WO2018212542A1 - Catalyst for reforming of methane using carbon dioxide, and preparation method therefor - Google Patents

Abstract

The present invention relates to a catalyst for reforming of methane using carbon dioxide and a preparation method therefor and, more specifically, to a catalyst for reforming of methane using carbon dioxide and a preparation method therefor, the catalyst being configured such that: an active ingredient is supported on an alumina support which has been surface-modified with phosphorus; as a result, the formation of an inactive phase and the sintering of the active ingredient are suppressed, even in a high-temperature reaction, due to the bond between the alumina support and the active ingredient; and thus the activity stability of the catalyst can be improved.

Description

Catalyst for methane reforming reaction using carbon dioxide and its preparation method

The present invention relates to a catalyst for methane reforming reaction using carbon dioxide and a method for preparing the same.

With global warming, the government has announced plans to reduce greenhouse gases, and the burden on the industry is increasing as the Korean government has set the target for reducing greenhouse gas emissions to 37% of its 2030 emission projections.

As an important alternative for greenhouse gas reductions, not to reduce carbon dioxide emissions, but to make use of the emitted carbon dioxide is an important topic. One of the many ways to resource carbon dioxide is to produce syngas through the reforming reaction of methane using carbon dioxide.

The reforming reaction of methane using carbon dioxide not only has the advantage of simultaneously removing carbon dioxide and methane, which causes global warming, but also the synthesis gas (H ₂ : CO = 1: 1), which has a higher carbon monoxide content than other reforming methods. Synthetic gas produced can be reacted with high value-added chemicals such as oxoalcohol, dimethyl ether (DME), polycarbonate (PC) and acetic acid. It can be used as. The carbon dioxide reforming reaction of the methane is shown in the following scheme.

<Scheme>

This carbon dioxide reforming reaction is a very strong endothermic reaction. The equilibrium conversion, the theoretical maximum conversion at a given temperature, increases with increasing temperature, causing the reaction to occur at temperatures above 650 ° C., and usually at a high temperature of 850 ° C. However, the reaction at high temperature easily sinters and oxidizes the catalyst particles (active component), thereby reducing the active point of the catalyst, causing carbon deposition, and seriously lowering the catalyst activity. Development is required.

In particular, in the reforming reaction, a large amount of greenhouse gas treatment is possible, and a catalyst having high mechanical and thermal durability is required, and the conventional literature mainly focuses only on the invention for improving the performance of the catalyst.

As a conventional catalyst for reforming reaction, Korean Patent No. 1164024 limits the content of the active ingredient to a specific ratio to optimize the content of the active ingredient and impregnate each active metal separately, followed by a carrier impregnated with the entire active metal. A cobalt based catalyst for carbon dioxide reforming reaction of methane prepared by the process of firing is proposed.

However, in the case of such a cobalt-based catalyst, although the generation ratio of carbon monoxide is high, and there is an advantage that the reaction can proceed stably under relatively long-term operating conditions, the active ingredient under the carbon precipitation and high temperature reaction conditions (above 800 ° C) as described above. The problem of formation of an inactive phase due to sintering, oxidation and the like has not been solved.

In addition, Korean Patent No. 1366418 discloses an alumina (Al ₂ O ₃ ) catalyst support whose surface is modified with magnesium oxide (MgO); Nickel and cobalt as catalytically active ingredients; And calcium oxide, which is a catalyst enhancer, wherein the catalyst active ingredient and the catalyst enhancer are supported on the catalyst support, and the magnesium oxide proposes a catalyst for steam reforming of methane forming a spinel structure with alumina.

In Korean Patent No. 1432621, a synthesis gas prepared by supporting a nickel-cerium composite, a nickel-cobalt composite, or a nickel-cerium-cobalt composite on yMgO- (100-y) Al ₂ O ₃ , a carrier having a high surface area spinel structure A reforming catalyst for production, a syngas production method using the same, and a syngas production reactor are proposed.

U.S. Pat.No.57,444,19 supports the support of silica, alumina, zirconia, etc., which is pre-coated with nickel or cobalt with alkaline earth metals depending on the presence of precious metals in connection with steam reforming including oxygen reforming and carbon dioxide reforming. This catalyst and U. S. Patent No. 4026823 disclose a zirconia supported nickel catalyst in which cobalt is added to nickel as a steam reforming catalyst for hydrocarbons.

However, these catalysts also do not fundamentally solve the above problems occurring during the reforming reaction.

An object of the present invention is to solve the above problems, by supporting the active ingredient on the surface-modified alumina support with phosphorus, sintering and formation of an inactive phase of the active ingredient even at high temperature due to the bonding between the alumina support and the active ingredient It is to provide a catalyst for the reforming reaction of methane using carbon dioxide and a method for producing the same, which can improve the activity stability of the catalyst by inhibiting.

