KR100912725B1 - New catalysts for methane reforming with carbon dioxide to syngas, preparation method thereof and preparation method of syngas using there catalysts and carbon dioxide - Google Patents

Abstract

The present invention relates to a catalyst for syngas production from natural gas using carbon dioxide, a method for preparing the same, and a method for producing syngas from natural gas using the catalyst and carbon dioxide. More particularly, tungsten is used as a catalyst for syngas production from natural gas using carbon dioxide. A catalyst in which a nickel (Ni) metal is supported on a carrier of a carbide (WC), a method for preparing the same, and a method for preparing a synthesis gas from natural gas using the catalyst and carbon dioxide.

Tungsten carbide, nickel, carbon dioxide, methane, syngas

Description

New catalysts for methane reforming with carbon dioxide to syngas, preparation method about and preparation method of syngas using there catalysts and carbon dioxide}

The present invention relates to a catalyst for syngas production from natural gas using carbon dioxide, a method for preparing the same, and a method for producing syngas from natural gas using the catalyst and carbon dioxide. More particularly, tungsten is used as a catalyst for syngas production from natural gas using carbon dioxide. A catalyst in which a nickel (Ni) metal is supported on a carrier of a carbide (WC), a method for preparing the same, and a method for preparing a synthesis gas from natural gas using the catalyst and carbon dioxide.

Methane is a compound consisting of CH ₄ with a molecular formula, which is the simplest alkane compound and the main component of natural gas. The bonding angle of methane is 109.5 degrees. When one methane is burned by oxygen, one carbon dioxide (CO ₂ ) molecule and two water molecules (H ₂ O) are produced.

Methane attracts attention as a fuel because it is relatively rich in alkanes. However, under standard conditions, methane is only in the gaseous state, which makes the process of transporting methane very difficult. In addition, the cost of the transportation process and maintenance costs are not so economically effective. In terms of environmental aspects, although carbon dioxide in the atmosphere is 220 times higher than methane, and methane has a lower impact on global warming than carbon dioxide, methane reduction technology is urgent as the greenhouse effect of methane is 25 times higher than that of carbon dioxide. . In response, research to convert methane into syngas has been activated.

Synthesis gas refers to a mixed gas of hydrogen (H ₂ ) and carbon monoxide (CO). Looking at the production process of this synthesis gas, hydrogen and carbon monoxide are generated by reforming a liquid hydrocarbon compound or natural gas through an oxidant. Biomass, such as coal or wood chips, are produced through a gasification process. The produced syngas is mainly used for synthesizing compounds such as ammonia and methanol. Recently, the synthesis gas is used in the synthesis of Fischer-Tropsch or in the manufacturing process of next-generation synthetic fuel such as DME (Di-Methyl-Ether). It is growing in importance as an intermediate raw material gas, and one of the high value-added processes is also counted.

The process of producing syngas from natural gas is distinguished by the type of oxidant that oxidizes methane. An example of a process for generating a synthesis gas from natural gas according to the type of oxidant for oxidizing methane includes a catalytic partial oxidation reaction using oxygen as a methane oxidant, steam reforming using water as an oxidant, and carbon dioxide reforming using carbon dioxide. In the case of the carbon dioxide reforming method, the synthesis gas is generated through the reaction between carbon dioxide and methane, which is the main culprit of the greenhouse effect, thereby greatly contributing to the carbon dioxide reduction policy and appropriately coping with the carbon dioxide emission regulation law that may hinder the speed of industrial development. It is known as one of the reforming process methods that can be greatly economically and environmentally beneficial. Syngas produced from methane reforming using carbon dioxide is generally used for the production of compounds such as oxoalcohol, polycarbonate, acetic acid, and the like.

In the reforming method of carbon dioxide, methane is reformed from methane oxidant, carbon dioxide, and the carbonization process of activated carbon produced by methane and carbon monoxide produced by dissociation of carbon dioxide is more effective at coke than other reforming processes. The production rate is very fast, and the catalyst life is shortened, which makes it difficult to use. Therefore, in order to reduce the coke formation selectivity for the practical use of the methane reforming process from carbon dioxide, a carrier with enhanced basicity is used, or an alkali metal, an evaporation accelerator which vaporizes the coke formed on the surface of the carrier having a large surface area, is added. Research is ongoing.

Looking at the prior art related to the production of syngas, US Pat. No. 6,312,669 describes a catalyst containing alkali metal in the support for coke to have an electronegativity of 13 or less as a support for precious metals when preparing synthesis gas from hydrocarbons and carbon dioxide. It is disclosed that the durability is excellent.

