KR100510321B1 - Catalysts for refining reformed gas and process for selectively removing carbon monoxide in reformed gas using the same - Google Patents

Abstract

The present invention relates to a catalyst for reforming a reformed gas and a method for selectively removing carbon monoxide in the reformed gas by using the same, and more particularly, a noble metal and an alkali metal, an alkaline earth metal or a complex thereof on a commercial support. A catalyst prepared by supporting in a form; Or a catalyst prepared by supporting a precious metal on a support including an alkali metal, an alkaline earth metal or a complex thereof as a constituent of the support, and a method for selectively removing carbon monoxide in the reformed gas using the catalyst. When using a catalyst according to the present invention to purify the hydrogen-rich reformed gas produced by the reforming reaction of hydrocarbons or alcohols, PROX (preferential oxidation) is excellent because the selective oxidation ability of carbon monoxide is excellent, and the consumption rate of hydrogen by side reactions is low Simplification and weight reduction of the process configuration can be achieved.

Description

Catalyst for refining gas purification and method for selectively removing carbon monoxide in the reformed gas using the same {Catalysts for refining reformed gas and process for selectively removing carbon monoxide in reformed gas using the same}

The present invention relates to a catalyst for reforming a reformed gas and a method for selectively removing carbon monoxide in the reformed gas using the same, and more particularly, supporting a precious metal and optionally an alkali metal, an alkaline earth metal or a complex thereof on a commercial support. The reformed gas purification catalyst, and a method for selectively removing carbon monoxide in the reformed gas using the same.

Fuel cell is an environmentally friendly technology that produces better power and energy conversion efficiency and emits less pollutants than conventional internal combustion engines because electricity is produced by the oxidation reaction mechanism of hydrogen and oxygen. Many empirical experiments have been conducted on the applicability of fuel cells, especially in small power generation systems, considering the economics, stability and ease of use. use.

However, about 1% of carbon monoxide remains in the reformed gas produced through the reforming reaction, and when carbon monoxide is injected into the fuel cell stack, which is an electricity production part, irreversibly adsorbs onto the surface of the platinum catalyst electrode. In general, concentrations below 20 pm should be maintained because they lower the power generation efficiency of fuel cells (KA starz, et al. , "Characteristic of platinum-based electrocatalysts for mobile PEMFC pplications", J. power sources , 84 , 167-). 172 (1999).

Therefore, before entering the stack, the low concentration of carbon monoxide contained in the reformed gas should be removed. In particular, the process of selectively oxidizing only carbon monoxide using a catalyst is called PROX (preferential oxidation). At this time, oxygen or air is used as the oxidizing agent.

To date, catalysts in which precious metals are supported on supports such as alumina and zeolite have been used as active catalysts. These catalysts have low selectivity to carbon monoxide, which results in high hydrogen consumption, and increases in reactor temperature due to side reactions such as hydrogen oxidation. Therefore, there is a problem in the practicality of the catalyst because the selectivity for the oxidation reaction of carbon monoxide is lowered. In addition, the reactivity is reduced by the water and carbon dioxide contained in the reformed gas.

On the other hand, the applicant has carried out a study to produce a catalyst having a better performance in the selective oxidation of carbon monoxide than conventional catalysts, as a result of the alkali metal, alkaline earth metal or the like on a support having a large specific surface area such as montmorillonite The invention was carried out by inventing a catalyst in which these complexes are supported together with a noble metal, and a catalyst in which a noble metal is supported on a bentonite support, which is a support containing an alkali metal, an alkaline earth metal or a complex thereof, having excellent selectivity of carbon monoxide. It was filed in 2002-14777. SUMMARY OF THE INVENTION The present invention provides a catalyst prepared by using a precious metal and an alkali metal, an alkaline earth metal, or a combination thereof in the production of a catalyst for selectively oxidizing carbon monoxide present as impurities in a reformed gas containing excess hydrogen. It is excellent in the oxidation reaction, the catalyst supporting the precious metals on the support to which the alkali metal, alkaline earth metal or a complex thereof is added is superior to the selective oxidation of carbon monoxide. In other words, "a catalyst in which noble metals, alkali metals, alkaline earth metals, or a combination thereof coexists has excellent performance for selective carbon monoxide oxidation." However, there is a continuous need to develop a catalyst having excellent performance for selective carbon monoxide oxidation using not only a specific support such as montmorilite or bentonite, but also commonly used commercial supports.

