Method for upcycling greenhouse gas into long-chain hydrocarbons using molten catalyst, molten catalyst therefor, and hydrocarbon composition prepared therefrom

Abstract

The present invention relates to a method for upcycling greenhouse gas into long-chain hydrocarbons, the method comprising the steps of: injecting a reaction gas containing greenhouse gas into a reactor; contacting the reaction gas and a two-layered molten catalyst disposed in the reactor, the two-layered molted catalyst including a first molten catalyst layer and a second molten catalyst layer positioned on the first molten catalyst layer, to induce a reaction; and obtaining a product containing hydrocarbons through the reaction through a single process.

Description

Method for upcycling greenhouse gases into long-chain hydrocarbons using a molten catalyst, a molten catalyst for the same, and a hydrocarbon composition produced therefrom

[0001] The present invention relates to a method for upcycling greenhouse gases into long-chain hydrocarbons using a molten catalyst, a molten catalyst for the same, and a hydrocarbon composition produced therefrom.

[0002]

[0003] Reducing emissions and effectively utilizing greenhouse gases, particularly carbon dioxide (CO2) and methane (CH4), which are identified as the primary causes of global warming, is an immediate global challenge. Carbon Capture and Utilization (CCU) technology, which converts these gases into useful chemicals or fuels rather than simply capturing and storing them, is garnering attention as a key strategy for realizing a carbon-neutral society. In particular, the technology to directly synthesize long-chain hydrocarbons from greenhouse gases is of great importance in replacing the existing fossil fuel-based chemical industry and establishing a sustainable supply system for fuels and chemical raw materials.

[0004] The most representative hydrocarbon synthesis technology known to date is the Fischer-Tropsch synthesis method (hereinafter referred to as the FT synthesis method), which has a history of over 100 years. The FT synthesis method primarily involves a step of producing syngas (a mixture of H2 and CO) from coal, natural gas, biomass, or greenhouse gases such as carbon dioxide or methane. The syngas produced in this way is then reacted under high temperature (typically 200–350 °C) and high pressure (typically 5–40 atmospheres) conditions on an iron (Fe) or cobalt (Co)-based solid catalyst to be converted into hydrocarbons of various lengths. However, the FT synthesis method has technical and economic limitations, such as (1) the complexity of the multi-stage process that must first produce synthesis gas, (2) high energy consumption and equipment costs due to high temperature and high pressure reaction conditions, and (3) the need for a separate reforming process or hydrogen production facility through water electrolysis, particularly to produce synthesis gas from greenhouse gases.

[0005] In addition to the FT synthesis method, various studies have been conducted to synthesize hydrocarbons using greenhouse gases. For example, electrochemical CO2 reduction technology has the advantage of being operable at room temperature and pressure and easy to utilize renewable energy, but it is mainly limited to producing C1-C2 compounds with a small number of carbon atoms, such as formic acid, carbon monoxide, methane, and ethylene, and there are still difficulties in synthesizing long-chain hydrocarbons with C6 or more with high efficiency.

[0006] Regarding thermochemical methods, the alkane aromatization process using solid acid catalysts such as zeolites has been studied. This method is used, for example, with butane (C4H 10Although the potential to produce hydrocarbons up to C17 by reacting carbon dioxide with methane was demonstrated, it was pointed out that the product contained a large amount of polycyclic aromatic hydrocarbons (PAHs), which can cause environmental pollution. Additionally, alkanes with a larger number of carbon atoms than methane were often used as the main reactants.

[0007] The methane dry reforming reaction is primarily used to produce synthesis gas by reacting methane with carbon dioxide; while this process can generate small amounts of short-chain hydrocarbons (C2-C3) as byproducts, it is unsuitable for obtaining long-chain hydrocarbons as the main product.

[0008] In summary, existing greenhouse gas conversion and hydrocarbon synthesis technologies have faced one or more challenges in efficiently synthesizing long-chain hydrocarbons, such as multi-stage processes, harsh reaction conditions, a limited range of product carbon atoms, the potential for hazardous byproduct generation, or low productivity and selectivity. Therefore, there is an urgent need for the development of innovative technologies capable of directly converting major greenhouse gases, such as carbon dioxide and methane, into C7 or longer long-chain hydrocarbons in an environmentally friendly manner through a one-pot process under milder conditions and with high efficiency and selectivity.