In addition, it has been reported that the catalyst having a nickel metal supported on the support surface composed of cerium-zirconium oxide has excellent durability against coke generated during the methane steam reforming reaction due to the effect of changing the oxidation number of cerium oxide and zirconia having low acid strength. (N. Laositipojana, S. Assabumrungrat, Appled Catalysis General: A (2005) 200).

In addition, the coke deposition rate can be reduced due to the intermediate reaction between the heat-resistant lanthanum oxide (La ₂ O ₃ ) carrier and carbon dioxide (CO ₂ ). It has been reported that the syngas production process is effective and high in activity for a long time (Xenophon E. Verykios, International Journal of Hydrogen Energy 28 (2003) 1045).

The prior art has a problem in that it is difficult to commercialize because the catalyst production method including expensive precious metals and / or metal oxides is complicated and disadvantages in price competition.

The present invention is to provide a catalyst and a method for preparing the catalyst that can be used when producing a synthesis gas from natural gas.

The present invention provides a catalyst in which tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material in the production of syngas from natural gas.

The present invention is to provide a method for preparing a catalyst in which a tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material in preparing a synthesis gas from natural gas.

According to the present invention, in preparing a synthesis gas from natural gas, natural gas including methane (CH ₄ ) gas is used as a reaction gas, and the reaction gas and carbon dioxide are used as a tungsten carbide carrier, and nickel is used as an active material. The present invention provides a method for producing a synthesis gas from natural gas by using a catalyst supported on the catalyst or tungsten carbide prepared by the above-mentioned manufacturing method as a carrier, and reacting nickel as an active material in the presence of a catalyst supported on the carrier. .

According to the present invention, a catalyst having nickel metal supported on a relatively inexpensive tungsten carbide carrier is used. Thus, when a synthesis gas production process is performed from methane reforming using carbon dioxide, a relatively low temperature is achieved through the combined effect of tungsten carbide and nickel metal. Phosphorus activity is high around 700 ℃ and 750 ℃, and the activity of the catalyst is increased by reducing the carbon deposited on the catalyst by the activated carbon produced, and the content of carbon deposited on the catalyst is lowered. Long time operation is possible.

The present invention represents a catalyst that can be used when producing syngas from natural gas.

The present invention represents a catalyst that can be used in the production of syngas from natural gas containing methane (CH ₄ ) gas.

The present invention can be used in the production of syngas from natural gas, and represents a catalyst in which tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material.

The present invention can be used in the production of syngas from natural gas containing methane (CH ₄ ) gas, and represents a catalyst in which tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material.

The catalyst of the present invention can be used as an active material that can increase the activation of methane contained in natural gas.

The catalyst of the present invention can increase the activation of methane contained in natural gas using nickel metal (Ni metal) as the active material.

Hydrocarbon compounds such as CH ₃ , CH ₂ , CH and carbon are generated in the process of adsorbing and dissociating methane gas to the nickel metal supported on the carrier in the catalyst of the present invention, and generated by dissociation of methane gas. Hydrocarbon compounds react with carbon dioxide, an oxidant, to produce syngas.

Nickel metal used as the catalytically active material of the present invention is known as a catalyst having a high rate of generation of hydrocarbon compounds activated from methane, but carbon deposited on the surface of the catalyst, particularly the surface of nickel, is the catalyst active material. Very high rate has the disadvantage of lowering the activity of the catalyst. However, due to the exchange of active oxygenation generated by decomposition of carbon of tungsten carbide (WC), which is a carrier of the catalyst, and carbon dioxide, which is an oxidant, carbon deposited on the surface of nickel can be removed, and thus the activity of the catalyst can be maintained for a long time. That is, the catalyst of the present invention can remove carbon deposited on the surface of nickel as an active material due to the exchange action of carbon and active oxygen of tungsten carbide as a carrier, wherein the removal of carbon deposited on the surface of nickel is represented by the following reaction formula ( 1) to the same as Scheme (5).

Ni + CH ₄ → Ni-CH ₃ , Ni-CH ₂ , Ni-CH or Ni-C ... Scheme (1)

CO ₂ → CO + O * ... Scheme (2)

WC + O * ↔ WO + C * ... Scheme (3)

WO + Ni-C ↔ WC + Ni + O * ... Scheme (4)

C * + O * ↔ CO ... Scheme (5)

The catalyst of the present invention may be supported by 0.001 to 30% of nickel as the active material based on the total weight of the catalyst.

