Direct hydrogenation catalyst for carbon dioxide, method for producing the same, and method for producing hydrocarbon compounds using the same

Abstract

The present invention relates to a catalyst useful for the direct hydrogenation reaction of carbon dioxide, a method for producing the same, and a method for producing hydrocarbon compounds using the same, and provides a metal-oxide catalyst comprising an oxide-based carrier and catalyst particles containing iron supported on the carrier, a method for producing the same, and a method for producing hydrocarbon compounds using the same.

Description

[Technical Field]

[0001] This application claims priority under Korean Patent Application No. 10-2023-0119552 dated September 8, 2023, and all content disclosed in the said Korean Patent Application is incorporated herein by reference.

[0002] The present invention relates to a catalyst useful for the direct hydrogenation reaction of carbon dioxide, a method for producing the same, and a method for producing hydrocarbon compounds by the direct hydrogenation reaction of carbon dioxide using the same. [Background technology]

[0003] Coal and oil, as fossil fuels accounting for more than 50% of total energy, have been used as important energy sources for humanity for the past several centuries, and through these various energy conversion processes, humanity has emitted thermodynamically stable carbon dioxide without any further post-treatment processes.

[0004] However, in recent years, carbon dioxide has become known as the main greenhouse gas, accounting for 55% of the contribution to global warming, and various technologies for removing carbon dioxide have been proposed. Among these, the technology that uses catalysts to hydrogenate carbon dioxide and convert it into high-value-added chemical fuels such as α-olefins or liquid-phase fuels such as gasoline and diesel is the most preferred because it is easy to integrate with conventional industrial processes, a large market for the produced products has been secured, and it can easily process large amounts of carbon dioxide.

[0005] Carbon dioxide conversion technology is a technique that converts carbon dioxide, the most stable of the carbon compounds, into other useful compounds. For example, there is a technique that converts carbon dioxide into carbon monoxide, methanol, and hydrocarbon compounds through hydrogenation.

[0006] Generally, the hydrogenation of carbon dioxide consists of a first step, in which carbon dioxide supplied as a reactant is converted into carbon monoxide via the Reverse Water Gas Shift (RWGS) reaction, and a second step, in which the produced carbon monoxide combines with hydrogen and is converted into hydrocarbons via the Fischer-Tropsch (FTS) synthesis reaction. At this time, the reverse water gas shift reaction of the first step is an endothermic reaction, and can be represented by the following Formula 1.

[0007]

Math

[0008] The reverse water gas shift reaction in the first step is a reversible reaction, and can be carried out under conditions that provide partial conversion of carbon dioxide and hydrogen. Carbon monoxide produced in the first step undergoes the Fischer-Tropsch synthesis (FTS) reaction of the second step, wherein said Fischer-Tropsch synthesis reaction is exothermic and can be represented by the following Formula 2.

[0009]

Math

[0010] In some cases, the reverse water gas shift reaction of the first step and the Fischer-Tropsch synthesis reaction of the second step are each configured as separate processes and connected in series. However, since the reverse water gas shift reaction of the first step is an endothermic reaction that requires a high reaction temperature to ensure a high conversion rate, there is a problem that the energy efficiency of the entire conversion process decreases. Accordingly, research is being conducted on the direct hydrogenation of carbon dioxide, which allows the reverse water gas shift reaction of the first step and the Fischer-Tropsch synthesis reaction of the second step to be carried out simultaneously using a single catalyst and a single process.

[0011] Such a direct carbon dioxide hydrogenation reaction, in which the reverse water-gas shift reaction and the Fischer-Tropsch synthesis reaction are simultaneously performed in one catalyst and one process, is an exothermic reaction, and can be represented by the following formula 3.

[0012] [Mathematical formula]

[0013] In particular, during the Fischer-Tropsch synthesis reaction, if reaction heat accumulates inside the catalyst particles, this causes problems such as a decrease in selectivity towards the hydrocarbon to be synthesized and deterioration of the catalyst, therefore it is extremely important to rapidly remove the reaction heat from the catalyst particles. Accordingly, when forming a fixed catalyst bed, methods have been adopted in which a certain amount of inert support is included, or arbitrary inert particles are mixed with catalyst particles to form the catalyst layer, thereby appropriately adjusting reactivity.

[0014] However, when an inert support is used, since the support itself is a porous material, the catalyst material penetrates into the interior of the support, causing a catalytic reaction to also occur inside the support, which makes it difficult to control the exothermic reaction inside the support; when inert particles are physically mixed with catalyst particles for use, there are problems in that uniform mixing is difficult, regions where the catalyst material aggregates form, and non-uniform reactions occur.

[0015] In addition, in terms of heat control and reaction efficiency, slurry reactions such as fluidized bed reactions are effective. In this case, securing the mechanical properties of the catalyst is required, so methods have been adopted in which a structural promoter is added to the catalyst. However, when an inactive structural promoter is added, the content of the active component decreases, and there is a problem that the phenomenon of reduction in carbon dioxide conversion rate caused by the decrease of the active component is severe. [PRIOR ART DOCUMENTS] [PATENT DOCUMENTS]

[0016] [Patent Document 1] KR10-1405090B1(Jun. 02, 2014) [Overview of the project] [Problems that the invention aims to solve]

[0017] The present invention aims to solve the above-mentioned problems and to provide a catalyst useful for the direct hydrogenation reaction of carbon dioxide that has high reaction activity due to containing a high content of catalytically active components, and excellent specific surface area and mechanical properties due to containing structural co-catalyst components.

