KR20120070696A - Tungsten based catalysts for carbon dioxide reforming of methane and preparing method of syngas using the same - Google Patents

Abstract

The present invention relates to a tungsten-based catalyst for carbon dioxide reforming of methane and a method for producing a synthesis gas using the same, and more particularly, one or more of zirconium and lanthanum together with a platinum group element and tungsten, a carrier comprising silica, alumina or a mixture thereof. The present invention relates to a catalyst supported on the present invention, and to a method for producing a synthesis gas containing carbon monoxide and hydrogen by using the catalyst for carbon dioxide reforming of methane. The tungsten-based catalyst of the present invention is excellent in stability and activity due to excellent carbon deposition phenomenon even in a long time reaction, and when applied to the synthesis gas manufacturing process can produce a synthesis gas with a high carbon monoxide content, it has a great effect on global warming It can make use of the carbon dioxide that is mad.

Description

Tungsten based Catalysts for Carbon dioxide reforming of Methane and Preparing method of Syngas using the same}

The present invention relates to a tungsten-based catalyst for carbon dioxide reforming of methane and a method for producing a synthesis gas containing hydrogen and carbon monoxide using such a tungsten-based catalyst. Tungsten-based catalyst of the present invention is excellent in stability and activity, can be produced in a synthesis gas having a high content of carbon monoxide when applied to the synthesis gas manufacturing process, it is possible to resource the carbon dioxide which has a great impact on global warming.

Carbon dioxide has been recognized as a relatively harmless substance, but recently, it is classified as a major substance causing global warming and is classified as an emission control substance under the Climate Change Convention. Therefore, global attention is focused on the method of reducing the amount of carbon dioxide produced or fixing the emitted carbon dioxide physically and chemically. As one of the chemical treatment methods of carbon dioxide, there is a method for producing various compounds by producing a synthesis gas of a mixture of carbon monoxide and hydrogen by a dry reforming reaction using a mixed gas of methane and carbon dioxide as shown in Scheme 1 below. . This is a very useful technique for treating such mixed gases simultaneously, given the enormous amounts of greenhouse gases such as methane and carbon dioxide in the plant, which are generated from mixed landfills and fossil fuels from landfills.

[Reaction Scheme 1]

Syngas is a mixed gas containing hydrogen and carbon monoxide as main constituents, and is a method of coal gasification, steam reforming of hydrocarbons using natural gas, or partial oxidation reforming using oxygen. Has been manufactured. The coal gasification method requires an expensive coal gasification heater and a large-scale plant. In the steam reforming of hydrocarbons and the partial oxidation reforming of hydrocarbons, as a reforming gas, carbon dioxide, oxygen, steam, or a mixture thereof is used. There is a need for a reforming catalyst having high heat resistance that can be applied to an endothermic reaction at a high temperature (700 to 1200 ° C). Currently, nickel-based catalysts, which are widely known as catalysts for reforming reactions, have high activity and are used commercially, but have a large problem in the durability of catalysts due to the rapid generation of coke. Recently, a method for producing syngas through reforming of methane using carbon dioxide has been disclosed. If such a technique can be applied on a commercial scale, it is expected to be able to resource the carbon dioxide emitted.

In the method of producing syngas, the reforming reaction of methane using carbon dioxide can produce syngas (H ₂ : CO = 1: 1) having a much higher carbon monoxide content than other reforming methods. It can be used as a raw material for Ropsch synthesis to produce high value added chemicals such as oxoalcohol, dimethyl ether, polycarbonate and acetic acid. In addition, the generated syngas is high in purity, one of the industrial manufacturing method of hydrogen can be applied to the existing process technology and many studies. However, commercially available catalysts such as nickel-based catalysts used in the reforming reaction are economically disadvantageous as the reaction proceeds at high temperature, and the catalyst is severely deactivated due to the sintering effect by carbon deposition during the reforming reaction, resulting in significant durability. There is a downside to falling.

