KR100224472B1 - Iron-catalyst for preparing hydrocarbon - Google Patents

Abstract

The present invention relates to a method for producing a hydrocarbon using an iron hybrid catalyst, and more particularly, iron (Fe) as a main catalyst, zinc (Zn), vanadium (V), chromium (Cr) and An iron hybrid catalyst, in which at least one selected from manganese (Mn) is co-precipitated at a specific composition ratio, is used as a catalyst in a hydrocarbon production process by hydrogenation of carbon dioxide to improve the conversion of carbon dioxide and selectivity of C ₂₊ hydrocarbons. It relates to a method for producing a hydrocarbon using an iron hybrid catalyst.

Description

Method for producing hydrocarbon using iron hybrid catalyst

The present invention relates to a method for producing a hydrocarbon using an iron hybrid catalyst, and more particularly, iron (Fe) as a main catalyst, zinc (Zn), vanadium (V), chromium (Cr) and An iron hybrid catalyst, in which at least one selected from manganese (Mn) is co-precipitated at a specific composition ratio, is used as a catalyst in a hydrocarbon production process by hydrogenation of carbon dioxide to improve the conversion of carbon dioxide and selectivity of C ₂₊ hydrocarbons. It relates to a method for producing a hydrocarbon using an iron hybrid catalyst.

Recently, due to the rapid industrialization, interest in preserving the global environment is gradually increasing, and in particular, global warming is the most macroscopic phenomenon and a problem that has a great influence on human survival. This causes global warming due to the release of warming gases such as carbon dioxide and accumulation in the atmosphere, causing changes in ecosystems, damage to industrial activities such as agriculture, and subsidence of the ground due to rising sea levels. It is expected to cause the most serious problems of environmental destruction.

There is an urgent need to prevent the increase of carbon dioxide concentration (about 55%) that affects global warming among the warming gases released into the atmosphere. Due to such necessity, there is an active movement to regulate the amount of carbon dioxide generated while reducing the use of fossil fuels internationally. As a result, in 1990, the level of carbon dioxide emitted from Rio de Janeiro, Brazil, in 2000 was set at 1990 level. Came to regulate. However, due to the industrial structure of 73% of the energy sources that depend on fossil fuels such as petroleum and coal, it is impossible to completely block carbon dioxide emission in a short time. Since it is reused, technical development related to this is urgent.

Currently, various researches are being conducted on the recycling method of carbon dioxide. Among them, chemical immobilization by hydrogenation of carbon dioxide provides fuel and resources at the same time, so it does not change the existing industrial system significantly and maintains convenience when using fossil fuel. There is an advantage. The fields most studied as chemical immobilization by hydrogenation of carbon dioxide include methanol synthesis 1 and synthesis of hydrocarbons by hydrogenation.

The synthesis of the methanol has been actively studied and has made considerable progress and has reached the stage of practical use. However, due to the thermodynamic limitations of the synthesis, it is difficult to increase the conversion to methanol and also has a limit on the utility value as a fuel.

On the other hand, the synthesis of hydrocarbons is not only significantly less thermodynamically limited than methanol, but also has great significance in that it can be replaced by current energy sources and raw materials of the petrochemical industry. Hydrocarbon synthesis can be divided into two main methods.

The first method is a two-step synthesis method of synthesizing methanol by converting carbon dioxide and synthesizing a hydrocarbon compound through a continuous reaction of the produced methanol. [Japanese Patent Laid-Open No. 11-190,638, Japanese Patent Laid-Open No. 4-120,191 The second method is to directly synthesize hydrocarbons by reacting carbon dioxide with hydrogen.

G, A, Somorjai, J Catal, 52, 291, 1978; C. H. Bartholomew., J Catal, 52, 291, 1978; M. D. Lee, Bull. Chem. Soc. Jpn., 62, 2756, 1989].