[0018] Furthermore, the present invention aims to provide a method for producing the catalyst. Furthermore, the present invention aims to provide a method for producing hydrocarbon compounds, which includes a direct hydrogenation reaction step of carbon dioxide in the presence of the catalyst. [Means for solving the problem]

[0019] To solve the above problems, the present invention provides a catalyst, a method for producing the same, and a method for producing hydrocarbon compounds. (1) The present invention relates to a metal-oxide catalyst comprising an oxide-based support and catalyst particles containing iron supported on the support, wherein the surface area of ​​the catalyst is 1 m² 2 The present invention provides a catalyst with an iron content of 5 mg to 15 mg per unit.

[0020] (2) The present invention provides the catalyst described in (1) above, wherein the iron is contained in an amount of 50% by weight or more and 65% by weight or less relative to 100% by weight of the catalyst.

[0021] (3) The present invention relates to a catalyst with a specific surface area of ​​50 m². 2 / g~100m 2 The present invention provides the catalyst described in (1) or (2) above, which is / g.

[0022] (4) The present invention provides a catalyst according to any one of the above (1) to (3), wherein the oxide-based support is one or more selected from the group consisting of SiO2, Al2O3, and zeolite.

[0023] (5) The present invention provides a catalyst according to any one of the above claims (1) to (4), wherein the iron is a hematite phase.

[0024] (6) The present invention provides a catalyst according to any one of the above (1) to (5), wherein the iron is activated by one or more selected from the group consisting of magnetite, iron carbide, and metallic iron (Fe).

[0025] (7) The present invention provides a catalyst according to any one of the above (1) to (6), wherein the catalyst particles further contain a co-catalyst metal, and the co-catalyst metal is one or more selected from the group consisting of copper, potassium, and sodium.

[0026] (8) The present invention provides a catalyst according to any one of the above (1) to (7), wherein the catalyst particles further contain one or more co-catalyst metals selected from the group consisting of copper, potassium, and sodium, and the co-catalyst metals are present in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the catalyst.

[0027] (9) The present invention provides a catalyst for the direct hydrogenation reaction of carbon dioxide, as described in any one of (1) to (8) above.

[0028] (10) The present invention comprises the steps of (S1) producing iron oxide catalyst particles, (S2) supporting a co-catalyst metal on the catalyst particles, and (S3) drying and then calcining, wherein step (S1) comprises the steps of (S1-1) dissolving an iron precursor in a solvent to produce a first solution with an iron weight concentration of 20 g / L to 100 g / L, adding an oxide support to the first solution and dispersing it to produce a second solution, (S1-2) raising the temperature of the second solution to 40°C to 90°C while stirring, adding an aqueous precipitant solution to produce a precipitate containing iron oxide supported particles, and washing and filtering the precipitate and then drying it, wherein the oxide support in step (S1-1) has a surface area of ​​1 m² 2The present invention provides a method for producing a catalyst according to any one of the above (1) to (9), wherein the catalyst is introduced in an amount such that the iron content per unit is 10 mg to 150 mg, and the co-catalyst metal in step (S2) is supported in an amount such that the weight ratio of iron to co-catalyst metal is 5 to 15.

[0029] (11) The present invention provides a method for producing a catalyst as described in (10), wherein the aqueous solution of the precipitant in step (S1-2) contains the precipitant at a weight concentration of 50 g / L to 250 g / L, and the precipitant is one or more selected from the group consisting of sodium carbonate, ammonium carbonate, aqueous ammonia, and sodium hydroxide.

[0030] (12) The present invention provides a method for producing a catalyst as described in (10) or (11), wherein the aqueous solution of the precipitant in step (S1-2) is added until the pH in the reactor becomes 7 to 8.

[0031] (13) The present invention provides a method for producing a catalyst according to any one of the above (10) to (12), wherein the iron precursor is one or more selected from the group consisting of iron nitrates, sulfates, acetates, chlorides, bromides, iodides, and hydrates thereof.

[0032] (14) The present invention provides a method for producing a catalyst according to any one of the above (10) to (13), wherein the stirring in step (S1-2) is performed at a speed of 100 rpm to 1000 rpm.

[0033] (15) The present invention provides a method for producing a catalyst according to any one of the above (10) to (14), wherein, in step (S1-2), the mixture is stirred for a further 0.5 to 24 hours after the addition of the aqueous solution of the precipitant.

[0034] (16) The present invention provides a method for producing a catalyst according to any one of the above (10) to (15), wherein the co-catalyst metal in step (S2) is one or more selected from the group consisting of copper, potassium, and sodium.

[0035] (17) In the present invention, step (S2) is performed by an Incipient Wetness Impregnation Method, providing a method for producing a catalyst according to any one of (10) to (16).

[0036] (18) The present invention provides a method for producing a catalyst according to any one of the above (10) to (17), wherein the drying in steps (S1-3) and (S3) is carried out at 100°C to 200°C for 5 to 24 hours, respectively.

[0037] (19) The present invention provides a method for producing a catalyst according to any one of the above (10) to (18), wherein the calcination in step (S3) is carried out by heat treatment at a temperature of 200°C to 600°C for 1 to 12 hours.

[0038] (20) The present invention provides a method for producing a hydrocarbon compound, comprising a direct hydrogenation reaction step of carbon dioxide in the presence of a catalyst described in any one of the above (1) to (9). [Effects of the Invention]

[0039] The catalyst according to the present invention contains a high content of iron as a catalytic component and has a specific range of specific surface area and iron content per unit surface area of ​​the catalyst, thereby exhibiting high catalytic reaction activity, excellent carbon dioxide conversion rate and TOF (turnover frequency), and excellent selectivity for high value-added C5 or higher hydrocarbon compounds.