[0009]

[0010] The present invention aims to overcome the limitations of the prior art mentioned in the background art above and to achieve the following objectives.

[0011] First, the purpose is to provide a new method that can directly and efficiently synthesize the desired hydrocarbon in a single process (one-pot process) by solving the problems of complex and energy-consuming multi-stage processes that require a separate synthesis gas production step or harsh reaction conditions of high temperature and high pressure, such as the existing Fischer-Tropsch (FT) synthesis method, when producing long-chain hydrocarbons using greenhouse gases, particularly carbon dioxide and methane, as raw materials.

[0012] Second, the purpose is to provide a technology capable of producing long-chain hydrocarbons with high yield and selectivity that have a wide range of industrial value and are broad in the C7 to C33 range, going beyond the limitations of short-chain compounds (e.g., C1-C6) mainly generated in electrochemical carbon dioxide reduction technologies.

[0013] Third, the purpose is to provide a method for producing hydrocarbons in a more environmentally friendly manner by minimizing or controlling the generation of harmful byproducts, such as polycyclic aromatic hydrocarbons (PAHs), which can be problematic in some thermochemical conversion processes.

[0014] Fourth, the purpose is to provide a novel molten catalyst system exhibiting excellent activity and controlled selectivity that enables the effective conversion of greenhouse gases as described above.

[0015] Fifth, the purpose is to provide a long-chain hydrocarbon composition that is manufactured through the method and catalyst system of the present invention and has a specific carbon number distribution and chemical composition, which can be usefully applied in various industrial fields such as fuels and chemical raw materials.

[0016]

[0017] A method for upcycling greenhouse gases into long-chain hydrocarbons according to one embodiment of the present invention is characterized by comprising the steps of: injecting a reaction gas containing greenhouse gases into a reactor; inducing a reaction by contacting the reaction gas with a two-stage molten catalyst comprising a first molten catalyst layer disposed within the reactor and a second molten catalyst layer located above the first molten catalyst layer; and obtaining a product containing hydrocarbons in a single process through the reaction.

[0018] In one embodiment, the hydrocarbon may be characterized as being a long-chain hydrocarbon having 7 or more carbon atoms. The hydrocarbon may have a carbon number in the range of 33 or fewer.

[0019] In one embodiment, the reaction gas may be characterized by comprising at least one selected from the group consisting of methane, carbon dioxide, hydrogen, water, CO, ethane, propane, butane, ethene, propene, and butene.

[0020] In one embodiment, the reaction may be characterized by being carried out at a temperature of 250 ℃ to 1,200 ℃.

[0021] In one embodiment, the reaction may be characterized by being carried out at a pressure of atmospheric pressure to 50 atmospheres.

[0022] In one embodiment, the first molten catalyst layer is an alloy comprising at least one metal component that exists in a liquid state within an operating temperature range and contributes to the activation of greenhouse gas reactants or the formation of carbon-carbon bonds, and the second molten catalyst layer comprises at least one metal halide, wherein the metal halide is selected from the group consisting of a first metal halide that exhibits Lewis acid properties to promote hydrocarbon chain growth and a second metal halide that forms a eutectic mixture with the first metal halide to improve the stability and fluidity of the molten salt layer.

[0023] In one embodiment, at least one metal component constituting the first molten catalyst layer may be selected from the group consisting of metal-based materials including gallium (Ga), bismuth (Bi), tin (Sn), nickel (Ni), copper (Cu), and iron (Fe), and their salts (halides, nitrates, and carbonates).

[0024] In one embodiment, at least one metal halide constituting the second molten catalyst layer may be characterized as being selected from the group consisting of metal halides including manganese, potassium, lithium, calcium, magnesium, and copper.