In the results of the above study, when the hydrocarbon having 2 or more carbon atoms (C ₂₊ hydrocarbon) was produced from carbon dioxide by the second method, the conversion was lower than 25%, and the yield of total hydrocarbons was lower than 25% due to the production of carbon monoxide. In addition, the production of methane (CH ₄ ) is also very low, yielding a C ₂₊ hydrocarbon yield of 20% or less, which is problematic for industrial use.

The inventors of the present invention have tried to solve the above problems in the conventional method for producing a hydrocarbon by hydrogenation of carbon dioxide, and as a result, do not use the carrier at all, but only iron as a main component, zinc, vanadium, chromium and An iron hybrid catalyst composed by coprecipitation of at least one selected from manganese was prepared, and the present invention was completed by reacting hydrogen and carbon dioxide gas on an iron hybrid catalyst.

Accordingly, the present invention provides a method for producing a high value-added hydrocarbon with high yield by hydrogenating carbon dioxide on a catalyst as a means for efficiently utilizing carbon dioxide, which is a major hazard of the global environment, as a chemical industry or an energy source. have.

The present invention features iron as a main catalyst without a separate carrier, and an iron hybrid catalyst for preparing a hydrocarbon in which at least one selected from zinc, vanadium, chromium and manganese is co-precipitated as a promoter.

In addition, the present invention is a method for producing a hydrocarbon by hydrogenation of carbon dioxide, carbon dioxide and hydrogen in the iron hybrid catalyst under the reaction temperature of 100 ~ 500 ℃ and reaction pressure of 1 ~ 100 atm: 1: 1.0 ~ Another feature is a method for producing a hydrocarbon which carries out hydrogenation of carbon dioxide by introducing a mixed gas mixed at a volume ratio of 5.0 to 2000 ml / g-catalyst at a space velocity of time.

Referring to the present invention in more detail as follows.

The present invention provides a new hybrid hybrid catalyst for producing a hydrocarbon, in which at least one selected from the cocatalyst iron, zinc, vanadium, chromium and manganese has a constant content ratio, and carbon dioxide and hydrogen are reacted on the catalyst. It relates to a process for producing high value-added C ₂₊ hydrocarbons.

The iron hybrid catalyst according to the present invention is co-precipitated with zinc (Zn), vanadium (V), chromium (Cr), and manganese (Mn) as cocatalysts to iron (Fe) as a main catalyst, and the preparation method thereof is described in detail. The explanation is as follows.

An iron-catalyst oxide was titrated at 1-100 mL / hr until the pH was in the range of 6.0-8.5 using a basic solution such as ammonia water, using a mixed solution containing an aqueous solution of an iron-containing salt and an aqueous solution of a promoter including zinc. To form. And it dried at 80-200 degreeC for 12 to 48 hours, and bakes at 400-700 degreeC.

At this time, the salt containing the iron or salt of the promoter metal including zinc is selected from chloride, nitrate, sulfide, acetate and oxal oxide. Maintaining the aqueous solution of the salts in 0.5 ~ 1.0M concentration is advantageous in terms of adjusting the pH.

In addition, when the pH is out of the above range in the titration of the mixed solution, the particle size is increased due to the electric duplexing effect, so that the surface area of the catalyst is reduced and the catalytic reactivity is poor.

Iron (Fe) contained as the main catalyst metal is contained 10 to 90% by weight in the total catalyst, preferably 50 to 90% by weight in the total catalyst, and the promoter metal including zinc is 1: 0.1 to 10 won based on iron. It is coprecipitated, preferably it is coprecipitated in the ratio of 1: 0.1-1.0. According to the present invention, when the cocatalyst metal is coprecipitated with iron at less than 0.1 atomic ratio, the basicity of the catalyst is not sufficiently increased, which is not suitable for the activity of acidic carbon dioxide, and when it is coprecipitated in excess of 10 atomic ratio. The total content of iron as an active ingredient is reduced so much that the activity of the catalyst is lost.

