JPH08295503A - Method for removing CO in hydrogen gas - Google Patents

Abstract

(57) [Abstract] [Problem] C in a relatively high temperature range of 100 ° C. or higher
Provided is a method for removing CO in hydrogen gas, which is capable of selectively converting and removing O and sufficiently reducing the CO concentration.
Provided is a method for efficiently producing a hydrogen-containing gas for a fuel cell in which the CO concentration is sufficiently reduced by applying this CO removal method, and the hydrogen-containing gas obtained by this method is used as a fuel for a low temperature fuel cell. The present invention provides a fuel cell system having excellent heat recovery efficiency while preventing poisoning of the hydrogen electrode of the fuel cell of the power generator by CO, prolonging the life of the cell and improving the output stability. In a method of selectively converting and removing CO by bringing hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ into contact with a catalyst, ruthenium is supported on titanium oxide as the catalyst. A catalyst is used. This method is applied to reformed gas to produce hydrogen-containing gas for fuel cells.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selectively removing CO from hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ , more specifically, for producing various hydrogen. Fuel [eg methane or natural gas (LNG), propane, butane or petroleum gas (LP
G), naphtha, kerosene, light oil, hydrocarbon fuels such as synthetic petroleum, alcohol fuels such as methanol and mixed alcohols, city gas, etc.], and CO is selected from reformed gas obtained by steam reforming The present invention relates to a method for removing CO in hydrogen gas that can be well converted and removed.

The present invention also relates to a method for producing a hydrogen-containing gas for a fuel cell using this CO removal method, and more particularly to a method for producing a hydrogen-containing gas for a polymer electrolyte fuel cell.

[0003]

2. Description of the Related Art Power generation by a fuel cell has various advantages such as low pollution, low energy loss, selection of installation place, expansion, operability, etc. There is. Various types of fuel cells are known depending on the type of fuel or electrolyte, operating temperature, etc. Among them, hydrogen is used as a reducing agent (active material) and oxygen (air, etc.) is used as an oxidizing agent. Hydrogen-oxygen fuel cells (low-temperature operation fuel cells) have been most developed and put into practical use, and are expected to become even more popular in the future.

There are various types of such hydrogen-oxygen fuel cells depending on the type of electrolyte and the structure of the electrodes. Typical examples thereof include phosphoric acid fuel cells, KOH type fuel cells, and solid state fuel cells. There are polymer electrolyte fuel cells and the like. In the case of such a fuel cell, particularly a low temperature operation type fuel cell such as a polymer electrolyte fuel cell, platinum (platinum catalyst) is used for an electrode. However, the platinum (platinum catalyst) used in the electrodes is easily poisoned by CO, so if the fuel contains CO above a certain level, the power generation performance will decline, or depending on the concentration, power generation will not be possible at all. There is a serious problem that it ends up. Since the deterioration of the catalytic activity due to the CO poisoning is remarkable especially at low temperatures,
This problem is particularly serious in the case of a low temperature operation type fuel cell.

Therefore, pure hydrogen is preferable as a fuel for a fuel cell using such a platinum-based electrode catalyst.
From a practical point of view, various fuels that are cheap and have excellent storage properties, or have already been equipped with a public supply system [eg, methane or natural gas (LNG), petroleum gas (LPG) such as propane, butane, etc.] , Hydrocarbons such as naphtha, kerosene, and light oil, alcohol-based fuels such as methanol, city gas, and other fuels for hydrogen production] The fuel cell power generation system incorporating such a reforming facility is being widely spread. However, since such reformed gas generally contains a considerable concentration of CO in addition to hydrogen, this CO is converted into CO ₂ which is harmless to the platinum-based electrode catalyst, and the CO concentration in the fuel is reduced. There is a strong demand for the development of a technology for reducing this. At that time, the CO concentration is usually 1000 pp
It is considered desirable to reduce the concentration to m or less, preferably 100 ppm or less, and more preferably 10 ppm or less.

In order to solve the above problems, as one of means for reducing the concentration of CO in fuel gas (hydrogen-containing gas such as reformed gas), a shift reaction represented by the following formula (1) A technique utilizing (water gas shift reaction) has been proposed.

