KR101570943B1 - A perovskite-like catalyst supported on alumina having a bimodal pore structure for combined steam and co_2 reforming reaction with methane and a preparation method thereof - Google Patents

Abstract

The present invention relates to a perovskite catalyst carried on an alumina support with a bimodal pore structure for a mixed reforming reaction and a manufacturing method thereof, capable of obtaining a high conversion rate of methane and carbon dioxide by carrying a metal catalyst with a perovskite structure of LaSrNiO_3 as an active ingredient on a Al_2O_3 support with a bimodal pore structure and inhibiting inactivation of a catalyst through sintering of nickel as an active ingredient, even when the catalyst is reacted at high temperatures.

Description

[0001] The present invention relates to a perovskite catalyst for mixed reforming supported on an alumina support having a double pore structure, and a method for producing the perovskite-like catalyst supported on an alumina support,

The present invention relates to a perovskite catalyst for mixed reforming supported on an alumina support having a double pore structure and a method for producing the same.

The development of renewable alternative energy resources around the world is an important issue due to the development of alternative energy resources by limited reserves of fossil fuels and global warming due to CO ₂ . Natural gas and carbon dioxide are used as reactants to provide alternative energy for developing energy such as carbon dioxide and environmentally friendly hydrogen and synthetic gas. In particular, DME It is an indispensable process that can provide the raw material synthesis gas with appropriate H ₂ / CO ratio in synthesis process and GTL (Gas to liquid) technology.

Methods for producing syngas using natural gas include partial oxidation of methane (POM) using oxygen, steam reforming of methane (SRM), methane carbon dioxide reforming carbon dioxide reforming of methane (CDR).

The reaction formula of the reforming reaction and the calorific value of the reforming reaction can be summarized as follows.

(1) Partial Oxidation of Methane (POM): CH ₄ + 0.5O ₂ = 2H ₂ + CO, ΔH = - 44 kJ / mol

(2) Steam reforming reaction of methane (SRM): CH ₄ + H ₂ O = 3H ₂ + CO, ΔH = 226 kJ / mol

(3) Carbon Dioxide Reforming Reaction of Methane (CDR): CH ₄ + CO ₂ = 2H ₂ + 2CO, ΔH = 261 kJ / mol

The syngas produced in each reforming reaction has different H ₂ / CO ratios. The partial oxidation reaction (POM) of methane is an exothermic reaction and can be used as a reforming reaction useful for methanol / hydrocarbon synthesis reaction by obtaining a H ₂ / CO ratio of about ₂ suitable for methanol synthesis reaction and Fischer-Tropsch reaction conditions. In the case of the steam reforming reaction (SRM) of methane, the reaction conditions of high temperature (700 ° C ~ 1,200 ° C) are required due to strong endothermic reaction, and H ₃ / CO ₂ ratio suitable for the hydrogen production process and ammonia synthesis reaction is obtained .

Methane and carbon dioxide reforming (CDR) is a reforming reaction using carbon dioxide as a raw material. Because it is easy to thermo-dynamically form coke, deactivation of the catalyst occurs well. Therefore, combined steam and CO ₂ reforming with methane steam reforming methane (CSCR). In the case of the CSCR reforming reaction, the molar ratio of the reactant CH ₄ / CO ₂ / H ₂ O and the recycle ratio of the unreacted material are controlled by controlling the effective utilization of the carbon dioxide and the inactivation of the catalyst by the carbon deposition, The H ₂ / CO molar ratio optimally required in subsequent unit processes such as the synthesis reaction and the Fischer-Tropsch reaction can be easily controlled to 2, and thus a catalyst system for this purpose has been extensively studied (Korean Patent No. 10-1068995) .

The catalyst system used in the reforming reaction can be divided into two types. One is a method using a catalyst in which a small amount of noble metal such as Pt, Rh, Ru, etc. is supported, or a nickel- . The noble metal catalysts are known to exhibit excellent catalytic activity and low deactivation phenomenon, but their price competitiveness is poor, so that nickel catalysts are being used more frequently in the commercialization process. However, since the mixed reforming reaction is generally carried out at a high temperature reaction condition, there is a problem that the stability of the catalyst due to the formation of the coke and sintering is reduced in the case of the nickel catalyst.