The obtained iron hybrid catalyst material must be subjected to an appropriate pre-treatment treatment to obtain a catalyst effective for the present invention. The pretreatment consists of reduction and activation of the catalyst.

First, the reduction process of the catalyst consists of flowing hydrogen at 1000 to 2000 ml / g-catalyst and hourly flow rate for 12 to 16 hours at a temperature of 1 to 20 atm and 250 to 600 ° C. The complex oxide consisting of iron oxide and zinc oxide, vanadium oxide, chromium oxide or manganese oxide is converted into a mixture of metal states.

In addition, in order to show high activity of the catalyst in the conversion reaction of carbon dioxide to hydrocarbon, the catalyst is activated. The activation process is a mixture of 1 to 20 volumes of hydrogen / carbon dioxide at a temperature of 10 to 50 atmospheres and a temperature of 200 to 500 ° C. After flowing the gas through the catalyst for 1 to 2 hours at 1000 to 2000 ml / g-catalyst and hour flow rate, 600 to 1800 ml of inert gas such as nitrogen, argon and helium at 1 to 20 atm and 100 to 500 ° C. / g-catalyst, activating reaction by flowing for 1 to 2 hours while flowing to the catalyst at a flow rate of time.

The catalyst, which has undergone such reduction butt activation, is present in the carbonized state of the mixed metal to effectively activate the carbon dioxide.

In converting a mixed gas of carbon dioxide and hydrogen into a hydrocarbon through a catalytic reaction according to the present invention, a reactor selected from a fixed bed reactor in a gas phase, a fluidized bed reactor, and a reactor in the form of a liquid slurry may be used. In the reaction conditions, the mixing ratio of carbon dioxide and hydrogen as a raw material gas is suitably in the range of 1: 1.0 to 5.0 by volume, reaction temperature of 100 to 500 ° C, reaction pressure of 1 to 100 atmospheres, and 1000 to 2000 ml / g-catalyst. It is preferable that the hydrogenation reaction of carbon dioxide proceeds in the space velocity range of time.

At this time, when the volume ratio of the mixed gas is out of the above range, high conversion cannot be expected. When the reaction temperature is less than 100 ° C., the reaction rate is insufficient, and the conversion rate is low. When the reaction temperature exceeds 500 ° C., the formation of small molecules is advantageous. As a large amount of methane is produced, the selectivity of C ₂₊ decreases. In addition, when the reaction pressure is less than 1 atm, the reaction rate is too slow and a large amount of by-product methane is produced. At pressures exceeding 100 atm, problems in the reaction operation may occur.

In the general method for producing hydrocarbons by catalytic reduction reaction of hydrogen with carbon dioxide, conventionally, an iron catalyst supported on iron (Fe) as a catalyst was used. However, in the present invention, iron and iron are used without using a specific carrier. An iron hybrid catalyst co-precipitated with a promoter metal is used. That is, a mixed metal such as iron oxide-zinc oxide (Fe ₂ O ₃ -ZnO) is used as a catalyst to form a mixed metal through a reduction process of a catalyst by hydrogen, and then a catalyst is activated through a mixed gas of carbon dioxide and hydrogen. Make a carbonized mixed metal. Thereafter, a hydrocarbon was prepared by catalytic reduction of carbon dioxide with hydrogen under the above reaction conditions, which shows improved conversion and high C ₂₊ hydrocarbon selectivity compared to the conventional method.

Accordingly, the present invention features a catalytic process for producing hydrocarbons with high conversion and C ₂₊ selectivity for hydrogenation of carbon dioxide and is particularly useful in the field of using hydrocarbons as energy or preparing compounds therefrom.