In the catalyst of the present invention, nickel may be supported by 0.01 to 20% based on the total weight of the catalyst as an active material.

In the catalyst of the present invention, nickel may be supported as an active material by 0.1 to 15% based on the total weight of the catalyst.

The catalyst of the present invention may use tungsten carbide as a carrier.

In the catalyst of the present invention, tungsten carbide is a carrier, as mentioned above, tungsten oxide is formed by active oxygenation in which carbon of tungsten carbide is separated from carbon dioxide, and the tungsten oxide is tungsten by exchange with carbon deposited in nickel. The oxide is reduced to tungsten carbide, and carbon deposited on the surface of nickel, the active material of the catalyst, can be removed.

The present invention shows a method for producing a catalyst that can be used when producing syngas from natural gas.

The present invention shows a method for producing a catalyst that can be used in the production of syngas from natural gas containing methane (CH ₄ ) gas.

The present invention can be used when producing a synthesis gas from natural gas, and shows a method for producing a catalyst in which tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material.

The present invention can be used in the production of syngas from natural gas containing methane (CH ₄ ) gas, and shows a method for producing a catalyst in which tungsten carbide is used as a carrier and nickel is supported on the carrier as an active material.

A method for producing a catalyst in which tungsten carbide of the present invention is used as a carrier and nickel is supported on the carrier as an active material includes supporting, drying, calcining, carbonizing and reducing the nickel precursor in a tungsten compound.

The method for preparing a catalyst in which tungsten carbide of the present invention is used as a carrier and nickel is supported on the carrier as an active material includes (1) supporting a nickel precursor on a tungsten compound, and (2) drying the tungsten compound on which the nickel precursor is supported. (3) calcining the tungsten compound carrying the dried nickel precursor, (4) carbonizing the tungsten compound carrying the baked nickel precursor, and carbonizing the tungsten compound, (5) carrying the carbonized nickel precursor Reducing the nickel precursor of the prepared tungsten compound.

When the nickel precursor is supported on the tungsten compound, the nickel precursor may be any one selected from the group consisting of nickel nitrate and nickel chloride.

When the nickel precursor is supported on the tungsten compound, the nickel precursor, which is one selected from the group of nickel nitrate and nickel chloride, is supported on the tungsten compound by impregnation, and the nickel content supported on the tungsten compound is 0.001 to 30 based on the total weight of the catalyst. %, Preferably it is 0.01-20%, More preferably, it can carry so that it may become 0.1 to 15%.

When the nickel precursor is supported on the tungsten compound, the nickel precursor is any one selected from the group consisting of nickel nitrate and nickel chloride, and has a nickel precursor having a concentration of 0.01M to 10M, preferably 0.1M to 5M, more preferably 0.5M to 3M. Supported by the tungsten compound by impregnation, the nickel content supported on the tungsten compound may be supported to 0.001 to 30%, preferably 0.01 to 20%, more preferably 0.1 to 15% based on the total weight of the catalyst. . In this case, when the nickel precursor is provided in the form of an aqueous solution, the nickel precursor may be supported on the tungsten compound by adding a tungsten compound to the aqueous nickel precursor solution and evaporating water through an evaporator.

When the nickel precursor is supported on the tungsten compound, the tungsten compound may be any one selected from the group consisting of tungsten carbide (WC), tungsten oxide (WO ₂ ), and tungsten oxide (WO ₃ ).

The tungsten oxide (WO ₂ ), tungsten oxide (WO ₃ ) may be tungsten carbide by the carbonization process of the catalyst to be described later.

When drying the tungsten compound carrying the nickel precursor in the drying may be carried out at 50 to 120 ℃ 5 to 50 hours, preferably 10 to 40 hours, more preferably 15 to 30 hours.

When drying the tungsten compound carrying the nickel precursor in the drying may be carried out at 80 to 100 ℃ 5 to 50 hours, preferably 10 to 40 hours, more preferably 15 to 30 hours.

When the tungsten compound on which the dried nickel precursor is supported is calcined, the nickel precursor becomes nickel oxide and the tungsten compound becomes tungsten oxide (WO ₂ or WO ₃ ).

Firing of the tungsten compound on which the dried nickel precursor is carried is calcined at 200 to 750 ° C, preferably 300 to 700 ° C, more preferably 400 to 600 ° C for 30 minutes to 10 hours, preferably 1 to 8 hours. More preferably 10 to 10,000 cc / min g, preferably 20 to 1,000 cc / min g, and more preferably 50 to 100 cc / min g, for 2 to 5 hours. have.