CO + H ₂ O = CO ₂ + H ₂ (1) However, in the method based only on this shift reaction, there is a limit to the reduction of the CO concentration due to restrictions on chemical equilibrium, and the CO concentration is generally 1%. It is difficult to

Therefore, as a means for reducing the CO concentration to a lower concentration, a method has been proposed in which oxygen or an oxygen-containing gas (air or the like) is introduced (added) into the reformed gas to convert CO into CO _2. There is. However, in this case, since a large amount (up to 75% by volume) of hydrogen is present in the reformed gas,
When trying to oxidize CO, hydrogen is also oxidised, and C
The O concentration may not be reduced sufficiently.

As a method for solving this problem,
By introducing oxygen or an oxygen-containing gas into the reformed gas, CO is converted into C
A method of using a catalyst that selectively oxidizes only CO when it is oxidized to O ₂ .

As a CO oxidation catalyst, catalyst systems such as Pt / alumina, Pt / SnO ₂ , Pt / C, Co / TiO ₂ , popcalite, Pd / alumina and the like have been conventionally known. Since the humidity resistance is not sufficient, the reaction temperature range is low, and the selectivity for CO oxidation is low, a small amount of CO in a large amount of hydrogen such as reformed gas is 1000 ppm or less, preferably Is 100pp
In order to reduce the concentration to m or lower, more preferably 10 ppm or lower, a large amount of hydrogen must be sacrificed by oxidation at the same time.

Japanese Unexamined Patent Publication No. 5-201102 describes a method for producing a CO-free hydrogen-containing gas for selectively removing CO from a hydrogen-enriched CO-containing gas and supplying it to a fuel cell system for automobiles. There is. The catalyst used here has Rh or Ru supported on a carrier. Alumina is used as the carrier, the reaction conditions are such that the reaction temperature is 120 ° C. or lower, preferably 100 ° C. or lower, and the gas composition has an O ₂ : CO ratio of less than 1: 1. ing. The CO concentration of the gas used as an example is as low as 900 ppm. Under this condition, CO is selectively oxidized to obtain a hydrogen-containing gas containing no CO (CO: 10 ppm or less), but there is a problem that it can be applied only to a gas having a low CO concentration.

Further, JP-A-5-258764, (in addition to hydrogen, CO _2: 20 volume%, CO: 7 to 10% by volume) reformed gas in the reformer of methanol F
CO concentration is reduced to 1% by volume using an e-Cr catalyst,
Further, CO is at least 1 selected from Rh, Ni and Pd.
It is described that it is reduced by methanation using a catalyst containing one or more species as a catalyst component. Further, it is described that Fe, Co, Ru or Ir is added as a catalyst component in addition to the above catalyst component.

The CO that cannot be reduced by the catalyst is oxidized and removed by the plasma generated by the plasma generator. By this method, a reformed gas that does not poison the platinum catalyst used as the electrode of the polymer electrolyte fuel cell can be provided, but this method has a problem that the reactor becomes large because the plasma generator is used. . In addition, the reaction temperature of the methanation reaction is 150 to
Since it is carried out at 500 ° C, preferably 300 ° C, not only CO but also CO ₂ is methanated, and a large amount of H ₂ used as a fuel is consumed, which is not suitable as a CO removal device from hydrogen gas for fuel cells. There is a problem that is.

[0014]

The present invention efficiently and selectively converts and removes CO in hydrogen gas in a relatively high temperature range of 100 ° C. or higher, preferably 100 to 300 ° C., to obtain a sufficient CO concentration. It is an object to provide a method for removing CO in hydrogen gas that can be reduced.

Another object of the present invention is to provide a method for efficiently producing a hydrogen-containing gas for a fuel cell in which the CO concentration is sufficiently reduced by applying this CO removal method.

The present invention also uses the hydrogen-containing gas obtained by this method as a fuel for a hydrogen-oxygen type fuel cell, particularly a low temperature type fuel cell such as a polymer electrolyte type fuel cell, and to provide a fuel cell hydrogen electrode for a power generator. It is an object of the present invention to provide a fuel cell system having excellent heat recovery efficiency while preventing poisoning due to CO, prolonging the life of the cell and improving the stability of output.

[0017]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, by using a catalyst in which ruthenium is supported on titanium oxide, CO in hydrogen gas is relatively reduced. The inventors have found that it can be efficiently converted and removed at high temperatures, and have completed the present invention based on this finding.