The literature published to date indicates that catalyst deactivation is significantly slower for noble metal catalysts (AT Ashcroft, AK Cheetham, MLH Green, and PDF Vernon, Nature, 225, 352 (1991)). However, from an economical point of view, it is difficult to use a noble metal catalyst in a commercial process that requires a large amount of catalyst. Therefore, many studies have been conducted to improve the durability of catalysts by modifying existing nickel-based catalysts using cocatalysts or additives. It is done. Hou et al. Found that the addition of a small amount of Ca in the carbon dioxide reforming reaction on a Ni / α-Al ₂ O ₃ catalyst aids the diffusion of Ni and enhances the interaction between Ni-Al ₂ O _3, thereby sintering Ni. Has been reported to increase catalyst activity and stability [Journal of Molecular Catalysis A: Chemical Volume 249, Issues 1-2, 18 April 2006, Pages 53-59]. Arena et al. Investigated the effects of alkali promoters such as Na, Li, and K on Ni / MgO catalysts on the reducibility, morphology, active surface area, and electrical properties of the catalysts. [Catalysis Communications Volume 2, Issue 2, May 2001 , Pages 49-56]. In addition, Choi et al. Reported a study result of adding Co, Cu, Zr, Mn, Mo, Ti, Ag, and Sn in Ni / Al ₂ O ₃ . It is said that only the catalyst showed some improved activity. On the other hand, it is reported that the addition of Mn slightly lowers the catalytic activity while significantly suppressing carbon deposition, and that firing at a higher temperature is higher than that of the catalyst calcined at a low temperature [Journal of Alloys and Compounds Volume]. 469, Issues 1-2, 5 February 2009, Pages 298-303].

Looking at the catalyst for the reforming reaction of methane using the existing carbon dioxide, [Chem. Lett., 1953 (1992)] shows a Ni-MgO catalyst, and Korean Patent No. 10-0395095 discloses a nickel-manganese-alumina catalyst. In addition, [J. Chem. Soc., Chem. Commun., 71 (1995)] and Inter. J. Hydro. Ene. 28 (2003), 1045 discloses a catalyst in which nickel metal is supported on a lanthanum oxide (La ₂ O ₃ ) carrier, and in Korean Patent No. 10-0482646, a nickel metal is supported on a carrier surface composed of cerium zirconium oxide. Korean Patent No. 10-0912725 discloses a catalyst in which nickel metal is supported on a tungsten carbide (WC) carrier. Korean Patent No. 10-0336968 proposes a nickel-based reforming catalyst in which alkali metals, alkaline earth metals, and the like are supported as a promoter on zirconia carriers modified with alkaline earth metals and group IIIB metals. In addition, Korean Patent No. 10-0110984 discloses a catalyst in which nickel is supported on a silicon-containing carrier such as zeolite, silica, silicate, and silica-alumina together with an alkali metal and an alkaline earth metal promoter, and Korean Patent No. 10-0264160 Shows a nickel catalyst supported on an alumina airgel carrier. In Korean Patent No. 10-0732729, methane is a triple (mixed gas of carbon dioxide, oxygen and water vapor) reforming catalysts, and yttrium is essential to a zirconia carrier and is doped with a mixed metal containing a metal selected from lanthanide and alkaline earth metal elements. One nickel-based catalyst is disclosed.

As described above, in the reforming reaction of methane using carbon dioxide, as with steam reforming, attempts have been made to develop a high performance nickel-supported catalyst having a low cost and strong resistance to carbon deposition, but faced limitations due to the short catalyst life of nickel. Doing. Accordingly, researches on noble metal catalysts having greater resistance to carbon deposition and better activity than nickel catalysts have been actively conducted.