As mentioned above, in the calcined catalyst, the nickel precursor becomes nickel oxide and the tungsten compound becomes tungsten oxide (WO ₂ or WO ₃ ), so that the carbonization process is performed to form tungsten oxide, which is the carrier of the catalyst, in the form of tungsten carbide. After the carbonization process, a reduction process is performed to reduce the nickel oxide to nickel metal.

The carbonization of the tungsten compound carrying the calcined nickel precursor to carbonization of the tungsten compound as a carrier with tungsten carbide results in carbonization of 600 to 950 ° C, preferably 650 to 900 ° C, more preferably 700 to 850 ° C for 30 minutes. Carbonization reaction gas space velocity of 10 to 100,000 cc / min g, preferably 20 to 10,000 cc / min g, more preferably 20 to 20 hours, preferably 2 to 15 hours, more preferably 5 to 10 hours Can be performed in an atmosphere of 50 to 1,000 cc / min g.

The carbonization reaction gas may be any one selected from hydrocarbon gas and carbon monoxide having 1 to 10 carbon atoms.

The carbonization reaction gas may be a gas selected from methane, ethane, propane, and carbon monoxide.

The carbonization reaction gas may be a gas selected from methane, propane, and carbon monoxide.

The carbonization reaction gas may use carbon monoxide.

The tungsten compound on which the nickel precursor is supported may be carbonized to carbonize the tungsten compound as a carrier with tungsten carbide and then reduce nickel oxide to nickel metal.

The reduction in the above is for 10 minutes to 4 hours, preferably 30 to 3 hours, more preferably 50 minutes to 2 hours at 100 to 900 ° C, preferably 200 to 800 ° C, more preferably 300 to 700 ° C. It can be performed in an atmosphere of hydrogen or a reaction gas space velocity of 10 to 100,000 cc / min g.

As the reaction gas containing hydrogen in the reduction step, a reaction gas consisting of 5 mol% to 99 mol% of hydrogen and 1 mol% to 95 mol% of inert gas may be used. At this time, the inert gas may be any one selected from nitrogen (N), helium (He), neon (Ne), argon (Ar).

The present invention includes a method for producing syngas from natural gas.

In the method for producing syngas from natural gas of the present invention, in the synthesis gas from natural gas, natural gas including methane (CH ₄ ) gas as a reaction gas, the reaction gas and carbon dioxide mentioned above It includes tungsten carbide as a carrier, and reacting nickel as an active material in the presence of a catalyst supported on the carrier.

Method for producing a synthesis gas from natural gas of the present invention, in the production of synthesis gas from natural gas, using natural gas containing methane (CH ₄ ) as a reaction gas, the reaction gas and carbon dioxide prepared above It includes tungsten carbide as a carrier, and reacting nickel as an active material in the presence of a catalyst supported on the carrier.

When preparing the synthesis gas from the natural gas, the natural gas can be used that the content of methane gas contained in the natural gas is 10 mol% to 50 mol%.

When preparing the synthesis gas from the natural gas, natural gas may use methane gas.

When preparing a synthesis gas from the natural gas, carbon dioxide may be reacted by supplying a carbon dioxide ratio (CO ₂ / CH ₄ ) to methane in the reaction gas to be 0.1 to 20.

When preparing the synthesis gas from the natural gas, carbon dioxide may be reacted by supplying the carbon dioxide ratio (CO ₂ / CH ₄ ) to methane in the reaction gas to be 0.2 to 10.

When preparing the synthesis gas from the natural gas, carbon dioxide may be reacted by supplying the carbon dioxide ratio (CO ₂ / CH ₄ ) to methane in the reaction gas to be 0.5 to 8.

When preparing the synthesis gas from the natural gas, the reaction gas and carbon dioxide can be reacted by supplying at a space velocity of 100 to 100,000 cc / hr g.

When preparing a synthesis gas from the natural gas, the reaction gas and carbon dioxide can be reacted by supplying a space velocity of 200 ~ 80,000cc / hr g.

When preparing the synthesis gas from the natural gas, the reaction gas and carbon dioxide can be reacted by supplying at a space velocity of 500 to 50,000 cc / hr g.

A catalyst in which tungsten carbide of the present invention is used as a carrier and nickel is supported on the carrier as an active material, a method for preparing the same, and a catalyst in which nickel is supported on the carrier as the carrier, and a method for producing the catalyst The method for preparing syngas from natural gas using a tungsten carbide prepared by the carrier as a carrier and nickel supported on the carrier as an active material was investigated. The present invention relates to the above-mentioned components, temperature, It is preferable to produce a synthesis gas from a catalyst, a method for preparing the same, and natural gas by various conditions such as time.