That is, the present invention is a method for selectively converting CO to remove by contacting a hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ with a catalyst, wherein the catalyst is titanium oxide. The present invention provides a method for removing CO in hydrogen gas, which is characterized in that a catalyst supporting ruthenium is used.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The method for removing CO according to the present invention is applied to a hydrogen gas such as a reformed gas obtained by reforming a hydrogen-producing fuel that can be converted into a fuel gas containing hydrogen by a reforming reaction. Is preferably used to selectively remove CO and is preferably used to produce a hydrogen-containing gas for a fuel cell, but is not limited thereto.

A method for producing a hydrogen-containing gas for a fuel cell from a reformed gas will be described below.

1. Reforming Step of Fuel In the method of the present invention, a reformed gas (containing hydrogen as a main component and CO
CO contained in the fuel gas containing) is selectively converted and removed using a catalyst to produce a desired hydrogen-containing gas having a sufficiently reduced CO concentration. The step (reforming reaction) can be performed by any method such as the method implemented or proposed in the conventional fuel cell system, as shown below. Therefore, in a fuel cell system equipped with a reforming device in advance, the reformed gas may be prepared in the same manner by using it as it is.

The fuel used as a raw material for this reforming reaction contains hydrogen as a main component and C
Various types and compositions of hydrogen-producing fuels that can be converted to a fuel gas containing O can be used, and specifically, for example, hydrocarbons such as methane, ethane, propane, butane (either alone or as a mixture). , Or natural gas (L
NG), petroleum gas (LPG), naphtha, kerosene, light oil, hydrocarbon fuels such as synthetic petroleum, methanol, ethanol,
Alcohols such as propanol and butanol (may be used alone or as a mixture), as well as various city gases, syngas,
Coal or the like can be used as appropriate. Of these,
What kind of fuel for hydrogen production should be used may be determined in consideration of various conditions such as the scale of the fuel cell system and the circumstances of fuel supply, but normally, methanol, methane or LNG, propane or LPG is used. , Naphtha or lower saturated hydrocarbon, city gas containing methane, etc. are preferably used.

The steam reforming reaction (steam reforming) is the most common reforming reaction, but depending on the raw material, a more general reforming reaction (for example, thermal reforming reaction such as thermal decomposition or catalytic cracking). And various catalytic reforming reactions such as shift reaction, partial oxidation reforming, etc.) can be appropriately applied.
At that time, different types of reforming reactions may be appropriately combined and used. For example, since the steam reforming reaction is generally an endothermic reaction, the steam reforming reaction and partial oxidation may be combined to supplement this endothermic amount, or the CO generated by the steam reforming reaction (by-product) may be subjected to a shift reaction. Use H ₂ O
Various combinations are possible, such as reacting with and partially converting it into CO ₂ and H ₂ in advance.

In such a reforming reaction, the catalyst or reaction conditions are generally selected so that the yield of hydrogen is as large as possible, but it is difficult to completely suppress the CO by-product, and even if the shift reaction However, there is a limit to the reduction of CO concentration in the reformed gas.

In practice, in the steam reforming reaction of hydrocarbons such as methane, the following formula (2) or (3): CH ₄ + 2H _{2 is used in} order to obtain the yield of hydrogen and suppress the by-product of CO. O → 4H ₂ + CO ₂ (2) C _n H _m + 2nH ₂ O → (2n + m / 2) H ₂ + nCO ₂ (3) The conditions should be selected so that the reaction represented by the formula is as selective as possible. preferable.

Similarly, for the steam reforming reaction of methanol, the reaction represented by the following formula (4): CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (4) is as selective as possible. It is preferred to choose the conditions to occur.

Furthermore, even if CO is modified and reformed by utilizing the shift reaction represented by the above formula (1), since this shift reaction is an equilibrium reaction, a considerable amount of CO remains. Therefore, the reformed gas produced by such a reaction contains CO ₂ and unreacted water vapor and a small amount of CO in addition to a large amount of hydrogen.

As the catalyst effective for the reforming reaction, there are known various catalysts depending on the type of raw material (fuel), the type of reaction, the reaction conditions and the like. Specific examples of some of them include, for example, Cu-Zn as an effective catalyst for steam reforming of hydrocarbons and methanol.
O-based catalyst, Cu-Cr ₂ O ₃ -based catalyst, supported Ni-based catalyst, C
u-Ni-ZnO-based catalyst, Cu-Ni-MgO-based catalyst,
Examples thereof include Pd-ZnO-based catalysts, and examples of the catalyst effective for catalytic reforming reaction and partial oxidation of hydrocarbons include supported Pt-based catalysts and supported Ni-based catalysts. Of course, the catalyst that can be used for the reforming reaction is not limited to those exemplified above,
An appropriate material may be appropriately selected and used according to the type of raw material (fuel), the type of reaction, the reaction conditions, and the like.