The present invention also provides a method for producing a synthesis gas that can stably produce a synthesis gas having a high carbon monoxide content from a gas containing methane and carbon dioxide using the catalyst.

In order to achieve the above object, one embodiment of the present invention, in the catalyst for the methane reforming reaction using carbon dioxide, the cobalt is supported as an active ingredient on the support, the support is phosphorus surface-modified phosphorus alumina surface It provides a catalyst for methane reforming reaction using carbon dioxide, characterized in that the alumina support.

In a preferred embodiment of the present invention, the phosphorus-alumina support may be characterized in that it contains 0.5 to 5% by weight relative to the total weight of the phosphorus-alumina support.

In one preferred embodiment of the present invention, the catalyst may be characterized in that the cobalt is supported by 1 to 10% by weight based on the total weight of the catalyst.

In a preferred embodiment of the present invention, the alumina may be characterized in that the specific surface area of 10 m ² / g ~ 300 m ² / g.

Another embodiment of the present invention comprises the steps of (a) surface modification of alumina with a phosphorus precursor, followed by calcining to obtain a phosphorus-alumina support; And (b) supporting the cobalt precursor on the obtained phosphorus-alumina support, followed by calcining to provide a catalyst, thereby providing a catalyst for methane reforming reaction using carbon dioxide.

In another preferred embodiment of the invention, the phosphor precursor is phosphoric acid (H ₃ PO ₄ ), phosphorus oxychloride (POCl ₃ ), phosphorus pentoxide (P ₂ O ₅ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO _4), dimethyl ammonium phosphate _{((NH 4) 2 HPO 4} ), triethyl phosphate _{((C 2 H 5) 3} PO 4) and at least one species selected from the group consisting of phosphorus trichloride (PCl ₃₎ It may be characterized by.

In a preferred different embodiment of the invention, the cobalt precursor, _{Co (NO 3) 2, Co} (OH) 2, CoCl 2, CoSO 4, Co 2 (SO 4) 3, CoF 3 and selected from the group consisting of CoCO ₃ It can be characterized by one or more kinds.

In another preferred embodiment of the present invention, the phosphorus-alumina support may be characterized in that it contains 0.5 to 5% by weight relative to the total weight of the phosphorus-alumina support.

In another preferred embodiment of the present invention, the catalyst may be characterized in that the cobalt is supported by 1 to 10% by weight based on the total weight of the catalyst.

In another preferred embodiment of the present invention, the firing of step (a) may be characterized in that performed for 1 to 12 hours at 300 ℃ ~ 900 ℃.

In another preferred embodiment of the present invention, the firing of step (b) may be characterized in that it is carried out for 1 to 12 hours at 300 ℃ ~ 900 ℃.

Another embodiment of the present invention provides a method for preparing syngas using the catalyst to produce syngas from a gas comprising methane and carbon dioxide.

In another embodiment of the present invention, under 600 ℃ to a temperature of 900 ℃, 0.05 MPa to 2 MPa pressure and 30,000 ml / g The space velocity of the _{cat and} hr to 120,000 ml / g _{cat and} hr containing methane and carbon dioxide Provided is a method for producing syngas from a gas.

In another embodiment of the present invention, the reactor may be characterized in that it is selected from the group consisting of a fixed bed reactor, a fluidized bed reactor and a slurry reactor.

The catalyst for methane reforming reaction using carbon dioxide according to the present invention is prepared by supporting an active ingredient on an alumina support surface-modified with phosphorus, and thus, methane using carbon dioxide rather than a conventional catalyst for reforming reaction due to strong bonding between the alumina support and the active ingredient. In the high temperature reforming reaction, the sintering of the active ingredient is delayed, and the formation of the inactive phase of the cobalt aluminate phase is suppressed, thereby improving the activity stability of the catalyst.

In addition, the method for producing a synthesis gas according to the present invention generates a high carbon monoxide synthesis gas, which is a raw material for high value-added products such as oxo alcohol, dimethyl ether, polycarbonate, acetic acid, etc., thereby making it possible to resource carbon dioxide, a greenhouse gas. .

1 is a graph showing the methane conversion and deactivation of the catalyst prepared in Examples 1 to 4 and Comparative Example 1.

Figure 2 is a graph showing the carbon dioxide conversion and deactivation of the catalyst prepared in Examples 1 to 4 and Comparative Example 1.

3 is a graph showing the carbon deposition amount and the methane inactivation rate of the catalyst prepared in Examples 1 to 4 and Comparative Example 1.