[0025] A hydrocarbon composition according to one embodiment of the present invention is prepared by a method according to one embodiment of the present invention and comprises hydrocarbons having a carbon number in the range of C7 to C33, wherein the hydrocarbons comprise a plurality of compound groups selected from aliphatic hydrocarbons, aromatic hydrocarbons, and oxyoxides.

[0026] A hydrocarbon composition according to one embodiment of the present invention comprises a plurality of hydrocarbon compounds having a carbon number in the range of C7 or higher, wherein the plurality of hydrocarbon compounds comprise (i) one or more aliphatic hydrocarbons selected from cyclohexane derivatives, cyclohexadiene derivatives, cyclopentadiene derivatives having alkyl groups, and linear olefins, (ii) one or more aromatic hydrocarbons selected from alkylbenzene derivatives and polycyclic aromatic hydrocarbon derivatives, and (iii) one or more oxygenates selected from aromatic aldehydes, ketones, and esters.

[0027] In one embodiment, the composition is prepared under reaction temperature conditions ranging from 250°C to 1,200°C, and may be characterized in that the relative content ratio of the aliphatic hydrocarbon, the aromatic hydrocarbon, and the oxygenate changes according to the reaction temperature.

[0028] In one embodiment, the composition may be characterized in that C8-C13 hydrocarbons among C7-C18 range hydrocarbons are included in a relatively high proportion compared to hydrocarbons of other carbon number ranges.

[0029] A molten catalyst according to another embodiment of the present invention is characterized by comprising: a first molten catalyst layer comprising one or more selected from the group consisting of metal-based materials including gallium (Ga) and bismuth (Bi), tin (Sn), nickel (Ni), copper (Cu) and iron (Fe) and their salts, and providing a first Lewis acid site; and a second molten catalyst layer disposed on top of the first molten catalyst layer, comprising one or more selected from the group consisting of metal halides including manganese, potassium, lithium, calcium, magnesium and copper, and providing a second Lewis acid site to promote the production of long-chain hydrocarbons.

[0030] In one embodiment, the first molten catalyst layer comprises an alloy of gallium (Ga) and bismuth (Bi), and the composition ratio is GaxBi 1-x (Here, x is the mole fraction of gallium (Ga) in the range of 0.11 to 0.50) It can be characterized as such.

[0031] In one embodiment, the second molten catalyst layer may be characterized by comprising a mixture of manganese halide and alkali metal halide, wherein the molar ratio of manganese halide to alkali metal halide is 33:67 to 67:33.

[0032] An upcycling system for greenhouse gases into long-chain hydrocarbons according to another embodiment of the present invention is characterized by comprising: (a) a reaction gas supply unit including a plurality of mass flow controllers (MFCs) that supply a plurality of reaction gases containing greenhouse gases at a controlled flow rate; (b) a vertical reactor made of quartz tube material connected to the reaction gas supply unit, having a two-stage molten catalyst disposed inside, and in which the reaction gas comes into contact with the molten catalyst to undergo a chemical reaction; (c) a temperature control unit including a high-temperature electric furnace that surrounds the outside of the reactor and controls the internal temperature; and (d) a product recovery unit connected to the outlet of the reactor to condense long-chain hydrocarbons among the gaseous products discharged and recover them in a liquid or solid state.

[0033] In one embodiment, the molten catalyst comprises a first molten catalyst layer and a second molten catalyst layer located above the first molten catalyst layer, wherein the first molten catalyst layer is an alloy comprising at least one metal component that exists in a liquid state within an operating temperature range and contributes to the activation of greenhouse gas reactants or the formation of carbon-carbon bonds, and the second molten catalyst layer comprises at least one metal halide, wherein the metal halide is selected from the group consisting of a first metal halide that exhibits Lewis acid properties to promote hydrocarbon chain growth and a second metal halide that forms a eutectic mixture with the first metal halide to improve the stability and fluidity of the molten salt layer.

[0034] In one embodiment, the reactor may be characterized by having a quartz filter with pores formed in its central portion to support the molten catalyst, and the reaction gas may pass through the quartz filter and be injected into the molten catalyst layer in the form of bubbles.

[0035]

[0036] The present invention provides the following excellent effects by solving the above problem.

