KR20230040742A - Catalyst for Direct Hydrogenation Reaction of Carbon dioxide - Google Patents

Abstract

The present invention relates to a catalyst for direct hydrogenation of carbon dioxide, and more specifically, to a catalyst for direct hydrogenation of carbon dioxide, which has excellent heat transfer performance and thermomechanical properties, thereby ensuring high selectivity and conversion rate for a desired hydrocarbon. The catalyst for direct hydrogenation of carbon dioxide comprises a core particle made of an alumina ball and an outer particle layer attached while surrounding the surface of the core particle, wherein the outer particle layer is composed of powdered catalyst particles including iron (Fe), copper (Cu), aluminum (Al), and potassium (K).

Description

Catalyst for Direct Hydrogenation Reaction of Carbon dioxide}

The present invention relates to a catalyst for the direct hydrogenation of carbon dioxide, and more particularly, to a catalyst for the direct hydrogenation of carbon dioxide for the direct production of liquid hydrocarbons from carbon dioxide.

Coal and petroleum are fossil energies that account for more than 50% of total energy, and have been used as important energy sources for mankind for the past several centuries. Through various energy conversion processes, mankind can produce thermodynamically stable carbon dioxide without a separate post-processing process. have been ejecting

However, recently, as it is known that carbon dioxide is a major greenhouse gas that accounts for 55% of global warming, various technologies for removing carbon dioxide have been proposed. Technologies for converting liquid fuels, such as gasoline or diesel, are the most preferred in terms of being easy to technically link with existing industrial processes, securing a large-scale market for generated products, and being able to easily process a large amount of carbon dioxide.

Although the reaction mechanism for the synthesis of hydrocarbons by hydrogenation of carbon dioxide has not yet been clarified, it is generally known that the reaction proceeds in two stages. Specifically, the hydrogenation reaction of carbon dioxide is a first step in which carbon dioxide supplied as a reactant is converted into carbon monoxide by a reverse water gas shift (RWGS) reaction and the produced carbon monoxide is Fischer-Tropsch (Fischer-Tropsch) Tropsch, FTS) consists of a second step in which hydrogen is combined with hydrogen and converted into hydrocarbons by the reaction. At this time, the reverse water gas shift reaction of the first step is an endothermic reaction and can be represented by Equation 1 below.

This first stage reverse water gas shift reaction is a reversible reaction, and its reverse reaction (reaction of CO and H ₂ O to CO ₂ and H ₂ ) is known as the water gas shift reaction. The reverse water gas shift reaction can be carried out under conditions that provide partial conversion of CO ₂ and H ₂ , resulting in a total product mixture comprising carbon monoxide (CO) and H ₂ O. Thereafter, the carbon monoxide generated in the first step undergoes a Fischer-Tropsch synthesis (FTS) reaction in the second step. The FTS reaction is exothermic and can be represented by Equation 2 below. “CH ₂ ” in Equation 2 below represents a common hydrocarbon moiety that can be incorporated into larger molecules such as ethylene (C ₂ H ₄ ) or propylene (C ₃ H ₆ ).

In particular, during the Fischer-Tropsch synthesis reaction, it is very important to quickly remove the reaction heat from the catalyst particles. This is because when the reaction heat accumulates inside the catalyst particles, the selectivity for the hydrocarbon to be synthesized decreases and the catalyst deteriorates. . Therefore, when configuring a fixed bed catalyst layer, a method of including a certain amount of an inert support (see Patent Document 0001) or mixing arbitrary inert particles with catalyst particles to form a catalyst layer to appropriately adjust the reactivity has been conventionally performed.

However, when using an inert support, since the support itself is a porous material, the catalytic material permeates into the support and a catalytic reaction occurs inside, making it difficult to control the exothermic reaction inside the support. In the case of mixing and using, there is a disadvantage in that uniform mixing is difficult, and the reaction occurs non-uniformly because a portion of the catalyst material is agglomerated.