On the other hand, there is an example of applying the alkali metal and alkaline earth metal as a catalyst component, for example, flue gas oxidation catalyst, automotive three-way catalyst and the like. The role of alkali metals (Ba, La, K) in these catalysts is to secure the durability of the catalyst by inhibiting the sintering of the active metal and reducing the specific surface area of the support (particularly active alumina) at high temperature. (Johansson. EM, "Catalytic combustion of gasified biomass over hexaaluminate catalysts: influence of palladium loading and ageing: Applied Catalysis A: General 180, 199 (1999)). No. 2001-0073509 is prepared by physically mixing a platinum-supported catalyst (Pt / Al ₂ O ₃ ) and Zr, Ba, K oxides on the surface of alumina, and then grinding and mixing it to an average particle size of 8 to 10 μm. It is disclosed that the catalyst can secure stable activity in the simultaneous removal of volatile organic compounds (VOCs) and carbon monoxide even after high temperature (1000 ° C.) degradation.

However, there has been no attempt to use a composite oxide catalyst of a noble metal and an alkali metal, an alkaline earth metal or a combination thereof for the selective oxidation of carbon monoxide in an over-hydrogen reforming gas, as disclosed herein.

Accordingly, the present inventors have conducted research to solve the problems as described above, the bentonite support, which is a support containing a precious metal and an alkali metal, which is a basic concept of Korean Patent Application No. 2002-14777, or a precious metal and alkali In view of the fact that the catalyst supported on the montmorillonite support at the same time shows excellent performance in the selective oxidation of carbon monoxide, it has been found that the above principle can be applied to any commercially available supports. The catalyst for reforming gas purification in which a noble metal and optionally an alkali metal, an alkaline earth metal or a complex thereof are supported on the support has excellent carbon monoxide selective oxidation performance, and particularly has excellent selectivity of carbon monoxide. That the decrease in concentration can be minimized. The present invention has been completed based on this.

Accordingly, an object of the present invention is to provide a catalyst for reforming gas purification having excellent selective oxidation ability to carbon monoxide.

It is another object of the present invention to provide a method for selectively removing carbon monoxide in a reformed gas which can be reduced in weight and miniaturized while minimizing hydrogen consumption in a hydrogen-rich reformed gas using the catalyst.

Provided according to an embodiment of the present invention for achieving the above object, the reforming gas refining catalyst is a rhodium, platinum, on a support composed of at least one metal or an oxide thereof selected from the group consisting of transition metals and amphoteric metals. At least one precious metal selected from the group consisting of iridium, ruthenium and palladium and at least one metal selected from the group consisting of alkali metals and alkaline earth metals are supported, and the content of the precious metals is 0.01 to 10% by weight based on the weight of the support. The content of the alkali metal and alkaline earth metal is characterized in that 0.01 to 20% by weight.

The catalyst for reforming gas purification, provided according to another embodiment of the present invention for achieving the above object, is selected from the group consisting of at least one metal selected from the group consisting of alkali metals and alkaline earth metals, and transition metals and amphoteric metals. At least one precious metal selected from the group consisting of rhodium, platinum, iridium, ruthenium and palladium is supported on a support composed of at least one metal or an oxide thereof, and the content of the precious metal is 0.01 to 10 weight based on the weight of the support. %, The content of the alkali metal and alkaline earth metal contained in the support is characterized in that 1 to 90% by weight based on the weight of the support.

The method for selectively removing carbon monoxide in the reformed gas of the present invention for achieving the above another object is a reformed gas having a molar ratio of hydrogen / carbon monoxide of 30 to 250 in the selective oxidation reaction zone including the catalyst and carbon monoxide in the reformed gas It is characterized by reacting oxygen having a molar ratio of 0.4 to 10 with respect to a reformed gas space velocity (GHSV) of 1,000 to 100,000 hr ⁻¹ and 50 to 300 ° C.

Hereinafter, the present invention will be described in more detail.

As described above, the present invention relates to a reforming gas purification catalyst having a noble metal and optionally an alkali metal, an alkaline earth metal or a composite thereof supported on a commercial support, and a process for selectively oxidizing and removing carbon monoxide in the reformed gas using the same. In particular, it is important to minimize the phenomenon that the hydrogen concentration is reduced by reacting the oxygen supplied into the reaction zone with the hydrogen of the reformed gas.