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

Example 1

Fe (NO ₃ ) ₃ · 9H ₂ O and Zn (NO ₃ ) ₂ · 6H ₂ O were mixed with 3.6g and 0.3g respectively to make a catalyst system having an atomic ratio of 9: 1 by Fe: Zn. The solution was brought to 100 ml. The pH was maintained below 1.0. While maintaining the resulting aqueous solution at 50-60 ° C. with stirring, 0.3 M ammonia water was titrated at a rate of 100 ml / hr until the pH of the whole solution reached 6.0-8.5. After stirring the precipitated solution for another 1 hour, filtration and washing with tertiary distilled water were repeated several times. After drying at 120 ° C. for 24 hours, calcining was carried out at 450 ° C. for 12 hours in an air atmosphere to prepare a catalyst.

2 to implementation

Fe (NO ₃ ) ₃ · 9H ₂ O and Zn (NO ₃ ) ₂ · 6H ₂ O were mixed with 2.9g and 0.9g respectively to make a catalyst system having an Fe: Zn of 7: 3 by an atomic ratio. The solution was adjusted to 100 ml. The pH was maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

Example 3

Fe (NO ₃ ) ₃ · 9H ₂ O and Zn (NO ₃ ) ₂ · 6H ₂ O were mixed 2.0g and 1.5g, respectively, in order to make a catalyst system having an atomic ratio of 5: 5 by Fe: Zn. The solution was adjusted to 100 ml. The pH was maintained below 1.0.

Since the catalyst manufacturing method was carried out in the same manner as in Example 1.

Example 4

Fe (NO ₃ ) ₃ · 9H ₂ O and Zn (NO ₃ ) ₂ · 6H ₂ O were mixed 1.2g and 2.1g, respectively, in order to make a catalyst system having an atomic ratio of Fe: Zn 3: 7. The solution was adjusted to 100 ml. The pH was maintained below 1.0.

Since the catalyst manufacturing method was carried out in the same manner as in Example 1.

Example 5

0.4g and 2.7g of Fe (NO ₃ ) ₃ · 9H ₂ O and Zn (NO ₃ ) ₂ · 6H ₂ O were mixed in water to make a catalyst system with Fe: Zn 1: 9 by atomic ratio. The solution was adjusted to 100 ml, with the pH maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

6 to implementation

To make a catalyst system with Fe: V of 9: 1 by atomic ratio, 0.12 g of V ₂ O ₅ powder and 5.4 g of oxalic acid were completely dissolved in 60 ml of water at 80 ° C. to prepare an aqueous solution, followed by 5 g of Fe (NO ₃ ) ₃ · 9H. ₂ O was added and the total solution was adjusted to 100 ml. The pH was maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

Example 7

Fe (NO ₃ ) ₃ · 9H ₂ O and Cr (NO ₃ ) ₃ · 6H ₂ O were mixed with 3.6g and 0.4g respectively to make a catalyst system with Fe: Cr 9: 1 in atomic ratio and completely dissolved in water. The solution was adjusted to 100 ml. The pH was maintained below 1.0. After the catalyst production method was carried out in the same manner as in Example 1.

Example 8

Fe (NO ₃ ) ₃ · 9H ₂ O and Mn (NO ₃ ) ₂ · 6H ₂ O were mixed in 3.6g and 0.28g, respectively, to make a catalyst system having an atomic ratio of 9: 1 by Fe: Mn. The solution was adjusted to 100 ml. The pH was maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

Comparative Example 1

4.0 g of Fe (NO ₃ ) ₃ · 9H ₂ O was taken to make an iron catalyst containing no zinc, and completely dissolved in water. The total solution was adjusted to 100 ml. The pH was maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

Comparative Example 2

In order to make the iron-free zinc catalyst, 9 g of Zn (NO ₃ ) ₂ .6H ₂ O was taken and completely dissolved in water, and the total solution was adjusted to 100 ml. The pH was maintained below 1.0.

After the catalyst production method was carried out in the same manner as in Example 1.