[0037] First, the method for producing long-chain hydrocarbons according to one embodiment of the present invention synthesizes long-chain hydrocarbons in the C7 or higher range by directly contacting a reaction gas containing a greenhouse gas (e.g., carbon dioxide, methane, etc.) with a specific two-stage molten catalyst in a single process, thereby significantly simplifying the process compared to existing multi-stage processes (e.g., synthesis of FT after synthesis of synthesis gas), and thereby reducing facility investment costs and operating costs and increasing energy efficiency.

[0038] Second, unlike existing technologies that are limited to producing short-chain hydrocarbons with C6 or less or C10 or less, the method of the present invention can produce long-chain hydrocarbons with a wide distribution of carbon numbers ranging from C7 or more (C33 or less) with high yield, thereby enabling the securing of various hydrocarbon resources that can be utilized as raw materials for high-value-added chemical products, diesel, jet fuel, etc.

[0039] Third, the molten catalyst system and manufacturing method according to the present invention can operate effectively even under relatively mild pressure conditions (e.g., near atmospheric pressure), thereby significantly improving the stability and ease of operation of the equipment compared to some existing processes that require ultra-high pressure conditions.

[0040] Fourth, the present invention provides flexibility to adjust the average carbon chain length, carbon number distribution, and chemical composition (e.g., relative proportions of aliphatic hydrocarbons, aromatic hydrocarbons, and oxyoxides) of the resulting long-chain hydrocarbon mixture to suit specific applications by precisely controlling process variables such as the reaction temperature (e.g., 600°C to 900°C), the metal and salt composition of the catalyst, and the composition and flow rate of the reaction gas. For example, under certain temperature conditions, cycloalkane series may be predominantly produced, or under other temperature conditions, the production of specific aromatic hydrocarbons containing ethyl functional groups may be prominent.

[0041] Fifth, the molten catalyst having a two-stage structure of the present invention exhibits high activity in the conversion reaction of greenhouse gases and excellent selectivity for the target long-chain hydrocarbon. In addition, the molten catalyst can have the effect of suppressing the decrease in catalyst activity by allowing carbon deposits (coke) that may be generated during the reaction to float to the surface due to the difference in density, which can be advantageous for ensuring long-term operational stability.

[0042] Sixth, by utilizing major greenhouse gases, carbon dioxide and methane, as direct raw materials and converting them into useful chemical resources, the present invention can simultaneously achieve greenhouse gas reduction and carbon resource utilization, thereby actively contributing to the realization of carbon neutrality and a circular economy; this is expected to play an important role in enhancing the sustainability of the existing fossil fuel-based chemical industry.

[0043] However, the effects of the present invention are not limited to those described above, but include all effects naturally realized through the various configurations proposed in the present invention.

[0044]

[0045] FIG. 1 is a conceptual diagram of a process for one-pot upcycling of C1 greenhouse gases into long-chain hydrocarbons according to one embodiment of the present invention.

[0046] FIG. 2 is a configuration diagram of an experimental apparatus for a thermochemical upcycling system according to one embodiment of the present invention.

[0047] Figure 3 is a photograph of a catalyst cooled after a reaction according to one embodiment of the present invention.

[0048] FIG. 4 shows the results of producing long-chain hydrocarbons using a GB+MK molten catalyst according to one embodiment of the present invention, wherein (A) shows the CH4 and CO2 conversion rates for various catalyst combinations, (B) shows the CH4 and CO2 conversion rates for a reference catalyst at different reaction temperatures, (C) shows the total GC-MS spectrum of the product when using a reference catalyst and a comparison catalyst, (D) shows the relative amount of long-chain hydrocarbons produced according to reaction time, (E) shows the relative content of major chemical groups in the product according to operating time, and (F) shows the normalized relative abundance of compounds according to the number of carbon atoms.

[0049] FIG. 5 shows the chemical structure of a long-chain hydrocarbon according to a reaction temperature according to one embodiment of the present invention, where (A) is the chemical structure of the main product, (B) is the color and relative content of the product solution according to the operating temperature, and (C) is the result of the 1H-13C HSQC NMR spectrum analysis.

