formed of a platinum-titanium oxide catalyst. The material is wash-coated with a material to which cerium or ruthenium is added, and includes a metal honeycomb 13 mainly composed of nickel and a filler 9 such as glass wool for preventing the reformed gas from slipping through.

In the present embodiment, the amount of platinum carried on the catalyst layer 3 was 5 g per liter of the catalyst layer 3, cerium was 10 g per liter of the catalyst layer volume, and ruthenium was 0.5 g per liter of the catalyst layer. The dimensions of the metal honeycomb 13 are as follows:
The number of cells per cylinder of 3 cm in diameter and 8 cm in length and 1 cm ² in cross section was 400 cells.

Further, in the present embodiment, a cooling pipe 14 as a flow path for flowing a cooling medium is provided on the outer periphery of the reaction vessel main body 1 on the side of the discharge port 4, and the cooling medium is The gas is allowed to flow from the gas discharge port 4 side to the gas inlet port 2 side.

Further, at the installation position of the cooling pipe 14, a temperature detecting section 7a and a heating section 6a are provided.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, a cooling pipe 14 is provided on the outer periphery of the reaction vessel main body 1 on the side of the discharge port 4 so that the cooling medium flows from the fuel gas discharge port 4 side to the introduction port 2 side. It was distributed to.

In the reaction vessel main body 1 having such a structure, the reformed gas is introduced into the reaction vessel main body 1 through the reformed gas inlet 2 and is subjected to the temperature detection sections 7 and 7a and the heating sections 6 and
a, the temperature at the inlet 2 side of the reaction vessel body 1 is set to 300
When the temperature at the outlet 4 was set to 250 ° C., the concentration of carbon monoxide at the outlet 4 of the reaction gas was about 0.3 ° C.
%. Under these conditions, continuous operation was performed for 100 hours, but after 100 hours, the concentration of carbon monoxide at the outlet 4 of the reformed gas was 0.4%, and there was almost no change over time.

As described above, according to the present embodiment, by providing an appropriate temperature distribution in the reaction vessel main body 1, an efficient reaction can be stably performed, so that the size of the reaction vessel main body 1 can be reduced. Can be.

In the present embodiment, the cooling pipe 14 is installed on the outer periphery of the reaction vessel main body 1 on the side of the discharge port 4. However, the inside of the wall of the reaction vessel main body 1 at the same position, the inner wall of the reaction vessel main body 1, Alternatively, the structure may be such that it is embedded in the metal honeycomb 13.

Therefore, in the present embodiment, at least a part of the catalyst support is provided with a cooling pipe 14 for flowing a cooling medium, so that at least a part of the reaction vessel main body 1 is brought to a temperature suitable for the reaction. Can be cooled.

[Sixth Embodiment] FIG. 4 is a cross-sectional view showing a sixth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention.

The configuration of the catalyst layer 3 in this embodiment is such that three rectangular parallelepiped metal honeycombs 15 each having a length of 3 cm and a length of 8 cm are arranged in parallel.
A manifold 16 is arranged at both ends of the metal honeycomb 15, and a flow path is formed by the manifold 16 so that the reformed gas entering from the reformed gas inlet 2 passes through each metal honeycomb 15 in a meandering (serpentine) shape in order.

Each metal honeycomb 15 is wash-coated with a material containing nickel as a main component and adding cerium and ruthenium to a platinum-titanium oxide catalyst.

In this embodiment, the amount of platinum carried on the catalyst layer 3 was 5 g per liter of the catalyst layer 3, cerium was 10 g per liter of the catalyst layer, and ruthenium was 0.5 g per liter of the catalyst layer. Cooling pipes 14 for flowing a cooling medium are provided above and below each metal honeycomb 15, and flow the cooling medium in parallel with and opposite to the reformed gas.

Next, the operation of the present embodiment will be described.

In this embodiment having the above-described structure, when the reformed gas is introduced from the inlet 2 to the reaction vessel main body 1, the concentration of carbon monoxide at the outlet 4 is about 0.3%.
It became. Under these conditions, continuous operation was performed for 100 hours. After 100 hours, the concentration of carbon monoxide at the outlet 4 was 0.4%, and there was almost no change over time.

As described above, according to the present embodiment, three metal honeycombs 15 are arranged in parallel, the manifolds 16 are arranged at both ends of the metal honeycombs 15, and the flow path of the reformed gas and the flow path of the cooling medium are meandering. Thus, the reformed gas and the cooling medium can be efficiently contacted with a simple structure. Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

In FIG. 4, only one cooling pipe 14 is shown for the sake of simplicity. However, a plurality of cooling pipes may be used, and not only the top and bottom of each metal honeycomb 15 but also the partition wall or the bottom of each metal honeycomb 15. You may install in the side part of the reaction container main body 1.

