KR101359990B1 - Catalyst for Reforming of Methane with the Enhanced Stability for Sulfur components, Preparing Method Thereof and Methane Reforming Method Using The Catalyst - Google Patents

Abstract

The present invention is a catalyst for methane reforming reaction having excellent catalytic activity and stability in the presence of sulfur components, specifically H ₂ S and excellent durability against sulfur, specifically H ₂ S, a preparation method thereof, and reaction in the presence of the catalyst. A reforming reaction of methane is carried out at a temperature of 750 to 900 ° C., a reaction pressure of 0.5 to 10 atm, and a space velocity of 100 to 6,000 L (CH ₄ ) / Kgcat / h. CeO ₂ -ZrO ₂ of the present invention The catalyst in which rhodium (Rh) is supported on the support has excellent durability against sulfur, specifically hydrogen sulfide (H ₂ S), present in the by-product gas. Therefore, it shows excellent catalytic activity and stability in the reforming reaction of methane using sulfur, specifically byproduct gas containing hydrogen sulfide. Thus, the desired syngas and hydrogen are obtained at high conversion in the methane reforming reaction.

Description

Catalyst for Reforming of Methane with the Enhanced Stability for Sulfur components, Preparing Method Thereof and Methane Reforming Method Using The Catalyst}

The present invention relates to a catalyst for methane reforming reaction having excellent durability against sulfur, a preparation method thereof, and a methane reforming method using the catalyst. More specifically, the present invention provides a catalyst for methane reforming reaction having excellent catalytic activity and stability in the presence of sulfur components, specifically H ₂ S and excellent durability against sulfur, specifically H ₂ S, a preparation method thereof, and the catalyst. It relates to a methane reforming method using.

In the steel industry, a large amount of byproduct gas is generated during operation. By-product gas is divided into COG (coke oven gas), LDG (LD converter gas) and BFG (Blast furnace gas) .In the by-product gas, mainly fuel materials and chemicals such as H ₂ , CH ₄ , CO and CO ₂ Basic raw materials for synthesis are included as main ingredients. For example, the coke oven gas (COG) generated in the coke manufacturing process of domestic steel mills is 700 ~ 850? Is discharged at a high temperature, and coke oven gas is H ₂ about 55%, CO 10% and CH ₄ About 25% and the like.

In addition, although the content of impurities may vary depending on the pretreatment process, unrefined COG contains, in many cases, several hundreds to thousands of ppm H ₂ S, and most of the purified COG gas contains about tens to hundreds of ppm. H ₂ S is included.

On the other hand, synthesis gas and hydrogen are produced by the reforming reaction of methane present in the by-product gas. The reforming reaction of methane producing syngas and hydrogen is largely carried out by steam reforming of methane (SRM), partial oxidation of methane (POM) using oxygen, and methane and carbon dioxide reforming ( Carbon dioxide reforming of methane (CDR) and mixed reforming reaction (SCR-combined stream and CO2 reforming with CO2; SRM + CDR) can be largely divided into carbon monoxide and hydrogen (H ₂ / CO) ratios generated from each reforming reaction. Can be used differently depending on the optimally required ratio in subsequent processes.

Generally, nickel-based catalysts have been generally used when syngas is produced using methane that does not contain impurities that cause catalyst poisoning, such as H ₂ S. For example, Korean Patent Publication No. 2006 -132293 and 2005-51820.

However, the H ₂ S present in the by-product gas is known to inactivate the catalyst by poisoning the nickel-based catalyst, and when the by-product gas contains H ₂ S that causes the catalyst deactivation, Research reports on catalyst systems that can be used for reforming reactions are insignificant.

Even when the methane reforming reaction is carried out using Pt, Pd and Rh series noble metal catalysts as a catalyst system having excellent durability against H ₂ S, in the presence of H ₂ S at high concentrations (hundreds to thousands of ppm), the catalyst is generally deactivated. Proceeds abruptly.

Therefore, a method of preparing a synthesis gas by removing the sulfur in a sulfur-containing gas, specifically H ₂ S in advance by a desulfurization process, is generally described, for example, described in US Patent No. 6,692,711. have.

Furthermore, in the case of steam reforming of methane (SRM) reaction using methane from which H ₂ S is currently used commercially, the reaction temperature is 750 to 850 ° C and the molar ratio of steam and methane is 4 to 6: 1. Ni / Al ₂ O ₃ catalyst system is mainly used in the research, but due to the problem of deactivation of the catalyst by carbon deposition, studies on catalyst systems containing transition metals and alkali metals as precious metals or cocatalysts are being conducted. [Journal of Molecular Catalysis A 147 (1999) 41].

Therefore, there is a need for the development of a catalyst system that shows excellent durability against methane reforming reaction using a by-product gas containing a large amount of sulfur, specifically hydrogen sulfide (H ₂ S).

The present invention provides a catalyst for methane reforming having excellent durability against sulfur, specifically hydrogen sulfide (H ₂ S).

The present invention provides a method for preparing a catalyst for methane reforming reaction having excellent durability against sulfur, specifically hydrogen sulfide (H ₂ S).

The present invention is to provide a methane reforming method using a catalyst for methane reforming reaction excellent in sulfur, specifically hydrogen sulfide (H ₂ S).

According to a first aspect of the present invention,

And a specific surface area of 20 ~ 80 ㎡ / g, a weight ratio of CeO ₂ / ZrO ₂ is 0.3≤CeO ₂ / ZrO ₂ ≤4.0 of CeO ₂ -ZrO ₂ CeO ₂ -ZrO ₂ on a support A catalyst having 0.2 to 5 parts by weight of rhodium per 100 parts by weight of the support and having a specific surface area of 20 to 50 m 2 / g is provided.

According to a second aspect of the present invention,

In the first aspect, the catalyst is provided with a catalyst for use in the reforming of methane in which H ₂ S is present at 3000 ppmv or less.

According to a third aspect of the present invention,

In a second aspect, the reforming of the methane is provided with a catalyst which is steam reforming of methane, mixed reforming, partial oxidation of methane using oxygen or methane and carbon dioxide reforming.

According to a fourth aspect of the present invention,

CeO ₂ -ZrO ₂ Provided is a method for preparing a catalyst comprising supporting a rhodium in an amount of 0.2 parts by weight to 5.0 parts by weight based on a metal content with respect to 100 parts by weight of the support, and calcining at 400 to 800 ° C.

According to a fifth aspect of the present invention,

In the fourth aspect, the CeO ₂ -ZrO ₂ Preparing a mixed solution by adding a cerium precursor solution to a solution of citric acid in ethylene glycol and adding a zirconium precursor solution to a solution of citric acid in another ethylene glycol;

Stirring the mixed solution at 50˜100 ° C .;

Removing water in the mixed solution heated to 120 to 130 ° C. for 5 to 10 hours to form a sol; And

Provided is a method for preparing a catalyst prepared by a sol-gel method comprising calcining the sol at 400 to 900 ° C. for 3 to 5 hours.

According to a sixth aspect of the present invention,

In the fourth aspect, the CeO ₂ -ZrO ₂ The support is prepared by dissolving a cerium precursor and a zirconium precursor in water to prepare a mixed solution;

Coprecipitation by adding a basic precipitant aqueous solution to pH 9-10 to the mixed solution;

Aging at 50-90 ° C. for 2-10 hours to obtain a precipitate;

Filtering, washing and drying the precipitate; And

Provided is a method for preparing a catalyst prepared by a coprecipitation method comprising calcining the precipitate at 400 to 900 ° C. for 3 to 5 hours.