[0050] FIG. 6 shows the results of catalyst characteristic analysis according to one embodiment of the present invention, where (A) is an SEM / EDS elemental mapping image, (B) is an XRD analysis result, (C) is an in-situ high-temperature XRD analysis result, and (D) is an XPS analysis result.

[0051] FIG. 7A compares the GC-MS analysis results when only synthesis gas is injected and when methane + carbon dioxide is injected, according to one embodiment of the present invention. FIG. 7B shows the GC-MS spectra of hydrocarbon products for various catalysts according to one embodiment of the present invention. FIG. 7C shows the 71Ga NMR spectrum analysis results of a solution according to one embodiment of the present invention. FIG. 7D shows the Cl 2p XPS spectrum analysis results according to one embodiment of the present invention. FIG. 7E compares the GC-MS analysis results according to various reaction gas combinations according to one embodiment of the present invention. FIG. 7F shows the change in relative content of a CDCl3 solution according to the injected gas according to one embodiment of the present invention.

[0052] FIGS. 8A-E are GC-MS spectra of long-chain hydrocarbon generation results using various metal combination catalysts according to one embodiment of the present invention, where (A) shows the result using SnBi + LiCl, (B) shows the result using NiBi + CaCl2, (C) shows the result using CuBi + MgCl2, (D) shows the result using FeBi + CuCl2, and (E) shows the result using a high-entropy catalyst (FeSnNiCuBi + complex salt).

[0053] FIG. 9 is a graph showing the change in (A) methane conversion rate and (B) carbon dioxide conversion rate according to operating pressure in one embodiment of the present invention.

[0054] FIG. 10 is a graph of data showing that methane pyrolysis (methane as a reactant) was carried out in a temperature range of 700 ℃ to 1100 ℃ using a GaBi catalyst, as an example of an operating temperature range according to one embodiment of the present invention.

[0055] FIG. 11 is an example relating to an ethylene reactant according to one embodiment of the present invention, and is a graph of GC MS spectrum data for a hydrocarbon product when ethylene pyrolysis is carried out at 900 °C using C2H4 as the reactant.

[0056] FIG. 12 is an example of a hydrocarbon product in the range of C33 or lower according to one embodiment of the present invention, and is a GC MS spectrum graph of the hydrocarbon product when CH44sccm and CO24sccm were tested as reactants at 900°C for 17 hours using a GB+MK catalyst, showing peaks for C32 and C33 products at RT=44.94 and 45.96 min.

[0057]

[0058] The embodiments of the present invention are illustrative for the purpose of explaining the technical concept of the present invention. The scope of rights according to the present invention is not limited to the embodiments presented below or the specific description thereof.

[0059] All technical and scientific terms used in this invention, unless otherwise defined, have the meaning generally understood by those skilled in the art to which this invention pertains. All terms used in this invention are selected for the purpose of further explaining this invention and are not selected to limit the scope of rights according to this invention.

[0060] Expressions such as "comprising," "having," "having," etc. used in the present invention should be understood as open-ended terms implying the possibility of including other embodiments, unless otherwise stated in the phrase or sentence containing such expressions.

[0061] Unless otherwise stated, singular expressions described in the present invention may include the meaning of the plural form, and this applies likewise to singular expressions described in the claims.

[0062]

[0063] The effective reduction and utilization of greenhouse gases—identified as the primary causes of global warming and climate change, particularly carbon dioxide (CO2), whose atmospheric concentration is continuously increasing, and methane (CH4), which causes a powerful greenhouse effect—are urgent global challenges. Against this backdrop, the importance of Carbon Capture and Utilization (CCU) technology is growing day by day. This technology goes beyond simply capturing and sequestering greenhouse gases to chemically converting them into useful materials or energy sources for recycling. In particular, the technology to directly synthesize hydrocarbons from methane and / or carbon dioxide—specifically long-chain hydrocarbons in the C7 and higher ranges used as core raw materials for fuels and various chemical industries—holds significant importance in reducing dependence on fossil fuels and establishing sustainable chemical and energy production systems.