The reforming device is not particularly limited, and any type such as a device commonly used in a conventional fuel cell system can be applied, but many reforming processes such as steam reforming reaction and decomposition reaction are possible. Since the reaction is an endothermic reaction, generally, a reaction device or a reactor (heat exchanger type reaction device or the like) having a good heat supply property is preferably used. Examples of such a reaction device include a multi-tube reactor and a plate fin reactor, and examples of the heat supply method include heating by a burner or the like, a method using a heating medium, and a catalyst utilizing partial oxidation. The heating includes, but is not limited to, heating by combustion.

The reaction conditions for the reforming reaction differ depending on other conditions such as the raw material used, the reforming reaction, the catalyst, the type of the reaction apparatus, the reaction system, etc., and may be appropriately determined. In any case, the conversion rate of the raw material (fuel) is sufficient (preferably 10%).
It is desirable to select various conditions such that the hydrogen yield rate is as high as possible and the hydrogen yield rate is as high as possible. Further, if necessary, a method of separating unreacted hydrocarbons and alcohols and recycling may be adopted. Further, if necessary, the generated or unreacted CO ₂ or water may be appropriately removed.

In this way, a desired reformed gas having a high hydrogen content and sufficiently reduced fuel components other than hydrogen, such as hydrocarbons and alcohol, is obtained. The CO concentration in the obtained reformed gas is usually
It is suitable to keep it to 0.10 mol or less, preferably 0.04 mol or less, and the CO concentration is adjusted to such a relatively low concentration at the stage of this reforming step, so that CO The burden of the conversion removal reaction of is reduced accordingly.

Although the method of the present invention shows good results in the selective conversion and removal of CO even with hydrogen gas having a low CO ₂ content, the catalyst used in the present invention is used for the selective conversion and removal of CO. In such a case, CO can be selectively converted and removed efficiently even under the condition that a large amount of CO ₂ is present in the reformed gas. Therefore, in the present invention, the reformed gas having a CO ₂ concentration that is generally used in a fuel cell system, that is, CO ₂ is 10 to 40% by volume, preferably 15 to 3
A reformed gas containing 0% by volume is used. CO in reformed gas
_In order to reduce the content of ₂ to less than 10% by volume, it is necessary to remove it by a gas cleaning device or the like, and as a result, there are disadvantages that control is complicated, the system is upsized, and cost is increased. On the other hand, when the content of CO ₂ exceeds 40% by volume, the hydrogen partial pressure in the resulting hydrogen-containing gas for a fuel cell becomes low and the voltage of the fuel cell is lowered. In addition, the method of the present invention has a low CO concentration (0.6% by volume or less)
The O concentration can also be effectively reduced, and the CO concentration is high (0.6 to
The CO concentration in hydrogen gas (2.0% by volume) can also be effectively reduced.

2. CO selective conversion removal step In the method of the present invention, the CO obtained as described above,
Hydrogen gas containing CO ₂ and O ₂ is brought into contact with the catalyst to selectively convert and remove CO in hydrogen gas such as reformed gas.

In the method of the present invention, a catalyst in which ruthenium is supported on titanium oxide is used as the catalyst. By using this catalyst, the selective conversion and removal of CO can be efficiently performed in a wide temperature range including a relatively high temperature of 80 to 350 ° C. even under the condition that carbon dioxide gas is present in hydrogen gas at 10% or more. . Further, the CO conversion / removal reaction is an exothermic reaction similarly to the side reaction hydrogen oxidation reaction, and it is effective to improve the power generation efficiency by recovering the generated heat and utilizing it in the fuel cell. is there.