In the present invention, in order to ensure the stability of the catalyst, the deactivation of the catalyst by the sintering phenomenon of the metal catalyst is suppressed by using a perovskite-structured catalyst containing a metal such as nickel as an active ingredient. In particular, It is possible to provide a catalyst for mixed reforming which is excellent in activity by using alumina having a double pore structure prepared by using carbon black as a template in order to improve the dispersibility of the structural catalyst component.

The first aspect of the present invention is a catalyst for mixed reforming reaction in which natural gas is reformed simultaneously with water vapor and carbon dioxide, which is produced by using carbon black as a template, An alumina support having a double pore structure in which mesopores are simultaneously formed; And a metal oxide having a perovskite structure supported on the support.

A second aspect of the present invention is a method for producing a carbon black composite material, comprising the steps of: (1) preparing a mixture support of carbon black and alumina by coprecipitating carbon black and an alumina precursor; Co-depositing the mixture support of carbon black and alumina with a metal oxide precursor (step 2); And removing the carbon black by firing the coprecipitated product (step 3). The present invention also provides a method for producing a catalyst for mixed reforming according to the first aspect of the present invention.

A third aspect of the present invention provides a method for performing a mixed reforming reaction for simultaneously reforming a natural gas with steam and carbon dioxide in the presence of a catalyst for mixed reforming reaction according to the first aspect of the present invention.

Hereinafter, the configuration of the present invention will be described in detail.

In general, the metal oxide catalyst of the perovskite structure has a formula of ABO ₃ , and rare earth metals such as lanthanum (La), barium (Ba) and cerium (Ce) are used for the A site, and cobalt (Fe), nickel (Ni), or the like is generally used. Perovskite catalysts have chemical stability and can be used stably in various chemical reaction environments and can maintain a very stable structure even at high temperatures. On the other hand, due to the disadvantage of not having a porous material and having a low specific surface area, the catalyst support does not have a wide application range.

In the mixed reforming reaction in which the natural gas is reformed simultaneously with steam and carbon dioxide, the perovskite-structured catalyst needs to improve the reactivity by increasing the contact area with methane, carbon dioxide, and water in the vapor phase. It is important to increase the contact area so that the oxide of the perovskite structure is uniformly dispersed on the support by the fine particles so that the active ingredient and the gaseous reactant can sufficiently react.

In the present invention, an alumina support having a double-pore structure in which carbon black is used as a template and mesopores formed by carbon black and mesopores possessed by alumina are simultaneously formed has a large specific surface area, The dispersibility of the metal oxide of the perovskite structure can be increased and the sintering phenomenon of nickel can be reduced even at a high temperature due to the perovskite structure, so that the catalyst deactivation can be efficiently controlled, And the present invention is based on this.

In the present invention, the double-pore structure may be composed of mesopores of 30 nm to 60 nm formed by carbon black and mesopores of 3 nm to 10 nm possessed by alumina.

In the present invention, in order to produce an alumina support having a double pore structure having a large specific surface area, the double-pore structure can remove carbon black after preparing a mixture support of carbon black and alumina. Preferably, the double-pore structure can be obtained by coprecipitating a mixture support of carbon black and alumina with a metal oxide precursor, followed by firing to remove carbon black.

Carbon black can be largely removed at a calcination temperature of 400 to 900 DEG C, preferably about 800 DEG C, so that pores occupied by carbon black form large pores of 30 nm to 60 nm, preferably about 40 nm, It is possible to produce a support having a double-pore structure in which pores of 3 nm to 10 nm, preferably 6 nm to 8 nm, due to pores of alumina itself are present at the same time.

Preferably, the content of alumina in the mixture support of carbon black and alumina may be from 2.5 to 30% by weight. If the content of alumina in the mixture support of carbon black and alumina is less than 2.5% by weight, the specific surface area of the catalyst decreases and the dispersibility of perovskite, which is an active component of the catalyst, decreases. And the dispersibility of the perovskite active ingredient may decrease due to an increase in the content of Al ₂ O ₃ .

In the present invention, the alumina support of the double-pore structure may have a specific surface area of 100 m < 2 > / g or more. Such a large specific surface area can be produced by adjusting the content of alumina in the mixture support of carbon black and alumina to 2.5 to 30% by weight as described above.