[0064] However, most hydrocarbon synthesis technologies currently commercialized or under research and development, such as the Fischer-Tropsch process, electrochemical reduction, or other thermochemical conversion methods, have limitations including the complexity of multi-stage processes, the requirement for harsh reaction conditions of high pressure or high temperature, the limited production of mainly short-chain hydrocarbons, the generation of unwanted byproducts, and low energy efficiency or low selectivity.

[0065] Accordingly, the main purpose of the present invention is to provide a new upcycling method that directly and efficiently synthesizes various hydrocarbons, particularly long-chain hydrocarbons with a C7 or higher range, from greenhouse gases including methane and / or carbon dioxide in a one-pot process using a two-stage molten catalyst system to solve the various problems of the conventional technology described above.

[0066] More specifically, the present invention aims to overcome the disadvantages of existing solid catalyst-based processes and enable the selective production of desired long-chain hydrocarbons by effectively dispersing a reaction gas within a molten catalyst layer that maintains a liquid state at a high temperature (e.g., in the range of 250°C to 1,200°C) and inducing a reaction by sufficiently contacting the catalyst.

[0067]

[0068] Hereinafter, a method for upcycling greenhouse gases into long-chain hydrocarbons according to one embodiment of the present invention will be described in more detail with reference to the drawings.

[0069] Figure 1 schematically illustrates a conceptual diagram of an upcycling process for greenhouse gases into long-chain hydrocarbons according to one embodiment of the present invention.

[0070] Referring to FIG. 1, the system of the present invention includes a reactant supply unit, a reactor filled with a molten catalyst, and a product recovery unit for recovering the generated hydrocarbon.

[0071] Greenhouse gases, including methane (CH4) and / or carbon dioxide (CO2), supplied from the reactant feed section are injected into the bottom of the reactor. The injected reaction gas passes through a two-stage molten catalyst layer provided inside the reactor. The molten catalyst layer is arranged as a first molten catalyst layer and a second molten catalyst layer according to the flow direction of the injected reaction gas. For example, the first molten catalyst layer and the second molten catalyst layer above it may be positioned sequentially. In this process, the reaction gas effectively comes into contact with the molten catalyst and is converted into various hydrogen or hydrocarbon products through a chemical reaction. A purging gas (e.g., Ar) may be supplied to the top of the reactor. Gaseous products and unreacted gases exiting the reactor are guided through a discharge line to a product recovery section containing a condenser. In the condenser, long-chain hydrocarbons, primarily in the C7 or higher range, are condensed and captured in a liquid or solid state, and uncondensed gases (e.g., hydrogen (H2), carbon monoxide (CO), unreacted methane and carbon dioxide, etc.) can be discharged outside the system or transferred to additional analysis or recycling processes.

[0072] Below, we will examine each component and operating principle of the present invention in more detail.

[0073] Greenhouse gas upcycling according to the present invention can be carried out within the reaction system shown in FIGS. 1 and 2.

[0074] The reactor can be constructed as a vertically installed quartz tube, and the molten catalyst of the two-stage structure described above is filled inside. A porous quartz filter is formed in the middle part of the quartz tube, so that a molten catalyst layer is positioned on this filter and a molten salt layer is formed on top of it.

[0075] The reaction gas is injected into the bottom of the reactor by controlling the flow rate through individual Mass Flow Controllers (MFCs).

[0076] The injected reaction gas passes through the pores of the quartz filter, dispersed in the form of fine bubbles, and rises as it passes through the molten catalyst layer. This bubble column method maximizes the contact area between the gaseous reactants and the liquid molten catalyst and secures sufficient reaction time, thereby increasing mass transfer and reaction efficiency.

[0077] Inert purging gas such as argon (Ar) is supplied to the upper space of the reactor through a separate MFC to minimize incidental gaseous reactions and control the internal atmosphere of the reactor.

[0078] The temperature of the reactor can be precisely controlled using an external high-temperature electric furnace and thermocouples (TC01, TC02) installed internally or externally. The temperature of the reactor may be 250 ℃ to 1,200 ℃, preferably 600 ℃ to 900 ℃. The reaction pressure may be controlled within the range of atmospheric pressure to 50 atmospheres. An electronic pressure controller (EPC) that ensures safety by releasing gas when the set pressure is exceeded may be installed at the reactor inlet and equipped with a pressure gauge.