To support ruthenium, for example, Ru
Cl₃・ NH₂O, Ru₂(OH)₂Cl_Four・ 7 NH₃・ 3H
₂O, K₂(RuCl_Five(H₂O)), (NH_Four)₂(RuC
l_Five(H₂O)), K₂(RuCl_Five(NO)), RuBr
₃・ NH₂O, Na₂RuO_Four, Ru (NO) (NO₃)₃,
(Ru₃O (OAc)₆(H₂O)₃) OAc ・ nH₂O,
K_Four(Ru (CN)₆) ・ NH₂O, K₂(Ru (NO₂)_Four
(OH) (NO)), (Ru (NH₃)₆) Cl₃, (R
u (NH₃)₆) Br₃, (Ru (NH₃)₆) Cl₂, (R
u (NH₃)₆) Br₂, (Ru₃O₂(NH₃)₁₄) Cl₆
・ H₂O, (Ru (NO) (NH₃)_Five) Cl₃, (Ru
(OH) (NO) (NH₃)_Four) (NO₃) ₂, (RuCl
₂(PPh₃)₃), (RuCl₂(PPh₃)_Four), (Ru
ClH (PPh₃)₃) ・ C₇H₈, (RuH₂(PPh₃)
_Four), (RuClH (CO) (PPh₃)₃), (RuH₂
(CO) (PPh₃)₃), (RuCl₂(Cod))_n,
(Ru (CO)₁₂), (Ru (acac)₃), (Ru
(HCOO) (CO)₂) _n, (Ru₂I_Four(P-cyme
ne)₂) Is dissolved in water, ethanol, etc.
A catalyst preparation liquid obtained by disintegrating is used. Especially preferred
KuCl RuCl₃, Ru₂(OH)₂Cl_Four・ 7 NH₃・ 3
H₂O is used.

As the titanium oxide used as the carrier, an oxide of titanium represented by Ti _m O _n (m and n represent a positive number) is used. The Ti _m O _n, for _{example, TiO, Ti 2 O 3,} TiO 2, TiO 3 or the like. In particular, as TiO ₂ , that is, titania, amorphous type, rutile type, anatase type and the like are used.

The amount of ruthenium supported in the supporting treatment is not particularly limited, but usually 0.1 to 10% by weight of ruthenium is preferable with respect to titanium oxide, and 0.3 to 3 is particularly preferable.
The weight% range is optimal. If the content of ruthenium is too low, the CO conversion activity becomes insufficient, while if the support rate is too high, the amount of ruthenium used will be unnecessarily excessive and the catalyst cost will increase.

The conditions of the supporting treatment are not particularly limited and may be appropriately selected according to various situations, but usually from room temperature to 90 ° C.
In, the carrier may be contacted with the catalyst preparation liquid for 1 minute to 10 hours.

After supporting ruthenium on the carrier, the obtained catalyst is dried. Before use as a catalyst, it is preferable to carry out a calcining treatment, or a calcining treatment and hydrogen reduction. As a drying method, for example, natural drying, a rotary evaporator or a blow dryer is used. After drying, the catalyst is usually 350-550 ° C, preferably 380
Firing is usually performed at ˜500 ° C. for 2 to 6 hours, preferably 2 to 4 hours. Hydrogen reduction is usually carried out under a hydrogen flow of 450 to 5
1 to 5 at a temperature of 50 ° C., preferably 480 to 530 ° C.
It is carried out for an hour, preferably 1-2 hours.

There are no particular restrictions on the shape and size of the catalyst thus prepared, and examples thereof include powder, sphere, granule, honeycomb, foam, fiber, cloth, plate, Various commonly used shapes and structures such as a ring shape can be used.

A hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ is brought into contact with the catalyst obtained as described above to carry out a selective conversion and removal reaction of CO.

Hydrogen gas obtained by adding an oxygen-containing gas to the reformed gas
In general, pure oxygen (O ₂), Air or
Oxygen-enriched air is preferably used. Addition of the oxygen-containing gas
The amount added is preferably oxygen / CO (molar ratio) of 0.5 to
It is suitable to adjust to 5, and more preferably 1 to 4.
It is right. If this ratio is small, the CO removal rate will be low,
If it is too large, the amount of hydrogen consumed becomes too large, which is not preferable.

The reaction pressure is usually atmospheric pressure to 10 kg / cm.
² G, preferably atmospheric pressure to 4 kg / cm ² G, particularly preferably atmospheric pressure to ² kg / cm ² G. here,
If the reaction pressure is set too high, it is economically disadvantageous because the power for increasing the pressure needs to be increased correspondingly, and especially when it exceeds 10 kg / cm ² G, the regulation of the High Pressure Gas Control Law is high. In addition, there is a problem that the safety limit is lowered because the explosion limit is widened.

The above reaction is usually carried out in a very wide temperature range of 100 ° C. or higher, preferably 100 to 300 ° C.
It can be preferably carried out while stably maintaining the selectivity for the CO conversion reaction. If the reaction temperature is lower than 100 ° C., the reaction rate becomes slow, and therefore the CO removal rate (conversion rate) tends to be insufficient in a practical SV (space velocity) range.