Experimental Example

0.5 g of the catalysts prepared in Examples 1 to 8 and Comparative Examples 1 to 2 were collected and reduced in a fixed bed reactor for 16 hours under a hydrogen stream of 45 ° C. and 2000 ml / g-catalyst. Subsequently, a mixed gas (volume ratio of hydrogen / carbon dioxide = 3) was flowed into the catalyst for 1 hour at a flow rate of 2000 ml / g-catalyst and an hour at 10 atm and 300 ° C, and then 1800 ml of nitrogen gas at 10 atm and 300 ° C. Activated by flowing the catalyst for 1 hour at a flow rate of / g-catalyst. The hydrogenation reaction was then carried out by contacting the catalyst with a mixture of carbon dioxide and hydrogen (volume ratio of H ₂ / CO ₂ = 3) at D atmospheric pressure and 300 ° C. at a flow rate of 1800 mL / g-catalyst.

After 12 hours of contact, the same concentration of product was obtained and the reaction proceeded for 48 hours. The results obtained at this time are shown in Table 1 below.

TABLE 1

As described in Table 1, it can be seen that the Fe-Zn catalysts prepared in Examples 1 to 5 according to the present invention are particularly excellent in activity. In the case of Fe-Zn catalysts, the addition of zinc to iron increases the basicity of the catalyst, thereby increasing the tendency for carbon dioxide to adsorb on the catalyst surface and facilitating activation. The same phenomenon is also observed in Examples 6 to 9 each containing vanadium, chromium and manganese as promoters together with iron. In addition, unsaturated hydrocarbons (olefins) produced during the reaction can be resorbed on the catalyst surface to delay the conversion to saturated hydrocarbons, resulting in olefins with high added value up to 60% or higher, The conversion rate of carbon dioxide is increased by 10% or more than the catalyst of the comparative example used alone. On the other hand, Comparative Example 1 using the iron monocatalyst and Comparative Example 2 using the zinc monocatalyst showed low reactivity and yield.

The iron hybrid catalyst for hydrocarbon production according to the present invention has zinc, vanadium, chromium, and manganese mixed with iron to increase the basicity of the catalyst surface, thereby facilitating the adsorption of carbon dioxide and delaying the adsorption of olefins and thus the activity of the catalyst and This increases the selectivity.

Claims (6)

In the method for producing a hydrocarbon by hydrogenation of carbon dioxide, iron is used as a main catalyst without a separate carrier, wherein an iron hybrid catalyst phase in which at least one selected from zinc, vanadium, chromium and manganese is co-precipitated Under a reaction temperature of 100 to 500 ° C and a reaction pressure of 1 to 100 atm, a mixture gas containing carbon dioxide and hydrogen in a volume ratio of 1.0 to 5.0 is introduced at a space velocity of 1000 to 2000 ml / g-catalyst and time. A method for producing a hydrocarbon, characterized in that to carry out hydrogenation of carbon dioxide. The method of claim 1, wherein the hydrogenation is performed in a slurry slurry, a gaseous fixed bed reactor, or a fluidized bed reactor. The method of claim 1, wherein the iron (Fe) in the iron hybrid catalyst is contained 10 to 90% by weight based on the total catalyst. The method of claim 1, wherein zinc, vanadium, chromium, and manganese are co-precipitated with an iron ratio of 1: 0.1 to 10 with respect to iron (Fe) in the iron hybrid catalyst. The hydrocarbon mixture of claim 1, wherein the iron hybrid catalyst is reduced by flowing hydrogen for 12 to 16 hours at a flow rate of 1000 to 2000 ml / g-catalyst at 1 to 20 atm and 250 to 600 ° C. Manufacturing method. The method of claim 1, wherein the iron hybrid catalyst is a mixed gas having a mixing ratio of hydrogen / carbon dioxide of 1 to 20 volumes at 10 to 50 atm and a temperature of 200 to 500 ℃ 1 to 1000 ~ 2000 mL / g-catalyst, time flow rate After passing for 2 hours, the method of producing a hydrocarbon, characterized in that activated by injecting an inert gas for 1 to 2 hours at a flow rate of 600 ~ 1800 ml / g-catalyst, at a temperature of 1 to 20 atm and 100 ~ 500 ℃.