[0040] Furthermore, the catalyst manufacturing method according to the present invention allows for the production of a catalyst containing a specific range of iron and having a specific range of specific surface area and iron content per unit surface area by adjusting the ratio of an oxide-based support and an iron precursor to support iron on the support, drying, and then supporting a co-catalyst metal thereon in a controlled ratio.

[0041] Furthermore, the hydrocarbon production method according to the present invention, by using the catalyst, exhibits excellent carbon dioxide conversion rate and TOF, and high selectivity for C5 or higher hydrocarbon compounds, making it even more useful for the production of C5 or higher hydrocarbon compounds. [Modes for carrying out the invention]

[0042] The terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0043] The present invention provides a catalyst useful for the direct hydrogenation reaction of carbon dioxide, particularly the Fischer-Tropsch synthesis reaction, a method for producing the same, and a method for producing hydrocarbon compounds using the same. The present invention will be described in more detail below.

[0044] catalyst The present invention provides a catalyst that is supported on a carrier, has excellent specific surface area and mechanical properties, and exhibits excellent catalytic activity.

[0045] The catalyst according to one embodiment of the present invention is a metal-oxide catalyst comprising an oxide-based support and catalyst particles containing iron supported on the support, wherein the surface area of ​​the catalyst is 1 m². 2 It is characterized by an iron content of 5 mg to 15 mg per serving.

[0046] Furthermore, the catalyst contains iron at a concentration of 50% to 65% by weight relative to 100% by weight of the catalyst, and has a specific surface area of ​​50 m². 2 / g~100m 2 / g is also acceptable.

[0047] Generally, the hydrogenation reaction of carbon dioxide consists of two steps: the first step in which the carbon dioxide supplied as a reactant is converted to carbon monoxide by a reverse water-gas shift (RWGS) reaction, and the second step in which the resulting carbon monoxide combines with hydrogen by a Fischer-Tropsch (FTS) reaction to form hydrocarbons.

[0048] In particular, during Fischer-Tropsch synthesis reactions, methods have been employed to add structural co-catalysts (structural promoters, supports) to the catalyst in order to control the reaction heat inside the catalyst particles and improve their mechanical properties. However, when inert structural co-catalysts are added, the content of the catalytically active component decreases, leading to a significant decrease in the carbon dioxide conversion rate due to the reduction in the active component.

[0049] Furthermore, when the first step, the reverse water-gas shift reaction, and the second step, the Fischer-Tropsch synthesis reaction, are carried out as separate processes in a continuous manner, the first step, the reverse water-gas shift reaction, is an endothermic reaction requiring a high reaction temperature to ensure a high conversion rate. This leads to a problem of reduced energy efficiency in the overall conversion process. Therefore, research is being conducted on direct hydrogenation reactions of carbon dioxide that can perform the first step, the reverse water-gas shift reaction, and the second step, the Fischer-Tropsch synthesis reaction, simultaneously with a single catalyst and process. The development of such catalysts is therefore necessary.

[0050] The catalyst according to one embodiment of the present invention contains a high iron content in a form in which catalyst particles are supported on an oxide-based support which is a structural co-catalyst, and has a specific range of specific surface area and iron content per unit surface area. As a result, in a process in which the Fischer-Tropsch synthesis reaction and the reverse water-gas shift reaction are carried out simultaneously with the Fischer-Tropsch synthesis reaction, it has the effect of having high catalytic reaction activity, excellent carbon dioxide conversion rate and TOF (turnover frequency), and excellent selectivity for high value-added C5 or higher hydrocarbon compounds.

[0051] The catalyst according to one embodiment of the present invention is a metal-oxide supported catalyst, comprising an oxide-based support and catalyst particles supported on the support, wherein the catalyst particles comprise iron. Further, the iron may be in a hematite phase.

[0052] Further, before being used in the carbon dioxide direct hydrogenation reaction, the catalyst is activated by pretreatment for use, and in this process, the iron may be activated into one or more selected from the group consisting of magnetite, iron carbide and metallic iron (Fe).

[0053] As another example, the iron in the catalyst is contained in the catalyst as a hematite phase, and may be activated into one or more selected from the group consisting of magnetite, iron carbide and metallic iron (Fe) by pretreatment.

[0054] Further, the catalyst may contain 50 wt% to 65 wt% of iron relative to 100 wt% of the catalyst, and the specific surface area of the catalyst is 50 m 2 / g to 100 m 2 / g, and the iron content per 1 m 2 of surface area of the catalyst may be 5 mg to 15 mg. Specifically, the catalyst may contain 55 wt% to 60 wt% of iron relative to 100 wt% of the catalyst, the specific surface area of the catalyst is 52 m 2 / g to 70 m 2 / g, and the iron content per 1 m 2 of surface area of the catalyst may be 8 mg to 12 mg. In this case, during the production of hydrocarbon compounds by the carbon dioxide direct hydrogenation reaction using the catalyst, the catalyst has sufficient catalytically active components, excellent catalytic reaction activity, and excellent selectivity to hydrocarbon compounds of C5 or more and carbon dioxide conversion rate.

[0055] As a structural promoter, the oxide-based support functions to improve the mechanical strength and specific surface area of the catalyst, and specifically, may be one or more selected from the group consisting of SiO2, Al2O3 and zeolite.