The alumina support having a double pore structure produced by the above method has a wide specific surface area and thus can have an effect of increasing the dispersibility of the perovskite structure oxide as an active ingredient. Also, alumina, which is a support produced by the above method, has excellent thermal and mechanical properties and can be used as a support for various catalytic reactions and alumina having various structures can be manufactured according to the calcination temperature. Generally, as the temperature increases, the phase transition from gamma-alumina to alpha-alumina occurs and the specific surface area may be greatly reduced. In the present invention, as described above, the alumina support may be prepared on the gamma-alumina phase by maintaining the firing temperature at 400 to 900 ° C., preferably about 800 ° C., in the process of removing the carbon black. Alumina generally has a wide specific surface area, excellent mechanical strength, and a spinel type crystal lattice. The spinel type structure includes a vacant cation structure that imparts properties unique to gamma-alumina, and thus can be applied in various fields in the catalyst field.

In the present invention, by using an alumina support having a double-pore structure having thermal stability and excellent properties and supporting a metal oxide having a perovskite structure thereon, it has a wide specific surface area by taking advantage of the perovskite structure, It is possible to provide a catalyst exhibiting excellent activity in the mixed reforming reaction in which the inactivation of the catalyst is suppressed at an early stage and the conversion of methane and carbon dioxide can be maintained at a high level.

In the present invention, the perovskite-structured metal oxide is a LaSrNiO ₃ -based catalyst containing nickel (Ni), lanthanum (La) and strontium (Sr), and has the formula La _x Sr _{1 - x} NiO ₃ 0.95) perovskite oxide.

Preferably, the metal oxide of the perovskite structure may contain nickel (Ni) in an amount of 5 to 15% by weight based on the weight of the alumina support. If the amount of nickel contained in the perovskite structure metal oxide is less than 5 wt% based on the weight of the alumina support, there is a possibility that the active ingredient of the catalyst is insufficient and the reactivity of the mixed reforming is lowered. If the amount of nickel exceeds 15 wt% There is a disadvantage in that the specific surface area of the catalyst is decreased due to an increase in the amount of the active ingredient, and the catalyst production cost is increased due to an increase in the amount of nickel used, which is not economical.

In the present invention, a LaSrNiO ₃ -based catalyst prepared by adding lanthanum and strontium to nickel, which is a main catalyst component, has a perovskite structure in the form of La _x Sr _{1 - x} NiO ₃ (x is 0.5 to 0.95) Was used for the reaction. Due to the characteristics of the perovskite structure, the sintering of nickel is reduced even at a high temperature of 850 캜, and the catalyst deactivation can be efficiently controlled.

Preferably, the catalyst for the mixed reforming reaction according to the present invention comprises a step (step 1) of preparing a mixture support of carbon black and alumina by coprecipitating carbon black and an alumina precursor; Co-depositing the mixture support of carbon black and alumina with a metal oxide precursor (step 2); And a step of calcining the coprecipitated product to remove carbon black (step 3).

The step 1 is a step of coprecipitating carbon black and an alumina precursor to prepare a mixture support in which carbon black and alumina are mixed.

In the first step, the alumina precursor is an aluminum age trade _{(aluminum nitrate; Al (NO 3} ) 2 · 6H 2 O), aluminum isopropoxide (aluminum isopropoxide; Al [OCH ( CH 3) 2] 3) , or (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonia water (NH ₃ OH) or a mixture thereof may be used as the precipitating agent. And can be used without limitation as long as it is known in the art to be generally usable as an alumina precursor and precipitant.

In the coprecipitation step, the pH of the solvent may be adjusted to 7 to 8, preferably in an aqueous solution, and the coprecipitation reaction may be aged at a temperature in the range of 40 to 90 ° C to precipitate the precipitate, A precipitate can be obtained. In this case, it is appropriate to maintain the aging time at less than 1 to 10 hours, preferably at 2 to 8 hours because the structure of the alumina support excellent in activity is advantageous over the range of the aging time shown, and the aging time is less than 1 hour The structure of the alumina component is not well developed and the formation of pores having a size of 6 to 8 nm is difficult to form, so that the specific surface area of the alumina support is not widely developed, and when the time exceeds 10 hours, the alumina particle size increases, And the synthesis time increases, which is not economical.

Step 2 is a step of co-depositing a mixture support of carbon black and alumina with a metal oxide precursor to support a metal oxide of perovskite structure on a mixture support of carbon black and alumina.

In the present invention, a mixture support of carbon black and alumina is co-treated with a metal oxide precursor to produce La _x Sr _{1 - x} NiO ₃ (x is in the range of 0.5 to 0.95) in a mixture support of carbon black and alumina, Lt; RTI ID = 0.0 > perovskite < / RTI > metal oxide.