[Seventh Embodiment] FIG. 5 is a cross sectional view showing a seventh embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention.

As shown in FIG. 5, each of the metal honeycombs 17a and 17b in the catalyst layer of the present embodiment is mainly composed of nickel and has a cylindrical shape having a diameter of 3 cm and a length of 4 cm, and a cross-sectional area of 1 cm. ^The number of cells per ² was 400 cells.

Metal honeycomb 1 on reformed gas inlet 2 side
A material obtained by adding cerium to a platinum-aluminum oxide catalyst is used for 7a, and a material obtained by adding cerium and ruthenium to a platinum-titanium oxide catalyst by wash coating is used for the metal honeycomb 17b on the outlet 4 side.

The amount of platinum supported on the metal honeycomb 17a is as follows:
While 5 g per liter of catalyst layer and 10 g per liter of cerium catalyst layer, the metal honeycomb 17
The amount of supported platinum on b was 3 g per liter of catalyst layer volume,
Cerium was 10 g per liter of catalyst layer volume, and ruthenium was 0.3 g per liter of catalyst layer volume.

The reaction vessel body 1 on the side of the metal honeycomb 17b
A cooling pipe 14 for circulating a cooling medium is installed on the outer periphery of the cooling gas pipe. The cooling pipe 14 circulates the cooling medium so as to flow from the fuel gas outlet 4 side to the inlet port 2 side.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, the reformed gas is introduced into the reaction vessel main body 1 from the introduction port 2, and the temperature detection sections 7, 7a and the heating sections 6, 6a introduce the reformed gas into the reaction vessel main body 1. When the temperature on the second side was set to 330 ° C. and the temperature on the outlet 4 side was set to 250 ° C., the outlet 4
Was about 0.5%. Under these conditions, continuous operation was performed for 100 hours.
The carbon monoxide concentration at the outlet 4 after 0 hour is 0.6%
And there was almost no change with time.

As described above, according to the present embodiment, the catalyst layer 3
Since the applied catalyst is made different depending on the position, the reduction reaction of carbon monoxide can be promoted by using the most suitable catalyst with respect to the temperature distribution inside the reaction vessel main body 1 or the composition of the reformed gas. . Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

[Eighth Embodiment] Next, an eighth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention will be described with reference to FIG.

As shown in FIG. 5, each of the metal honeycombs 17a and 17b in the catalyst layer of the present embodiment is mainly composed of nickel and has a cylindrical shape having a diameter of 3 cm and a length of 4 cm, and a cross-sectional area of 1 cm. ^The number of cells per ² was 400 cells.

The metal honeycomb 17 on the reformed gas inlet 2 side
For a, a material obtained by adding cerium to a platinum-titanium oxide catalyst is used, and for a metal honeycomb 17b on the reforming gas outlet 4 side, a material obtained by adding ruthenium to a platinum-titanium oxide catalyst by wash coating is used. I have.

The amount of platinum carried on the metal honeycomb 17a is as follows:
While 5 g per liter of catalyst layer and 10 g per liter of cerium catalyst layer, the metal honeycomb 17
The amount of supported platinum on b was 3 g per liter of catalyst layer volume,
Ruthenium was 0.3 g per liter.

The reaction vessel body 1 on the side of the metal honeycomb 17b
A cooling pipe 14 for circulating a cooling medium is provided on the outer periphery of the cooling gas pipe. The cooling pipe 14 circulates the cooling medium so as to flow from the fuel gas outlet 4 side to the inlet port 2 side.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, the reformed gas is introduced into the reaction vessel main body 1 from the introduction port 2 and is introduced into the reaction vessel main body 1 by the temperature detecting sections 7 and 7a and the heating sections 6 and 6a. When the temperature on the second side was set to 300 ° C. and the temperature on the outlet 4 side was set to 220 ° C., the outlet 4
Was about 0.3%. Under these conditions, continuous operation was performed for 100 hours.
0 hours later, the concentration of carbon monoxide at the outlet 4 is 0.4%.
And there was almost no change with time.

As described above, according to the present embodiment, the catalyst layer 3
The amount of the catalyst per unit volume of the catalyst layer 3 or the amount of the additive added to the catalyst varies depending on the position of the catalyst layer 3. The reaction to reduce carbon monoxide can be promoted by using a catalyst to which an additive has been added. Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

Ninth Embodiment Next, a ninth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention will be described with reference to FIG.