In US Patent No. 5068057, Pt / Al ₂ O ₃ and Pd / Al ₂ O ₃ catalysts are known, and in WO 92 / 11,199, precious metal-supported alumina catalysts such as iridium, rhodium, ruthenium, etc. It has been shown to exhibit long life. WO 2004/103555 and WO 2008/099847 disclose a catalyst having a spinel structure as a metal oxide containing copper as an essential element and having at least one element selected from nickel, cobalt and platinum group elements. However, although reforming with carbon dioxide is mentioned, the examples are limited to methanol and dimethylether steam reforming. WO 2002/081368 discloses iron or iron oxides containing Ti, Zr, V, Nb, Cr, Mo, Al, Ga, Mg, Sc, Ni, or Cu as steam reforming catalysts, There are few considerations on the reduction rate, H ₂ / CO selectivity and inhibition of carbon deposition that can occur when reducing. Korean Patent No. 10-0938779 discloses a catalyst using a complex metal oxide containing Cu-Fe or Sn-Fe, but the deactivation is insufficient. In addition, Japanese Patent Application Laid-Open No. 11-276893 discloses the reforming reaction of methane by carbon dioxide on a metal oxide catalyst using a hydrotalcite precursor using noble metals (Rh, Pd, Ru) and transition metals (Ni) as active metals. It is known. However, although the conversion rate of methane was more than 90% at 800 ° C., even though expensive precious metals were used, the conversion rate drastically decreased in the temperature range below that, and the catalyst containing 5% by weight of rhodium at 600 ° C. (methane conversion rate of about 50%) Except for the methane conversion rate of less than 30% has been reported. U. S. Patent No. 5744419 discloses on a carrier such as silica, alumina, zirconia, which is pre-coated with nickel or cobalt with alkaline earth metals in accordance with the presence of precious metals in connection with steam reforming including oxygen reforming and carbon dioxide reforming. The supported catalyst is known from U. S. Patent No. 4026823, a nickel catalyst supported on zirconia in which cobalt is added to nickel as a steam reforming catalyst for hydrocarbons.

However, the noble metal catalyst as described above has a problem in that it is difficult to apply commercially because of high manufacturing cost.

Accordingly, the inventors of the present invention have repeatedly studied the resources of carbon dioxide which have a great influence on global warming. As a result, the present inventors have developed a tungsten-based catalyst in which an active metal containing tungsten is impregnated on the surface of the carrier, and the carbon dioxide reforming of methane is performed. When applied as a catalyst of the reaction, it was found that not only the durability of the reaction for a longer time than the nickel-based catalyst, the stability and activity of the catalyst at low temperature, but also the synthesis gas having a high content of carbon monoxide can be prepared to complete the present invention. It became.

Accordingly, an object of the present invention is to provide a catalyst for carbon dioxide reforming of methane having excellent durability, stability, and activity, and a method for producing a synthesis gas containing hydrogen and carbon monoxide using the catalyst.

The present invention is characterized by a tungsten-based catalyst for carbon dioxide reforming of methane represented by the following formula (1).

[Formula 1]

X-W-Y / Z

In Formula 1, X is at least one selected from platinum, palladium, rhodium, iridium, ruthenium, Y is at least one selected from zirconium and lanthanum, Z is at least one selected from silica and alumina as a carrier, and X is 0.1 to 10 parts by weight, tungsten is 3 to 25 parts by weight, and Y is 1 to 30 parts by weight based on 100 parts by weight.

In addition,

Preparing a mixture in which at least one carrier selected from silica and alumina is loaded with X component, tungsten and Y component in accordance with the composition ratio of Chemical Formula 1;

Drying the mixture at a temperature of 50-110 ° C. to produce a dry matter; And

200 to the dry matter? Firing at a temperature of 900 ° C .;

Characterized in that the method for producing a tungsten-based catalyst represented by the formula (1) comprising a.

In addition, the present invention is characterized by a method for producing a synthesis gas containing carbon monoxide and hydrogen by reacting a mixed gas having a volume ratio of 1: 0.5 to 2.0 of methane and carbon dioxide under the tungsten-based catalyst.

The tungsten-based catalyst for carbon dioxide reforming of methane according to the present invention has a specific ratio of the active ingredient including tungsten at a specific ratio, which is superior to the conventional nickel-based catalyst to suppress the carbon deposition phenomenon to maintain a high reaction activity for a long time, at a low temperature Excellent catalytic activity and stability. In addition, the carbon dioxide reforming reaction of methane to which such a catalyst is applied generates a synthesis gas having a high carbon monoxide ratio, which is a raw material for high value-added products such as oxo alcohol, dimethyl ether, polycarbonate, and acetic acid. Can be.