[0056] Furthermore, considering that the oxide-based support should not adversely affect the performance and physicochemical properties of the catalyst through the interaction between the improvement of the catalyst's mechanical strength and specific surface area and the bonding force with the catalyst components, the oxide-based support may be SiO2 or Al2O3.

[0057] The catalyst particles may optionally further contain a co-catalyst metal, and the co-catalyst metal may be one or more selected from the group consisting of copper, potassium, and sodium.

[0058] Furthermore, the catalyst particles may further contain one or more selected from the group consisting of copper, potassium, and sodium, and the co-catalyst metal may be present in an amount of 0.1 to 20 parts by weight, specifically 1 to 20 parts by weight, per 100 parts by weight of catalyst. Furthermore, if the catalyst contains two or more of the aforementioned co-catalyst metals, the two or more co-catalyst metals may be present in equal amounts to each other.

[0059] If the catalyst particles further contain copper, the reducing power of the catalyst increases further, and if the catalyst particles further contain potassium, the basicity of the catalyst surface can be increased, which is advantageous in terms of improving the selectivity of hydrocarbon compounds of C5 or higher.

[0060] Catalyst manufacturing method The present invention provides a method for producing the catalyst. A method for producing the catalyst according to one embodiment of the present invention includes the steps of: producing iron-oxide catalyst particles (S1); supporting a co-catalyst metal on the catalyst particles (S2); and calcining after drying (S3), wherein step (S1) includes: dissolving an iron precursor in a solvent to produce a first solution with an iron weight concentration of 20 g / L to 100 g / L; adding an oxide-based support to the first solution and dispersing it to produce a second solution (S1-1); raising the temperature of the second solution to 40°C to 90°C while stirring, adding a precipitant aqueous solution to produce a precipitate containing iron-oxide-based supported particles (S1-2); and washing and filtering the precipitate and then drying it (S1-3), wherein the oxide-based support in step (S1-1) has a surface area of ​​1 m² 2 The amount added is such that the iron content per unit is 10 mg to 150 mg, and the co-catalyst metal in step (S2) is supported in an amount such that the weight ratio of iron to co-catalyst metal is 5 to 15. The method for producing the catalyst will be described in more detail below, broken down into steps.

[0061] (S1) Step Step (S1) is a step to produce iron-oxide catalyst particles in which iron, which is a catalytically active component, is supported on an oxide-based support, and may be carried out by the steps of: dissolving an iron precursor in a solvent to produce a first solution with an iron weight concentration of 20 g / L to 100 g / L; adding and dispersing the oxide-based support in the first solution to produce a second solution (S1-1); raising the temperature of the second solution to 40°C to 90°C while stirring, adding an aqueous solution of a precipitating agent to produce a precipitate containing iron-oxide supported particles (S1-2); and washing and filtering the precipitate and then drying it (S1-3).

[0062] Step (S1-1) is a preliminary step for producing a precipitate, which is an iron-oxide catalyst cake, by coprecipitation of an iron precursor and an oxide-based support, thereby supporting iron, which is a catalytically active component derived from the iron precursor, on the support. This is carried out by dissolving the iron precursor in a solvent to produce a first solution with an iron weight concentration of 20 g / L to 100 g / L, and then adding and dispersing the oxide-based support to the first solution to produce a second solution.

[0063] Specifically, the first solution is an iron precursor dissolved in a solvent, and the iron precursor can be any iron precursor that is widely used in the industry, for example, one or more selected from the group consisting of iron nitrates, sulfates, acetates, chlorides, bromides, iodides, and hydrates thereof. Specifically, the iron precursor may be one or more selected from iron nitrate, iron chloride, iron sulfate, iron acetate, and hydrates thereof.

[0064] Furthermore, the solvent used in the first solution may be one or more selected from distilled water, ethanol, methanol, and acetone, and specifically may be distilled water.

[0065] Furthermore, the second solution is prepared by adding and dispersing an oxide-based support in the first solution, and in this case, the oxide-based support may be one or more selected from the group consisting of SiO2, Al2O3, and zeolite.

[0066] Furthermore, during the production of the second solution, the oxide-based carrier has a surface area of ​​1 m². 2 The amount added may be such that the iron content per unit is 10 mg to 150 mg. Specifically, the oxide-based carrier has a surface area of ​​1 m². 2 The amount added may be such that the iron content per serving is 15mg to 130mg, 20mg to 100mg, or 25mg to 80mg.

[0067] Steps (1-2) described above involve a coprecipitation reaction between an iron precursor and an oxide-based support, thereby supporting iron, which is a catalytically active component derived from the iron precursor, on the support, and producing a precipitate that is an iron-oxide-based catalyst cake. This step may be carried out by raising the temperature of the second solution to 40°C to 90°C while stirring, and adding an aqueous solution of a precipitating agent. The stirring may be carried out at a speed of 100 rpm to 1000 rpm. If the aqueous solution of the precipitating agent is added while stirring under the above conditions, the oxide-based support can be uniformly dispersed in the solution, and the iron, which is a catalytically active component, can be uniformly precipitated on the surface of the oxide-based support, thereby obtaining iron-oxide-based catalyst particles with a uniform composition.

[0068] Furthermore, the aqueous solution of the precipitating agent may be added until the pH in the reactor reaches 7 to 8, and after the addition is complete, the mixture may be stirred for a further 0.5 to 24 hours, during which the stirring may be carried out while maintaining the stirring speed and temperature at the time of adding the aqueous solution of the precipitating agent.