Figure 4 is an image before and after the reforming reaction of the catalyst prepared in Example 2 and Comparative Example 1.

5 is an X-ray diffraction graph after the reforming reaction of the catalysts prepared in Example 2 and Comparative Example 1. FIG.

Figure 6 is a graph of the conversion rate of the reforming reaction time of the catalyst prepared in Example 2.

7 is a graph of conversion rate versus reforming reaction time of the catalyst prepared in Comparative Example 1. FIG.

Hereinafter, with reference to the accompanying drawings, a catalyst for methane reforming reaction using carbon dioxide according to the present invention and a method for preparing the same according to the present invention so that those skilled in the art can easily carry out the present invention with reference to the accompanying drawings. Will be described in detail.

In describing the principles of the preferred embodiment of the present invention in detail, if it is determined that the detailed description of the related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the configuration shown in the embodiments and drawings described herein is only one of the most preferred embodiment of the present invention and does not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

In one aspect, the present invention provides a catalyst for methane reforming reaction using carbon dioxide in which cobalt is supported as an active ingredient, wherein the support is a phosphorus-alumina support surface-modified with phosphorus on an alumina surface. It relates to a catalyst for the methane reforming reaction used.

In another aspect, the present invention, (a) surface-modified alumina with a phosphorus precursor, and then calcined to obtain a phosphorus-alumina support; And (b) supporting the obtained cobalt precursor on the obtained phosphorus-alumina support, followed by calcining to prepare a catalyst, which relates to a method for preparing a catalyst for methane reforming reaction using carbon dioxide.

Conventional catalysts used in the reforming reaction of methane using carbon dioxide are known to use transition metals such as cobalt, nickel, zirconia as active ingredients, and alumina, silica and the like as support components. However, even if the catalyst uses the same components, it is known that the catalytic activity is completely different depending on the treatment method and the mixture of each component.

Therefore, in the present invention, in order to improve the stability of the activity of the catalyst, alumina, which is a support component, is surface-modified with a phosphorus precursor to obtain a phosphorus-alumina support, and after the cobalt precursor is supported on the obtained phosphorus-alumina support, the catalyst is calcined. By producing a strong bond between the support and the active ingredient, it is possible to delay the sintering of the active ingredient even at a high temperature reaction and to suppress the formation of an inactive cobalt aluminate phase to improve the active stability of the catalyst.

At this time, the alumina has a support component having a high specific surface area, and a specific surface area of ^{10 m 2 / g ~ 300 m} 2 / g. When the specific surface area of the alumina is less than 10 m ² / g, the reduction of specific surface area may occur greatly in the surface treatment process of phosphorus, which may cause a problem that the specific surface area of the surface-modified support with phosphorus may be excessively small. If it exceeds 300 m ² / g it is preferable to maintain the above range because the phenomenon of clogging of the fine pores in the process of phosphorus is severe or the thermal stability is reduced.

Such alumina is surface modified with a phosphorus precursor to obtain a phosphorus-alumina support.

The phosphorus precursor is generally used in the art, and is not particularly limited. Specifically, phosphoric acid (H ₃ PO ₄ ), phosphorus oxychloride (POCl ₃ ), phosphorus pentoxide (P ₂ O ₅ ), and ammonium di Hydrogen phosphate (NH ₄ H ₂ PO ₄ ), diammonium phosphate ((NH ₄ ) ₂ HPO ₄ ), triethyl phosphate ((C ₂ H ₅ ) ₃ PO ₄ ), phosphorus trichloride (PCl ₃ ), etc. have.

The alumina surface modification of such phosphorus precursor can be carried out using a method such as commonly used impregnation method, coprecipitation method, spraying method, ion exchange method, etc., and calcined to obtain a phosphorus-alumina support.

The firing is carried out for 1 to 12 hours at 300 to 900 ℃, preferably for 2 to 6 hours at 500 to 700 ℃ bar, if the firing temperature and time is less than 300 ℃ or 1 hour surface of the alumina by the phosphorus precursor The effect of phosphorus addition may be reduced due to the slight modification effect, and the specific surface area of the support may be reduced due to the blockage of micropores due to the sintering phenomenon exceeding 900 ° C or 12 hours. It is good to keep.

The phosphorus-alumina support prepared by the above process contains 0.5 to 5% by weight of phosphorus based on the total weight of the phosphorus-alumina support, and the specific surface area is 10 to 300 m ² / g, preferably 100 to 200 m ² / g.

With respect to the total weight of the phosphorus-alumina support, when the phosphorus is less than 0.5% by weight, the effect of changing the alumina surface property due to the addition of phosphorus is small, so that the effect of increasing the reactivity is insignificant. The clogging of fine pores may be serious and may cause a problem that the specific surface area of the catalyst is reduced.