1 is a graph showing an XRD analysis of the catalyst prepared in Example 7.
Figure 2 shows the conversion rate of methane and carbon dioxide over the reaction time of the carbon dioxide reforming reaction of methane using the catalyst prepared in Example 5.
Figure 3 shows the conversion of methane and carbon dioxide over the reaction time of the carbon dioxide reforming reaction of methane using the catalyst prepared in Example 7.
Figure 4 shows the conversion of methane and carbon dioxide over the reaction time of the carbon dioxide reforming reaction of methane using the catalyst prepared in Comparative Example 3.

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

The present invention relates to a catalyst for carbon dioxide reforming of methane represented by the following formula (1) using tungsten as the main catalyst.

[Formula 1]

X-W-Y / Z

In Formula 1, X is at least one selected from platinum, palladium, rhodium, iridium, ruthenium, Y is at least one selected from zirconium and lanthanum, Z is at least one selected from silica and alumina as a carrier, and X is 0.1 to 10 parts by weight, tungsten is 3 to 25 parts by weight, and Y is 1 to 30 parts by weight based on 100 parts by weight.

It is generally known that other transition metals such as cobalt, nickel, zirconium, and the like are used as active ingredients in the catalyst used in the reforming reaction of methane and carbon dioxide, and alumina and silica are used as carrier components. However, even if the catalyst is used the same components, the activity is known to appear completely different depending on the mixing ratio of each component, that is, the relative ratio. Accordingly, the present inventors have developed a three-phase tungsten catalyst in which the active metal is dispersed in a carrier by using tungsten as the main catalyst and selectively using a transition metal previously proposed as a cocatalyst, and controlling its content at an optimum ratio. .

X is at least one selected from platinum group elements platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), and ruthenium (Ru), and Z is silica (SiO ₂ ) and alumina (Al _2). 0.1 to 100 parts by weight of one or more carriers selected from O ₃ ). 10 parts by weight, preferably 0.2? It is recommended to use 5 parts by weight. When the content of X is less than 0.1 part by weight, the effect of increasing the activity of the X component may not appear, and even if it exceeds 10 parts by weight, the benefits of the increase according to the increase may be insignificant, and the economy may be inferior. It is desirable to.

The tungsten (W) is used as the main catalyst and 3 to 3 parts by weight of the carrier. 25 parts by weight, preferably 10? It is recommended to use 20 parts by weight. If the content of tungsten is less than 3 parts by weight, the conversion of methane and carbon dioxide may be lowered, and if it exceeds 25 parts by weight, rapid carbon deposition may occur, resulting in deactivation of the catalyst, thereby reducing the life of the catalyst.

The Y is at least one selected from zirconium (Zr) and lanthanum (La), 1 to 1 part by weight based on 100 parts by weight of the carrier. 30 parts by weight, preferably 5? It is preferable to use it in the range of 20 parts by weight, but if the content of Y is less than 1 part by weight, the effect of increasing the activity may not appear.

The present invention also relates to a method for preparing the tungsten-based catalyst represented by Chemical Formula 1 by supporting the X component, tungsten and Y component on at least one carrier selected from silica and alumina, and drying and calcining.