Preferably, the molar ratio of La / Sr / Ni can be adjusted to 0.09 / 0.01 / 0.1. However, the composition and composition of the perovskite are not limited to the above-mentioned molar ratios because they can be manufactured with various composition ratios and constituent components to form a general perovskite structure.

The coprecipitation performed in step 2 may be performed under the same conditions as in step 1 above.

The La, Sr, and Ni precursors are generally used in the art and include, but are not limited to, nitrate salts, chloride salts, bromide salts, acetate salts, and / Acetylacetonate salt and the like can be used, and a nitrate salt can be preferably used. Specifically, in one embodiment of the present invention, La (NO ₃ ) ₃ .6H ₂ O was used as La precursor, Sr (NO ₃ ) ₂ .6H ₂ O was used as Sr precursor, Ni ₃ ) ₂ · 6H ₂ O was used.

Step 3 is a step of forming a double pore structure by firing the co-precipitated product to remove carbon black.

The metal oxide-supported Al ₂ O ₃ -CB mixture support of the perovskite structure prepared in the step 2 is calcined in the range of 400 to 900 ° C. which is a temperature for burning the carbon black in the step 3, The alumina support having a double-pore structure in which a metal oxide of a perovskite structure is supported. When the calcination temperature is less than 400 ° C, the perovskite catalyst component is not suitable for the formation of the gamma-alumina phase due to the incomplete combustion of carbon black, and the dispersibility and reducibility of the perovskite catalyst component are poor. The dispersibility of perovskite, which is an active component of the catalyst for mixed reforming reaction, may decrease. Therefore, it may be desirable to maintain the calcination temperature range.

The present invention can provide a method for performing a mixed reforming reaction by simultaneously modifying natural gas with steam and carbon dioxide in the presence of the catalyst for mixed reforming according to the present invention.

Preferably, the method for performing the mixed reforming reaction using the catalyst for mixed reforming according to the present invention comprises the steps of: i) applying the mixed reforming catalyst according to the present invention to a mixed reforming reactor; ii) reducing and activating the catalyst; And iii) performing the mixed reforming reaction by the activated mixed reforming catalyst.

Before performing the mixed reforming reaction, the catalyst for mixed reforming according to the present invention may be activated by reduction under a hydrogen atmosphere at a temperature of 600 to 900 ° C. Preferably, the reduction process can be performed under H ₂ (5%) / N ₂ reducing gas for 6 to 24 hours, preferably about 12 hours.

The reactions can be performed in a fixed bed or fluid bed reactor as a synthesis reactor, but are not limited thereto.

The step of performing the mixed reforming reaction of the step iii) may be carried out under the general mixed reforming reaction conditions. Preferably, the reaction temperature in the mixed reforming reaction may be 600 ° C. to 1000 ° C., the reaction pressure may be 1 to 25 kg / cm 2, and the space velocity may be 1,000 to 50,000 h ^-1 , no.

The catalyst for mixed reforming reaction according to the present invention is prepared by supporting a perovskite structure metal catalyst of LaSrNiO ₃ , which is an active ingredient, on an Al ₂ O ₃ support having a double pore structure, and even when reacting at a high temperature, Deactivation of the catalyst by sintering is suppressed, and high conversion of methane and carbon dioxide can be obtained.

1 is a pore structure diagram of a LaSrNiO ₃ / Al ₂ O ₃ (10) catalyst according to the BET analysis result.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for further illustrating the present invention, and the scope of the present invention is not limited to these examples.

Example  One: LaSrNiO ₃ / Al ₂ O ₃ (2.5) catalyst preparation and Mixed reforming  reaction

Alumina was prepared by coprecipitation as a support for the catalyst for mixed reforming reaction used in the present invention, and an Al ₂ O ₃ -CB (carbon black) mixture was prepared for the formation of the double pore structure. A mixture with an Al ₂ O ₃ / CB weight ratio of 2.5 / 97.5 was prepared by coprecipitation. To this end, the Na ₂ CO ₃ precipitant (0.61 g) was dissolved in 200 g of distilled water, and the alumina precursor was dissolved in 200 g of tertiary distilled water containing aluminum nitrate (Al (NO ₃ ) ₂ .9H ₂ O) After dissolving, it was used. Specifically, it was carried out as follows.