In addition, when the specific surface area of the phosphorus-alumina support is less than 10 m ² / g, there is a problem in that the dispersibility of cobalt decreases during the surface modification process of the cobalt component, thereby decreasing the catalytic activity, and when it exceeds 300 m ² / g. In the cobalt and the phosphorus-alumina support, there may be a problem that the reactivity of the cobalt is reduced by reducing the reactivity of the cobalt.

Next, after supporting the phosphorus-alumina support and the cobalt precursor, it is baked for 1 to 12 hours at 300 to 900 ° C, preferably for 2 to 6 hours at 500 to 700 ° C. In this case, the catalyst may be prepared by a method generally used in the art, and specifically, may be supported by carrying out a method such as impregnation and coprecipitation.

As an example, the impregnation method is carried out in an aqueous solution or an alcohol solution for 30 to 720 minutes at 20 ~ 90 ℃, the precipitate prepared by the above process after drying for about 24 hours in an oven at 100 ℃ or more and used as a catalyst do.

In addition, the co-precipitation method co-precipitates the cobalt precursor in an aqueous solution of pH 7-8 on the slurry of the phosphorus-alumina support, and then matures in the range of 40-90 ° C. to filter and wash the precipitate so that the content of the cobalt component is the total weight of the catalyst. With respect to, it is prepared to contain from 1 to 10% by weight. In the coprecipitation, a pH of 7 to 8 may be used to maintain a basic precipitation agent. Specifically, as the basic precipitant, sodium carbonate, calcium carbonate, ammonium carbonate, ammonia water, or the like is preferably used. The aging time of the catalyst is appropriately maintained at less than 0.1 to 10 hours, preferably 0.5 to 8 hours, since the formation of a support containing cobalt having good activity in the given aging time range is advantageous, and the aging time is If it is short, the dispersibility of cobalt decreases, which is disadvantageous in terms of catalytic activity, and if it exceeds 10 hours, the particle size of cobalt increases, which decreases the active point and the synthesis time, which is not economical.

The cobalt / phosphorus-alumina catalyst prepared by the above method is first washed and dried to prepare a cobalt / phosphorus-alumina catalyst carrying the final cobalt. The precipitate prepared by the above method is subjected to a washing process and then dried in an oven at 80 ° C. or more for one day, and then the precipitate is directly used for catalyst synthesis, or calcined after further supporting additional active ingredients other than cobalt. Can be used. At this time, the additional active ingredient may be nickel, copper, manganese, tungsten, zirconium and the like.

Wherein the cobalt precursor is not particularly restricted to be commonly used in the art, in particular _{Co (NO 3) 2, Co} (OH) 2, CoCl 2, CoSO 4, Co 2 (SO 4) 3, CoF 3 and CoCO _It may be at least one selected from the group consisting of ₃ , preferably a nitrate precursor is generally used.

After the cobalt precursor is supported on the phosphorus-alumina support, if the firing conditions are less than 300 ° C. or less than 1 hour, the solvent and precursor components used in the manufacturing process may remain in the catalyst, which may cause an increase in side reactions. In the case of more than 12 hours, the particle size increases due to the sintering phenomenon of the active ingredient, thereby reducing the dispersibility of the active ingredient such as cobalt and at the same time decreasing the specific surface area of the support, thus adversely affecting the methane reforming reaction. It is desirable to maintain the catalyst preparation range.

The catalyst is supported by 1 to 10% by weight of cobalt based on the total weight of the catalyst. If the supported amount is less than 1% by weight, there is a problem in that the reactivity decreases because there is not enough active ingredient to show methane reforming reactivity using carbon dioxide. And, if it exceeds 10% by weight it is preferable to maintain the above range because the problem of economical efficiency is lowered due to the increase in the catalyst manufacturing cost.

The catalyst for methane reforming reaction using carbon dioxide according to the present invention prevents migration between the active ingredient at high temperature due to the strong bonding between the alumina support surface-modified with phosphorus and the active ingredient, thereby delaying the sintering phenomenon of the active ingredient, The formation of cobalt aluminate phases can be suppressed to improve the activity stability of the catalyst.

In addition, the present invention relates to a method for producing a synthesis gas for producing a synthesis gas from a gas containing methane and carbon dioxide using the catalyst described above in another aspect.

The reactor used in the carbon dioxide reforming reaction of methane is generally used in the art, but is not particularly limited. Specifically, a fixed gas phase fixed bed reactor, a fluidized bed reactor, or a slurry slurry may be used.