In the step of preparing a mixture in which the X component, tungsten and Y component are supported on the carrier, the supporting method is not particularly limited. For example, various kinds of impregnation methods such as heating impregnation method, room temperature impregnation method, vacuum impregnation method, atmospheric impregnation method, evaporation drying method, pore filling method, incipient wetness method, and immersion method, spraying method, or ion exchange method, etc. It can be adopted. The X component, tungsten and Y component can be supported on the carrier by using the precursor compound. Specifically, as the platinum precursor, PtCl ₄ , H ₂ PtCl ₆ , Pt (NH ₃ ) ₄ Cl ₂ , (NH ₄ ) ₂ PtCl ₂ , H ₂ PtBr ₆ , NH ₄ [Pt (C ₂ H ₄ ) Cl ₃ ], At least one selected from Pt (NH ₃ ) ₄ (OH) ₂ and Pt (NH ₃ ) ₂ (NO ₂ ) ₂ includes (NH ₄ ) ₂ PdCl ₆ , (NH ₄ ) ₂ PdCl ₄ , Pd as a palladium precursor. At least one selected from (NH ₃ ) ₄ Cl ₂ , PdCl _2, and Pd (NO ₃ ) _{2 may be} selected from the group consisting of Na ₃ RhCl ₆ , (NH ₄ ) ₂ RhCl ₆ , Rh (NH ₃ ) ₅ Cl ₃ and At least one selected from RhCl ₃ may be (NH ₄ ) ₂ IrCl ₆ , IrCl ₃ , H ₂ IrCl ₆ , or a mixture thereof as the iridium precursor. Also, ruthenium precursors include RuCl ₃ nH ₂ O, Ru (NO). (NO ₃ ) ₃ , Ru (NO ₃ ) ₃ , Ru ₂ (OH) ₂ Cl ₄ 7NH ₃ 3H ₂ O and K ₂ (RuCl ₅ (H ₂ O)) may be used one or more selected, preferably from the viewpoint of handling, Ru (NO) · (NO ₃ ) ₃ or Ru (NO ₃ ) ₃ It is preferable to use.

The main catalyst, tungsten is WO ₃ , WCl _{4 ,} WCl ₆ And at least one of WOCl ₄ may be used as a precursor, preferably WO ₃ . In addition, as a zirconium precursor, ZrCl ₄ , ZrCl ₂ , ZrO (NO ₃ ) ₂ ㆍ H ₂ O, ZrO ₂ , Zr (OH) ₄ , ZrClOH, Zr (NO ₃ ) ₄ ㆍ 5H ₂ O, ZrOCl ₂ ㆍ 8H ₂ O and Zr (SO ₄ ) ₂ and more than, and, preferably, it is better to use a Zr (NO _{3) 4} and 5H ₂ O or ZrOCl ₂ 8H ₂ O and from the viewpoint of handling. In addition, as a lanthanum precursor, LaCl _{3 ,} LaCl ₃ .7H ₂ O, La (OH) _3, La (NO ₃ ) _3, La (NO ₃ ) ₃ ㆍ 6H ₂ O, La ₂ O _3, La ₂ (SO ₄ ) may be used at least one member selected from among ₃ · 8H ₂ O and LaCl ₃ • 6H ₂ O, it is preferred to use a nitrate.

In supporting the X component, the tungsten and the Y component on the carrier using the precursor compound, it is more preferable to individually support each component rather than dissolving the entire precursor compound for each component in water. This is because the active component can be more evenly dispersed on the surface of the carrier by supporting the components, and the mutual synergistic effect can effectively prevent carbon deposition, which is the main cause of catalyst deactivation.

The drying step of the mixture is 50? 5 at 110 ℃? It is recommended to carry out for 24 hours. If the drying temperature is less than 50 ° C, the production time increases due to the lowering of the evaporation rate of the aqueous solution. It is desirable to maintain this range as there may be a problem of increased pore size.

In addition, the firing of the dried product is 200? 5 at 900 ℃? Preference is given to performing for 24 hours. If the calcination temperature is less than 200 ° C, the physical properties of the catalyst do not change and only the dried state is maintained, so that it is difficult to form a chemical bond as a catalyst.If the firing temperature is higher than 900 ° C, the degree of oxidation of the catalyst is large and the phase decomposition of the catalyst starts to occur. Therefore, it is preferable to maintain the above range.

In general, the reforming catalyst of methane and carbon dioxide performs a function as a catalyst through an appropriate pretreatment process, that is, a reduction reaction, before the reaction. However, the catalyst of the present invention is uniformly distributed on the surface of the carrier tungsten and cocatalyst X component, Y component, thereby preventing carbon deposition, which is the main cause of deactivation due to the mutual synergy effect, without the reduction process It stably sustains the activity of the catalyst.