According to a seventh aspect of the present invention,

In the fifth or sixth aspect, the support has a specific surface area of 20 to 80 m 2 / g, and the weight ratio of CeO ₂ / ZrO ₂ is 0.3 ≦ CeO ₂ / ZrO ₂ ≦ 4.0.

According to an eighth aspect of the present invention,

In the fifth or sixth aspect, the catalyst has a specific surface area of 20 to 50 m 2 / g.

According to a ninth aspect of the present invention,

In the presence of the catalyst of the first aspect, a reforming reaction of methane is carried out at a reaction temperature of 750 to 900 占 폚, a reaction pressure of 0.5 to 10 atmospheres, and a space velocity of 100 to 6,000 L (CH ₄ ) / Kgcat / h.

According to a tenth aspect of the present invention,

In a ninth aspect, the by-product gas is provided with a reforming reaction of methane containing less than 3000 ppmv H ₂ S.

According to an eleventh aspect of the present invention,

In the ninth aspect, the reforming of the methane is provided by the reforming of methane, which is steam reforming of methane, mixed reforming, partial oxidation of methane using oxygen, or methane and carbon dioxide reforming.

CeO ₂ -ZrO ₂ of the present invention A catalyst on which a rhodium (Rh) is supported on a support (hereinafter also referred to as 'Rh / CeO ₂ -ZrO ₂ ') has excellent durability against sulfur present in by-product gas, specifically hydrogen sulfide (H ₂ S). Therefore, it shows excellent catalytic activity and stability in the reforming reaction of methane using sulfur, specifically byproduct gas containing hydrogen sulfide. Thus, the desired syngas and hydrogen are obtained at high conversion in the methane reforming reaction.

The catalyst of the present invention is a selective reforming reaction of methane with by-product gas, for example by-product gas with H ₂ S present in hundreds to thousands of ppm in COG, for example steam reforming (SRM) and mixing of methane. SCR-combined stream and CO ₂ reforming with CO ₂ ; SRM + CDR, partial oxidation of methane (POM) using oxygen, and methane and carbon dioxide reforming (dry reforming) It can be used for dry reforming, carbon dioxide reforming of methane (CDR).

On the other hand, the synthesis gas (specifically, synthesis gas containing hydrogen, carbon monoxide and carbon dioxide) obtained in the reforming reaction of methane using by-product gas in the presence of the catalyst of the present invention synthesizes methanol, synthesizes dimethyl ether (DME) It can be utilized in the Ropsch reaction process, and hydrogen can be used to produce hydrogen fuel.

1 is a graph showing the results of a methane reforming reaction carried out in the presence of the catalysts of Examples 1, 3 and Comparative Example 7. FIG.

The present invention is to provide a catalyst having excellent durability against hydrogen sulfide (H ₂ S) present in the by-product gas and a method for producing the same. Specifically, inactivation of the catalyst due to poisoning of hydrogen sulfide present in the by-product gas is suppressed to provide a catalyst having excellent catalytic activity and stability for the reforming reaction of methane using the by-product gas containing a large amount of hydrogen sulfide, and a method for preparing the same. will be.

The catalyst of the present invention is a combination of a catalytically active component and a specific component as a support. In addition, the catalyst of the present invention is due to the discovery that the weight ratio of the metal oxides constituting the support, the support and / or the specific surface area of the catalyst, significantly improved the durability to hydrogen sulfide of the specifically controlled catalyst.

According to an embodiment of the present invention, CeO ₂ -ZrO ₂ A catalyst in which rhodium is supported as a catalytically active component on a support is provided. The CeO ₂ -ZrO ₂ support has a specific surface area of 20 to 80 m 2 / g, preferably 25 to 60 m 2 / g. The support having the specific surface area is due to an increase in the interaction between rhodium and the support due to a decrease in the conversion rate of methane due to poor dispersibility and a decrease in the particle size of rhodium due to excessive dispersion of rhodium due to the rhodium active ingredient being properly dispersed in the support. The problem of reduced catalytic activity due to the reduced reducibility of a rhodium does not arise excessively.

The CeO ₂ -ZrO ₂ support the weight ratio of the metal oxide CeO ₂ / ZrO ₂ in the (CeO ₂ with a support comprising a ZrO ₂₎ is 0.3≤CeO ₂ / ZrO ₂ ≤4.0, preferably 0.5≤CeO ₂ / ZrO ₂ ≤ 4.0 is good. When the weight ratio is less than 0.3 or more than 4.0, the dispersibility and reducibility of the active ingredient, rhodium, may decrease due to a decrease in the specific surface area of the support, thereby reducing the catalytic activity. By using a support having a weight ratio of CeO ₂ / ZrO _{2 in} the above range, excellent catalytic activity and methane conversion in the by-product gas reforming reaction containing H ₂ S are ensured.

Rh as the catalytically active component is CeO ₂ -ZrO ₂ CeO ₂ -ZrO ₂ on the support It may be supported by 0.2 to 5 parts by weight based on 100 parts by weight of the support. If the amount of the active ingredient is less than 0.2 parts by weight, the activity is low due to the small amount of Rh showing activity in the reforming reaction. If the amount is more than 5 parts by weight, the activity of the catalyst decreases due to the decrease in dispersibility of Rh, and the catalyst production cost increases. . Thus, CeO ₂ -ZrO ₂ By supporting Rh in an amount of 0.2 to 5 parts by weight based on 100 parts by weight of the support, excellent catalytic activity and methane conversion in the by-product gas reforming reaction containing H ₂ S are ensured.

Meanwhile, CeO ₂ -ZrO ₂ The specific surface area of the catalyst on which the rhodium is supported on the support is preferably 20 to 50 m 2 / g. In the case where the specific surface area of the catalyst is in the above range, it is preferable in that the deactivation of the catalyst does not proceed rapidly due to a decrease in activity of the catalyst due to a decrease in dispersibility of rhodium and a decrease in specific surface area due to aggregation of the catalyst at reaction conditions.

According to another embodiment of the present invention the CeO ₂ -ZrO ₂ Provided is a method for preparing a catalyst having rhodium supported on a support. The catalyst according to an embodiment of the present invention is CeO ₂ -ZrO ₂ It is prepared by supporting Rh in an amount of 0.2 parts by weight to 5.0 parts by weight based on a metal content of 100 parts by weight of the support, and baking it at 400 ° C to 800 ° C.

The supporting of the rhodium active ingredient on the support can be carried out by any method known in the art, for example, by the impregnation method. That is, the Rh precursor solution may be added to the CeO ₂ —ZrO ₂ support to support the rhodium on the support by impregnation.

In this case, as the rhodium precursor, for example, nitrate, chloride salt and acetate salt of rhodium may be used alone or in combination of two or more thereof. More specifically, the rhodium active component is supported on the support by a method of adding a rhodium precursor solution in which a rhodium precursor is dissolved in a solvent to a CeO ₂ -ZrO ₂ support. As the solvent, at least one solvent selected from the group consisting of water, alcohol, specifically methanol, ethanol and propanol may be used. The solvent may be used alone or in combination of two or more thereof.