Accordingly, U.S. Patent Publication No. 2004-0251001 discloses a foil-type FTS synthesis catalyst, and Korean Patent Publication No. 2007-0010190 discloses an oxidizable core material, a zinc oxide shell around the core material, and Catalysts comprising catalytically active material in or on a shell based on one or more of the metals cobalt, iron, ruthenium and/or nickel have been disclosed.

However, the catalysts developed so far do not exhibit satisfactory physical properties in terms of heat transfer performance, and also have problems in that the thermal and mechanical properties of the catalysts are also deteriorated due to the occurrence of catalyst breakage.

The cracking phenomenon of such a catalyst can be mainly caused by chemical and physical causes. As a chemical cause, structural changes occur as iron oxide, an active material of iron-based catalysts, is converted into metallic iron or iron carbide. Physical cracking is caused by the friction and collision of catalyst particles. Such catalyst breakage not only causes catalyst deactivation but also interferes with normal and stable reaction operation, and small broken catalyst particles may be included in the product and degrade the quality of the product.

Therefore, long-term operation of the direct carbon dioxide hydrogenation reaction requires stability over the lifetime of the catalyst, and to this end, it is necessary to develop a catalyst with less catalyst breakage and excellent heat transfer performance.

US Patent Registration No. 4075231 (registration date: 1978.02.21) US Patent Publication No. 2004-0251001 (Publication date: 2004.12.16) Korean Patent Publication No. 2007-0010190 (published date: 2007.01.22)

The main object of the present invention is to solve the above-mentioned problems, and as a catalyst for direct hydrogenation of carbon dioxide, direct hydrogenation of carbon dioxide capable of securing high selectivity and conversion rate for a desired hydrocarbon by having excellent heat transfer performance and thermal and mechanical properties. It is to provide a catalyst for the reaction.

In order to achieve the above object, one embodiment of the present invention, the center particles made of alumina balls; And an outer shell particle layer attached while surrounding the surface of the central particle, wherein the outer shell particle layer is composed of powdered catalyst particles, and the powdery catalyst particles include iron (Fe), copper (Cu), aluminum (Al) and K It provides a catalyst for direct hydrogenation of carbon dioxide, characterized in that it comprises (potassium).

In a preferred embodiment of the present invention, the iron (Fe), copper (Cu), aluminum (Al) and K (potassium) are included in a weight ratio of 100: 5 to 30: 5 to 30: 15 to 40. can do.

In a preferred embodiment of the present invention, the alumina ball has a bulk density of 1.5 g/cm ³ to 2.5 g/cm ³ , a Mohs hardness of 7.5 or more, an impact strength of 25 kgf to 30 kgf, and a water absorption rate of 2 % to 5%.

In a preferred embodiment of the present invention, the thickness ratio of the outer particle layer (outer particle layer/center particle) to the central particle may be 0.08 to 0.25.

In a preferred embodiment of the present invention, the weight ratio of the outer shell particle layer (outer shell particle layer/central particle layer) to the central particle may be 0.20 to 0.25.

In a preferred embodiment of the present invention, the wear rate of the core particle and outer particle layer may be characterized in that 3.7% or less.

The catalyst for the direct hydrogenation of carbon dioxide according to the present invention has excellent heat transfer performance and thermal and mechanical properties, thereby exhibiting a high selectivity for a desired hydrocarbon, particularly a hydrocarbon having 3 or more carbon atoms, and a conversion rate of carbon dioxide, thereby producing hydrocarbons from carbon dioxide. can be useful for

1 is a schematic diagram of a catalyst for direct hydrogenation of carbon dioxide according to an embodiment of the present invention.
2 is a photograph of catalysts for direct hydrogenation of carbon dioxide prepared in Examples 1, 2, and 4 and Comparative Examples 1, 5, and 6 of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclatures used herein are those well known and commonly used in the art.

Terms such as “comprise”, “include” or “having” described in this specification indicate that there is a feature, numerical value, step, operation, component, part, or combination thereof described in the specification. It does not rule out the possibility that other features, figures, steps, operations, components, parts, or combinations thereof may exist or be added that have not been described.