The present invention also relates to a method for producing a synthesis gas containing carbon monoxide and hydrogen by reforming a mixed gas having a volume ratio of methane and carbon dioxide 1: 0.5 to 2.0 under the tungsten catalyst.

The reactor for the reforming reaction is not particularly limited as long as it is generally used in the art, and specifically, a fixed bed reactor, a fluidized bed reactor, or a reactor in the form of a liquid slurry may be used. The volume ratio of reactant methane and carbon dioxide is 1: 0.5? Although 2.0 is preferred, it is preferable to maintain the above range because the volume ratio is out of the above range, which results in an inefficient reaction in which only one reactant has a high conversion rate. The mixed gas may include inert gases nitrogen, helium, argon, etc. in addition to the reactants methane and carbon dioxide.

The reaction conditions are reaction temperature 650? 850 ° C., reaction pressure 0.01? 1 MPa and the space velocity of the mixed gas 500? 100,000 ml / g _cat ㆍ hr range, preferably 5,000? It is desirable to maintain a range of 50,000 ml / g _cat · hr. The reason why the reaction temperature is lower than that of the conventional nickel-based reforming catalyst is to prevent the carbonization of the catalyst and the change of the properties of the catalyst due to the high temperature reaction so as to maintain the catalyst activity stably. If the reaction temperature is less than 650 ° C., the reaction rate may not be sufficient and conversion may hardly occur. If the reaction temperature is higher than 850 ° C., carbonization of the catalyst may be started to promote deactivation. In addition, when the reaction pressure is increased, the activity of the catalyst is maintained stably, but it is not a largely applied variable. If it is out of the reaction pressure range, it is not preferable in terms of economics such as an increase in reactor installation cost. In addition, if the space velocity of the mixed gas is too low, there may be a problem that the productivity is too low, on the contrary, if too high, the contact time between the reactants and the catalyst is shortened there may be a problem that promotes the deactivation of the catalyst.

As described above, the tungsten-based catalyst of the present invention is evenly dispersed in the active metal on the surface of the carrier, and can be effectively applied to the reforming reaction of methane and carbon dioxide without the need for a reduction process. In addition, since the synthesis gas having a high ratio of carbon monoxide can be produced at a high conversion rate compared with the conventional catalyst for reforming methane and carbon dioxide, it is possible to resource the carbon dioxide for converting carbon dioxide into a raw material of high value added chemicals.

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 ]

Example 1

Zirconium precursor of ZrOCl ₂ and the 8H ₂ O were dissolved in water and then mixed with a carrier of SiO _2, dry was distilled under reduced pressure at 60 ℃ evaporate water at 60 ℃ 5 hours. Next, WO ₃ as a tungsten precursor and Ru (NO) · (NO ₃ ) ₃ as a ruthenium precursor were supported in this order, dried for 5 hours, and then calcined at 400 ° C. for 6 hours to give Ru-W. -Zr / SiO ₂ catalyst was prepared. Specific composition ratios are shown in Table 1 below.

Examples 2-14

In the same manner as in Example 1, to prepare a Ru-WY / Z catalyst in the component and composition ratio of Table 1. When lanthanum was selected as the Y component, La (NO ₃ ) ₃ ㆍ 6H ₂ O was used as the precursor, and Al ₂ O ₃ was used as the Z component. or SiO ₂ was used.

Examples 15-18

The same procedure as in Example 1 was carried out, but the XWY / Z catalyst was prepared using the components and composition ratios of Table 1 below. Platinum (Pt), palladium (Pd), rhodium (Rh) and iridium (Ir) were selected as X components, and H ₂ PtCl ₆ , (NH ₄ ) ₂ PdCl ₆ , (NH ₄ ) ₂ RhCl ₆ as precursors. And H ₂ IrCl ₆ were used, respectively.

Comparative Examples 1 and 2

The same procedure as in Example 1, except that W / SiO ₂ and Ru / SiO ₂ as shown in Table 1 Catalyst.

Comparative Example 3

In the same manner as in Example 1, to prepare a Ru-Ni-Zr / SiO ₂ catalyst in the component and composition ratio of Table 1 below. Ni (NO ₃ ) ₂ .6H ₂ O was used as the nickel precursor.