Thereafter, the solvent may be removed, dried, and calcined to prepare a catalyst. Removal of the solvent can be performed using, for example, a vacuum evaporator. In addition, the removal and drying conditions of the solvent can be carried out under general solvent removal and drying conditions to the extent that the physical properties of the catalyst can be dried without damage, and these conditions are not particularly limited. For example, the solvent may be removed by maintaining it at a temperature between 50 ° C. and 70 ° C. for a time sufficient to remove the solvent in the catalyst. At temperatures below 50 ° C, the solvent is difficult to evaporate smoothly during distillation under reduced pressure and may take a long time to dry. If the temperature is above 70 ° C, catalytically active components are mainly distributed on the outer surface of the support during distillation under reduced pressure. It is preferable to distill the solvent under reduced pressure in the above temperature range because there is a problem that the acid is falling.

For example, the drying may be performed in an oven, where the temperature of the oven may be 100 ° C to 200 ° C. By drying in the above temperature range, the solvent remains during the catalytic firing process, the rhodium particles move to the outer surface of the support particles, thereby preventing the problem of reducing the dispersibility of rhodium, and the rhodium precursor easily aggregates on the surface of the support The occurrence of the problem of decreasing dispersibility is prevented. The catalyst is preferably dried at the drying temperature for about 6 to 24 hours to remove more than 99% by weight of the solvent. Prolonged drying in excess of 24 hours has the disadvantage that the cost is excessively consumed.

The calcination temperature of the catalyst needs to be kept lower than the calcination temperature of the CeO ₂ -ZrO ₂ support to suppress the increase in particle size due to the sintering of rhodium which is an active ingredient. Accordingly, the firing of the catalyst may be performed at a temperature in the range of 400 ° C to 800 ° C, preferably 400 ° C to 750 ° C, which is lower than the firing temperature of the support. The calcination at the firing temperature does not cause a decrease in activity due to sintering of rhodium oxide during the reaction, as well as the reduction of the reduction of the catalyst due to the strong interaction of rhodium and the support and the catalytic activity of rhodium sintering in the sintering process. It is not preferable because no degradation problem occurs. In the said temperature range, it bakes enough by baking for about 3 to 12 hours, for example. In terms of cost, it is preferable to keep the firing time at 12 hours or less. Firing can be carried out in an air atmosphere.

CeO ₂ -ZrO ₂ The support can be prepared by sol-gel method or coprecipitation method.

CeO ₂ -ZrO ₂ The support can be prepared by the sol-gel method as follows. First, an aqueous solution of cerium precursor and an aqueous solution of zirconium precursor are mixed and heated to remove water in the mixed solution, preferably 99% by weight or more, to form a sol. The sol is then calcined to form CeO ₂ -ZrO ₂ Obtain a support. In the cerium precursor solution and the zirconium precursor aqueous solution, the content of cerium precursor and zirconium precursor is CeO ₂ -ZrO ₂ The weight ratio of the support during manufacture CeO ₂ / ZrO ₂ is an amount such that the 0.3≤CeO ₂ / ZrO ₂ ≤4.0.

Specifically, cerium precursor solution (A) is prepared by adding cerium precursor aqueous solution to a solution in which citric acid is dissolved in ethylene glycol. On the other hand, a zirconium precursor solution (B) is prepared by adding a zirconium precursor aqueous solution to a solution in which citric acid is dissolved in another ethylene glycol.

As the cerium precursor and the zirconium precursor, metal precursors generally used in the art may be used. Although not limited to this, the cerium precursor is, for example, at least one selected from the group consisting of cerium chloride, cerous nitrate, cerous oxalate and cerous carbonate. Cerium precursors may be used alone or in combination of two or more. Although not limited thereto, zirconium precursors include, for example, zirconium chloride salts, nitrates (zirconium nitrate and / or zirconyl nitrate) and zirconyl acetate salts. ) And at least one type of zirconium precursor selected from the group consisting of zirconyl chloride may be used alone or in combination of two or more.

In the solution in which citric acid is dissolved in ethylene glycol mixed with the cerium precursor aqueous solution and the zirconium precursor aqueous solution, the content of ethylene glycol may be 10 to 40 mol per mol of the metal (Ce or Zr). The content of citric acid may be 2 to 10 moles per mole of metal (Ce or Zr). The use of excess citric acid and ethylene glycol is advantageous for the dispersibility of metal precursors, specifically cerium precursors and zirconium precursors. However, the use of excess citric acid and ethylene glycol make it difficult to decompose citric acid and ethylene glycol during catalyst preparation and firing. It is preferable to use citric acid and ethylene glycol in the above ranges as they may occur.

The cerium precursor solution (A) and the zirconium precursor solution (B) are stirred and mixed. Thereafter, the mixture is heated to remove water in the mixed solution to form a sol. The stirring and mixing may be performed at a temperature of 50 to 100 ° C. to maximize dispersibility of the cerium precursor and the zirconium precursor while maximally suppressing the evaporation of the cerium precursor solution and the zirconium precursor solution.

After the stirring and mixing, the mixed solution is heated to remove the water in the mixed solution by evaporation to form a sol. Heating can be performed, for example at 120 degreeC-130 degreeC for 5 to 10 hours. It is preferable to heat at 120 ° C to 130 ° C for 5 to 10 hours so that aggregation of the metal precursor due to rapid moisture evaporation is prevented.

The sol is then calcined to form CeO ₂ -ZrO ₂ Obtain a support. The firing may be performed at 400 to 900 ° C, preferably at 400 to 800 ° C for 3 to 5 hours. Rapid heating during firing may lead to a decrease in dispersibility due to sintering of cerium oxide and zirconium oxide, and therefore, it is preferable to increase the temperature at a heating rate of 3 to 7 ° C / min. Further, for example, cerium precursors and zirconium precursors are sufficiently converted to cerium oxides and zirconium oxides to form a suitable CeO ₂ -ZrO ₂ structure, so that thermal stability during the reforming reaction of methane using the catalyst according to one embodiment of the present invention is improved. 3 to 5 hours at 400 to 900 ° C. to ensure specific target reduction due to growth of the particle size and thereby to reduce the dispersibility of the rhodium supported on the support and to reduce the methane conversion rate when the catalyst is used in the methane reforming reaction. It is preferable to bake. Firing can be carried out in an air atmosphere.

CeO ₂ -ZrO ₂ The support can also be prepared by coprecipitation as follows. A cerium precursor and a zirconium precursor were dissolved in water to prepare a mixed solution, and a basic additive was added thereto to adjust the pH of the mixed solution to precipitate, filtration, washing, drying and firing the precipitate obtained by coprecipitation and aging of the cerium precursor and the zirconium precursor. CeO ₂ -ZrO ₂ Obtain a support.

First, a cerium precursor and a zirconium precursor are dissolved in water to prepare a mixed solution. In this case, the same precursor as described in the sol-gel method may be used as the cerium precursor and the zirconium precursor. In water of cerium precursor and a zirconium precursor is added in a weight ratio of CeO ₂ / ZrO ₂ in a CeO ₂ -ZrO ₂ support is obtained such that the 0.3≤CeO ₂ / ZrO ₂ ≤4.0. The lower the content of cerium precursor and zirconium precursor to water, the better the coprecipitation reaction, but the weight ratio of water / metal precursor (total amount of cerium precursor and zirconium precursor) is preferably 100 or less in consideration of catalyst production cost.

Thereafter, the mixed solution and the basic precipitant aqueous solution are slowly added to the vessel at a pH of 9-10 so that the cerium precursor and the zirconium precursor are co-precipitated. At this time, the coprecipitation reaction should be carried out while slowly mixing the aqueous solution of the metal precursor and the aqueous solution of the basic precipitant at the same time to maintain a uniform pH range and have a large specific surface area. A support that is m 2 / g can be prepared.