Alkaline metals, alkaline earth metals or composites thereof enrich the electron density of precious metals to enhance the chemical adsorption of reactants to the precious metal surface (SB Sharma, et al. , "Microcalorimetic Study of Silica- and Zeolite-Supported Platinum Catalysts"). ", J. Catal. , 148 , 198-204 (1994)), or a new form of adsorption of carbon monoxide is induced (GS Lane, et al. ," Infrared Spectroscopy of Adsorbed Carbon Monoxide on Platinum / Nonacidic Zeolite Catalysts ", J Catal. , 141 , 465-477 (1993).

In addition, in the formation of the composite oxide, as shown in Table 1 below, the alkali metal and the alkaline earth metal usable in the present invention have a stronger adsorption force to oxygen than the adsorption of hydrogen or carbon monoxide, so that the rate of oxidation reaction (RDS, The dissociation adsorption of oxygen, which is a reaction rate determing step, is facilitated to increase the oxygen concentration on the surface of the catalyst. For this reason, the selective oxidation rate of carbon monoxide on the catalyst surface is enhanced. That is, when an alkali metal, an alkaline earth metal or a complex thereof is present in the form of a noble metal catalyst metal and a complex oxide, an alkali metal, an alkaline earth metal or a complex thereof affects the oxidation activity of carbon monoxide. It was applied to the selective oxidation of carbon monoxide present as impurities in the reformed gas.

Chemical Adsorption Properties by Metal Type Metal group gas O ₂ CO H ₂ Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Ru, Os + + + Ni, Co + + + Pd, Rh, Pt, Ir + + + Mn, Cu + + ± Al, Au + + － Li, Na, K + － － Mg, Ag, Zn, Cd, In, Si, Ge, Sn, Pb, As, Sb, Bi + － －

+: Strong chemisorption, ±: weak chemisorption,-: no adsorption (Jens Hangen, Industrial Catalysis, Wiley-VCH press, p102, 1999)

In the present invention, a catalyst prepared by supporting a precious metal and an alkali metal, an alkaline earth metal or a composite thereof on the commercial support in the form of a composite oxide; Alternatively, it has been found that the performance of the catalyst prepared by supporting a precious metal on a support including an alkali metal, an alkaline earth metal, or a composite thereof as a constituent of the support in the selective oxidation of carbon monoxide is excellent.

According to one embodiment of the invention, the support usable in the present invention comprises at least one metal selected from the group consisting of transition metals and amphoteric metals or oxides thereof, preferably Al, Si, Zr, Ti, Mn, Mo, It is composed of at least one metal or oxide thereof selected from the group consisting of W, Fe, Co, Ni, Cu, Zn, Ga, Bi, Sn, and Ce.

In one embodiment of the present invention, the precious metal supported on the support is at least one precious metal selected from the group consisting of rhodium, platinum, iridium, ruthenium and palladium, the content of which is 0.01 to 10% by weight based on the weight of the support And preferably 0.2 to 5.0% by weight. At this time, if the content of the noble metal is less than 0.01% by weight, the oxidizing power at low temperature is lowered, and if the content of the noble metal exceeds 10% by weight, the cost is increased compared to the increase in efficiency, which is not economically desirable, and the crystal size of the noble metal is increased to selectivity. There is a problem that the reduction of the high temperature activity and the decrease of.

In addition, the alkali metals and alkaline earth metals that can be used in one embodiment of the present invention are alkali metals (Li, Na, K, Rb, Cs and mixtures thereof) corresponding to group 1A on the periodic table and alkaline earth metals corresponding to group 2A ( At least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, Ra, and mixtures thereof, and the content thereof is 0.01 to 20.0% by weight, preferably 0.5 to 10.0% by weight, based on the weight of the support. to be. In this case, when the content of the alkali metal and alkaline earth metal is less than 0.01% by weight, the effect on the activity of the catalyst is insignificant, and when the content of the alkali metal and the alkaline earth metal is more than 20% by weight, there is a problem of reducing the number of active sites of the catalyst.