Hereinafter, the content of the present invention will be described in detail through examples and test examples. However, these are intended to explain the present invention in more detail, and the scope of the present invention is not limited thereto.

Example 1 Preparation of Tungsten Carbide Catalyst Supported with Nickel Metal (1)

Tungsten carbide was added to 0.6 M nickel nitrate aqueous solution, impregnated with impregnation so that tungsten carbide as a carrier was loaded with 10% nickel relative to the total weight of the catalyst, and water was evaporated through a rotary evaporator to tungsten carbide. Nickel nitrate was supported on the substrate.

The nickel nitrate supported on tungsten carbide was dried at 100 ° C. for 24 hours.

After drying, the nickel nitrate was supported on tungsten carbide and calcined at 650 ° C. for 3 hours at an air space velocity (GHSV) of 100 cc / min g to change the nickel nitrate to nickel oxide.

After the firing, the nickel oxide supported on the tungsten carbide was set to a carbon monoxide space velocity (GHSV) of 200 cc / min g and carbonized at 800 ° C. for 2 hours to produce tungsten oxide (WO ₂ or WO ₃₎ formed on the tungsten carbide after the firing process. ) Was carbonized to tungsten carbide (WC).

After the carbonization, the nickel oxide is supported on tungsten carbide by reducing nickel oxide in a gas atmosphere containing hydrogen mixed with 10 mol% hydrogen and 90 mol% nitrogen for 40 minutes at 750 ° C. A catalyst supported with phosphorous nickel metal was prepared.

In the catalyst preparation, the carbonization process is completed and the XRD analysis of the catalyst before the reduction process is shown in FIG. 1.

1, it can be seen that the tungsten carbide (WC) and nickel oxide (NiO) peaks, which are catalyst carriers, are clearly visible. In this case, the reason for the presence of Ni oxide instead of nickel (Ni) metal is that nickel oxide itself has a high oxide production rate, and thus, when carbonization is completed during the catalyst manufacturing process, it exists as nickel oxide. When this nickel oxide undergoes a reduction process, it becomes nickel metal. In other words, the nickel oxide is reduced to nickel metal before the reaction, and the reaction is performed immediately after the reduction process. Therefore, the nickel oxide (NiO) is shown in the XRD analysis graph of the catalyst after the carbonization process in the preparation of the catalyst, which means that the nickel metal supported on the tungsten carbide, which is a carrier, is in an oxidized state, so that Ni is properly supported on the WC. I can tell.

Example 2 Preparation of Tungsten Carbide Catalyst Supported with Nickel Metal (2)

Except that the carbonization time during the carbonization for 8 hours was prepared in the same manner as in Example 1 to prepare a catalyst in which the active material nickel metal supported on the tungsten carbide carrier.

Example 3 Synthesis Gas Production (1)

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 1.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 18,000cc / hr g to produce a synthesis gas.

Example 4 Synthesis Gas Production (2)

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 2.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 18,000cc / hr g to produce a synthesis gas.

As shown in Examples 1 and 2, the conversion of methane when syngas was prepared by reacting methane and carbon dioxide in the presence of the catalyst prepared in Examples 1 and 2, respectively, was prepared by varying carbonization time with carbon monoxide. Conversion rates of carbon dioxide are shown in FIG. 3, respectively.

As shown in FIGS. 2 and 3, the activity of the catalyst carbonized for 8 hours (Example 4) is higher than that of the catalyst carbonized for 2 hours (Example 3). It was confirmed that when the carbonization time was 2 hours, the tungsten oxide produced during the calcination process could not be sufficiently converted to tungsten carbide, resulting in low catalytic activity. Therefore, in order to increase the catalytic activity, the carbonization time should be sufficiently progressed.

Example 5 Preparation of Tungsten Carbide Catalyst Supported with Nickel Metal (3)

Tungsten carbide was added to 0.6 M nickel nitrate aqueous solution to impregnate tungsten carbide with 5% nickel by weight based on the total weight of the catalyst by impregnation. Tungsten carbide was evaporated by rotary evaporator. Nickel nitrate was supported on the substrate.

The nickel nitrate supported on tungsten carbide was dried at 100 ° C. for 24 hours.