As the basic precipitant, any silver basic precipitant generally known in the art may be used, but is not limited thereto. For example, ammonia water (NaOH), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), and sodium bicarbonate (NaHCO ₃ ) may be used alone or in combination of two or more thereof. The basic precipitant aqueous solution may be prepared by dissolving the basic precipitant in water, and the concentration of the basic precipitant is not particularly limited.

The coprecipitation reaction of cerium and zirconium precursors proceeds smoothly at pH 9-10, so that the precipitate is obtained at an excellent yield so that the pH is 9-10.

Thereafter, it is aged to obtain a precipitate. After coprecipitation, the aging process is carried out at 50 ° C to 90 ° C for 2 hours to 10 hours, preferably 2 hours to 8 hours. By aging at the above aging temperature and time range, the structure of the CeO ₂ -ZrO ₂ support is well formed so that the dispersibility of rhodium on the support is good, and thus, when using a catalyst, excellent methane conversion can be obtained. Specifically, the structure of the support is well formed by aging in the above temperature range, the excessive increase in the particle size of the support is prevented to prevent the problem of reducing the specific surface area. Specifically, by aging in the above time range, the structure of the support is well formed, and the support surface area decreases due to the increase of the agglomeration of the particles of the cerium precursor and the zirconium precursor, thereby preventing a large specific surface area, specifically, the specific surface area of 20-80 m 2. A support is obtained which is / g, preferably 25-60 m 2 / g.

After aging, the precipitate formed by filtration is taken and washed. The drying is then carried out in an oven at 100 ° C. or higher, specifically in the range from 100 ° C. to 150 ° C. for 12 hours to 24 hours. Drying is preferably carried out for 12 hours to 24 hours at 100 ℃ or more temperature that can remove the solvent present in the pores. On the other hand, when drying at a temperature higher than 150 ℃, drying time can be shortened, but the specific surface area of the support may be reduced, it is preferable to dry in the above temperature range.

After drying, thereby forming a CeO ₂ -ZrO ₂ Obtain a support. The firing may be performed at 400 to 900 ° C, preferably at 400 to 800 ° C for 3 to 5 hours. Rapid firing during firing may cause a decrease in dispersibility due to sintering of cerium oxide and zirconium oxide, and therefore, it is preferable to increase the temperature at a heating rate of 3 ° C./min to 7 ° C./min. The firing process and conditions are the same as the sol-gel method.

The CeO ₂ -ZrO ₂ support, specifically, the sol-gel method and a metal oxide in the CeO ₂ -ZrO ₂ support is prepared by co-precipitation method the weight ratio of CeO ₂ / ZrO ₂ is 0.3≤CeO ₂ / ZrO ₂ ≤4.0, preferably Is 0.5 ≦ CeO ₂ / ZrO ₂ ≦ 4.0. Specifically, in the sol-gel method and the coprecipitation method, the cerium precursor and the zirconium precursor have a CeO ₂ / ZrO ₂ weight ratio of 0.3 ≦ CeO ₂ / ZrO ₂ ≤4.0, preferably 0.5≤CeO ₂ / ZrO ₂ ≤4.0 Used in quantity. In addition, the specific surface area of the CeO ₂ -ZrO ₂ support is 20 to 80 m ₂ / g, preferably 25 to 60 m 2 / g. The specific surface area of the support may be adjusted in the above range depending on the firing temperature, the content of the cerium precursor and the zirconium precursor. In addition, in the case of the sol-gel method, the content of ethylene glycol and citric acid used, and in the case of the coprecipitation method, may be adjusted according to the type of basic precipitant.

Rh / CeO ₂ -ZrO ₂ of the present invention The catalyst as H ₂ S, specifically, several hundred to thousands ppmv, is more specifically, preferably used for the reforming reaction of methane is less than 3000 ppmv H ₂ S present. The reforming reaction of methane also includes reforming the by-product gas containing methane. That is, Rh / CeO ₂ -ZrO ₂ of the present invention The catalyst is methane reforming with H ₂ S, specifically hundreds to thousands of ppm H ₂ S, specifically steam reforming (SRM) and mixed reforming (SCR-combined stream and CO ₂ reforming with methane). CO ₂ ; SRM + CDR).

According to another aspect of the present invention, Rh / CeO ₂ -ZrO ₂ according to one embodiment of the present invention There is also provided a reforming reaction of methane with a reaction temperature of 700-900 ° C., a reaction pressure of 0.5-10 atm and a space velocity of 100-6,000 L (CH ₄ ) / Kgcat / h.

The methane reforming reaction includes steam reforming of methane (SRM), mixed reforming (SCR-combined stream and CO ₂ reforming with CO ₂ ; SRM + CDR), and partial oxidation of methane using oxygen (autothermal reforming, partial). oxidation of methane (POM), or methane and carbon dioxide reforming (dry reforming, carbon dioxide reforming of methane; CDR), preferably steam reforming (SRM) or mixed reforming of methane. Reaction (SCR-combined stream and CO ₂ reforming with CO ₂ ; SRM + CDR).

If the reaction temperature is less than 700 ℃ in the mixed reforming reaction conditions there is a problem that the deactivation of the catalyst suddenly occurs by carbon deposition by Boudourd reaction (2CO → C + CO ₂ ΔH = -172 kJ / mol), the reaction temperature is When it exceeds 900 ℃, the conversion rate of methane and carbon dioxide is excellent, but it is difficult to select the reactor material for reforming, and it is necessary to process the secondary heat exchange of the hot by-product gas discharged at about 850 ℃, which reduces the energy efficiency of the entire reforming process. Problems will arise.

If the reaction pressure is less than 0.5 atm, there may be a problem that the initial investment cost increases due to the increase in the size of the reactor, and if the pressure exceeds 10 atm, the size of the reactor is reduced to reduce the investment cost, but thermodynamically produced coke on the catalyst surface It may not be preferable because the catalyst deactivation may proceed rapidly, and a process of boosting the by-product gas generated in the steel mill to an additional 10 atm or more may reduce the economic efficiency of the process.

If the space velocity is 100L (CH ₄₎ / If Kgcat / h under is not desirable in the problem of reduced throughput in the waste gas, the space velocity is 6,000 exceeds (CH ₄₎ / Kgcat / h, the one-pass conversion of methane It is desirable to maintain the above reaction conditions because a problem of decreasing may occur. The concentration of H ₂ S in methane or by-product gas to be used in the reforming reaction using the catalyst according to one aspect of the present invention is preferably 3000 ppmv or less. When the concentration of H ₂ S exceeds 3000 ppmv, the deactivation of the catalyst may proceed rapidly by blocking the active site of rhodium. When using a catalyst according to one embodiment of the present invention, the concentration of H ₂ S is 3000 ppmv or less by-product gas reforming, it is possible to ensure more than 50% methane conversion and / or more than 25% CO ₂ conversion.

The catalyst according to one aspect of the present invention may be used after reduction treatment in a temperature range of 500 to 800 ° C. as necessary before use in the reforming reaction. By hydrogen contained in the by-product gas, since the self-reduction of rhodium proceeds during the reforming reaction, the reduction pretreatment process of the catalyst can be omitted and used directly in the reforming reaction.