[0069] As another example, step (S1-2) may be carried out by heating the second solution to 40°C to 90°C in a reactor while stirring at a speed of 100 rpm to 1000 rpm, adding the aqueous solution of the precipitant until the pH in the reactor becomes 7 to 8, and then stirring further for 0.5 to 24 hours while maintaining the speed and temperature after the addition is complete.

[0070] The aqueous solution of the precipitating agent contains the precipitating agent at a weight concentration of 50 g / L to 250 g / L, and the precipitating agent may be one or more selected from the group consisting of sodium carbonate, ammonium carbonate, aqueous ammonia, and sodium hydroxide.

[0071] Step (S1-2) above is a step for separating iron-oxide catalyst particles from the prepared precipitate, which may be carried out by filtering, washing, and drying the precipitate.

[0072] The filtration and washing may be carried out by methods well known in the industry, and the drying may be carried out so that the precipitate is completely dried, for example, at 100°C to 200°C for 5 to 24 hours.

[0073] (S2) Step Step (S2) is a step for further supporting a co-catalyst metal component, which may be carried out by supporting the co-catalyst metal on the iron-oxide catalyst particles produced in step (S1), and the amount of co-catalyst metal supported may be such that the weight ratio of iron to co-catalyst metal is 5 to 15. The co-catalyst metal may also be one or more selected from the group consisting of copper, potassium, and sodium, and in this case, the supporting of the co-catalyst metal in step (S2) may be carried out by the Incipient Wetness Impregnation Method.

[0074] Here, the initial wetting impregnation method may be carried out using methods well known in the industry, and as an example, it may be carried out by sequentially performing the steps of crushing iron-oxide catalyst particles to obtain a powder and measuring the pore volume, adding and mixing an aqueous solution of co-catalyst metal precursor to the powder, and drying. In this case, the aqueous solution of co-catalyst metal precursor may be added in an amount equal to or an integer multiple of the pore volume, and if an integer multiple is added, the addition and drying may be repeated the same number of times as that integer multiple.

[0075] The aqueous solution of the co-catalyst metal precursor is a solution obtained by dissolving the co-catalyst metal precursor in distilled water, and the co-catalyst metal precursor may be one or more selected from the group consisting of nitrates, sulfates, acetates, chlorides, bromides, iodides, and hydrates thereof of the co-catalyst metal.

[0076] Specifically, when the co-catalyst metal is copper, the copper precursor may be one or more selected from the group consisting of copper nitrate, copper chloride, copper acetate, copper sulfate, and their hydrates, and more specifically, copper nitrate hydrate.

[0077] Furthermore, when the co-catalyst metal is potassium, the potassium precursor may be one or more selected from the group consisting of potassium nitrate, potassium chloride, potassium carbonate, potassium acetate, and potassium sulfate, and more specifically, potassium nitrate.

[0078] Furthermore, when the co-catalyst metal is sodium, the sodium precursor may be one or more selected from the group consisting of sodium nitrate, sodium chloride, sodium carbonate, sodium acetate, and sodium sulfate, and more specifically, sodium carbonate.

[0079] (S3) Step Step (S3) is a step for producing a catalyst in which catalyst particles have been converted into an oxide form by heat treatment, and may be carried out by drying and calcination. The drying may be carried out at 100°C to 200°C for 5 to 24 hours, and the calcination may be carried out by heat treatment at a temperature of 200°C to 600°C for 1 to 12 hours. If drying and calcination are carried out under the above conditions, the iron component in the catalyst can be completely oxidized to obtain a catalyst in the form of hematite, and impurities such as moisture, nitrogen oxides, and chlorides remaining in the catalyst can be removed.

[0080] Method for producing hydrocarbon compounds The present invention provides a method for producing hydrocarbon compounds from carbon dioxide using the catalyst described above.

[0081] According to one embodiment of the present invention, a method for producing a hydrocarbon compound includes a step of direct hydrogenation of carbon dioxide in the presence of the catalyst. Here, the direct hydrogenation reaction of carbon dioxide may be carried out in the same manner as well known in the art, except that the catalyst described above is used.

[0082] Specifically, the method for producing the hydrocarbon compound includes the steps of charging a catalyst into a reactor and performing a reduction treatment under a hydrogen atmosphere, and injecting a raw material gas and carrying out a direct hydrogenation reaction of carbon dioxide, wherein the direct hydrogenation reaction of carbon dioxide includes a reverse water gas shift (RWGS) reaction and a Fischer-Tropsch (FTS) reaction.

[0083] The reduction treatment may also be carried out by flowing hydrogen through the catalyst at a rate of 20 mL / g-catalyst / min to 100 mL / g-catalyst / min at 1 atm to 10 atm and 300°C to 500°C, while the direct hydrogenation reaction of carbon dioxide is carried out at 200°C to 500°C, with a reaction pressure of 1 atm to 100 atm and a space velocity of 100 h. -1 ~20,000h -1 You can go that way.

[0084] Furthermore, the above reaction can be carried out without limitation in all reactors widely used in the industry, including gas-phase fixed-bed reactors, fluidized-bed reactors, and liquid-phase slurry reactors.

[0085] Examples Hereinafter, embodiments of the present invention will be described in detail so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention may be realized in various different forms and is not limited to the embodiments described herein.