According to another embodiment of the present invention, the support usable in the present invention is an alkali metal (Li, Na, K, Rb, Cs and mixtures thereof) corresponding to group 1A on the periodic table and an alkaline earth metal (Be) At least one metal selected from the group consisting of Mg, Ca, Sr, Ba, Ra, and mixtures thereof; At least one metal selected from the group consisting of transition metals and amphoteric metals, preferably Al, Si, Zr, Ti, Mn, Mo, W, Fe, Co, Ni, Cu, Zn, Ga, Bi, Sn, and At least one metal selected from the group consisting of Ce; Or oxides thereof. At this time, the content of the alkali metal and alkaline earth metal contained in the support is 1 to 90% by weight, preferably 5.0 to 60.0% by weight of the support.

In another embodiment of the present invention, the precious metal supported on the support is at least one precious metal selected from the group consisting of rhodium, platinum, iridium, ruthenium and palladium, the content of which is 0.01 to 10% by weight based on the weight of the support. And preferably 0.2 to 5.0% by weight. At this time, if the content of the noble metal is less than 0.01% by weight, the oxidizing power at low temperature is lowered, and if the content of the noble metal exceeds 10% by weight, the cost is increased compared to the increase in efficiency, which is not economically desirable, and the crystal size of the noble metal is increased to selectivity. There is a problem that the reduction of the high temperature activity and the decrease of.

Meanwhile, precursors of the noble metals usable in the present invention include metal ammonium, metal chlorides, metal nitrates, metal acetates, etc. of the noble metals, and precursors of the cocatalyst components include metal chlorides, metal nitrates, metal citrate, and the like. May be used, and a form soluble in other liquid solvents may also be used.

On the other hand, a method of supporting the noble metal component and the alkali metal, alkaline earth metal or a composite thereof on a support is generally known in the art. For example, an excess solution impregnation method may be employed in which the support is pulverized to a size of about 0.1 to 500 µm, and impregnated with an aqueous solution of a precursor of a noble metal, an alkali metal, an alkaline earth metal or a composite thereof, and dried, calcined and reduced. It is not limited to this. At this time, the firing temperature is about 300 to 700 ° C, preferably about 300 to 450 ° C, and the reduction temperature is about 150 ° C to 500 ° C, preferably about 200 ° C to 350 ° C.

As described above, the catalyst according to the present invention is pulverized in the form of a powder having a diameter of 10 μm or less according to the process and the application to be applied to form a monolith, a metal plate, or a metal web. It can be prepared by coating on or by extrusion into a single or particle form. Optionally, the support may be extruded or injection processed in the form of a single or particle to support the active metal (noble metal) and the alkali metal, alkaline earth metal or a combination thereof. It is also possible to separately or simultaneously support precious metals and alkali metals, alkaline earth metals or composites thereof. The basic principle of the production method of such a catalyst or catalyst body is already well known in the art.

The method for selectively removing carbon monoxide using the catalyst according to the present invention may vary slightly depending on the concentration of carbon monoxide included in the reformed gas, but preferably, the reformed gas having a molar ratio of hydrogen / carbon monoxide of 30 to 250 and the Oxygen having a molar ratio of 0.4 to 10 relative to carbon monoxide in the reformed gas is reacted under a reformed gas space velocity (GHSV (STP)) of 1,000 to 100,000 hr ⁻¹ and 50 to 300 ° C. In particular, the active band of 100-230 degreeC and the space velocity of 5,000-80,000 hr <^-1> are more preferable.

As described above, according to the present invention, a catalyst prepared by supporting a precious metal and an alkali metal, an alkaline earth metal or a complex thereof on a commercial support in the form of a composite oxide; Or purifying hydrogen-rich reformed gas generated by reforming hydrocarbon or alcohol using a catalyst prepared by supporting a precious metal on a support including an alkali metal, an alkaline earth metal or a complex thereof as a constituent of the support. In this case, carbon monoxide has excellent selective oxidation ability, and since the consumption rate of hydrogen by side reaction is low, the structure of PROX process can be simplified and reduced in weight. In other words, catalysts prepared to coexist with precious metals and alkali metals, alkaline earth metals or composites thereof according to the composition of the present invention, even if the support is formed by any combination, shows excellent oxidation activity in the selective oxidation of carbon monoxide in the reformed gas. Can be.

The present invention can be more clearly understood by the following examples, which are only intended to illustrate the present invention and are not intended to limit the scope of the invention.