After drying, the nickel nitrate was supported on tungsten carbide and calcined at 650 ° C. for 3 hours at an air space velocity (GHSV) of 100 cc / min g to change the nickel nitrate to nickel oxide.

After the firing, the nickel oxide supported on tungsten carbide was carbonized at 800 ° C. for 8 hours at a carbon monoxide space velocity (GHSV) of 200 cc / min g.

After the carbonization, the nickel oxide is supported on tungsten carbide, and the nickel oxide is reduced in a gas atmosphere containing hydrogen mixed with 10 mol% hydrogen and 90 mol% nitrogen for 40 minutes at 750 ° C. A nickel metal supported catalyst was prepared.

<Example 6>

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 5.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 18,000cc / hr g to produce a synthesis gas.

<Example 7>

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 700 ° C. for 20 hours in the presence of the catalyst prepared in Example 5.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 18,000cc / hr g to produce a synthesis gas.

<Example 8>

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 5.

In the production of the synthesis gas, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.0, and the synthesis gas was prepared using a space velocity (GHSV) of methane gas and carbon dioxide as 18,000 cc / hr g.

Example 9

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 5.

The synthesis gas was prepared by supplying a ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) to 0.59, and a space velocity (GHSV) of methane gas and carbon dioxide to 18,000 cc / hr g.

<Example 10>

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 20 hours in the presence of the catalyst prepared in Example 5.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 25,000cc / hr g to prepare a synthesis gas.

Comparative Example 1

Alumina was added to a 0.6 M nickel nitrate aqueous solution to impregnate alumina as a carrier with 10% nickel relative to the total weight of the catalyst by impregnation, and water was evaporated through a rotary evaporator to evaporate nickel nitrate to alumina. It was supported.

The nickel nitrate supported on alumina was dried at 100 ° C. for 24 hours.

After drying, the nickel nitrate supported on alumina was calcined at 650 ° C. for 3 hours at an air space velocity (GHSV) of 100 cc / min g to change the nickel nitrate to nickel oxide.

After the calcination, the nickel oxide supported on the alumina was reduced in a gas atmosphere containing hydrogen mixed with 10 mol% hydrogen and 90 mol% nitrogen at 750 ° C. for 40 minutes to support nickel metal as an active material on alumina as a carrier. Catalyst was prepared.

Comparative Example 2

Synthetic gas was prepared by reacting methane gas with carbon dioxide at 750 ° C. for 10 hours in the presence of the catalyst prepared in Comparative Example 1.

In the synthesis gas production, the supply ratio of carbon dioxide to methane gas (CO ₂ / CH ₄ ) was 1.1, the space velocity (GHSV) of methane gas and carbon dioxide was 18,000cc / hr g to produce a synthesis gas.

In Example 6 to Example 10 and Comparative Example 2, when the reaction proceeds for 1 hour, 10 hours, and 20 hours after the synthesis gas is prepared, the reaction conversion rate and the yield of carbon monoxide, the main product, are as follows. Tables 1-6 are shown.

Comparing the activity of the catalyst having the same amount of nickel metal loaded on the tungsten carbide as the catalyst supporting the nickel metal using alumina as the carrier, the initial activity was relatively higher when the alumina carrier was used as shown in Table 1. Although shown in the results of Table 3, it can be seen that the inactivation rate of the catalyst is the highest when using an alumina carrier. The alumina carrier has a feature of transitioning from a temperature of 700 ° C. to a phase having a low surface area and having a higher acid strength than other oxide carriers.

In this experiment, carbon dioxide and activated methane produced in the process of dissociating carbon dioxide due to the high acid strength of alumina are proceeded in the direction that the reaction proceeds for a long time under the temperature condition above 700 ℃ and the surface area of the carrier decreases. The infiltration rate of the coke produced from the process proceeds very fast and it is confirmed that the specific activity is high. When tungsten carbide is used as a carrier, catalytic activity can be maintained for a long time due to the effect that carbon dioxide is dissociated and activated carbon produced in nickel metal is removed without being deposited by the action of exchanging activated oxygen and carbon atoms of tungsten carbide. It was confirmed that the activity of the catalyst was improved by reducing the inactivation rate.

Comparing the case of 5 wt% and 10 wt% of nickel metal in the catalyst using tungsten carbide as a carrier, it can be confirmed that the activity of the catalyst is higher when the nickel amount is low. The surface area of tungsten carbide used in the present invention is relatively low. The reason why the activity of 5% by weight is higher than 10% by weight is that in the case of a catalyst containing a large amount of nickel metal, the surface coverage of tungsten carbide is increased, thereby inhibiting the compounding effect between the aforementioned nickel metal and tungsten carbide. Therefore, by appropriately adjusting the surface area and nickel metal loading of tungsten carbide to activate the composite effect action will affect the catalytic activity.