[0086] Example 1 395 m³ in the precipitation reaction vessel 2 0.36 g of porous silica powder having a specific surface area of ​​1 m² was added to 200 mL of a solution prepared by dissolving iron nitrate hydrate (55.8 g / L) in distilled water, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m². 2The solution was added in an amount that resulted in an iron content of 78 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.4. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0087] The iron content in the Fe-SiO2 powder obtained after drying was 60% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-SiO2 powder by adding an aqueous solution containing 153 g / L of copper nitrate hydrate and 153 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 6. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0088] Example 2 200m in the precipitation reaction vessel 2 2.23 g of porous alumina (γ-Al2O3) powder with a specific surface area of ​​1 m² was added to a 200 mL solution of iron nitrate hydrate (55.8 g / L) dissolved in distilled water, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous alumina powder had a specific surface area of ​​1 m². 2 The solution was added in an amount that resulted in an iron content of 25 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.3. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0089] The iron content in the Fe-Al2O3 powder obtained after drying was 60% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-Al2O3 powder by adding an aqueous solution containing 62 g / L of copper nitrate hydrate and 62 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 10. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0090] Example 3 395 m³ in the precipitation reaction vessel 2 1.84 g of porous silica powder having a specific surface area of ​​1 m² / g and 200 mL of a solution of iron nitrate hydrate (55.8 g / L) dissolved in distilled water were added, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m² / g. 2 The solution was added in an amount that resulted in an iron content of 15 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.3. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0091] The iron content in the Fe-SiO2 powder obtained after drying was 63% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-SiO2 powder by adding an aqueous solution containing 153 g / L of copper nitrate hydrate and 153 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 5.5. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0092] Example 4 395 m³ in the precipitation reaction vessel 20.23 g of porous silica powder having a specific surface area of ​​1 m² / g and 200 mL of a solution prepared by dissolving iron nitrate hydrate (55.8 g / L) in distilled water were added, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m² / g. 2 The solution was added in an amount that resulted in an iron content of 121 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.1. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0093] The iron content in the Fe-SiO2 powder obtained after drying was 69% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-SiO2 powder by adding an aqueous solution containing 15 g / L of copper nitrate hydrate and 15 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 13. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0094] Example 5 395 m³ in the precipitation reaction vessel 2 0.41 g of porous silica powder having a specific surface area of ​​1 m² / g and 200 mL of a solution prepared by dissolving iron nitrate hydrate (55.8 g / L) in distilled water were added, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m² / g. 2 The solution was added in an amount that resulted in an iron content of 68 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.2. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0095] The iron content in the Fe-SiO2 powder obtained after drying was 68% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-SiO2 powder by adding an aqueous solution containing 50 g / L of copper nitrate hydrate and 50 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 12. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0096] Comparative Example 1 395 m³ in the precipitation reaction vessel 2 10.4 g of porous silica powder having a specific surface area of ​​1 m² was added to 200 mL of a solution prepared by dissolving iron nitrate hydrate (27.9 g / L) in distilled water, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m². 2 The solution was added in an amount that resulted in an iron content of 1.5 mg per unit. After the solution temperature reached 60°C, 72 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.5. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and completely dried at 110°C for at least 12 hours.

[0097] The iron content in the Fe-SiO2 powder obtained after drying was 30% by weight, and the iron content was adjusted by adding potassium. Potassium was supported on the Fe-SiO2 powder by adding an aqueous solution of 30 g / L of potassium carbonate so that the weight ratio of iron / potassium was 16. After adding potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0098] Comparative Example 2 395 m³ in the precipitation reaction vessel 22.23 g of porous silica powder having a specific surface area of ​​1 m² was added to a 200 mL solution of iron nitrate hydrate (55.8 g / L) dissolved in distilled water, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous silica powder had a surface area of ​​1 m². 2 The solution was added in an amount that resulted in an iron content of 13 mg per unit. After the solution temperature reached 60°C, 144 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.5. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and completely dried at 110°C for at least 12 hours.

[0099] The iron content in the Fe-SiO2 powder obtained after drying was 60% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-SiO2 powder by adding an aqueous solution containing 55 g / L of copper nitrate hydrate and 55 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 10. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0100] Comparative Example 3 200 mL of a solution of iron nitrate hydrate (55.8 g / L) dissolved in distilled water was added to a precipitation reaction vessel, and the temperature was raised to 60°C while stirring at 400 rpm. After the solution temperature reached 60°C, 120 g / L of aqueous sodium hydroxide solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.9. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and completely dried at 110°C for at least 12 hours.

[0101] The iron content of the Fe powder obtained after drying was adjusted by adding sodium. Sodium was supported on the Fe powder by adding an aqueous solution of 110 g / L dissolved sodium carbonate so that the weight ratio of iron / sodium was 13. After adding sodium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0102] Comparative Example 4 200m in the precipitation reaction vessel 2 0.56 g of porous alumina (γ-Al2O3) powder having a specific surface area of ​​1 m² was added to 200 mL of a solution prepared by dissolving iron nitrate hydrate (55.8 g / L) in distilled water, and the mixture was heated to 60°C while stirring at 400 rpm. At this time, the porous alumina powder had a specific surface area of ​​1 m². 2 The solution was added in an amount that resulted in an iron content of 100 mg per unit. After the solution temperature reached 60°C, 180 g / L of ammonium carbonate aqueous solution was added using a syringe pump at a rate of 2 mL / min until the pH in the reactor reached 7.0. After the addition was complete, the mixture was stirred further at 400 rpm for 2 hours while maintaining the temperature at 60°C to produce a precipitate. The pH of the slurry after precipitation was 7.1. The produced precipitate was filtered to separate it from the solvent, washed with 2.5 L of distilled water, and dried at 110°C for 12 hours (completely dry).