The reduction treatment of the catalyst can be carried out using hydrogen at a temperature of 500 ° C. to 800 ° C. which is lower than the reforming reaction temperature for about 1 hour to 5 hours. Since the metal oxide is not smoothly reduced at a temperature below 500 ° C., a problem of low initial catalyst activity may occur, and a reduction treatment at a high temperature exceeding 800 ° C. may cause a problem of reduced activity due to sintering of rhodium. If the reduction treatment time is less than 1 hour, there may be a problem that the initial activity is low because the proper reduction of Rh does not occur, and if it exceeds 5 hours, activity may decrease due to an increase in particle size by sintering of Rh. .

In the methane reforming reaction using the catalyst of the present invention, the conversion of CH ₄ is at least 50%, and the conversion of CO ₂ is at least 25%. Furthermore, in the reforming reaction of the present invention, a synthesis gas, specifically, a synthesis gas including hydrogen, carbon monoxide, and carbon dioxide is produced, and the synthesis gas is used in methanol synthesis reaction, dimethyl ether synthesis reaction, Fischer-Dropsch synthesis reaction, and the like. Can be used to produce high quality hydrogen fuel.

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples illustrate the invention and do not limit the invention.

Example  One

In this example, CeO ₂ -ZrO ₂ support was prepared by the sol-gel method. 269 g of citric acid (Citric acid) was dissolved in 348 g of ethylene glycol (Ethylene glycol) while stirring for 30 minutes at 60 ℃ to prepare a citric acid solution (1) dissolved in ethylene glycol. On the other _{hand, CeO 2 -ZrO 2 CeO 2 /} ZrO 2 on the support Cerium nitrate hydrate (Ce (NO ₃ ) ₂ ˜6H ₂ O) (0.75 g), a cerium precursor, weighted to 2.12, was completely dissolved in 30 ml of water to prepare an aqueous cerium nitrate solution. Thereafter, the cerium nitrate aqueous solution was gradually added to the citric acid solution (1) to prepare a mixed solution (A). The citric acid is five times the number of moles of cerium metal, the ethylene glycol is 20 times the number of moles of cerium metal.

In the same manner, citric acid solution (2) dissolved in ethylene glycol was prepared by dissolving 115 g of citric acid in 149 g of ethylene glycol for 30 minutes at 60 ° C. On the other hand, CeO ₂ -ZrO ₂ in the support CeO ₂ / ZrO ₂ ratio of 2.12, the Zr precursor to an appropriate amount of zirconium (IV) oxychloride _{(ZrCl 2 O 8H 2 O;} ? Zirconium (IV) oxychloridetahydrate) 0.41g Water 30 A complete dissolution in ml prepared an aqueous zirconium (IV) oxychloride solution. Thereafter, a zirconium (IV) oxychloride aqueous solution was gradually added to the citric acid solution (2) to prepare a mixed solution (B). The citric acid is 5 times the number of moles of zirconium metal, the ethylene glycol was used 20 times the number of moles of zirconium metal.

The mixed solution (A) and (B) were mixed and stirred at 60 ° C. for 30 minutes, and then the solution was heated at 120 ° C. to 130 ° C. for 5 hours to completely remove water in the solution to give a sol state. The sol material was heated to 800 ° C. at a temperature increase rate of 5 ° C./min, and then calcined at 800 ° C. for 4 hours in an air atmosphere to form a powdery CeO ₂ -ZrO _2. A support was obtained. The support composition had a ratio of CeO ₂ / ZrO ₂ based on metal oxide of 2.1 and a specific surface area of 32 m 2 / g.

Subsequently, a solution obtained by dissolving 0.154 g of rhodium nitrate (Rh (NO ₃ ) ₃ .xH ₂ O) (x is an integer of 3 to 6) as an active ingredient in 100 ml of tertiary distilled water was added to the CeO ₂ -ZrO ₂ support. It was added to 2 g to prepare a catalyst by the joining method. At this time, the amount of Rh metal in the catalyst was impregnated to 2 parts by weight based on 100 parts by weight of the support. Thereafter, the solvent was removed in a reduced pressure distillation apparatus at 50 to 70 ° C., and then dried at 120 ° C. for 12 hours, and then calcined at 750 ° C. for 5 hours in an air atmosphere to obtain a Rh / CeO ₂ -ZrO ₂ catalyst. In Table 1 it is represented by 2.0Rh / CeO ₂ -ZrO ₂ (2.1). The amount of Rh metal in the catalyst was 2 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 28 m 2 / g.

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 100 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  2

In the presence of the 2.0Rh / CeO ₂ -ZrO ₂ (2.1) catalyst of Example 1 prepared and reduced in the same manner as in Example 1, the reaction temperature of 850 ℃, reaction pressure 1 kg / ㎠, and space velocity 5,000 L (CH ₄ The reactant H ₂ O and methane were injected into the reactor at a molar ratio of 2: 1 (H ₂ O: methane) under the condition of) / Kgcat / h, and methane reforming was performed. At this time, the concentration of H ₂ S contained in methane was 100 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  3

In the presence of the 2.0Rh / CeO ₂ -ZrO ₂ (2.1) catalyst of Example 1 prepared and reduced in the same manner as in Example 1, the reaction temperature of 850 ℃, reaction pressure 1 kg / ㎠, and space velocity 2,000 L (CH ₄ The reactant H ₂ O and methane were injected into the reactor at a molar ratio of 2: 1 (H ₂ O: methane) under the condition of) / Kgcat / h, and methane reforming was performed. At this time, the concentration of H ₂ S contained in methane was 1000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  4

Dissolving 115 g of citric acid in 149 g of ethylene glycol with stirring for 30 minutes to prepare a citric acid solution (1) dissolved in ethylene glycol, and cerium nitrate hydrate (Ce (NO ₃ ) ₂ · 6H ₂ O) 0.32 g An aqueous solution was dissolved in 30 ml of water was added to prepare a mixed solution (A). Similarly, 269 g of citric acid was dissolved in 348 g of ethylene glycol with stirring for 30 minutes to prepare a citric acid solution (2) dissolved in ethylene glycol, and zirconium (IV) oxychloride (ZrCl ₂ O 8H ₂ O) 0.94 g An aqueous solution was dissolved in 30 ml of water was added to prepare a mixed solution (B). Using the mixed solution (A) and the mixed solution (B), a catalyst support having a ratio of CeO ₂ / ZrO ₂ of 0.4 and a specific surface area of 29 m 2 / g was prepared on a metal oxide basis.

Rh / CeO ₂ -ZrO ₂ by carrying the active ingredient to the content of Rh metal 2 parts by weight based on 100 parts by weight of the support in the same manner as in Example 1 A catalyst was prepared and shown in Table 1 as 2.0Rh / CeO ₂ -ZrO ₂ (0.4). The amount of Rh metal in the catalyst was 2 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 26 m 2 / g.

The catalyst was reduced before use in the reforming reaction in the same manner as in Example 1. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  5

Rhodium nitrate salt (Rh (NO ₃ ) ₃ .xH ₂ O) in 100 ml of tertiary distilled water such that the amount of Rh metal is 1 part by weight based on 100 parts by weight of the same catalyst support as in Example 1 (x is an integer of 3 to 6) ) Rh / CeO ₂ -ZrO _{2 in the} same manner as in Example 1 except that the solution in which 0.077 g was dissolved was impregnated into ₂ g of the CeO ₂ -ZrO ₂ support. A catalyst was prepared and shown in Table 1 as 1.0Rh / CeO ₂ -ZrO ₂ (2.1). The amount of Rh metal in the catalyst was 1 part by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 27 m 2 / g.