Example 1

Activated alumina (Aldrich, 19996-6, hereinafter Al ₂ O ₃ ) was used without any post-treatment, and the initial wet method (incipient wetness) was used as a catalyst preparation method. H ₂ PtCl ₆ · 6H ₂ O (Inuisho Precious Metals Co., LTD.) As a precursor of platinum and Mg (NO ₃ ) ₂ · H ₂ O (Junsei, 37580-1250) as a precursor of magnesium were dissolved in distilled water. In this case, the volume of the precursor solution was adjusted to 50% of the apparent volume of Al ₂ O ₃ . Then, ₂ mL of the precursor solution was mixed with Al ₂ O ₃ (5 g), sufficiently stirred until the precursor solution was evenly dispersed on the surface of Al ₂ O ₃ at room temperature, and then sufficiently dried in a drier maintained at 80 ° C. . The method was repeated several times until the supported amount of the catalyst precursor material was desired, and finally dried at 100 ° C. for 24 hours. Thereafter, the mixture was calcined in an air atmosphere of 400 ° C., after completion of the calcination process, the powder was pulverized again to have a particle size of 80 to 120 mesh, and reduced in a hydrogen atmosphere at 250 ° C. for 2 hours to complete the production of a catalyst. At this time, the input amount of the platinum precursor was 2% by weight based on Al ₂ O ₃ as the support, the input amount of magnesium precursor was adjusted to 2.5% by weight based on Al ₂ O ₃ as the support, completed The catalyst was represented by Pt-Mg / Al ₂ O ₃ .

The activity for selective oxidation of carbon monoxide of the catalyst prepared by the above method was measured using a quartz fixed bed reactor having an inner diameter of 4 mm. The composition of the reaction gas was 1.0 vol% of CO, 0.75 vol% of O ₂ , 75 vol% of hydrogen, 2.8 vol% of water, and 25.5 vol% of carbon dioxide. The stoichiometric ratio (O / CO) of oxygen / carbon monoxide used was maintained at 1.5. The ratio of reactant to catalyst was W / F = 0.1068gs / cm ³ and was measured 3 hours after the reactant feed so that the removal rate of carbon monoxide reached a steady state. The carbon monoxide concentration at the reactor inlet and outlet sides was measured to determine CO conversion (%) as shown in Equation 1 below.

The analysis of CO, O ₂ and CO ₂ was performed using Hewlett-Packard's HP-6890 gas chromatography equipped with two TCD (thermal conductivity detector) detector. Carbon monoxide and oxygen were separated into Molecular sieve 13x, and carbon dioxide was separated into Porapak Q column. At this time, the gas phase of mobile phase gas was expanded by using hydrogen to extend the lower limit of detection of CO and CO ₂ (5 ppm). A high sensitivity and linearity of the thermal conductivity detector can be obtained.

Hydrogen and hydrocarbons were measured using an HP-5890 equipped with TCD and a flame ionization detector (FID), respectively. Hydrogen was separated by Molecular sieve 5A, and mobile phase gas was used to obtain high sensitivity and linearity of TCD to low concentration range using argon. In the case of high temperature reaction, the production of methane is also possible, so it was measured using FID. At this time, methane was separated by a Molecular sieve 5A column.

Tests for catalytic activity were carried out in the temperature range of 130 ~ 230 ℃. As a result, the removal rate of carbon monoxide is as shown in FIG. According to the above results, when platinum and magnesium were supported on Al ₂ O ₃ in the form of a composite oxide, the carbon monoxide removal rate was 94.7% at 150 ° C., and Pt / Al in the temperature range of 150 ° C. to 200 ° C. the platinum than the ₂ O ₃ catalyst is a magnesium compound and a metal or at the same time that the catalyst is supported on Al ₂ O ₃ in the form of oxide can be obtained the result of the conversion of carbon monoxide from 1.4 to 3.2-fold increase.

Example 2

KNO ₃ (Junsei, 37395-1250) was used as a precursor of potassium to Al ₂ O ₃ using the same method as in Example 1 and then dried at 100 ℃. Platinum was supported on the dried catalyst, and drying, calcining, and reducing were carried out in the same manner as described in Example 1, and the finished catalyst was expressed as Pt-K / Al ₂ O ₃ . The activity measurement results of the catalyst are as shown in FIG. 1. The carbon monoxide removal rate of 97.9% was shown at the reaction temperature of 180 ° C. In the temperature range of 150 ° C to 230 ° C, platinum was supported on Al ₂ O ₃ in the form of potassium and complex oxides than Pt / Al ₂ O ₃ catalyst. As a result, the conversion rate of carbon monoxide increased by 1.5 to 5.2 times.