[0103] The iron content in the Fe-Al2O3 powder obtained after drying was 67% by weight, and the iron content was adjusted by adding copper and potassium. Copper and potassium were supported on the Fe-Al2O3 powder by adding an aqueous solution containing 50 g / L of copper nitrate hydrate and 50 g / L of potassium nitrate so that the weight ratio of iron / (copper + potassium) was 20. At this time, copper and potassium were supported in equal weights. After adding copper and potassium, the catalyst was produced by drying at 110°C for 12 hours and calcining at 400°C for 3 hours.

[0104] Experimental Example 1 The iron content (wt%), specific surface area, and iron content per unit surface area of ​​each catalyst produced in the examples and comparative examples were measured, and the results are shown in Table 1 below.

[0105] (1) Iron content (wt%) Iron content was measured using the ICP-OES method. 0.01 g of each catalyst was taken and placed in a container with hydrogen peroxide and 1 mL of hydrochloric acid, and heated on a hot plate to dissolve. Then, 2 drops of 50 wt% hydrofluoric acid aqueous solution were added to the container using a dropper, and 0.1 mL of boric acid (57 g / L) was added 2 hours after the addition of the hydrofluoric acid aqueous solution, and the mixture was allowed to stand for 12 hours to completely dissolve the catalyst. After confirming that the catalyst was completely dissolved and the solution was clear, the solution was diluted with tertiary ultrapure water to prepare analytical sample solutions. The iron content in each sample was measured using iCAP PRO (ThermoFischer).

[0106] (2) Specific surface area (m 2 / g) The specific surface area of ​​the catalysts was measured using a standard nitrogen isothermal adsorption method based on the Brunauer-Emmett-Teller (BET) theory. Each catalyst was pretreated at 150°C for 3 hours using BELPREP VAC II (MicrotracBEL), and then nitrogen isothermal adsorption results were obtained at 77K (-196°C) using BELSORP MAX (MicrotracBEL). The specific surface area was calculated by applying the BET theory in the range of P / P0 (Relative Pressure) 0.05-0.35.

[0107] (3) Iron content per unit surface area (mg / m²) 2 ) Surface area 1m 2 The iron content (mg) per unit was calculated from the iron content and specific surface area of ​​the catalyst using the following formula 4.

[0108] [Formula 4] Iron content per unit surface area (mg / m²) 2 ) = [Iron content (wt%) / Specific surface area (m²) 2 ( / g) × 1000 mg / g

[0109] [Table 1]

[0110] As shown in Table 1 above, the catalysts produced in Examples 1 to 5 were confirmed to satisfy the specific ranges presented by the present invention in terms of iron content, specific surface area, and iron content per unit surface area of ​​the catalyst. In contrast, Comparative Examples 1 to 4 either did not satisfy all of the characteristics of iron content, specific surface area, and iron content per unit surface area of ​​the catalyst, or did not satisfy two of the characteristics.

[0111] This confirms that the iron content, specific surface area, and iron content per unit surface area of ​​the catalyst, adjusted to a specific range as presented by the present invention, are properties obtained by the manufacturing method presented by the present invention, which involves controlling the ratio of iron to an oxide-based support when supporting iron on an oxide-based support, or controlling the co-catalyst metal to the measured weight ratio relative to iron.

[0112] Experimental Example 2 The catalyst activity was confirmed by performing a direct hydrogenation reaction of carbon dioxide using the catalysts produced in the examples and comparative examples, and the results are shown in Table 2 below.

[0113] 0.5 g of each catalyst was charged into a fixed-bed reactor (stainless steel, 3 / 8 inch diameter). Before starting the reaction, the catalysts were activated by reduction treatment under a carbon monoxide atmosphere (>99.9 vol%) at 400°C for 8 hours. Subsequently, the raw material gas (H2:CO2:N2 = 72:24:4 volume ratio) was flowed at a flow rate of 75 mL / min, and the reaction temperature was adjusted to 340°C and the reaction pressure to 20 bar. The reaction was carried out while maintaining a constant flow rate of the raw material gas, and the molar ratio of hydrogen to carbon dioxide in the raw material gas was set to 3. Nitrogen was added as an internal standard. During the total reaction process of 48 hours, the reactants and products in the gas phase were analyzed by gas chromatography (GC), and the products in the liquid phase and the incidentally generated water were recovered from a cooling trap. The components of the liquid phase products were analyzed using another GC. Flow analysis before and after the reaction was performed using real-time measurements and by observing changes in the concentration of nitrogen, which served as an internal standard. Based on the results measured using GC, the carbon dioxide (CO2) conversion rate, TOF (turnover frequency), and C5+ selectivity (%) were calculated.

[0114] [Table 2]

[0115] As shown in Table 2 above, Examples 1 to 5 were found to be superior to Comparative Examples 1 to 4 in terms of carbon dioxide (CO2) conversion rate, TOF (turnover frequency), and C5+ selectivity (%). Specifically, Examples 1 to 5 showed a remarkable increase of more than 10 times in C5+ selectivity (%) compared to Comparative Example 1, and the carbon dioxide (CO2) conversion rate and TOF (turnover frequency) also increased significantly by approximately 4 times and 2 times, respectively. Furthermore, Examples 1 to 5 showed comparable levels of carbon dioxide (CO2) conversion rate and TOF (turnover frequency) compared to Comparative Example 2, while showing improvements of approximately 1.25 times and 1.72 times in C5+ selectivity (%).