Since the CO conversion reaction in the CO conversion removal step is an exothermic reaction, the temperature of the catalyst layer rises due to the reaction. If the temperature of the catalyst layer becomes too high, the selectivity of CO conversion removal of the catalyst usually deteriorates.

In the above reaction, GHSV (supply volume velocity in standard state of supply gas and apparent space-based space velocity of catalyst layer used) is usually 5000 to 500.
It is preferable to select it in the range of 00h ^-1 . Here, if GHSV is made small, a large reactor is required, while if GHSV is made too large, the CO removal rate decreases. Preferably, it is selected in the range of 6000 to 20000 h ^-1 .

The reactor used for conversion and removal of CO is not particularly limited, and various types can be applied as long as they satisfy the above reaction conditions, but this conversion reaction is an exothermic reaction. Therefore, in order to facilitate temperature control, it is desirable to use a reaction device or a reactor having a good reaction heat removal property. Specifically, for example, a multi-tube type or a plate fin type heat exchange type reactor is preferably used. Depending on the case, a method of circulating the cooling medium in the catalyst layer or circulating the cooling medium outside the catalyst layer can also be adopted.

Since the hydrogen-containing gas produced by the method of the present invention has a sufficiently reduced CO concentration as described above, poisoning and deterioration of the platinum electrode catalyst of the fuel cell can be sufficiently reduced. , Its life and power generation efficiency
The power generation performance can be greatly improved. Also, this C
It is also possible to recover the heat generated by the O conversion reaction. In addition, C in hydrogen gas containing relatively high concentration of CO
The O concentration can be sufficiently reduced.

The hydrogen-containing gas obtained by the present invention can be suitably used as a fuel for various H ₂ combustion type fuel cells, and in particular, platinum (platinum catalyst) is used at least for the electrode of the fuel electrode (negative electrode). It is advantageously used as a fuel supply to various types of H ₂ combustion fuel cells of the type used (phosphoric acid fuel cells, KOH fuel cells, low-temperature fuel cells such as solid polymer electrolyte fuel cells). be able to.

In the conventional fuel cell system, between the reformer (when there is a reformer after the reformer, the shifter is also regarded as a part of the reformer) and the fuel cell, the present invention is provided. Incorporating an oxygen introducing device and an oxidation reaction device according to the above method, or in the case of already having an oxygen introducing device and a conversion reaction device, using the catalyst as a CO conversion removal catalyst, the reaction conditions are as described above. It is possible to configure a fuel cell system far superior to the conventional one also by adjusting to.

[0051]

EXAMPLES The present invention will now be described more specifically by showing examples of the present invention, but the present invention is not limited to these examples.

Example 1 Ethanol solution of ruthenium chloride (0.376M, 2c
Using a solution obtained by adding 50 cc of water to c) as an impregnating liquid,
Idemitsu Titania IT-S (manufactured by Idemitsu Kosan Co., Ltd .: amorphous type) was added to the impregnating solution as a carrier to age the catalyst. Ruthenium was loaded so as to be 1% by weight (metal conversion) with respect to the obtained catalyst.

The catalyst was dried using a rotary evaporator. After drying, in a muffle furnace at 120 ° C for 2
The firing was performed at 500 ° C. for 4 hours. Amorphous titania becomes a mixture of anatase type and rutile type after catalyst preparation.

The prepared catalyst was molded by a tablet molding machine, and the shape of the catalyst was adjusted to 16 to 32 mesh, 1c.
c After filling the reactor reaction tube, in a hydrogen stream, 500
Reduction treatment was carried out at 0 ° C for 1 hour. Then, a mixed gas having the following composition was passed through the catalyst layer in an amount of WHSV 10000 h ⁻¹ to carry out a CO conversion removal reaction. Reaction pressure is 1.0k
The reaction was performed at g / cm ² G and at the reaction temperatures shown in Table 1. Table 1 shows the reactor inlet CO concentration, the reactor outlet CO concentration, and the reaction temperature range where the reactor outlet CO concentration in this reaction is 10 ppm or less.

The products were identified by using a gas chromatograph. Further, the amounts of oxygen and hydrogen at the inlet and the outlet were determined by TCD, and the amounts of CO and CO ₂ were methanated using a methane converter and FID was used.