[0079] A product recovery unit is connected to the reactor outlet to collect the generated long-chain hydrocarbons. The product recovery unit includes a condenser through which cooling water is circulated, and the connecting pipe between the reactor outlet and the condenser is maintained at a constant temperature (e.g., 250–300°C) using a heating tape or the like to prevent high-boiling point hydrocarbons in the product from condensing in advance and causing blockage. In the condenser, long-chain hydrocarbons in the product discharged in the gaseous phase are liquefied or solidified and collected.

[0080] The molten catalyst used in the present invention is characterized by a two-stage structure consisting of a first molten catalyst layer and a second molten catalyst layer. This two-stage structure maximizes overall catalytic performance through interlayer interaction while each layer performs its own unique catalytic function.

[0081] The first molten catalyst layer exists in a liquid state within the operating temperature range and participates in the activation and conversion reactions of greenhouse gases (CH4, CO2) that are greenhouse gas reactants. The alloy constituting the first molten catalyst layer may include a first metal (M1) that provides Lewis acid sites for the oligomerization and cyclization reactions of alkanes, and a second metal (M2) that causes the alloy to exist in a liquid state at the reaction temperature. For example, the first metal may be at least one metal component constituting the first molten catalyst layer selected from the group consisting of metal-based materials including gallium (Ga), tin (Sn), nickel (Ni), copper (Cu), and iron (Fe) and their salts, and the second metal may be bismuth (Bi). More specifically, the first molten catalyst layer is M1 x M2 1-x An alloy having a composition (where x can be 0.01 to 0.5) may be used. In the case of a catalyst composed solely of a pure second metal, there is a problem of low catalytic activity, but in the present invention, by including a first metal together, the conversion rate of greenhouse gases is significantly increased.

[0082] A second molten catalyst layer is placed after the first molten catalyst layer in the direction of reactant flow and serves to promote the growth and selective production of long-chain hydrocarbons. For example, the second molten catalyst layer may include a first molten salt and a second molten salt. As the first molten salt, metal halides such as manganese (Mn), lithium (Li), calcium (Ca), magnesium (Mg), and copper (Cu) may be used, and as the second molten salt, alkali metal halides (e.g., potassium chloride, KCl) may be used. In this case, the molar ratio of the first molten salt to the second molten salt may be 0.33:0.67 to 0.67:0.33. The second molten catalyst layer provides additional Lewis acid sites capable of promoting carbon-carbon bond formation reactions, such as Friedel-Crafts alkylation or Diels-Alder reactions, thereby contributing to the growth of the chain lengths of the initial hydrocarbon intermediates generated in the first molten catalyst layer. Additionally, the first molten salt has a synergistic effect that improves the performance of the entire catalyst system by stabilizing the active sites of the first molten catalyst layer and controlling the diffusion of reaction intermediates through physical and chemical interactions at the interface with the first molten catalyst layer. Furthermore, by using the second molten salt together with the first molten salt, the total weight of the second molten catalyst layer is reduced while maintaining the conversion rate of the reaction gas, thereby improving operational stability by preventing salt layer collapse and alleviating filter clogging.

[0083] The molten catalyst of the present invention can be manufactured and activated in the following way.

[0084] First, precursors of the first metal and the second metal constituting the first molten catalyst layer (e.g., high-purity Ga and Bi shots) are mixed in a predetermined ratio and arc melted in a vacuum arc melter to produce a uniform alloy.

[0085] The manufactured metal alloy is loaded onto a porous support (e.g., a quartz filter) installed inside a reactor (e.g., a quartz tube).

[0086] Next, the salt precursors constituting the second molten catalyst layer are uniformly mixed and added to the top of the already loaded metal layer.