Comparing the catalytic activity with different reactant feed ratios in Table 1, the highest CO ₂ / CH ₄ value is 1.1 and the lowest is 0.59. Therefore, the feeding of the reactants should be considered as a factor affecting the catalytic activity in the control of the CO2 / CH4 ratio.

As can be seen in Tables 1 to 6, the catalytic activity is somewhat lower when the space velocity is 25,000 cc / hr g than 18,000 cc / hr g. This is because the equilibrium constant of the methane reforming reaction from carbon dioxide is rather low, so that the contact time between the catalyst and the reactant should be sufficient.

Table 1. Conversion of methane and carbon monoxide (reaction time: 1 hour)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CH ₄ % conversion CO ₂ conversion rate (%) H ₂ / CO Example 4 18,000 750 1.1 10 WC 69 68.3 0.74 Example 6 18,000 750 1.1 5 WC 81 81.6 0.68 Example 7 18,000 700 1.1 5 WC 51.3 47.9 0.68 Example 8 18,000 750 One 5 WC 70.4 78.1 0.7 Example 9 18,000 750 0.59 5 WC 51 82 0.78 Example 10 25,000 750 1.1 5 WC 68.5 71.2 0.77 Comparative Example 2 18,000 750 1.1 10 Al ₂ O ₃ 74 78.5 0.77

Table 2. Carbon monoxide yield (reaction time: 1 hour)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CO yield (%) Example 4 18,000 750 1.1 10 WC 71.2 Example 6 18,000 750 1.1 5 WC 82.2 Example 7 18,000 700 1.1 5 WC 83.5 Example 8 18,000 750 One 5 WC 90 Example 9 18,000 750 0.59 5 WC 80.8 Example 10 25,000 750 1.1 5 WC 83.2 Comparative Example 2 18,000 750 1.1 10 Al ₂ O ₃ 56.9

Table 3. Methane and Carbon Dioxide Conversion Rate (Reaction Time: 10 Hours)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CH ₄ % conversion CO ₂ conversion rate (%) H ₂ / CO Example 4 18,000 750 1.1 10 WC 72.5 72.3 0.73 Example 6 18,000 750 1.1 5 WC 77.9 78.6 0.67 Example 7 18,000 700 1.1 5 WC 48.2 44.5 0.71 Example 8 18,000 750 One 5 WC 72.3 80.1 0.7 Example 9 18,000 750 0.59 5 WC 50.2 83.1 0.77 Example 10 25,000 750 1.1 5 WC 68.8 70.3 0.76 Comparative Example 2 18,000 750 1.1 10 Al ₂ O ₃ 38 30 0.82

Table 4. Carbon monoxide yield (reaction time: 10 hours)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CO yield (%) Example 4 18,000 750 1.1 10 WC 70.2 Example 6 18,000 750 1.1 5 WC 84.2 Example 7 18,000 700 1.1 5 WC 81.7 Example 8 18,000 750 One 5 WC 86.2 Example 9 18,000 750 0.59 5 WC 79.2 Example 10 25,000 750 1.1 5 WC 81.2 Comparative Example 2 18,000 750 1.1 10 Al ₂ O ₃ 82.5

Table 5. Methane and Carbon Dioxide Conversion Rate (Reaction Time: 20 hours)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CH ₄ % conversion CO ₂ conversion rate (%) H ₂ / CO Example 4 18,000 750 1.1 10 WC 68.6 67.8 0.73 Example 6 18,000 750 1.1 5 WC 75.3 76.1 0.68 Example 7 18,000 700 1.1 5 WC 51 40.3 0.71 Example 8 18,000 750 One 5 WC 72.5 80 0.7 Example 10 25,000 750 1.1 5 WC 71.9 73.2 0.75

Table 6. Carbon Monoxide Yield (Reaction Time: 20 hours)

GHSV (cc / hr g) Temperature (℃) CO ₂ / CH ₄ Ni (wt%) carrier CO yield (%) Example 4 18,000 750 1.1 10 WC 69.2 Example 6 18,000 750 1.1 5 WC 83.2 Example 7 18,000 700 1.1 5 WC 82.1 Example 8 18,000 750 One 5 WC 87.1 Example 10 25,000 750 1.1 5 WC 74

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

Therefore, the present inventors found that nickel metal is supported on the surface of commercial tungsten carbide to promote methane activation and carbon dioxide is deposited due to the exchange of active oxygen produced during dissociation and carbon dioxide dissociation with carbon of tungsten carbide. Removed during the reaction to improve the catalytic activity for methane reforming using carbon dioxide, it was confirmed through the present invention to increase the life.