The present invention is a central particle made of alumina balls; And an outer shell particle layer attached while surrounding the surface of the central particle, wherein the outer shell particle layer is composed of powdered catalyst particles, and the powdery catalyst particles include iron (Fe), copper (Cu), aluminum (Al) and K It relates to a catalyst for direct hydrogenation of carbon dioxide, characterized in that it contains (potassium).

The catalyst for the direct hydrogenation of carbon dioxide according to the present invention has a double particle structure composed of a central particle 10 for heat exchange and an outer particle layer 30, which is a catalyst particle 25, shown in FIG. 1 as a schematic diagram.

The central particle 10 may be made of alumina, which is a heat transfer material, to satisfy the heat transfer performance and mechanical properties of the catalyst, and may have a ball shape with a diameter of 0.5 mm to 10 mm, preferably 0.5 mm to 5 mm. and can be made smaller or larger as needed.

At this time, in the present invention, the alumina ball applied as the central particle has a bulk density of 1.5 g/cm ³ to 2.5 g/cm ³ , a Mohs hardness of 7.5 or more, an impact strength of 25 kgf to 30 kgf, and a water absorption rate With this 2% to 5%, the durability and wear resistance of the catalyst support optimized for the direct hydrogenation of carbon dioxide can be obtained.

The bulk density of the alumina ball may be defined by Equation 1 below.

[Equation 1]

Bulk Density (g/cm ³ ) = Core Particle Weight (g)/Core Particle Volume (cm ³ )

On the other hand, the Mohs hardness of the alumina ball is a scale of hardness indicating whether the alumina ball is first damaged by which standard mineral is selected by selecting 10 kinds of standard minerals, and the Mohs hardness of the alumina ball may be 7.5 or more.

In addition, the impact strength of the alumina ball is measured with a universal testing machine. After extracting a plurality of samples, pressure is gradually applied to one of the samples with a compression tester to measure the pressure at the time of collapse of the alumina ball. The pressure was measured for all samples and the averaged impact strength may be 25 kgf to 30 kgf.

In addition, the water absorption rate of the alumina ball means the volume of water absorbed in a saturated state by the unit mass of the alumina ball, and can be determined by calculating according to Equation 2.

[Equation 2]

Water absorption rate (%) = (amount of water absorbed / weight of support) × 100

The water absorption rate of the alumina ball according to the present invention is 2% to 5%, and if the water absorption rate is less than 2%, it is difficult to bind the binder to the surface of the alumina ball, so the problem of reducing the adhesion of the catalyst powder during molding may occur. And, if it exceeds 5%, problems such as structural collapse during molding may cause a decrease in mechanical strength of the catalyst.

In addition, the catalyst according to the present invention may include a binder layer 20 surrounding the surface of the central particle to bind the above-described central particle 10 and the outer particle layer 30. The binder layer 20 may preferably include ceramic components such as silica, boehmite, and mixtures thereof, and oxide components including silicon, aluminum, or mixtures thereof, and oxygen.

When the binder layer is made of the ceramic component or the oxide component, a sol such as silica sol, boehmite sol, alumina sol, alumina alkoxide, and mixtures thereof is coated on the surface of the central particle, and then the coated central region. Powdery catalyst particles 25 are attached to the surface of the particles 10, and then fired at 400 ° C. to 600 ° C. for 1 hour to 4 hours to form a binder 20 layer. (10) and the outer shell particle layer 30 made of the powdery catalyst particles 25 are completely bound. For example, powder catalyst particles are placed on a plate, etc., and an appropriate amount of ceramic sol-coated core particles are placed thereon, and then the plate is moved or shaken in an appropriate way so that the powdery catalyst particles described below are formed on the adhesive surface of the ceramic sol-coated core particles. It can stick evenly.

The catalyst prepared in this way uses alumina balls with good heat transfer performance as core particles, but does not contain catalyst materials, so the reaction heat does not accumulate inside the catalyst and is quickly dispersed, so the catalyst does not deteriorate due to thermal problems, and the hydrocarbon to be produced The problem of deterioration in selectivity at high temperatures is also suppressed.