Wherein the reaction conditions while maintaining a space velocity of 600 ℃ to a reaction temperature of 900 ℃, 0.1 MPa to 2 MPa pressure and 30,000 ml / g _{cat and} hr to 120,000 ml / g _{cat and} hr, the reaction raw material CH ₄ / CO The molar ratio of ₂ is maintained in the range of 0.5 to 2.0.

If the reaction temperature is less than 600 ° C, the reaction rate is not sufficient and no conversion occurs. If the reaction temperature exceeds 900 ° C, carbonization of the catalyst starts and the deactivation is early. As the reaction pressure increases, the activity of the catalyst is maintained stably, but it is not a largely applied variable, and the initial reactor installation cost is high at a pressure exceeding 2 MPa.

When the reaction productivity is too low if the space velocity of the gas mixture is less than 30,000 ml / g _cat hr _and is greater than the 120,000 ml / g _cat hr _and is the deactivation of the catalyst because the shorter the contact time of the reactants and catalyst. When the mixing ratio of the methane and carbon dioxide is out of the range it is inclined to one side conversion, which is an inefficient reaction, it is preferable to maintain the range.

As described above, the catalyst prepared according to the present invention improves the activity stability of the catalyst in the carbon dioxide reforming reaction of methane, so that the high conversion and especially the CO / H ₂ Syngas having a high molar ratio can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

Γ-alumina (γ-Al ₂ O ₃ , Strem, SBET = 157 m ² / g, pore volume = 0.487 cm ³ / g) was used as a support, and H ₃ PO ₄ (Samchun, 85%) was used as a cobalt precursor as an active ingredient, Cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O, Samchun Chem., 97%). The γ-alumina was heat treated at 750 ° C. for 6 hours before being used as a support.

After the addition of acid precursor 0.633 g one to prepare a phosphoric acid solution was diluted by the addition of distilled water 200 ml, and _{then, γ-Al 2 O 3 20} g in the prepared acid solution to impregnate the person on γ-Al ₂ O ₃ support , Vigorously stirred at room temperature for 1 hour. After stirring the γ-Al ₂ O ₃ solution impregnated with phosphoric acid, the solvent used was removed using a vacuum distillation apparatus. The semi-dried phosphate-treated γ-Al ₂ O ₃ support was dried in a drying oven at 100 ° C., and then calcined at 500 ° C. for 4 hours to be used as a phosphorus-alumina support for Co loading. In this case, the phosphorus content was 1 wt% based on the total weight of the phosphorus-alumina support.

In order to carry the active ingredient on the phosphorus-alumina support, 2.469 g of cobalt precursor was added to 100 ml of distilled water to prepare a solution in which the active ingredient was dissolved, and then 10 g of the phosphorus-alumina support was added to the prepared cobalt solution. The mixture was stirred vigorously at room temperature for 1 hour. The cobalt-supported solution was removed by distillation using a vacuum distillation apparatus and dried in a drying oven at a temperature of 100 ° C. The dried catalyst was calcined at a temperature of 500 ° C. for 4 hours to prepare a catalyst such that the content of cobalt supported on the phosphorus-alumina support was 5 wt% based on the total weight of the catalyst.

Example 2

Γ-alumina (γ-Al ₂ O ₃ , Strem, SBET = 157 m ² / g, pore volume = 0.487 cm ³ / g) was used as a support, and H ₃ PO ₄ (Samchun, 85%) was used as a cobalt precursor as an active ingredient, Cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O, Samchun Chem., 97%). The γ-alumina was heat treated at 750 ° C. for 6 hours before being used as a support.

In order to impregnate the γ-Al ₂ O ₃ support, 1.266 g of phosphoric acid was added to 200 ml of distilled water to prepare a diluted phosphoric acid solution, and then 20 g of γ-Al ₂ O ₃ was added to the prepared phosphoric acid solution. The mixture was stirred vigorously at room temperature for 1 hour. After stirring the γ-Al ₂ O ₃ solution impregnated with phosphoric acid, the solvent used was removed using a vacuum distillation apparatus. The semi-dried phosphate-treated γ-Al ₂ O ₃ support was dried in a drying oven at 100 ° C., and then calcined at 500 ° C. for 4 hours to be used as a phosphorus-alumina support for Co loading. At this time, the phosphorus content was 2 wt% based on the total weight of the phosphorus-alumina support.

In order to support the active ingredient on the phosphorus-alumina support, 2.469 g of cobalt was added to 100 ml of distilled water to prepare a solution in which the active ingredient was dissolved, and then 10 g of the phosphorus-alumina support was added to the prepared cobalt solution. The mixture was stirred vigorously for 1 hour. The cobalt-supported solution was removed by distillation using a vacuum distillation apparatus and dried in a drying oven at a temperature of 100 ° C. The dried catalyst was calcined at a temperature of 500 ° C. for 4 hours to prepare a catalyst such that the content of cobalt supported on the phosphorus-alumina support was 5 wt%.