1 is a graph showing the XRD analysis of the catalyst before the reduction process after the carbonization process in the catalyst preparation in Example 1.

FIG. 2 shows the conversion of methane when syngas is produced by reacting methane and carbon dioxide in the presence of the catalysts prepared in Examples 1 and 2, and Example 3 is methane when syngas is prepared using the catalyst prepared in Example 1. Example 4 shows the conversion rate of, and Example 4 shows the conversion rate of methane when preparing the synthesis gas using the catalyst prepared in Example 2.

Figure 3 shows the conversion of carbon dioxide in the synthesis gas production by reacting methane and carbon dioxide in the presence of the catalyst prepared in Examples 1 and 2, Example 3 is the carbon dioxide in the synthesis gas production using the catalyst prepared in Example 1 Example 4 shows the conversion rate of, and Example 4 shows the conversion rate of carbon dioxide when syngas was prepared using the catalyst prepared in Example 2.

Claims (21)

delete delete delete delete delete delete (1) supporting a nickel precursor on a tungsten compound, (2) drying the tungsten compound on which the nickel precursor is supported; (3) calcining the tungsten compound carrying the dried nickel precursor; (4) carbonizing a tungsten compound carrying a baked nickel precursor to carbonize the tungsten compound, (5) a method for producing a catalyst comprising reducing a nickel precursor of a tungsten compound carrying a carbonized nickel precursor. The method of claim 7, wherein the nickel precursor is any one selected from the group consisting of nickel nitrate and nickel chloride. 8. The method according to claim 7, wherein the nickel precursor, which is one selected from the group of nickel nitrate and nickel chloride, is supported on the tungsten compound by impregnation, and the nickel content on the tungsten compound is 0.001 to 30% based on the total weight of the catalyst. Method for producing a catalyst. The method of claim 7, wherein any one selected from the group of nickel nitrates and nickel chlorides and the nickel precursor having a concentration of 0.01M to 10M is impregnated on the tungsten compound by impregnation, the nickel content of the tungsten compound is based on the total weight of the catalyst. A method for producing a catalyst, characterized in that 0.001 to 30%. The method of claim 7, wherein the tungsten compound is any one selected from the group consisting of tungsten carbide, tungsten oxide (WO ₂ ) and tungsten oxide (WO ₃ ). The method of claim 7, wherein the drying is performed at 50 to 120 ° C. for 5 to 50 hours. 8. The process according to claim 7, wherein the calcination is carried out at 200 to 750 DEG C for 30 minutes to 10 hours in an air flow atmosphere having an air space velocity of 10 to 10,000 cc / min g. The method for producing a catalyst according to claim 7, wherein the carbonization is carried out at 600 to 950 ° C for 30 minutes to 20 hours in an atmosphere of carbonization reaction gas space velocity of 10 to 100,000 cc / min g. The method for producing a catalyst according to claim 7, wherein the reduction is performed at 100 to 900 ° C. for 10 minutes to 4 hours in an atmosphere having a reaction gas space velocity of 10 to 100,000 cc / min g. 15. The method of claim 14, wherein the carbonization reaction gas is any one selected from methane, ethane, propane, and carbon monoxide. The process for producing a catalyst according to claim 15, wherein the reaction gas containing hydrogen is a reaction gas composed of 5 mol% to 99 mol% of hydrogen and 1 mol% to 95 mol% of inert gas. Inert gas is any one selected from nitrogen, helium, neon, argon. In producing syngas from natural gas, A natural gas containing methane (CH ₄ ) gas is used as a reaction gas, and the reaction gas and carbon dioxide are reacted in the presence of a catalyst prepared by the method of claim 7. Way. 19. The method for producing syngas from natural gas according to claim 18, wherein the content of methane gas contained in natural gas is 10 mol% to 30 mol%. 19. The method of claim 18, wherein the carbon dioxide is reacted by supplying the carbon dioxide ratio (CO ₂ / CH ₄ ) to methane in the reaction gas so as to be 0.1 to 20. The method of claim 18, wherein the reaction gas and carbon dioxide are reacted by supplying at a space velocity of 100 to 100,000 cc / hr g.

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