On the other hand, the outer shell particle layer 30 attached while surrounding the central particle is made of powdery catalyst particles 25 as described above, and the powdery catalyst particles are iron (Fe), copper (Cu), aluminum (Al) and K (potassium). At this time, the iron (Fe), copper (Cu), aluminum (Al) and K (potassium) may be included in a weight ratio of 100: 5 to 30: 5 to 30: 15 to 40 in the outer shell particle layer.

Among the outer shell particle layer composition, copper (Cu) serves as a cocatalyst to help iron reduction at low temperature, and is included in an amount of 5 to 30 parts by weight based on 100 parts by weight of iron in the outer shell particle layer composition. When the content of copper in the composition of the outer shell particle layer is less than 5 parts by weight with respect to 100 parts by weight of iron, a problem may occur that the activity of the catalyst is lowered and the hydrocarbon fraction having 3 or more carbon atoms is reduced due to poor promoter performance. If it exceeds parts by weight, a problem of increased coke production may occur.

In addition, in the composition of the outer shell particle layer, potassium (K) serves to help the adsorption of reactants on the surface of the catalyst and help the formation of iron carbide to help the chain reaction, the content of potassium is iron (Fe) 100 weight It may be included in the range of 15 parts by weight to 40 parts by weight per part. When the content of potassium (K) is less than the above-mentioned content range, the conversion rate of carbon dioxide is lowered and methane selectivity is high. There is a problem in that the catalyst pores are clogged, and thus the catalytic activity is lowered.

On the other hand, in the outer shell particle layer composition, aluminum (Al) serves as a structural improver to prevent sintering of the iron catalyst component, and aluminum (Al) is 5 parts by weight to 100 parts by weight of iron in the outer shell particle layer composition. 30 parts by weight. If the aluminum content is less than 5 parts by weight with respect to 100 parts by weight of iron, sintering of iron particles occurs and the size of the catalyst particles increases excessively, which may cause a problem in that the activity of the catalyst decreases. If it exceeds 30 parts by weight, the catalytic activity A problem that the activity of the catalyst is reduced due to excessive dilution of the components may occur.

Powdery catalyst particles applied to the outer shell particle layer may be prepared by a conventional method using precursor compounds of iron (Fe), copper (Cu), aluminum (Al), and potassium (K). For example, the powdery catalyst particles are mixed and co-precipitated with an iron precursor compound, a copper precursor compound, and an aluminum precursor compound to obtain a catalyst precursor slurry, and then aged to form a catalyst precursor precipitate. The formed catalyst precursor precipitate is washed with water and dried and calcined to obtain a catalyst oxide. It can be prepared by carrying a potassium precursor compound on the catalyst oxide obtained above, drying and calcining it.

At this time, as the precursor compound of iron, copper, aluminum, and potassium, any iron, copper, aluminum, and potassium precursor compound that can be used for preparing the catalyst may be used without particular limitation, and for example, copper, iron, aluminum, and potassium ions are contained. Nitric oxides, halides, oxides, hydroxides, organic products, etc. may be used.

The powdery catalyst particles 25 prepared as described above are attached while surrounding the surface of the central particle 10 to form the outer particle layer 30 . At this time, the thickness of the outer shell particle layer (outer shell particle layer/central particle layer) relative to the central particle may be 0.08 to 0.25.

If the thickness ratio of the outer particle layer to the central particle is less than 0.08, the shape of the coating surface is non-uniform, so that sufficient space for catalytic reaction cannot be secured, resulting in poor catalyst performance. In this case, the thickness of the outer particle layer becomes too thick, making it difficult to control heat generation, and the adhesion between the central particle portion and the outer particle layer weakens, causing a problem in that the strength of the catalyst is weakened.

In addition, the weight ratio of the outer shell particle layer (outer shell particle layer/central particle layer) to the central particle may be in the range of 0.2 to 0.25. If the weight ratio of the outer particle layer to the central particle is less than 0.2, sufficient catalyst powder to cover the central particle cannot be secured, resulting in poor catalyst performance. A problem of peeling of the coating may occur.