Catalytic activity evaluation

Example 1 above? In order to compare the performance of the catalyst prepared according to 18 and Comparative Examples 1 to 3, the reforming reaction of methane and carbon dioxide was carried out in the following manner. It was carried out for 50 hours, the average conversion rate of methane and carbon dioxide during the reaction time is shown in Table 1 below. First, the prepared catalyst was charged 0.2 g into the reactor in the size of 60 ~ 80 mesh. The reactor was a fixed bed tubular reactor with an external heating system, made of stainless steel 500 mm long and 9.25 mm internal. A mixed gas containing a volume ratio of methane and carbon dioxide of 1: 1 and 20% by volume of nitrogen was supplied to the reactor at a flow rate of 20,000 mL / g _cat · hr. The reforming reaction was carried out at a reaction temperature of 680 ~ 850 ℃ in atmospheric pressure. The gas released after the reaction was analyzed by the thermal conductivity detector of the on-line gas chromatography system.

division Ingredients and Composition Ratio reaction
Temperature
(℃) CH ₄
Average
Conversion rate
(%) CO ₂
Average
Conversion rate
(%) CO / H ₂
volume
ratio X W (Ni) Y Carrier Z
(100 parts by weight) ingredient Weight portion Weight portion ingredient Weight portion Example 1 Ru 0.5 10 Zr 5 SiO ₂ 680 24 39 1.6 Example 2 Ru 0.5 15 Zr 5 SiO ₂ 680 24 44 1.8 Example 3 Ru 0.5 20 Zr 5 SiO ₂ 680 27 48 1.3 Example 4 Ru 0.5 25 Zr 5 SiO ₂ 700 30 50 1.5 Example 5 Ru 1.0 10 Zr 5 SiO ₂ 700 48 59 1.2 Example 6 Ru 1.0 15 Zr 5 SiO ₂ 700 62 62 1.0 Example 7 Ru 1.0 20 Zr 5 SiO ₂ 700 63 64 1.0 Example 8 Ru 1.5 20 Zr 5 SiO ₂ 700 60 63 1.0 Example 9 Ru 0.5 10 La 5 Al ₂ O ₃ 700 57 60 1.1 Example 10 Ru 1.0 20 La 5 Al ₂ O ₃ 700 58 62 1.1 Example 11 Ru 1.5 20 La 5 Al ₂ O ₃ 700 58 61 1.1 Example 12 Ru 0.3 20 Zr 5 SiO ₂ 850 92 98 1.1 Example 13 Ru 0.5 20 Zr 9 SiO ₂ 850 93 100 1.1 Example 14 Ru 1.0 20 Zr 15 SiO ₂ 850 90 96 1.1 Example 15 Pt 0.1 10 Zr 5 SiO ₂ 750 30 34 1.1 Example 16 Pd 0.1 10 Zr 5 SiO ₂ 750 32 38 1.2 Example 17 Rh 0.2 10 Zr 5 SiO ₂ 750 29 36 1.2 Example 18 Ir 0.5 15 Zr 5 SiO ₂ 750 39 47 1.2 Comparative Example 1 - - 15 - - SiO ₂ 700 12 24 2.0 Comparative Example 2 Ru 1.0 - - - SiO ₂ 700 13 25 1.9 Comparative Example 3 Ru 0.5 (9) Zr 5 SiO ₂ 750 45 66 1.5

As shown in Table 1 above, Example 1? CO ₂ when using catalyst of 8 And the conversion of CH ₄ is 39 ~ 64%, 24 ~ 63%, respectively, it can be seen that the carbon monoxide was produced in more than 1.0 volume ratio relative to hydrogen. In addition, the catalysts of Examples 9 to 11 in which zirconium was replaced with lanthanum were also used in Example 5? It shows a similar conversion rate to 8, it can be seen that a high conversion rate can be obtained when the reaction temperature is a high temperature (850 ℃) as in Examples 12-14. In the case of using platinum, palladium, rhodium and iridium as X components as in Examples 15 to 18, the conversion rate of CO ₂ and CH ₄ was slightly reduced compared to the case of using ruthenium under a certain composition ratio. The results show that the tungsten-based catalyst acts as a promoter.