As shown in FIG. 5, each of the metal honeycombs 17a and 17b in the catalyst layer of the present embodiment is mainly composed of nickel and has a cylindrical shape having a diameter of 3 cm and a length of 4 cm, and a cross-sectional area of 1 cm. ^The number of cells per 2 is 400 for the metal honeycomb 17a on the reformed gas inlet 2 side and 6 for the metal honeycomb 17b on the reformed gas outlet 4 side.
00 cells.

A material obtained by adding cerium to a platinum-titanium oxide catalyst is used for the metal honeycomb 17a, and a material obtained by adding ruthenium to a platinum-titanium oxide catalyst is wash-coated for the metal honeycomb 17b.

The amount of platinum carried on the metal honeycomb 17a is as follows:
While 5 g per liter of catalyst layer and 10 g per liter of cerium catalyst layer, the metal honeycomb 17
The amount of supported platinum on b was 3 g per liter of catalyst layer volume,
Ruthenium was 0.3 g per liter.

The reaction vessel body 1 on the side of the metal honeycomb 17b
A cooling pipe 14 for circulating a cooling medium is installed on the outer periphery of the cooling gas pipe. The cooling pipe 14 circulates the cooling medium so as to flow from the fuel gas outlet 4 side to the inlet port 2 side.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, the reformed gas is introduced into the reaction vessel main body 1 from the introduction port 2, and is introduced into the reaction vessel main body 1 by the temperature detecting sections 7, 7a and the heating sections 6, 6a. When the temperature on the second side was set to 300 ° C. and the temperature on the outlet 4 side was set to 220 ° C., the outlet 4
Was about 0.3%. Under these conditions, continuous operation was performed for 100 hours.
0 hours later, the concentration of carbon monoxide at the outlet 4 is 0.4%.
And there was almost no change with time.

As described above, according to the present embodiment, the catalyst layer 3
Metal honeycombs 17a, 1 supporting the catalyst by the position of
Since the number of cells per unit cross-sectional area of 7b is different, the porosity of the foam as a support of the catalyst layer 3 is controlled according to the temperature distribution inside the reaction vessel main body 1 or the composition distribution of the reformed gas. By doing so, it is possible to promote the reduction reaction of carbon monoxide while optimizing the change in the surface area per unit volume of the catalyst along the flow direction of the reformed gas in the catalyst layer 3.
Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

[Tenth Embodiment] FIG. 6 is a cross-sectional view showing a tenth embodiment of a carbon monoxide reduction device for a fuel cell according to the present invention.

As shown in FIG. 6, each of the metal foams 18a and 18b in the catalyst layer of this embodiment is mainly composed of aluminum, and has a cylindrical shape having a diameter of 3 cm and a length of 4 cm. The size of the opening of the body (after the application of the catalyst) is such that the metal foam 18a on the reforming gas inlet 2 side is about 1.5 mm and the metal foam 18a on the reforming gas outlet 4 side is about 1.5 mm.
b was about 0.8 mm.

The metal foam 18a is made of a material obtained by adding cerium to a platinum-titanium oxide catalyst.
8b uses a material obtained by wash-coating a material obtained by adding ruthenium to a platinum-titanium oxide catalyst.

The amount of platinum supported on the metal foam 18a was 5 g per liter of the catalyst layer volume, and the amount of platinum supported on the metal foam 18b was 10 g per liter of the catalyst layer. The amount was 3 g per liter and the amount of ruthenium was 0.3 g per liter.

A cooling pipe 14 for flowing a cooling medium is provided on the outer periphery of the reaction vessel body 1 on the side of the metal foam 18b.
Flow from the side to the inlet 2 side.

Next, the operation of the present embodiment will be described.

In the present embodiment thus configured, the reformed gas is introduced into the reaction vessel main body 1 from the introduction port 2, and is introduced into the reaction vessel main body 1 by the temperature detecting sections 7, 7a and the heating sections 6, 6a. When the temperature on the second side was set to 300 ° C. and the temperature on the outlet 4 side was set to 220 ° C., the outlet 4
Was about 0.3%. Under these conditions, continuous operation was performed for 100 hours.
The carbon monoxide concentration at the outlet 4 after 0 hour is 0.4%
And there was almost no change with time.

As described above, according to the present embodiment, the catalyst layer 3
Foams 18a, 18b supporting the catalyst depending on the position of
The porosity of the foam as a support of the catalyst layer 3 is controlled according to the temperature distribution inside the reaction vessel main body 1 or the composition distribution of the reformed gas.
The change in the surface area per unit volume of the catalyst along the reformed gas flow direction in the catalyst layer 3 and the pressure loss of the catalyst layer 3 are optimized, and the reduction reaction of carbon monoxide can be promoted. Thereby, the reforming characteristics of the reaction vessel main body 1 can be improved, and the size of the reaction vessel main body 1 can be reduced.