In the catalyst for direct hydrogenation of carbon dioxide according to the present invention, the wear rate of the central and outer particle layers measured by putting the sample in a sieve shaker (Fritsch, analysetter 3) and sieving to calculate the mass ratio of the sample remaining in the sieve With a high-strength catalyst of 3.7% or less, the wear rate of the central particle layer and the outer particle layer satisfies the above range, so that not only the mechanical properties of the catalyst, but also high selectivity for hydrocarbons having 3 or more carbon atoms and carbon dioxide conversion rate can be exhibited.

In addition, the catalyst for direct hydrogenation of carbon dioxide according to the present invention has excellent heat transfer performance and excellent thermal and mechanical properties, so that it has high selectivity for desired hydrocarbons, especially hydrocarbons having 3 or more carbon atoms (C ₃₊ ) and high carbon dioxide Since it can be usefully used for direct hydrogenation of carbon dioxide to produce hydrocarbons from carbon dioxide by showing conversion rate, the catalyst of the present invention can be usefully used as a catalyst for a reactor in which the reaction occurs at high space velocity as well as a general fixed bed reactor.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited only to these.

<Example 1>

1-1: Preparation of powdery catalyst particles

A metal aqueous solution was prepared by dissolving 50 g of Fe(NO ₃ ) ₃ 9H ₂ O, 12.56 g of Al(NO ₃ ) ₃ 6H ₂ O, and 3.24 g of Cu(NO ₃ ) ₂ 6H ₂ O in 400 ml of distilled water. After preparing aqueous solutions of 34.62 g of K ₂ CO ₃ dissolved in 400 ml of distilled water, they were mixed and co-precipitated together. After stirring at 80 °C for 3 hours, it was cooled to room temperature (20 °C). The resulting precipitate was precipitated again by mixing distilled water three times as much as the precipitate slurry, discarding the filtrate, repeating the above process two more times, and filtering. After filtration, drying at 110 °C for 15 hours, and then calcined at 550 °C for 5 hours. The calcined product was impregnated with an aqueous solution in which 1.7 g of K ₂ CO ₃ was dissolved in 3.2 ml of distilled water per 10 g of catalyst, dried at 110 °C for 15 hours, and then calcined at 550 °C for 5 hours to obtain powdery catalyst particles.

1-2: Preparation of catalyst for direct hydrogenation of carbon dioxide

The powdery catalyst particles obtained in Example 1-1 were sufficiently placed on a plate, and alumina balls coated with alumina sol (diameter: 2 mm, bulk density: 1.9 g/cm ³ , Mohs hardness: 7.6, impact strength: 28 kgf, Moisture absorption rate: 3.6%) on the powder catalyst particles, shake the plate, put an appropriate amount on the alumina balls coated with alumina sol, and then shake the plate to place the powder catalyst particles on the surface of the boehmite sol coated alumina balls. made them adhere evenly. Then, after drying them at 110 ℃ for 15 hours, they were fired at 550 ℃ for 5 hours to bind each other so that they do not fall apart, and 100Fe-13Cu-12Al-15K with a weight ratio of iron, copper, aluminum and potassium of 100: 13: 12: 15 A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.11, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.24.

<Example 2>

It is prepared in the same manner as in Example 1, but the content of each precursor is adjusted so that the weight ratio of iron, copper, aluminum and potassium in the prepared catalyst is 100: 13: 12: 35 to have a 100Fe-13Cu-12Al-35K weight ratio composition A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.10, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.21.

<Example 3>

It is prepared in the same manner as in Example 1, but the content of each precursor is adjusted so that the weight ratio of iron, copper, aluminum and potassium in the prepared catalyst is 100: 13: 12: 40 to have a 100Fe-13Cu-12Al-40K weight ratio composition A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.11, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.22.

<Example 4>

A catalyst having a weight ratio composition of 100Fe-13Cu-12Al-15K was prepared using the same method as in Example 1, but using an alumina ball having a diameter of 3 mm. It was found that the thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.21, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.22.