Example 3

By using the same method as Example 1, a catalyst was prepared by supporting a precursor material after calcining hydrotalcite (Aldrich, 51176-5, HT) containing alkaline earth metal as a support of platinum at 400 ° C., The completed catalyst is indicated as Pt / HT. The activity measurement results of the catalyst are as shown in FIG. 1. At a temperature of 150 ° C., the conversion rate of carbon monoxide was 99.7%, which was very superior to that of the Pt / Al ₂ O ₃ catalyst.

Comparative Example 1

Platinum was supported on Al ₂ O ₃ to prepare a catalyst using the same method as in Example 1, and the completed catalyst was expressed as Pt / Al ₂ O ₃ , and the experimental results are shown in FIG. 1.

Example 4

Using the same method as in Example 1, platinum and magnesium were supported on silica (Aldrich, 38128-4, SiO ₂ ) to prepare a catalyst, and the completed catalyst was expressed as Pt-Mg / SiO ₂ . The activity measurement results of the catalyst are as shown in FIG. 2. The carbon monoxide removal rate was 77.0% at the reaction temperature of 180 ° C. In the range of 150 ° C to 200 ° C, the carbon monoxide conversion was 1.2 for the catalyst in which platinum was supported on SiO ₂ in the form of magnesium and complex oxide than the catalyst of Pt / SiO ₂ . The result was an increase of ˜2.0 times.

Example 5

Using the same method as in Example 1, a catalyst was prepared using calcium silicate (Aldrich, 37266-8, hereinafter referred to as CaSiO ₃ ) containing alkaline earth metal as a support of platinum, and the finished catalyst was Pt / CaSiO ₃ . Indicated. The activity measurement results of the catalyst are as shown in FIG. 2. At a temperature of 180 ° C., the conversion rate of carbon monoxide is 95.6%, and very excellent activity can be obtained.

Comparative Example 2

Platinum was supported on SiO ₂ using the same method as in Example 1 to prepare a catalyst, and the completed catalyst was expressed as Pt / SiO ₂ , and the experimental results are shown in FIG. 2.

Example 6

Using the same method as in Example 1, platinum and magnesium were supported on silica alumina (Davison Chemical, DL9195, SA) to prepare a catalyst, and the finished catalyst was expressed as Pt-Mg / SA. The activity measurement results of the catalyst are as shown in FIG. 3. According to the results, when platinum and magnesium were supported on SA in the form of a composite oxide, the removal rate of carbon monoxide was 76.2% at the reaction temperature of 200 ° C. In the range of 150 ° C to 200 ° C, platinum was more than magnesium catalyst of Pt / SA. The catalyst supported on SA in the form of a complex oxide with a carbon monoxide conversion was 2.3 to 22.8 times higher.

Comparative Example 3

Platinum was supported on SA in the same manner as in Example 1 to prepare a catalyst, and the completed catalyst was expressed as Pt / SA, and the experimental results are shown in FIG. 3.

Example 7

Using the same method as in Example 1, platinum and magnesium were supported on zirconium dioxide (Yakuri, 370211011, hereinafter ZrO ₂ ) to prepare a catalyst, and the completed catalyst was expressed as Pt-Mg / ZrO ₂ . The experimental results are shown in FIG. 4. According to the results, when hayeoteul supported in the form of a composite oxide of platinum and magnesium on ZrO _2, at a reaction temperature was 180 ℃ to obtain a carbon monoxide removal rate of 97.0%, in 180 ℃ ~230 ℃ range, than the Pt / ZrO ₂ catalyst The catalyst supported by platinum on ZrO ₂ in the form of magnesium and composite oxides showed a 1.9 to 3.0-fold increase in carbon monoxide conversion.

Example 8

Using the same method as in Example 1, a catalyst was prepared using calcium zirconate (Aldrich, 39619-2, hereinafter CaZrO ₃ ) containing an alkaline earth metal as a support of platinum, and the finished catalyst was Pt / CaZrO. ₃ . Experimental results are shown in Figure 4 below. The conversion rate of carbon monoxide at 150 ° C. was 99.2%, showing very good activity, and a very increased reaction activity was obtained in the temperature range.