[0116] Furthermore, Examples 1 to 5 showed comparable or slightly improved C5+ selectivity (%) compared to Comparative Examples 3 and 4, and demonstrated an improved carbon dioxide (CO2) conversion rate of approximately 5% to 12%, as well as a significant improvement in TOF (turnover frequency) of approximately 6% to 30%.

[0117] In this case, Examples 1 to 5 have a catalyst surface area of ​​1 m². 2 While the iron content per unit area falls within the range of 5 mg to 15.0 mg, the catalysts of Comparative Example 1 and Comparative Example 2 have a surface area of ​​1 m². 2 The iron content per unit was 1.2 mg and 3.0 mg, and the density of Fe sites on the catalyst surface, which are reaction active sites, was very low compared to Examples 1 to 6. In Comparative Examples 3 and 4, the surface area of ​​the catalyst was 1 m². 2 The iron content per unit is 19.4 mg and 15.5 mg, but the specific surface area is 35 m². 2 / g and 42m 2 The value was / g, and the usable catalyst surface area was about half that of Example 1.

[0118] From the above results, it was confirmed that catalysts satisfying the iron content, specific surface area, and iron content per unit surface area of ​​the catalyst as defined by the present invention have the effect of simultaneously improving carbon dioxide (CO2) conversion rate, TOF (turnover frequency), and C5+ selectivity (%).

Claims

1. A metal-oxide catalyst, The system comprises an oxide-based support and catalyst particles containing iron supported on the support, Surface area of ​​the catalyst 1 m ２ A catalyst with an iron content of 5 mg to 15 mg per unit.

2. The catalyst according to claim 1, wherein the iron is contained in an amount of 50% by weight or more and 65% by weight or less relative to 100% by weight of the catalyst.

3. The specific surface area of ​​the catalyst is 50 m². ２ / g to 100m ２ The catalyst according to claim 1, wherein the amount is / g.

4. The oxide-based support is SiO ２ Al ２ O ３ The catalyst according to claim 1, which is one or more selected from the group consisting of , and zeolite.

5. The catalyst according to claim 1, wherein the iron is the hematite phase.

6. The catalyst according to claim 1, wherein the iron is activated with one or more selected from the group consisting of magnetite, iron carbides, and metallic iron (Fe).

7. The catalyst particles further contain a co-catalyst metal, The catalyst according to claim 1, wherein the co-catalyst metal is one or more selected from the group consisting of copper, potassium, and sodium.

8. The catalyst particles further contain one or more co-catalyst metals selected from the group consisting of copper, potassium, and sodium. The catalyst according to claim 1, wherein the co-catalyst metal is contained in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the catalyst.

9. The catalyst according to claim 1, which is a catalyst for the direct hydrogenation reaction of carbon dioxide.

10. Step (S1) for producing iron-oxide catalyst particles, The steps include supporting a co-catalyst metal on the catalyst particles (S2), The process includes a step of firing after drying (S3), Step (S1) is a step (S1-1) in which an iron precursor is dissolved in a solvent to produce a first solution having an iron weight concentration of 20 g / L to 100 g / L, and an oxide-based support is added to the first solution and dispersed to produce a second solution, The second solution is heated to 40°C to 90°C while stirring, and an aqueous solution of the precipitating agent is added to produce a precipitate containing iron-oxide catalyst particles (S1-2), The steps include washing and filtering the precipitate and then drying it (S1-3), In step (S1-1), the oxide-based support has a surface area of ​​1 m². ２ Add an amount that provides 10 mg to 150 mg of iron per serving. A method for producing a catalyst, wherein the co-catalyst metal in step (S2) is supported in an amount such that the weight ratio of iron to co-catalyst metal is 5 to 15.

11. The aqueous solution of the precipitant in step (S1-2) contains the precipitant at a weight concentration of 50 g / L to 250 g / L. The method for producing a catalyst according to claim 10, wherein the precipitating agent is one or more selected from the group consisting of sodium carbonate, ammonium carbonate, aqueous ammonia, and sodium hydroxide.

12. The method for producing a catalyst according to claim 10, wherein the aqueous solution of the precipitant in step (S1-2) is added until the pH in the reactor becomes 7 to 8.

13. The method for producing a catalyst according to claim 10, wherein the iron precursor is one or more selected from the group consisting of iron nitrates, sulfates, acetates, chlorides, bromides, iodides, and hydrates thereof.

14. The method for producing a catalyst according to claim 10, wherein the stirring in step (S1-2) is performed at a speed of 100 rpm to 1000 rpm.

15. The method for producing a catalyst according to claim 10, wherein, in step (S1-2), after the addition of the aqueous solution of the precipitating agent is completed, the mixture is stirred for a further 0.5 to 24 hours.

16. The method for producing a catalyst according to claim 10, wherein the co-catalyst metal in step (S2) is one or more selected from the group consisting of copper, potassium, and sodium.

17. The method for producing a catalyst according to claim 10, wherein step (S2) is performed by an initial wetness impregnation method.

18. The method for producing a catalyst according to claim 10, wherein the drying in steps (S1-3) and (S3) is carried out at 100°C to 200°C for 5 to 24 hours, respectively.

19. The method for producing a catalyst according to claim 10, wherein the calcination in step (S3) is carried out by heat treatment at a temperature of 200°C to 600°C for 1 to 12 hours.

20. A method for producing a hydrocarbon compound, comprising a direct hydrogenation reaction step of carbon dioxide in the presence of the catalyst described in claim 1.

Images