<Comparative Example 1>

A catalyst having a weight ratio composition of 100Fe-13Cu-12Al was prepared by preparing in the same manner as in Example 1, except for the potassium precursor compound. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.09, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was found to be 0.21.

<Comparative Example 2>

It was prepared in the same manner as in Example 1, but the content of each precursor was adjusted so that the weight ratio of iron, copper, aluminum and potassium in the prepared catalyst was 100: 13: 12: 9 to have a 100Fe-13Cu-12Al-9K weight ratio composition A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.10, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.23.

<Comparative Example 3>

It is prepared in the same manner as in Example 1, but the content of each precursor is adjusted so that the weight ratio of iron, copper, aluminum and potassium in the prepared catalyst is 100: 13: 12: 11 to have a 100Fe-13Cu-12Al-11K weight ratio composition A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.08, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.20.

<Comparative Example 4>

It is prepared in the same manner as in Example 1, but the content of each precursor is adjusted so that the weight ratio of iron, copper, aluminum and potassium in the prepared catalyst is 100: 13: 12: 60 to have a 100Fe-13Cu-12Al-60K weight ratio composition A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.11, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.25.

<Comparative Example 5>

It was prepared in the same manner as in Example 1, but instead of the copper precursor compound Cu(NO ₃ ) ₂ 6H ₂ O, 4.16 g of Co(NO ₃ ) ₂ 6H ₂ O was mixed to have a 100Fe-12Co-12Al-15K weight ratio composition. A catalyst was prepared. It was found that the thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.10, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.20.

<Comparative Example 6>

It was prepared in the same manner as in Example 1, but instead of the copper precursor compound Cu(NO ₃ ) ₂ 6H ₂ O, 3.83 g of Zn(NO ₃ ) ₂ 6H ₂ O was mixed to have a 100Fe-13Zn-12Al-15K weight ratio composition. A catalyst was prepared. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.09, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.21.

<Comparative Example 7>

A catalyst having a weight ratio composition of 100Fe/13Cu/12Al/15K was prepared by putting the catalyst of Example 1 in a sieve shaker and sieving to thin the shell. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.05, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.15.

<Comparative Example 8>

A catalyst having a weight ratio composition of 100Fe-13Cu-12Al-15K was prepared by repeating adding the catalyst layer to the catalyst of Example 1 one or more times to adjust the thickness of the layer and the diameter of the particles. The thickness ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle of the prepared catalyst was 0.34, and the weight ratio of the outer shell particle layer (outer shell particle layer/central particle) to the central particle was 0.47.

division catalyst alumina ball
Diameter (mm) Thickness ratio of outer particle layer/center particle Weight ratio of outer particle layer/center particle Example 1 100Fe-13Cu-12Al-15K 2 0.11 0.24 Example 2 100Fe-13Cu-12Al-35K 2 0.10 0.21 Example 3 100Fe-13Cu-12Al-40K 2 0.11 0.22 Example 4 100Fe-13Cu-12Al-15K 3 0.21 0.22 Comparative Example 1 100Fe-13Cu-12Al 2 0.09 0.21 Comparative Example 2 100Fe-13Cu-12Al-9K 2 0.10 0.23 Comparative Example 3 100Fe-13Cu-12Al-11K 2 0.08 0.20 Comparative Example 4 100Fe-13Cu-12Al-60K 2 0.11 0.25 Comparative Example 5 100Fe-12Co-12Al-15K 2 0.10 0.20 Comparative Example 6 100Fe-13Zn-12Al-15K 2 0.09 0.21 Comparative Example 7 100Fe-13Cu-12Al-15K 2 0.05 0.15 Comparative Example 8 100Fe-13Cu-12Al-15K 2 0.34 0.47

<Experimental Example 1: Catalytic Characteristics Evaluation>

In order to evaluate the physical properties of the catalysts prepared in Examples and Comparative Examples, photographs were taken of the catalysts prepared, and wear rates were measured by the method described below, and the results are shown in Table 2 and FIG. 2, respectively.