Comparative Example 4

Platinum was supported on ZrO ₂ to prepare a catalyst using the same method as in Example 1, and the completed catalyst was expressed as Pt / ZrO ₂ , and the experimental results are shown in FIG. 4.

Example 9

Using the same method as in Example 1, platinum and magnesium were supported on rutile crystalline titanium dioxide (Aldrich, 224227, Rutile, hereinafter TiO ₂ (R)) to prepare a catalyst. The finished catalyst was Pt-Mg / TiO ₂ (R). Catalytic activity was carried out at a temperature range of 130 ℃ to 230 ℃, the experimental results are shown in Figure 5 below. The carbon monoxide removal rate was 70.9% at the reaction temperature of 200 ° C. In the range of 180 ° C to 230 ° C, platinum was supported on TiO ₂ (R) in the form of magnesium and complex oxide than Pt / TiO ₂ (R). As a result, the conversion rate of carbon monoxide increased by 1.3 to 2.7 times.

Comparative Example 5

A catalyst was prepared by supporting platinum on TiO _2- (R) using the same method as in Example 1, and the completed catalyst was expressed as Pt / TiO _2- (R), and the experimental results are shown in FIG. 5. As shown.

Example 10

Using the same method as in Example 1, platinum and magnesium were supported on anatase crystalline titanium dioxide (Yakuri, 34025, Anantase, hereinafter TiO ₂ (A)) to prepare a catalyst, and the finished catalyst was Pt-Mg / TiO. ₂ (A). Catalytic activity was measured in the range of 130 ℃ to 230 ℃, the experimental results are shown in Figure 6 below. According to the results, showed a carbon monoxide removal rate of 98.3% at a reaction temperature of 180 ℃, at a temperature ranging from 180 ℃ ~230 ℃, TiO ₂ in the form of a platinum complex oxide and magnesium than the catalyst of Pt / TiO ₂ (A) ( The catalyst supported on A) obtained 1.5 to 1.9 times higher conversion of carbon monoxide.

Example 11

Using the same method as in Example 1, a catalyst was prepared using calcium titanate (Aldrich, 37260-9, hereinafter referred to as CaTiO ₃ ) containing alkaline earth metal as a support of platinum, and the finished catalyst was Pt / CaTiO _3. Marked as. Catalytic activity was measured in the range of 150 ℃ to 230 ℃, the experimental results are shown in Figure 6 below. At 180 ° C, the conversion of carbon monoxide was 97%, which means that Pt / TiO ₂ (A) Very good activity was obtained compared to Pt / TiO ₂ (R).

Comparative Example 6

A catalyst was prepared by supporting platinum on TiO _2- (A) using the same method as in Example 1, and the finished catalyst was expressed as Pt / TiO _2- (A), and the experimental results are shown in FIG. As shown.

Example 12

Platinum, magnesium and ruthenium were supported on Al ₂ O ₃ to prepare a catalyst using the same method as Example 1, wherein RuCl ₃ (Aldrich, 20622-9) was used as a precursor of ruthenium. The completed catalyst was represented by Pt-Ru-Mg / Al ₂ O ₃ , and the experimental results are shown in FIG. 7. According to the results, when platinum, ruthenium and magnesium were supported on Al ₂ O ₃ in the form of a composite oxide, the carbon monoxide removal rate was 63.5% at a reaction temperature of 150 ° C., and Pt− was in the temperature range of 130 ° C. to 200 ° C. Compared with the Ru / Al ₂ O ₃ catalyst, the conversion of carbon monoxide was 1.2-1.3 times higher than that of platinum and ruthenium supported on Al ₂ O ₃ in the form of magnesium and complex oxides.

Comparative Example 7

A catalyst was prepared by supporting platinum and ruthenium on Al ₂ O ₃ using the same method as in Example 1, and the completed catalyst was expressed as Pt-Ru / Al ₂ O ₃ , and the experimental results are shown in FIG. 7. As shown.

As described above, when the precious metal and the alkaline earth metal are supported in the form of a composite oxide on various supports as shown in Examples 1, 2, 4, 6, 7, 9, 10, and 12, the precious metal alone is supported. The selective oxidation rate of carbon monoxide was higher than that of the catalysts (Comparative Examples 1 to 7), and as shown in Examples 9 to 10 above, when the metals and metal oxides of the same species had different physical and chemical properties, precious metals and alkalis, alkaline earth metals or The same result was obtained when these composites were supported in the form of composite oxides.