Example 2 As a ruthenium salt, Ru red [Ru ₂ (OH) ₂ Cl
₄ : 7NH ₃ .3H ₂ O] was used to prepare the catalyst. The catalyst was prepared by ruthenium salt (0.068g) in water (20c).
The solution dissolved in c) was used as an impregnating solution, and the same carrier as in Example 1 was used for impregnation and loading. After drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.

Example 3 A catalyst was prepared using RuCl ₃ as the ruthenium salt. The catalyst was prepared by using a solution prepared by adding 120 cc of water to an ethanol solution (0.356 M, 9 cc) in which a ruthenium salt was dissolved as an impregnating solution and CR-EL (titania: rutile type manufactured by Ishihara Sangyo) as a carrier. It was carried out by loading. After drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.

Comparative Example 1 RuCl ₃ was used as the ruthenium salt and Al ₂ was used as the carrier.
O ₃ (HKD-24: manufactured by Sumitomo Chemical Co., Ltd.) was carried out by impregnation using. After drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.

Comparative Example 2 RuCl ₃ was used as the ruthenium salt, and Si was used as the carrier.
O ₂ (CARIACTG-10: FUJI SILYS
IA CHEMICAL LTD. Manufactured by the company). After drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.

Example 4 Using the same catalyst as in Example 3, after drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.
Shown in

Example 5 A catalyst was prepared using RuCl ₃ as the ruthenium salt. The catalyst was prepared by using an ethanol solution (0.356 M, 9 cc) in which ruthenium salt was dissolved and 120 cc of water added as an impregnating solution, and using anatase titania manufactured by Wako Pure Chemical Industries, Ltd. as a carrier by impregnation and loading. went. After drying and firing, the reaction was carried out under the conditions shown in Table 1 under the same reaction conditions as in Example 3. The results are shown in Table 1. The anatase-type titania becomes a mixture of anatase-type and rutile-type after the catalyst preparation.

Example 6 Using the same catalyst as in Example 5, after drying and firing, the reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.
Shown in

[0063]

[Table 1] Supply gas composition CO: 0.6, 1% by volume, O ₂ (supplied by air): 2% by volume, CO ₂ : Inlet CO concentration is 0.6
15% by volume when the volume is%, and the inlet CO concentration is 1.0% by volume
At 25% by volume, H ₂ : balance

[0064]

According to the method of the present invention, CO in hydrogen gas having a high CO ₂ content can be efficiently and selectively converted over a relatively high temperature range, and a hydrogen-oxygen type fuel can be obtained. Poisoning of platinum on the hydrogen electrode of the battery with CO can be prevented, the life of the battery can be extended, and the output stability can be improved. Further, since the catalyst used in the present invention has a relatively high temperature range capable of selectively converting and removing CO, the heat generated by the conversion reaction can be recovered and utilized in the fuel cell to improve the power generation efficiency. be able to.

Claims (5)

[Claims] 1. A method for selectively converting and removing CO by bringing hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ into contact with the catalyst, wherein ruthenium is supported on titanium oxide as the catalyst. A method for removing CO in hydrogen gas, which comprises using the above catalyst. 2. The method for removing CO in hydrogen gas according to claim 1, wherein the ruthenium source of the catalyst in which ruthenium is supported on titanium oxide is RuCl ₃ . 3. The ruthenium source of the catalyst comprising ruthenium supported on titanium oxide is Ru red [Ru ₂ (OH) ₂ Cl ₄
· 7NH ₃ · 3H ₂ O], The method for removing CO in hydrogen gas according to claim 1. 4. A hydrogen gas containing hydrogen as a main component and containing CO ₂ , CO and O ₂ is reformed into a fuel gas for hydrogen production which is convertible into a fuel gas containing at least hydrogen by a reforming reaction. The method for removing CO in hydrogen gas according to any one of claims 1 to 3, which is a mixed gas obtained by mixing an O ₂ -containing gas with the obtained reformed gas. 5. A reformed gas obtained by reforming a hydrogen-producing fuel that can be converted into a fuel gas containing at least hydrogen by a reforming reaction, the reformed gas containing hydrogen as a main component and CO ₂ and CO. In a method for producing a hydrogen-containing gas for a fuel cell, wherein a mixed gas formed by mixing an oxygen-containing gas with a contained reforming gas is brought into contact with a catalyst to selectively convert and remove CO, CO is removed. 4. A method for producing a hydrogen-containing gas for a fuel cell, which is performed by the method according to any one of 4 above.