Wear rate: Using a sieve shaker (Fritsch, analysette 3), sieving time: 5 min, amplitude: 1 mm, frequency: 18 mesh size under the conditions of 50 Hz to 60 Hz The mass ratio of the worn amount was calculated using the sieve of .

division Wear rate (%) Example 1 1.68 Example 4 3.70 Comparative Example 7 0.51 Comparative Example 8 24.34

As shown in FIG. 2 and Table 2, it was confirmed that the wear rate also increased as the thickness ratio of the outer particle layer to the center particle increased.

<Experimental Example 2: Measuring the direct hydrogenation reaction of carbon dioxide according to the potassium content of the catalyst>

The RWGS reaction and the FTS reaction were simultaneously performed using a fixed-bed reactor (stainless steel material, diameter 3/8 inch). To measure and control the reaction temperature, a thermocouple was installed inside the reaction tube to control the temperature during the reaction. For the reaction, first, a quartz fiber (quartz wool) was placed under the catalyst inside the reaction tube, and 0.4 g of the catalyst obtained in Examples and Comparative Examples was loaded thereon. Before the reaction, the catalyst was activated at 500 °C using a mixed gas for reduction (hydrogen/argon = 5/95 molar ratio).

The actual reaction was carried out at 300 ° C using a mixed gas of hydrogen / carbon dioxide / argon = 72 / 24 / 4 molar ratio, and the reaction was carried out at a space velocity (GHSV) of 1,500 ml / g _cat hr under a pressure of 25 barg. The molar ratio of hydrogen and carbon dioxide in the mixed gas was set to 3, and the weight of the central particle was excluded from the space velocity calculation. During the 100-hour reaction process, the analysis of reactants and products was performed through gas chromatography (GC), and water generated by the reaction was recovered in a cooling trap.

The flow rate analysis before and after the reaction was accurately analyzed using a wet gas meter device in real time, and the carbon dioxide (CO ₂ ) conversion rate and selectivity for the reaction for 100 hours were calculated and shown in Table 3 accordingly.

division K/Fe
weight ratio CO ₂ conversion rate (%) CO yield
(%) HC yield
(%) CH ₄ selectivity
(%) C ₂ selectivity
(%) C ₃₊ selectivity
(%) Example 1 0.15 38.9 2.4 36.5 10.6 8.7 80.7 Example 2 0.35 37.3 2.7 34.6 11.8 9.9 78.3 Example 3 0.40 35.9 2.7 33.2 12.0 10.0 78.1 Example 4 0.15 35.8 2.5 33.3 9.9 8.5 81.7 Comparative Example 1 0.00 30.0 6.4 23.6 15.2 8.1 76.7 Comparative Example 2 0.09 33.3 3.0 30.4 12.1 10.8 77.1 Comparative Example 3 0.11 34.0 2.9 31.1 12.0 11.1 77.0 Comparative Example 4 0.60 32.9 2.9 30.0 9.8 8.7 81.5

As shown in Table 3, it was confirmed that the catalysts of Examples 1 to 4 had a higher CO ₂ conversion rate than the catalysts of Comparative Examples 1 to 4. In addition, when a certain level of potassium was supported (K / Fe weight ratio > 0.09), it was confirmed that the HC yield increased, and in particular, the selectivity of low-boiling hydrocarbons decreased.

<Experimental Example 3: Measurement of Direct Hydrogenation of Carbon Dioxide According to Catalyst Components and Catalyst Structure>

The RWGS reaction and the FTS reaction were simultaneously performed using a fixed-bed reactor (stainless steel material, diameter 3/8 inch). To measure and control the reaction temperature, a thermocouple was installed inside the reaction tube to control the temperature during the reaction. For the reaction, first, quartz wool was placed under the catalyst inside the reaction tube, and 0.4 g of the catalyst obtained in the above Examples and Comparative Examples was loaded thereon. Before the reaction, the catalyst was activated at 550 °C using a mixed gas for reduction (hydrogen/argon = 5/95 molar ratio). The actual reaction was carried out at 300 ° C using a mixed gas of hydrogen / carbon dioxide / argon = 72 / 24 / 4 molar ratio, and the reaction was carried out at a space velocity (GHSV) of 1,500 ml / g _cat hr under a pressure of 25 barg. The molar ratio of hydrogen and carbon dioxide in the mixed gas was set to 3, and the weight of the central particle was excluded from the space velocity calculation. During the 100-hour reaction process, the analysis of reactants and products was performed through gas chromatography (GC), and water generated by the reaction was recovered in a cooling trap.