In addition, as shown in Examples 3, 5, 8, and 11, alkali metals, alkaline earth metals, or composites thereof, which affect the oxidation reaction of carbon monoxide, are included as constituents in the support, even when present as precious metals and complex oxides. It was found that the oxidation reaction of carbon monoxide was increased by forming.

As a result, catalysts prepared to coexist with precious metals and alkali metals, alkaline earth metals or composites thereof according to the structure of the present invention, even if the support is composed of any combination, shows excellent oxidation activity in the selective oxidation of carbon monoxide in the reformed gas. And it was found.

As described above, catalysts prepared in the form of complex oxides using noble metals and alkali metals, alkaline earth metals or composites thereof in accordance with the present invention have very good selective oxidation performance on carbon monoxide in hydrogen-rich reforming gas. In addition, in the case of PROX process using the catalyst, as well as simplification, miniaturization and light weight of the process configuration, there is an advantage that can achieve excellent economic efficiency.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

1 shows Example 1 (Pt-Mg / Al ₂ O ₃ catalyst), Example 2 (Pt-K / Al ₂ O ₃ catalyst), Example 3 (Pt / HT catalyst), and Comparative Example 1 of the present invention. A graph showing the results of selective carbon monoxide oxidation according to the temperature of (Pt / Al ₂ O ₃ catalyst).

2 is a selective carbon monoxide oxidation results according to the temperature of Example 4 (Pt-Mg / SiO ₂ catalyst), Example 5 (Pt / CaSiO ₃ catalyst), and Comparative Example 2 (Pt / SiO ₂ catalyst) of the present invention A graph representing.

3 is a graph showing the results of selective carbon monoxide oxidation according to the temperature of Example 6 (Pt-Mg / SA catalyst) and Comparative Example 3 (Pt / SA catalyst) of the present invention.

4 is a selective carbon monoxide oxidation result according to the temperature of Example 7 (Pt-Mg / ZrO ₂ catalyst), Example 8 (Pt / CaZrO ₃ catalyst), and Comparative Example 4 (Pt / ZrO ₂ catalyst) of the present invention A graph representing.

5 is a graph showing the results of selective carbon monoxide oxidation according to the temperature of Example 9 (Pt-Mg / TiO ₂ (R) catalyst) and Comparative Example 5 (Pt / TiO ₂ (R) catalyst) of the present invention.

6 shows the temperature of Example 10 (Pt-Mg / TiO ₂ (A) catalyst), Example 11 (Pt / CaTiO ₃ catalyst), and Comparative Example 6 (Pt / TiO ₂ (A) catalyst) of the present invention. A graph showing the results of selective carbon monoxide oxidation according to.

7 is a graph showing the results of selective carbon monoxide oxidation according to the temperature of Example 12 (Pt-Ru-Mg / Al ₂ O ₃ catalyst) and Comparative Example 7 (Pt-Ru / Al ₂ O ₃ catalyst) of the present invention to be.

Claims (6)

delete (Iii) at least one metal selected from the group consisting of alkali metals and alkaline earth metals; And (ii) at least one metal selected from Al, Si, Zr, Ti, Mn, Mo, W, Fe, Co, Ni, Cu, Zn, Ga, Bi, Sn, and Ce; A noble metal selected from the group consisting of rhodium, platinum, iridium, ruthenium and palladium is supported on the support made of oxide, and the content of the noble metal is 0.01 to 10% by weight based on the weight of the support. Catalysts for selectively removing carbon monoxide in the reformed gas, characterized in that the content of the alkali metal and alkaline earth metal contained in the content is 1 to 90% by weight based on the weight of the support. delete The catalyst of claim 2, wherein the catalyst is coated on a monolith, a metal plate, or a metal web after being ground to a diameter of 10 μm or less. The catalyst according to claim 2, wherein the catalyst is in the form of a single body or an extrusion process. Claim 2 1,000~100,000hr oxygen having a molar ratio of 0.4 to 10 relative to carbon monoxide in the hydrogen / carbon monoxide in the reformed gas and the reformed gas molar ratio is 30-250 in the selective oxidation reaction zone comprising a catalyst according to the ^anti--1 A method for selectively removing carbon monoxide in the reformed gas, characterized in that the reaction is carried out under the conditions of the reformed gas space velocity (GHSV) and 50 to 300 ° C.