The catalyst was reduced before use in the reforming reaction in the same manner as in Example 1. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  6

Rhodium nitrate salt (Rh (NO ₃ ) ₃ xH ₂ O) in 100 ml of tertiary distilled water such that the amount of Rh metal is 0.5 parts by weight based on 100 parts by weight of the same catalyst support as in Example 1 (x is an integer of 3 to 6) ) Rh / CeO ₂ -ZrO _{2 in the} same manner as in Example 1, except that a solution in which 0.039 g was dissolved was impregnated into ₂ g of the CeO ₂ -ZrO ₂ support. A catalyst was prepared and shown in Table 1 as 0.5Rh / CeO ₂ -ZrO ₂ (2.1). The amount of Rh metal in the catalyst was 0.5 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 27 m 2 / g.

The catalyst was reduced before use in the reforming reaction in the same manner as in Example 1. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. After 10 hours of reforming The average conversion of methane at steady state is shown in Table 1 below.

Example  7

H ₂ O and methane as reactants at the reaction temperature of 900 ° C., reaction pressure of 1 kg / cm 2, and space velocity of 2,000 L (CH ₄ ) / Kgcat / h in the presence of a catalyst prepared and reduced in the same manner as in Example 6 Was injected into the reactor at a molar ratio of 2: 1 (H ₂ O: methane) to carry out reforming of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below. Table 1 shows the catalyst of this example as 0.5Rh / CeO ₂ -ZrO ₂ (2.1) -900.

Example  8

Rh / CeO _{2 in the} same manner as in Example 1, except that a rhodium chloride salt (RhCl ₃ ) solution was impregnated so that the amount of the Rh metal was 2 parts by weight based on 100 parts by weight of the support. -ZrO ₂ Catalyst.

The rhodium chloride salt solution was prepared by impregnating a solution of 0.081 g of rhodium chloride salt in 100 ml of tertiary distilled water to ₂ g of the CeO ₂ -ZrO ₂ support. Table 1 shows the catalyst as 2.0Rh / CeO ₂ -ZrO ₂ (2.1) -RhCl ₃ . The amount of Rh metal in the catalyst was 2 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 29 m 2 / g.

The catalyst was reduced before use in the reforming reaction in the same manner as in Example 1. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Into the reactor at a molar ratio of methane, the methane reforming reaction was performed. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  9

In this example, CeO ₂ -ZrO ₂ support was prepared by coprecipitation method. 1.48 g of cerium nitrate hydrate (Ce (NO ₃ ) ₂ .6H ₂ O) as a cerium precursor in 200 ml of water and zirconium (IV) oxychloride (ZrCl ₂ O 8 H ₂ O; zirconium (IV) oxychlorideoctahydrate) 0.80 as a zirconium precursor g was added to prepare a mixed solution of cerium precursor and zirconium precursor. Subsequently, as a basic precipitant, 2M ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) aqueous solution was slowly added to a solution of pH 10 to coprecipitate and aged at 70 ° C. for 3 hours to form a precipitate. . After that, the precipitate was collected by filtration and washed with distilled water. The precipitate obtained was dried at 120 ° C. for 12-15 hours.

After drying, the temperature was raised to 800 ° C. at a temperature increase rate of 5 ° C./min and calcined in an air atmosphere for 5 hours to prepare a CeO ₂ -ZrO ₂ support. The composition of CeO ₂ -ZrO ₂ support was based on the metal oxide ratio of CeO ₂ / ZrO ₂ was 2.12 and the specific surface area was 30 m 2 / g.

Meanwhile, ₂ g of CeO in powder form prepared above was dissolved in a solution in which 0.154 g of rhodium nitrate salt (Rh (NO ₃ ) ₃ xH ₂ O) (x is an integer of 3 to 6) was dissolved in 100 ml of tertiary distilled water. _{A 2} -ZrO ₂ support was added so that the content of rhodium metal in the catalyst was 2 parts by weight relative to 100 parts by weight of the support. Thereafter, the solvent was removed in a vacuum distillation apparatus at 60 ° C., then dried in an oven at 120 ° C. for about 12 hours, and then calcined at 750 ° C. for 5 hours in an air atmosphere to obtain a Rh / CeO ₂ -ZrO ₂ catalyst. In Table 1, it is represented as 2.0Rh / CeO ₂ -ZrO ₂ (2.1)-((NH ₄ ) ₂ CO ₃ ). The amount of Rh metal in the catalyst was 2 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 27 m 2 / g.

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Then, the reaction temperature is 850 ℃ under the presence of a catalyst, a reaction pressure of 1 kg / ㎠, and a space velocity of _{2,000 L (CH 4) / Kgcat} / h condition and the reaction of H ₂ O and methane in the H ₂ O: methane 2 Methane was reformed by injection into the reactor at a molar ratio of 1: 1. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  10

A catalyst support was prepared in the same manner as in Example 9 except that a 0.2 N sodium carbonate (Na ₂ CO ₃ ) aqueous solution was used as the basic precipitant and the specific surface area was 27 m 2 / g. The composition of the prepared CeO ₂ -ZrO ₂ catalyst support was based on the metal oxide ratio of CeO ₂ / ZrO ₂ was 2.12 and the specific surface area was 27 m 2 / g. The specific surface area of the support depends on the type of basic precipitant.

Thereafter, the catalyst support was impregnated with a rhodium nitrate salt in the same manner as in Example 9 to impregnate 2 parts by weight of Rh metal with respect to 100 parts by weight of the support to prepare a catalyst having a specific surface area of 27 m 2 / g. In Table 1 the catalyst is represented as 2.0Rh / CeO ₂ -ZrO ₂ (2.1)-((NH ₄ ) ₂ CO ₃ ).

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O :) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was injected into the reactor at a molar ratio of methane to carry out reforming of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Example  11

In the presence of the catalyst of Example 1 prepared and reduced in the same manner as in Example 1, the reactant was reacted under the conditions of a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. H ₂ O, methane and carbon dioxide were injected into the reactor in a 2: 1: 0.5 molar ratio (H ₂ O: methane: CO ₂ ) to perform a mixed reforming reaction (SRM + CDR) of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  One

Rhodium nitrate salt (Rh (NO ₃ ) ₃ .3) in 100 ml of tertiary distilled water using a commercially available Al ₂ O ₃ catalyst support having a specific surface area of 200 m 2 / g and a content of rhodium metal of 1 part by weight relative to 100 parts by weight of the support. xH ₂ O) (x is an integer of 3 to 6) Rh / Al ₂ O _{3 in the} same manner as in Example 1, except that a solution of rhodium nitrate salt in which 0.077 g is dissolved was impregnated into ₂ g of Al ₂ O ₃ support. Catalyst was prepared. The specific surface area of the catalyst was 86 m 2 / g, and in Table 1 the catalyst was represented as 1.0Rh / Al ₂ O ₃ .