For the W / SiO ₂ catalyst of Comparative Example 1 using only tungsten as the main catalyst and the Ru / SiO ₂ catalyst of Comparative Example 2 using only ruthenium as the promoter, CO ₂ And the conversion of CH ₄ is shown to 24 to 25%, 12 to 13%, respectively, each catalyst shows a degree of conversion, but the results were significantly lower than the conversion of Examples 1 to 14 combining them. This is because the three-phase tungsten-based catalyst of the present invention exhibits a synergistic effect due to the bonding between the active metals by containing a specific component in an appropriate composition ratio. In the Ru-Ni-Zr / SiO ₂ catalyst of Comparative Example 3 in which tungsten was replaced with nickel, the average conversion rates of CO ₂ and CH ₄ were relatively high at 66% and 45%, respectively, up to 20 hours after the start of the reaction. As shown in Fig. 4, a sharp carbon deposition occurred after 20 hours of the reforming reaction, and the conversion rate was drastically reduced.

2 to 3 show the conversion of methane and carbon dioxide over time using the catalysts of Example 5 and Example 7, respectively. Unlike the results of FIG. 4 using a nickel catalyst, since the conversion rate of methane and carbon dioxide was maintained without a sharp decrease from the beginning of the reaction after about 40 hours, it was confirmed that stable activity was maintained for a long time by suppressing carbon deposition on the surface of the catalyst. have. As such, even at low temperatures around 700 ° C., a high carbon dioxide conversion rate of more than 60% is observed, and it is judged that the long-term activity remains stable due to mutual synergies rather than characteristics of each component.

After all, when the tungsten-based catalyst according to the present invention is applied to the carbon dioxide reforming reaction of methane, it is possible to produce a synthesis gas having a high carbon monoxide ratio from carbon dioxide, so that it can be confirmed that it is possible to convert the carbon dioxide into a raw material of high value-added chemical products. there was.

Claims (5)

Tungsten-based catalyst for carbon dioxide reforming of methane represented by Formula 1 below:
[Formula 1]
XWY / Z
In Formula 1, X is at least one selected from platinum, palladium, rhodium, iridium, ruthenium, Y is at least one selected from zirconium and lanthanum, Z is at least one selected from silica and alumina as a carrier, and X is 0.1 to 10 parts by weight, tungsten is 3 to 25 parts by weight, and Y is 1 to 30 parts by weight based on 100 parts by weight.
Preparing a mixture in which at least one carrier selected from silica and alumina is supported with an X component, tungsten and a Y component in accordance with the composition ratio of Chemical Formula 1 below;
Drying the mixture at a temperature of 50-110 ° C. to produce a dry matter; And
200 to the dry matter? Firing at a temperature of 900 ° C .;
Method for producing a tungsten-based catalyst represented by the formula (1) comprising:
[Formula 1]
XWY / Z
In Formula 1, X is at least one selected from platinum, palladium, rhodium, iridium, ruthenium, Y is at least one selected from zirconium and lanthanum, Z is at least one selected from silica and alumina as a carrier, and X is 0.1 to 10 parts by weight, tungsten is 3 to 25 parts by weight, and Y is 1 to 30 parts by weight based on 100 parts by weight.
A method of preparing a synthesis gas containing carbon monoxide and hydrogen by reacting a mixed gas having a volume ratio of 1: 0.5 to 2.0 under a tungsten catalyst of claim 1.
According to claim 3, wherein the reaction is a synthesis gas containing carbon monoxide and hydrogen, characterized in that carried out at a reaction temperature of 650 ~ 850 ℃, reaction pressure 0.01 ~ 1 MPa and space velocity 500 ~ 100,000 mL / g _cat ㆍ hr How to make.
The method of claim 3, wherein the reaction is performed in a fixed bed, fluidized bed, or slurry reactor.

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