Example 3

Γ-alumina (γ-Al ₂ O ₃ , Strem, SBET = 157 m ² / g, pore volume = 0.487 cm ³ / g) was used as a support, and H ₃ PO ₄ (Samchun, 85%) was used as a cobalt precursor as an active ingredient, Cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O, Samchun Chem., 97%). The γ-alumina was heat treated at 750 ° C. for 6 hours before being used as a support.

After manufacturing the phosphoric acid solution was diluted by the addition of phosphoric acid 1.898 g of distilled water 200 ml, and then added to the γ-Al ₂ O ₃ 20 g in the prepared acid solution to impregnate the person on γ-Al ₂ O ₃ support, The mixture was stirred vigorously at room temperature for 1 hour. After stirring the γ-Al ₂ O ₃ solution impregnated with phosphoric acid, the solvent used was removed using a vacuum distillation apparatus. The semi-dried phosphate-treated γ-Al ₂ O ₃ support was dried in a drying oven at 100 ° C., and then calcined at 500 ° C. for 4 hours to be used as a phosphorus-alumina support for Co loading. At this time, based on the total weight of the phosphorus-alumina support, the phosphorus content was 3 wt%.

In order to support the active ingredient on the phosphorus-alumina support, 2.469 g of cobalt was added to 100 ml of distilled water to prepare a solution in which the active ingredient was dissolved, and then 10 g of the phosphorus-alumina support was added to the prepared cobalt solution. The mixture was stirred vigorously for 1 hour. The cobalt-supported solution was removed by distillation using a vacuum distillation apparatus and dried in a drying oven at a temperature of 100 ° C. The dried catalyst was calcined at a temperature of 500 ° C. for 4 hours to prepare a catalyst such that the content of cobalt supported on the phosphorus-alumina support was 5 wt%.

Example 4

Γ-alumina (γ-Al ₂ O ₃ , Strem, SBET = 157 m ² / g, pore volume = 0.487 cm ³ / g) was used as a support, and H ₃ PO ₄ (Samchun, 85%) was used as a cobalt precursor as an active ingredient, Cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O, Samchun Chem., 97%). The γ-alumina was heat treated at 750 ° C. for 6 hours before being used as a support.

After manufacturing the phosphoric acid solution was diluted by the addition of phosphoric acid 2.531 g of distilled water 100 ml, and then added to the γ-Al ₂ O ₃ 20 g in the prepared acid solution to impregnate the person on γ-Al ₂ O ₃ support, The mixture was stirred vigorously at room temperature for 1 hour. After stirring the γ-Al ₂ O ₃ solution impregnated with phosphoric acid, the solvent used was removed using a vacuum distillation apparatus. The semi-dried phosphate-treated γ-Al ₂ O ₃ support was dried in a drying oven at 100 ° C. and then calcined at 500 ° C. for 4 hours to be used as a phosphorus-alumina support for Co loading. In this case, the phosphorus content was 4 wt% based on the total weight of the phosphorus-alumina support.

In order to support the active ingredient on the phosphorus-alumina support, 2.469 g of cobalt was added to 100 ml of distilled water to prepare a solution in which the active ingredient was dissolved, and then 10 g of the phosphorus-alumina support was added to the prepared cobalt solution. The mixture was stirred vigorously for 1 hour. The cobalt-supported solution was removed by distillation using a vacuum distillation apparatus and dried in a drying oven at a temperature of 100 ° C. The dried catalyst was calcined at a temperature of 500 ° C. for 4 hours to prepare a catalyst such that the content of cobalt supported on the phosphorus-alumina support was 5 wt%.

Comparative Example 1

In order to carry the active ingredient on the same alumina support as Example 1, 2.469 g of the same cobalt precursor as in Example 1 was added to 100 ml of distilled water to prepare a solution in which the active ingredient was dissolved, and then 10 g of the alumina support to the prepared cobalt solution. After the addition, the mixture was stirred vigorously at room temperature for 1 hour. The cobalt-supported solution was removed by distillation using a vacuum distillation apparatus and dried in a drying oven at a temperature of 100 ° C. The dried catalyst was calcined at a temperature of 500 ° C. for 4 hours to prepare a catalyst such that the content of cobalt supported on the alumina support was 5 wt%.