First, 10 g of carbon black and 100 g of tertiary distilled water were put in a three-necked flask and stirred. Each of the prepared solutions was poured into a three-necked flask at a constant rate of 80 ° C. for 1 hour, stirred at pH = 7 for 2 hours, and then dried in an oven at 110 ° C. for 12 hours to remove Al ₂ O ₃ 2.5) -CB mixture.

Next, a coprecipitation method was used to prepare a perovskite catalyst including nickel by using the Al ₂ O ₃ (2.5) -CB support prepared above. In this case, Na ₂ CO ₃ precipitant (0.5 g) (Ni (NO ₃ ) ₂ .6H ₂ O) (0.037 g) as a nickel precursor to form a LaSrNiO ₃ structure having a perovskite structure as an active ingredient and a solution of lanthanum precursor La (NO ₃ ) ₃ .6H ₂ O (0.048 g) and strontium precursor Sr (NO ₃ ) ₂ .6H ₂ O (0.0013 g) were dissolved in 200 g of tertiary distilled water. At this time, the molar ratio of La / Sr / Ni in the perovskite structure was fixed to 0.09 / 0.01 / 0.1, and the content of nickel was 12 wt% based on the weight of the Al ₂ O ₃ (2.5) support. Each of the precipitant and metal precursor solution was mixed with a solution of Al ₂ O ₃ (2.5) -CB dispersed in 200 g of tertiary distilled water in a slurry state at pH = 7 and at 80 ° C. for 1 hour, After the catalyst was washed with stirring at a temperature and filtered, it was dried in an oven at 110 ° C. for 12 hours or more and calcined at 800 ° C. for 3 hours to prepare a final reaction catalyst for mixed reforming reaction. The catalyst prepared by the above method was LaSrNiO ₃ / Al ₂ O ₃ (2.5). The surface area of the catalyst before the reaction according to the BET analysis was 170 m ² / g.

Before carrying out the mixed reforming reaction, 0.1 g of the catalyst was charged into the reactor, and the reaction was carried out after reduction treatment for 3 hours under hydrogen (5 vol% H ₂ / N ₂ ) atmosphere at 800 ° C. The reaction was carried out at a reaction temperature of 850 ° C. and a reaction pressure of 0.1 MPa and a space velocity of 18,000 L (CH ₄ ) / kgcat / hr based on methane was used as a reactant. The reactants were CH ₄ : CO ₂ : H ₂ O: N ₂ The molar ratio was fixed at a ratio of 1: 0.34: 1.2: 0.2, and the reaction was carried out for 40 hours or more. The conversion of methane to carbon dioxide and the molar ratio of H ₂ / CO were used The activity of the catalyst was analyzed. The results of the reaction are shown in Table 1.

Example  2: LaSrNiO ₃ / Al ₂ O ₃ (5) catalyst preparation and Mixed reforming  reaction

The catalyst was prepared in the same manner as in Example 1, except that a LaSrNiO ₃ / Al ₂ O ₃ (5) catalyst having a weight ratio of Al ₂ O ₃ -CB of 5/95 was prepared. The surface area of the catalyst before the reaction Was 106 m ² / g.

The catalyst was used for the mixed reforming reaction in the same manner as in Example 1, and the reaction was carried out for at least 40 hours. The conversion of methane to carbon dioxide and the conversion of H ₂ / CO mol The activity of the catalyst was analyzed using the ratio. The results of the reaction are shown in Table 1.

Example  3: LaSrNiO ₃ / Al ₂ O ₃ (10) catalyst preparation and Mixed reforming  reaction

The catalyst was prepared in the same manner as in Example 1, except that a LaSrNiO ₃ / Al ₂ O ₃ (10) catalyst having a weight ratio of Al ₂ O ₃ -CB of 10/90 was prepared. The surface area of the catalyst before the reaction Was 144 m ² / g.

The catalyst was used for the mixed reforming reaction in the same manner as in Example 1, and the reaction was carried out for at least 40 hours. The conversion of methane to carbon dioxide and the conversion of H ₂ / CO mol The activity of the catalyst was analyzed using the ratio. The results of the reaction are shown in Table 1.

Example  4: LaSrNiO ₃ / Al ₂ O ₃ (15) catalyst preparation and Mixed reforming  reaction

The catalyst was prepared in the same manner as in Example 1, except that a LaSrNiO ₃ / Al ₂ O ₃ (15) catalyst having a weight ratio of Al ₂ O ₃ -CB of 10/90 was prepared. The surface area of the catalyst before the reaction Lt; ² > / g.