The flow rate analysis before and after the reaction was accurately analyzed using a wet gas meter device in real time, and the carbon dioxide (CO ₂ ) conversion rate and selectivity for the reaction for 100 hours were calculated and shown in Table 4 accordingly.

division CO ₂ conversion rate (%) CO yield
(%) HC yield
(%) CH ₄ selectivity
(%) C ₂ selectivity
(%) C ₃ + selectivity
(%) Example 1 38.9 2.4 36.5 10.6 8.7 80.7 Comparative Example 5 41.0 2.0 39.1 17.1 13.4 69.6 Comparative Example 6 26.6 3.8 22.8 14.0 11.7 74.4 Comparative Example 7 20.3 6.6 13.8 13.8 11.4 74.8 Comparative Example 8 29.7 4.1 25.6 10.6 8.5 80.9

As shown in Table 4, it was confirmed that the catalyst of Example 1 had a high CO ₂ conversion rate and high selectivity for hydrocarbons (C ₃₊ ) having 3 or more carbon atoms compared to the catalysts of Comparative Examples 6 to 8. In the case of the catalyst of Comparative Example 5, it was confirmed that the CO ₂ conversion rate was the highest, but the selectivity for high-boiling point hydrocarbons (C ₃₊ ) was remarkably low.

Therefore, the catalyst for direct hydrogenation of carbon dioxide according to the present invention has excellent heat transfer performance and thermal and mechanical properties, thereby exhibiting high selectivity for desired hydrocarbons, particularly hydrocarbons having 3 or more carbon atoms, and conversion rate of carbon dioxide, thereby producing hydrocarbons from carbon dioxide. It was confirmed that it can be usefully used for synthesis.

The present invention has been described above with reference to the accompanying drawings and embodiments, but these are merely exemplary, and those skilled in the art can make various modifications and equivalent other embodiments therefrom. will understand Therefore, the technical protection scope of the present invention should be determined by the claims below.

10: central particle
20: binder layer
25: powdery catalyst particles
30: outer shell particle layer

Claims (6)

Core particles made of alumina balls; and
Including an outer part particle layer attached while surrounding the surface of the central part particle,
The outer shell particle layer is composed of powdery catalyst particles, and the powdery catalyst particles contain iron (Fe), copper (Cu), aluminum (Al) and K (potassium). Catalyst for direct hydrogenation of carbon dioxide, characterized in that .
According to claim 1,
The iron (Fe), copper (Cu), aluminum (Al) and K (potassium) are contained in a weight ratio of 100: 5 to 30: 5 to 30: 15 to 40 Catalyst for direct hydrogenation of carbon dioxide.
According to claim 1,
The alumina ball has a bulk density of 1.5 g / cm ³ to 2.5 g / cm ³ , a Mohs hardness of 7.5 or more, an impact strength of 25 kgf to 30 kgf, and a water absorption rate of 2% to 5%. Catalyst for direct hydrogenation of carbon dioxide.
According to claim 1,
A catalyst for direct hydrogenation of carbon dioxide, characterized in that the thickness ratio of the outer shell particle layer (outer shell particle layer / central particle layer) to the central particle is 0.08 to 0.25.
According to claim 1,
A catalyst for direct hydrogenation of carbon dioxide, characterized in that the weight ratio of the outer shell particle layer (outer shell particle layer / central particle layer) to the central particle is 0.2 to 0.25.
According to claim 1,
A catalyst for direct hydrogenation of carbon dioxide, characterized in that the wear rate of the central particle and outer particle layers is 3.7% or less.

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