The catalyst was reduced for 4 hours under a hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Then, in the presence of the catalyst, reactants H ₂ O and methane in a 2: 1 molar ratio (H) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h ₂ O: methane) was injected into the reactor to perform a methane reforming reaction (SRM). At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  2

Rhodium nitrate salt (Rh (NO ₃ ) ₃ xH ₂ O) (x) in 100 ml of tertiary distilled water so that the rhodium metal content is 1 part by weight in 100 parts by weight of a commercially available SiO ₂ catalyst support having a specific surface area of 350 m 2 / g. Is an integer of 3 to 6) Rh / SiO ₂ catalyst was prepared in the same manner as in Example 1 except that a solution of rhodium nitrate salt in which 0.077 g dissolved therein was impregnated into ₂ g of SiO ₂ support. The specific surface area of the catalyst was 58 m 2 / g, and in Table 1 the catalyst was indicated as 1.0Rh / SiO ₂ .

The catalyst was reduced for 4 hours under a hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Then, in the presence of the catalyst, reactants H ₂ O and methane in a 2: 1 molar ratio (H) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h ₂ O: methane) was injected into the reactor to perform a methane reforming reaction (SRM). At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  3

CeO nitrate hydrate (Ce (NO ₃ ) ₂ .6H ₂ O) is 0.08g and zirconium (IV) oxychloride (ZrCl ₂ O? 8H ₂ O) is 1.24g _A catalyst support having a ratio of ₂ / ZrO ₂ of 0.08 and a specific surface area of 20 m 2 / g was prepared, and rhodium nitrate salt (Rh ( NO ₃ ) ₃ x H ₂ O) (x is an integer of 3 to 6) in the same manner as in Example 1 except that a solution of rhodium nitrate salt in which 0.039 g was dissolved was impregnated into ₂ g of CeO ₂ -ZrO ₂ support. Rh / CeO ₂ -ZrO ₂ Catalyst. The amount of Rh metal in the catalyst was 0.5 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 18 m 2 / g. Table 1 shows the catalyst as 0.5Rh / CeO ₂ -ZrO ₂ (0.08).

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 12,500 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 100 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  4

Rhodium nitrate salt as an active ingredient in 100 ml of tertiary distilled water so that the amount of rhodium metal supported is 0.5 parts by weight and the amount of nickel metal supported by 15 parts by weight with respect to 100 parts by weight of a commercially available Al ₂ SO ₃ catalyst support having a specific surface area of 200 m 2 / g. A solution in which 0.039 g of Rh (NO ₃ ) ₃ xH ₂ O)) (x is an integer of 3 to 6) and 1.508 g of nickel nitrate salt Ni (NO ₃ ) ₃ 6H ₂ O) were dissolved in the CeO ₂ -ZrO _2. An Rh / Ni / Al ₂ O ₃ catalyst was prepared in the same manner as in Example 1, except that the catalyst was sequentially added to the support 2g to prepare the catalyst in a immersion manner. The specific surface area of the prepared catalyst was 79 m 2 / g, and in Table 1, the catalyst was expressed as 0.5Rh / 15Ni / Al ₂ SO ₃ .

The catalyst was reduced for 4 hours under a hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Then, in the presence of the catalyst, reactants H ₂ O and methane in a 2: 1 molar ratio (H) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 12,500 L (CH ₄ ) / Kgcat / h. ₂ O: methane) was injected into the reactor to perform a methane reforming reaction (SRM). At this time, the concentration of H ₂ S contained in methane was 100 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  5

Steam reforming of methane was carried out using only the support prepared in Example 1 above. The support used in this Comparative Example in Table 1 is represented by CeO ₂ -ZrO ₂ (2.1) as the ratio of CeO ₂ / ZrO _{2 on} the basis of metal oxides 2.12.

The support was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the support, the reactant H ₂ O and methane were 2: 1 molar ratio (H) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 12,500 L (CH ₄ ) / Kgcat / h. ₂ O: methane) was injected into the reactor to perform a methane reforming reaction (SRM). At this time, the concentration of H ₂ S contained in methane was 100 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  6

In this comparative example, a ZrO ₂ support was prepared by the sol-gel method. 269 g of citric acid (Citric acid) was dissolved in 348 g of ethylene glycol (Ethylene glycol) for 30 minutes at 60 ℃ to prepare a citric acid solution dissolved in ethylene glycol. Zirconium (IV) oxychloride (ZrCl ₂ O.8H ₂ O; zirconium (IV) oxychloridetahydrate) 0.93 g of zirconium precursor (ZrCl ₂ O. 8H ₂ O) completely dissolved in 30 ml of water to prepare a zirconium (IV) oxychloride aqueous solution. Thereafter, a zirconium (IV) oxychloride aqueous solution was slowly added to the citric acid solution to prepare a mixed solution. Thereafter, the mixed solution was heated at 120 to 130 ° C. for 5 hours to completely remove the water in the solution to obtain a sol state.

The sol material was heated to 800 ° C. at a temperature increase rate of 5 ° C./min, and then calcined at 800 ° C. for 4 hours to form ZrO _2. A support was obtained. The specific surface area of the support was 12 m 2 / g.

Thereafter, rhodium nitrate salt (Rh (NO ₃ ) ₃ .xH ₂ O) (x is 3 to 100 ml of tertiary distilled water) in the same manner as in Example 1 so that the rhodium metal content is 1 part by weight based on 100 parts by weight of the support. 6) 2 g of the support was added to a rhodium salt solution in which 0.077 g was dissolved. Thereafter, the solvent was removed in a vacuum distillation apparatus at 60 ° C., and then dried in an oven at 120 ° C. for about 12 hours, and then calcined at 750 ° C. for 5 hours in an air atmosphere to obtain a Rh / ZrO ₂ catalyst. It is represented by 1.0Rh / ZrO ₂ . The amount of Rh metal in the catalyst was 1.0 part by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 11 m 2 / g.

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  7

In this comparative example, the CeO ₂ support was prepared by the sol-gel method. 269 g of citric acid (Citric acid) was dissolved in 348 g of ethylene glycol (Ethylene glycol) for 30 minutes at 60 ℃ to prepare a citric acid solution dissolved in ethylene glycol. Meanwhile, 0.74 g of cerium nitrate hydrate (Ce (NO ₃ ) ₂ .6H ₂ O), a cerium precursor, was completely dissolved in 30 ml of water to prepare a cerium nitrate aqueous solution. Thereafter, the cerium nitrate aqueous solution was gradually added to the citric acid solution to prepare a mixed solution.

Thereafter, the mixed solution was heated at 120 to 130 ° C. for 5 hours to completely remove the water in the solution to obtain a sol state. Thereafter, the sol material was heated to 800 ° C. at a temperature increase rate of 5 ° C./min, and then calcined at 800 ° C. for 4 hours to form CeO _2. A support was obtained. The specific surface area of the support was 9 m 2 / g.

Thereafter, rhodium nitrate salt (Rh (NO ₃ ) ₃ .xH ₂ O) (x is 3 to 100 ml of tertiary distilled water) in the same manner as in Example 1 so that the rhodium metal content is 1 part by weight based on 100 parts by weight of the support. 6) 2 g of the support was added to a rhodium salt solution in which 0.077 g was dissolved. Thereafter, the solvent was removed in a vacuum distillation apparatus at 60 ° C., and then dried at 120 ° C. for at least 12 hours, and calcined at 750 ° C. for 5 hours in an air atmosphere to obtain a Rh / CeO ₂ catalyst. In Table 1, 1.0 Rh / It is represented by CeO ₂ . The amount of Rh metal in the catalyst was 1 part by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 7 m 2 / g.