The catalyst was used for the mixed reforming reaction in the same manner as in Example 1, and the reaction was carried out for at least 40 hours. The conversion of methane to carbon dioxide and the conversion of H ₂ / CO mol The activity of the catalyst was analyzed using the ratio. The results of the reaction are shown in Table 1.

Comparative Example  One: LaSrNiO ₃ / Al ₂ O ₃ (20) catalyst preparation and Mixed reforming  reaction

The catalyst was prepared in the same manner as in Example 1 except that a LaSrNiO ₃ / Al ₂ O ₃ (20) catalyst having a weight ratio of Al ₂ O ₃ -CB of 20/80 was prepared. The surface area of the catalyst before the reaction Was 96 m ² / g.

The catalyst was used for the mixed reforming reaction in the same manner as in Example 1, and the reaction was carried out for at least 40 hours. The conversion of methane to carbon dioxide and the conversion of H ₂ / CO mol The activity of the catalyst was analyzed using the ratio. The results of the reaction are shown in Table 1.

Comparative Example  2: LaSrNiO ₃ / Carbon black catalyst preparation and Mixed reforming  reaction

A catalyst was prepared in the same manner as in Example 1 except that the step of treating LaSrNiO ₃ / CB catalyst having a weight ratio of Al ₂ O ₃ -CB of 0/100 at 800 ° C. for 3 hours was omitted. Catalyst was prepared such that the molar ratio of La / Sr / Ni in the perovskite structure was fixed at 0.09 / 0.01 / 0.1 using coprecipitation so that the content of nickel was 12% by weight based on the weight of the carbon black support. The surface area of the catalyst before the reaction by the BET analysis was 19 m ² / g.

The catalyst was used for the mixed reforming reaction in the same manner as in Example 1, and the reaction was carried out for at least 40 hours. The conversion of methane to carbon dioxide and the conversion of H ₂ / CO mol The activity of the catalyst was analyzed using the ratio. The results of the reaction are shown in Table 1.

division Catalyst and composition *
_{(CB / Al 2 O 3 (} wt%)) CH ₄ conversion / CO ₂ Conversion ratio (carbon mole%) H ₂ / CO molar ratio Specific surface area
(M < 2 > / g) Example 1 _{LaSrNiO 3 / Al 2 O 3 (} 2.5) 99.6 / 43.8 1.85 170 Example 2 _{LaSrNiO 3 / Al 2 O 3 (} 5) 98.9 / 43.5 1.85 106 Example 3 _{LaSrNiO 3 / Al 2 O 3 (} 10) 99.5 / 41.7 1.86 144 Example 4 _{LaSrNiO 3 / Al 2 O 3 (} 15) 98.9 / 44.1 1.87 115 Comparative Example 1 _{LaSrNiO 3 / Al 2 O 3 (} 20) 98.9 / 36.5 1.91 96 Comparative Example 2 LaSrNiO ₃ / carbon black 69.8 / 14.7 2.15 19 * LaSrNiO ₃ perovskite structure catalyst is a catalyst prepared by co-precipitation at a molar ratio of La (0.9) / Sr (0.01) / Ni (0.1), and Al ₂ O ₃ is based on wt% of carbon black The activity of the catalyst was measured using an Al ₂ O ₃ -CB support prepared by coprecipitation at a temperature of 850 ° C. for 5 hours after stabilization of activity

The reaction was carried out using a catalyst for mixed reforming of perovskite structure containing nickel, lanthanum and strontium using an alumina support prepared by using carbon black as a template so as to have the double pore structure used in the present invention , High methane and carbon dioxide conversion rates could be secured. Particularly, as shown in Examples 1 to 4, in the case of the catalyst prepared by adjusting the amount of Al ₂ O ₃ precursor appropriately, the specific surface area of the catalyst and the high Due to the dispersibility, catalysts with 98% methane conversion and 41% carbon dioxide conversion were obtained. In order to form alumina having a double pore structure, it is preferable to prepare a support such that alumina is formed in an amount of 2.5 to 20 wt% based on the weight of the carbon black. The mixed reforming reaction including the perovskite active component of the LaSrNiO ₃ structure The above object can be achieved when the content of nickel in the perovskite is controlled to be 5 to 15 wt% based on the weight of the Al ₂ O ₃ support. However, as in the case of Comparative Example 1, it is difficult to form alumina having a large specific surface area when the content of alumina is more than 30% by weight based on the weight of carbon black. Thus, the carbon dioxide conversion is low at 850 ° C as compared with Examples 1 to 4 And the surface area of the catalyst was 96 m ² / g, which was relatively low. In Comparative Example 2, it was confirmed that the surface area of the catalyst was remarkably low, about 19 m ² / g, after the perovskite active component was supported on the carbon black support without pretreatment using alumina, and the catalysts of Comparative Examples 1 and 2 In the case of the catalysts of Examples 1 to 4 according to the present invention, a wide specific surface area in the range of 106 to 170 m ² / g could be secured.