Experimental Example 1

In order to evaluate the performance of the catalysts prepared in Examples 1 to 4 and Comparative Example 1, the reforming reaction of methane and carbon dioxide was carried out in the following manner, and the results are shown in FIGS. 1 and 2, respectively. 0.3 g of a catalyst having an average particle size of 250 µm prepared by Examples 1 to 4 and Comparative Example 1 was filled using quartz wool. The reactor used for the reforming reaction is a fixed bed reactor equipped with an external heating system, which is a tubular reactor of 1/4 inch diameter quartz. Before the reaction, the catalysts prepared in Examples 1 to 4 and Comparative Example 1 were reduced with 5% H ₂ -Ar at 750 ° C. for 1 hour. Catalytic reaction was performed by supplying a mixed gas of methane: carbon dioxide: nitrogen having a mixing molar ratio of 4: 4: 2 into the reactor at a space velocity of 60,000 ml / g _{cat ·} hr. At this time, the catalytic reaction was carried out at a reaction temperature condition of atmospheric pressure, 750 ℃, the gas discharged after the reaction was analyzed using a gas chromatography system equipped with a thermal conductivity detector (Thermal conductivity detector).

Examples 1 to 4 and Comparative Example 1 carried out under the above reaction conditions are shown in Figures 1 and 2 the conversion rate and inactivity of methane and carbon dioxide. The conversion rate of methane and carbon dioxide was quantified based on the reaction time of 20 hours, and the degree of deactivation was calculated by the difference between the conversion rate after 1 hour and the conversion rate after 20 hours.

As shown in FIGS. 1 and 2, the catalyst of Example 1 exhibited the highest conversion of methane and carbon dioxide, and the catalyst of Example 2 showed similar catalytic activity to the catalyst of Example 1, but with the least deactivation. The degree was shown. In addition, in the catalysts of Examples 3 and 4, not only the conversion rate of methane and carbon dioxide decreased but also the degree of deactivation also increased.

On the other hand, the catalyst of Comparative Example 1 showed a higher conversion rate than the catalyst of Example 4, but showed the greatest degree of deactivation. From the results of Examples 1 to 4, the activity and inactivation degree of the methane reforming catalyst proposed in the present invention were greatly influenced by the phosphorus content used for impregnation, and it can be interpreted that an optimum content exists. Comparison was made with Comparative Example 1 based on the catalyst of Example 2 with the least inactivation observed.

Experimental Example 2

After performing the reforming reaction of methane and carbon dioxide on the catalysts prepared in Examples 1 to 4 and Comparative Example 1, elemental analysis was performed to determine carbon deposition. The experiment was performed after the reforming reaction in the reaction conditions of Experimental Example 1, the catalyst recovered in Examples 1 to 4 and Comparative Example 1 was quantified the amount of carbon deposited in the catalyst using the Thermo Scientific FLASH EA-2000 equipment The results are shown in FIG. 3 in comparison with the degree of deactivation of the catalyst.

As shown in FIG. 3, the degree of inactivation of the catalyst in the methane reforming reaction was most observed in Comparative Example 1, and the lowest degree of inactivation was shown in Example 2. In addition, in Examples 3 and 4 catalysts, the degree of deactivation tended to increase. The amount of carbon deposition was lowest in Comparative Example 1, and the largest in Example 2. In general, many studies have been carried out to solve this problem as sintering phenomenon and carbon deposition of the active metal in the reforming reaction is the biggest cause of catalyst deactivation. The catalyst of the present invention showed a different behavior from the general cause of inactivation of the reforming reaction, and the catalyst of the present invention is thought to have other causes besides carbon deposition.

Experimental Example 3

During the reforming reaction of methane and carbon dioxide of the catalysts prepared in Example 2 and Comparative Example 1, catalyst images were taken before and after the reaction and X-ray diffraction analysis was performed to determine the reduction of active components by oxidation. The results are shown in FIGS. 4 and 5, respectively.

As shown in FIGS. 4 and 5, in the catalyst prepared in Comparative Example 1, the color of the upper and lower catalysts was changed from black to blue after the reaction, and the upper and lower X-ray diffraction analysis results showed that A decrease in the peak associated with the active ingredient cobalt was observed. This means that reduced cobalt has turned into cobalt oxide. In addition, after the reaction, the cobalt oxide CoO was not observed in the X-ray diffraction analysis due to the oxidation of cobalt, because the absolute amount of cobalt supported on the catalyst was small, and on the catalyst carrying 20 wt% cobalt, cobalt by oxidation was observed. X-ray diffraction peaks in oxide form were observed. No diffraction peaks of other cobalt oxide forms, Co ₂ O ₃ and Co ₃ O ₄ , were observed by the oxidation of cobalt. On the other hand, in the case of the catalyst prepared in Example 2, the color change of the upper and lower ends of the catalyst was not observed, and X-ray diffraction analysis showed that peaks related to cobalt, an active metal, were clearly observed without decreasing the peak size at the upper and lower ends. From this result, the catalyst proposed in the present invention was confirmed to maintain stable activity by inhibiting the oxidation of the cobalt-based catalyst in the reforming reaction of carbon dioxide and methane.