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  8

The catalyst of Example 1 was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Then, in the presence of the catalyst, the reactant H ₂ O, and methane at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 6,250 L (CH ₄ ) / Kgcat / h, was added at a 2: 1 molar ratio ( H ₂ O: methane) was injected into the reactor to perform a methane reforming reaction (SRM). At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  9

Catalyst supports 100 parts rhodium nitrate salt in 100ml of deionized water, the amount of Rh metal to be added 0.1 parts by weight based on _{(Rh (NO 3) 3 ·} xH 2 O) (x is an integer from 3 to 6) is dissolved in a solution of 0.008g Rh / CeO ₂ -ZrO _{2 in the} same manner as in Example 1 except for impregnating 2 g with the support A catalyst was prepared and shown in Table 1 as 0.1Rh / CeO ₂ -ZrO ₂ (2.1). The amount of Rh metal in the catalyst was 0.1 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 31 m 2 / g.

The catalyst was reduced for 4 hours under a hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Subsequently, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 6,250 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

Comparative Example  10

0.154 g of a rhodium nitrate salt (Rh (NO ₃ ) ₃ .xH ₂ O) (x is an integer of 3 to 6) dissolved in 100 ml of tertiary distilled water so that the amount of Rh metal was 2 parts by weight based on 100 parts by weight of the catalyst support. Rhodium salt solution was added to CeO ₂ -ZrO ₂ Rh / CeO ₂ -ZrO _{2 in the} same manner as in Comparative Example 3, except that it was impregnated with 2 g and the specific surface area of the catalyst was 17 m 2 / g. A catalyst was prepared and shown in Table 1 as 2.0Rh / CeO ₂ -ZrO ₂ (0.08). The amount of Rh metal in the catalyst was 2.0 parts by weight based on 100 parts by weight of the support, and the specific surface area of the catalyst was 17 m 2 / g.

The catalyst was reduced for 4 hours under hydrogen atmosphere at 750 ° C. prior to use in the reforming reaction. Thereafter, in the presence of the catalyst, reactants H ₂ O and methane were 2: 1 (H ₂ O) at a reaction temperature of 850 ° C., a reaction pressure of 1 kg / cm 2, and a space velocity of 2,000 L (CH ₄ ) / Kgcat / h. Methane) was introduced into the reactor at a molar ratio of methane. At this time, the concentration of H ₂ S contained in methane was 1,000 ppmv. The average conversion of methane at steady state after 10 hours of reforming is shown in Table 1 below.

As shown in Table 1, the weight ratio of CeO ₂ / ZrO ₂ is 0.3 to 4.0, the specific surface area of the support is 20 to 80 m 2 / g, and the CeO ₂ / ZrO ₂ prepared by the sol-gel method or coprecipitation method. On the catalyst of the present invention having a specific surface area of 20 to 50 m 2 / g, Rh supported from 0.2 to 5.0 parts by weight relative to 100 parts by weight of the CeO ₂ -ZrO ₂ support as an active ingredient on the support, the reaction temperature of 750 to 900 ℃, Reaction pressure of 0.5 to 10 atm and space velocity of 100 L (CH ₄ ) / Kgcat / h to 6,000 (CH ₄ ) / Kgcat / h in the by-product gas carried out under reforming reaction of methane with H ₂ S content of 3000 ppmv or less Conversion rates of CH ₄ of at least% were achieved. (Examples 1 to 7).

In addition, when the support material was prepared by the coprecipitation method using Example 8 and (NH ₄ ) ₂ CO ₃ and Na ₂ CO ₃ as the precursor of the active material (Example 9 and Example 10) It showed excellent catalytic activity under reaction conditions in which H ₂ S was present. Furthermore, the catalyst of the present invention also showed excellent catalytic activity in Example 11 used in the mixed reforming reaction, wherein the conversion rate of CO ₂ can be obtained in a range of 25% or more.

However, in the case of Comparative Examples 1 to 4 using Al ₂ O ₃ or SiO ₂ as the support and Ru and Ni as the active ingredients, the catalytic activity was reduced compared to the Examples. In particular, even in the case of using CeO ₂ and ZrO ₂ (Comparative Example 6 and Comparative Example 7), the object of the present invention could not be achieved. In addition, even when the support according to the present invention is used, the content of Rh as the active ingredient is less than 0.2 part by weight or the active ingredient is not included (Comparative Example 9 and Comparative Example 5) and the space velocity is less than 100 parts by weight of the support. Even in the early case (Comparative Example 8), the object proposed in the present invention could not be achieved.

In addition, in the results of Comparative Examples 3 and 10, which were conducted using a catalyst having a weight ratio of CeO ₂ / ZrO ₂ of 0.08, the objective of the present invention was used even when using a support that deviated from the weight ratio of CeO ₂ / ZrO ₂ presented in the present invention. Could not be achieved.

In addition, the conversion rates of methane over time of Examples 1, 3 and Comparative Example 7 are shown in FIG. 1, and Examples 1 and 3 showed excellent conversion rates of methane as compared to Comparative Example 7.

From the above results, it can be seen that the catalyst of the present invention exhibits excellent catalyst activity and stability even when hydrogen sulfide is present in methane gas. Therefore, it was confirmed that the intended effect was achieved in one embodiment of the present invention only when the catalyst was prepared by the method proposed in the present invention and the reforming reaction of the by-product gas was carried out under the reaction conditions.

Claims (11)

And a specific surface area of 20 ~ 80 ㎡ / g, a weight ratio of CeO ₂ / ZrO ₂ is a rhodium with respect to 100 parts by weight of CeO ₂ -ZrO ₂ support on the CeO ₂ -ZrO ₂ support 0.3≤CeO ₂ / ZrO ₂ ≤4.0 A catalyst used for reforming methane using by-product gas, which is supported by 0.2 to 5 parts by weight and has a specific surface area of 20 to 50 m 2 / g and H ₂ S is present at 3000 ppmv or less.
delete The catalyst of claim 1, wherein the methane reforming is steam reforming of methane, mixed reforming, partial oxidation of methane using oxygen, or methane and carbon dioxide reforming.
Preparing a mixed solution by adding a cerium precursor aqueous solution to a solution of citric acid in ethylene glycol and a zirconium precursor aqueous solution to a solution of citric acid in another ethylene glycol;
Stirring the mixed solution at 50˜100 ° C .;
Removing water in the mixed solution heated to 120 to 130 ° C. for 5 to 10 hours to form a sol; And
To the CeO ₂ -ZrO ₂ support prepared by the sol-gel method comprising the step of firing the sol for 3 to 5 hours at 400 to 900 ℃,
Supporting rhodium in an amount of 0.2 to 5.0 parts by weight based on metal content based on 100 parts by weight of the support; And
Firing at 400-800 ° C
Catalyst production method comprising a.
delete delete In claim 4 wherein the support is a specific surface area of 20 ~ 80㎡ / g, a weight ratio of CeO ₂ / ZrO ₂ is 0.3≤CeO ₂ / ZrO ₂ ≤4.0 catalyst production method.
The method of claim 4, wherein the catalyst has a specific surface area of 20 to 50 m 2 / g.
A method for reforming methane at a reaction temperature of 750 to 900 ° C., a reaction pressure of 0.5 to 10 atmospheres, and a space velocity of 100 to 6,000 L (CH ₄ ) / Kgcat / h in the presence of the catalyst of claim 1.
delete 10. The method of claim 9, wherein the methane reforming is steam reforming of methane, mixed reforming, partial oxidation of methane using oxygen, or methane and carbon dioxide reforming.

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