Also, as shown in FIG. 1, the catalyst component of the perovskite structure, which is an active component containing nickel, can be prepared in various compositions using the Al ₂ O ₃ support having a double pore structure prepared by the above method, As in the present invention, LaSrNiO ₃ Lt; RTI ID = 0.0 > perovskite < / RTI >

In the case of the mixed reforming catalyst prepared by the process according to the present invention, as shown in Table 1, it is possible to secure high conversion rates of methane and carbon dioxide, mainly due to the effect of suppressing the initial catalyst deactivation phenomenon It was considered. When the content of alumina with respect to the weight of carbon black is less than 2.5 wt% or exceeds 20 wt%, the specific surface area of the prepared alumina support decreases to less than 100 m ² / g, making it difficult to form a perovskite structure of small particles The conversion rate of methane and carbon dioxide at 850 ° C can be remarkably low. Therefore, the pore size of about 40 nm generated by the pores occupied by carbon black and the pore size of 6 to 8 nm Preparation ₂ O ₃ -CB mixture such that the the Al carbon black weight ratio 2.5 ~ 20wt% of the ₂ O ₃ containing to the Al surface area of the pores are present at the same time producing the alumina support having a dual pore structure less than 100 m ² / g It is possible to improve the dispersibility of the perovskite structure catalyst component as an active ingredient.

Experimental Example  1: Mix according to the present invention For reforming reaction  Catalyst XRD  analysis

X-ray diffraction (XRD) pattern analysis was performed after the mixed reforming reaction for the mixed reforming catalysts of Examples 1 to 4 was performed for 40 hours.

As a result, it was confirmed that the catalyst for the mixed reforming reaction of the present invention exhibited stable activity, in which the size of the Ni particles after the reaction calculated by XRD analysis remained below 35 nm.

Claims (9)

A supported catalyst for a mixed reforming reaction in which natural gas is simultaneously reformed with steam and carbon dioxide in a gas phase,
A catalyst in which carbon black is removed by firing a first precipitate prepared by coprecipitation of carbon black and an alumina precursor with a second precipitate co-precipitated with metal precursors forming a metal oxide of perovskite structure,
The porous alumina having the first pore structure is a double pore structure having a second pore structure (here, the first pore size < the second pore size) by the carbon black which is used as a template in the preparation of the catalyst and removed by firing. Support; And a metal oxide of a perovskite structure supported on the pores of the support,
Wherein the specific surface area of the supported catalyst is 100 m ² / g or more due to the first pore structure and the second pore structure.
The mixed reforming catalyst according to claim 1, wherein the double pore structure comprises mesopores of 30 nm to 60 nm formed by carbon black and mesopores of 3 nm to 10 nm possessed by alumina.
delete The mixed reforming catalyst according to claim 1, wherein the content of alumina in the first precipitate is 2.5 to 30 wt%.
delete The method of claim 1, wherein the metal oxide of the perovskite structure is LaSrNiO ₃ containing nickel (Ni), lanthanum (La), and strontium (Sr) having the formula La _x Sr _{1 - x} NiO ₃ ) Perovskite oxide. &Lt; / RTI &gt;
The mixed reforming catalyst according to claim 1, wherein the metal oxide of the perovskite structure contains nickel (Ni) in an amount of 5 to 15 wt% based on the weight of the support.
A method for producing a catalyst for mixed reforming reaction according to any one of claims 1, 2, 4, 6, and 7, comprising the steps of:
Coagulating the carbon black and the alumina precursor to produce a first precipitate (step 1);
Co-precipitating the first precipitate with a metal oxide precursor (step 2); And
And removing the carbon black by firing the coprecipitated second precipitate (Step 3).
A method for performing a mixed reforming reaction in which natural gas is reformed simultaneously with steam and carbon dioxide in the presence of the catalyst for the mixed reforming reaction according to any one of claims 1, 2, 4, 6,

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