Experimental Example 4

Long life evaluation of the reforming reaction of methane and carbon dioxide of Example 2 and Comparative Example 1 catalysts was carried out under the same conditions as in Experimental Example 1, and the results are shown in FIGS. 6 and 7, respectively.

6 and 7, the catalyst of Example 2 showed stable catalytic activity during the reforming reaction of 50 hours, whereas the catalyst of Comparative Example 1 was deactivated and the conversion rate of methane and carbon dioxide was drastically decreased. .

All simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

The catalyst for methane reforming reaction using carbon dioxide according to the present invention is prepared by supporting an active ingredient on an alumina support surface-modified with phosphorus, and thus, methane using carbon dioxide rather than a conventional catalyst for reforming reaction due to strong bonding between the alumina support and the active ingredient. Even in the high temperature reforming reaction, there is an industrial applicability because it has the effect of delaying the sintering of the active ingredient, suppressing the formation of the inactive cobalt aluminate phase and improving the activity stability of the catalyst.

In addition, the method for producing a synthesis gas according to the present invention generates a high carbon monoxide synthesis gas, which is a raw material for high value-added products such as oxo alcohol, dimethyl ether, polycarbonate, acetic acid, etc. Therefore, there is industrial applicability.

Claims (12)

In the catalyst for methane reforming reaction using carbon dioxide, cobalt supported on the support as an active ingredient, The support is a catalyst for methane reforming reaction using carbon dioxide, characterized in that the phosphorus-alumina support surface-modified alumina surface with phosphorus. The method of claim 1, The phosphorus-alumina support is a catalyst for methane reforming reaction using carbon dioxide, characterized in that the phosphorus is contained in an amount of 0.5% by weight to 5% by weight relative to the total weight of the phosphorus-alumina support. The method of claim 1, The catalyst is a catalyst for methane reforming reaction using carbon dioxide, characterized in that the cobalt is supported by 1 to 10% by weight based on the total weight of the catalyst. The method of claim 1, The alumina has a specific surface area of 10 m ² / g to 300 m ² / g catalyst for methane reforming reaction using carbon dioxide. (a) surface modification of the alumina with a phosphorus precursor, followed by calcining to obtain a phosphorus-alumina support; And (b) a method of preparing a catalyst for methane reforming reaction using carbon dioxide, comprising the step of preparing a catalyst by supporting a cobalt precursor on the obtained phosphorus-alumina support. The method of claim 5, The phosphorus precursor is phosphoric acid (H ₃ PO ₄ ), phosphorus oxychloride (POCl ₃ ), phosphorus pentoxide (P ₂ O ₅ ), ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), diammonium phosphate ( (NH ₄ ) ₂ HPO ₄ ), methane reforming with carbon dioxide, characterized in that at least one selected from the group consisting of triethyl phosphate ((C ₂ H ₅ ) ₃ PO ₄ ) and phosphorus trichloride (PCl ₃ ) Method for producing a catalyst for reaction. The method of claim 5, The cobalt precursor, _{Co (NO 3) 2, Co} (OH) 2, CoCl 2, CoSO 4, Co 2 (SO 4) 3, CoF 3 and at least carbon dioxide, characterized in that at least selected from the group consisting of CoCO ₃ Method for producing a catalyst for methane reforming reaction using. The method of claim 5, The phosphorus-alumina support is a method for producing a catalyst for methane reforming reaction using carbon dioxide, characterized in that the phosphorus is contained by 0.5% by weight to 5% by weight relative to the total weight of the phosphorus-alumina support. The method of claim 5, The catalyst is a method for producing a catalyst for methane reforming reaction using carbon dioxide, characterized in that the cobalt is supported by 1 to 10% by weight based on the total weight of the catalyst. The method of claim 5, Firing step (a) and firing step (b) is a method for producing a catalyst for methane reforming reaction using carbon dioxide, characterized in that performed for 1 to 12 hours at 300 ℃ ~ 900 ℃. A method for producing syngas from a gas comprising methane and carbon dioxide using the catalyst of claim 1. The method of claim 11, Under 600 ℃ to 900 ℃ temperature, 0.05 MPa to 2 MPa pressure and 30,000 ml / g The space velocity of the _{cat and} hr to 120,000 ml / g _{cat and} hr of a method of manufacturing a synthesis gas from a gas containing methane and carbon dioxide.

Images