[0117]

As described above, according to the present invention,
By forming at least a part of the catalyst support of the catalyst layer from at least one of a porous body of ceramics and metal, it is possible to efficiently reduce carbon monoxide with a simple configuration. A carbon oxide reduction device can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 2 is a cross-sectional view showing second, third, and fourth embodiments of the carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 3 is a cross-sectional view showing a fifth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 4 is a cross-sectional view showing a sixth embodiment of the carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 5 is a cross-sectional view showing seventh, eighth, and ninth embodiments of the carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 6 is a cross-sectional view showing a tenth embodiment of a carbon monoxide reduction device for a fuel cell according to the present invention.

FIG. 7 is a cross-sectional view showing a conventional carbon monoxide reduction device for a fuel cell.

[Description of Signs] 1 Reaction vessel main body 2 Reformed gas inlet 3 Catalyst layer 4 Reformed gas outlet 5 Granular catalyst 6 Heating unit (temperature adjusting unit) 7 Temperature detecting unit (temperature adjusting unit) 8 Ceramic honeycomb (porous) 9) Filler 10 Ceramic honeycomb (porous body) 11 Ceramic honeycomb (porous body) 12 Ceramic honeycomb (porous body) 13 Metal honeycomb (porous body) 14 Cooling pipe 15 Metal honeycomb (porous body) 16 manifold 17a, 17b Metal honeycomb (porous body) 18a, 18b Metal foam (porous body)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Ryo Harada, Inventor 2--4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Keihin Works (72) Inventor Masato Yoshino 2-chome, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Address Toshiba Corporation Keihin Plant F-term (reference) 4G040 EA02 EA03 EA05 EA06 EB32 4G140 EA02 EA03 EA05 EA06 EB32 EB34 5H027 AA06 BA01 BA17 KK42 MM16

Claims (10)

[Claims] 1. An inlet for a reformed gas containing at least carbon monoxide, a catalyst layer for converting carbon monoxide in the reformed gas introduced from the inlet to carbon dioxide, and the catalyst layer In the carbon monoxide reduction device for a fuel cell, comprising: a reaction vessel main body having an outlet through which a reformed gas having reduced carbon monoxide is discharged; and temperature adjusting means for adjusting the temperature of the reaction vessel main body, A carbon monoxide reduction device for a fuel cell, wherein at least a part of the catalyst support of the layer is formed of at least one of a porous body of ceramics and metal. 2. The carbon monoxide reduction device for a fuel cell according to claim 1, wherein at least a part of the catalyst support of the catalyst layer reacts carbon monoxide with water vapor to convert the carbon monoxide into carbon dioxide and hydrogen. A carbon monoxide reduction device for a fuel cell, wherein a catalyst is applied. 3. The fuel cell carbon monoxide reducing device according to claim 2, wherein a noble metal such as platinum, gold, or ruthenium is used as an active species of the shift catalyst. Carbon oxide reduction device. 4. The carbon monoxide reduction device for a fuel cell according to claim 2, wherein the applied shift catalyst includes cerium,
A carbon monoxide reduction device for a fuel cell, wherein at least one element selected from lanthanum, ruthenium, silicon, calcium, strontium, magnesium, and bismuth is added. 5. The carbon monoxide reduction device for a fuel cell according to claim 1, wherein a flow path for flowing a cooling medium is formed in at least a part of the catalyst support of the catalyst layer. Carbon monoxide reduction device for fuel cells. 6. The carbon monoxide reduction device for a fuel cell according to claim 1, wherein a flow path for a reformed gas and a flow path for flowing a cooling medium are formed in the reaction vessel main body in a meandering shape. A carbon monoxide reduction device for a fuel cell, comprising: 7. The carbon monoxide reducing device for a fuel cell according to claim 1, wherein the applied catalyst varies depending on the position of the catalyst layer. Reduction device. 8. The apparatus for reducing carbon monoxide for a fuel cell according to claim 1, wherein the amount of the catalyst per unit volume of the catalyst layer and the amount of the additive added to the catalyst depend on the position of the catalyst layer. An apparatus for reducing carbon monoxide for a fuel cell, wherein one of the amounts is different. 9. The carbon monoxide reduction device for a fuel cell according to claim 1, wherein a unit cross-sectional area of at least one of a ceramic and a metal porous body supporting a catalyst according to a position of the catalyst layer. A carbon monoxide reduction device for a fuel cell, wherein the number of cells per unit is different. 10. The carbon monoxide reduction device for a fuel cell according to claim 1, wherein the porosity of at least one of the ceramic and metal porous bodies supporting the catalyst is determined by the position of the catalyst layer. A carbon monoxide reduction device for a fuel cell, which is different.