[0087] Afterward, the reactor loaded with the catalyst is heated stepwise under a gas atmosphere containing hydrogen. For example, the metal alloy can be melted by heating to 600°C in the first step and maintained for a certain period of time, then cooled to ensure homogeneity, and then reheated to 750°C together with the salt layer to form a molten salt layer, and the catalyst can be activated through a reduction process for a certain period of time.

[0088] Finally, the hydrocarbon synthesis reaction is prepared by setting the reaction temperature to the target operating temperature. The reaction temperature is 250 ℃.

[0089] It can be up to 1,200 ℃, and preferably up to 600 ℃ to 900 ℃.

[0090] Figure 3 is a photograph showing the actual appearance of the catalyst cooled after the reaction through this process.

[0091]

[0092] Examples

[0093] Hereinafter, preferred embodiments are presented to aid in understanding the present invention; however, the following embodiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0094]

[0095] Example 1: Reference catalyst (Ga0 .11 Bi 0.89 Synthesis of long-chain hydrocarbons using MnCl2-KCl (67:33 at %)

[0096] In this embodiment, a two-stage molten catalyst was prepared as follows.

[0097] First, the first molten catalyst layer (Ga 0.11 Bi 0.89 Manufactured ).

[0098] High-purity gallium (Ga, 99.999%, Sigma-Aldrich) and bismuth (Bi, 4-30 mesh, 99.9%, Sigma-Aldrich) were weighed to achieve an atomic fraction (at %) of Ga:Bi = 11:89. The weighed metal precursors were loaded onto a water-cooled copper plate of a vacuum arc melting furnace (SAMVAC), and the interior of the chamber was 9×10 -5 Purging with argon (Ar) gas was performed until a target vacuum of Pa was reached. After undergoing a gettering process in which a titanium (Ti) getter was melted for approximately 40 seconds to remove residual oxygen, a current of approximately 100 A was applied to melt the metal precursors together and alloy them. To ensure homogeneity, the prepared alloy was flipped once and melted again, repeating this process. The Ga thus prepared 0.11 Bi 0.89 The alloy was then prepared to be loaded into the reactor.

[0099] For the preparation of the second molten catalyst layer (MnCl2-KCl, 67:33 at %), manganese chloride (MnCl2, ≥99%, Sigma-Aldrich) and potassium chloride (KCl, 99.0-100.5%, Sigma-Aldrich) powders were used. Before use, the manganese chloride powder was dried in a vacuum oven at 200°C for about 20 hours to remove moisture. The dried manganese chloride and potassium chloride were weighed to achieve an atomic fraction (at %) of MnCl2:KCl = 67:33, uniformly mixed, and prepared for loading onto the first molten catalyst layer.

[0100] Next, a two-stage catalyst layer was formed inside the reactor and activation was performed. A vertical reactor was used, consisting of a quartz tube with a length of 700 mm, an outer diameter of 12 mm, and an inner diameter of 10 mm, with a 1 mm thick G3 grade quartz filter welded to the center. First, the previously prepared Ga 0.11 Bi 0.89An amount equivalent to a height of approximately 2 cm of the alloy was loaded onto a quartz filter. Subsequently, under a mixed gas atmosphere of argon (Ar, 10 sccm) and hydrogen (H2, 10 sccm), the mixture was heated to 600 ℃ at a heating rate of 15 ℃ per minute and maintained for 30 minutes, after which the reactor was slowly cooled to room temperature. Next, an amount of MnCl2-KCl mixed salt powder equivalent to a height of approximately 0.5 cm was added to the cooled metal layer. Then, under a mixed gas atmosphere of Ar (10 sccm) and H2 (10 sccm), the mixture was heated again to 750 ℃ ​​at a heating rate of 15 ℃ per minute and the reduction process was carried out for 50 minutes. After reduction, the inside of the reactor was purged with Ar gas for approximately 1 hour and 30 minutes, and then the temperature was raised to the final reaction temperature of 800 ℃ to complete the preparation of the catalyst for the hydrocarbon synthesis reaction.

[0101] Figure 3 shows the catalyst cooled after the reaction.

[0102] The hydrocarbon synthesis reaction was carried out using the system as illustrated in Figures 1 and 2. Methane (CH4, 4 sccm) and carbon dioxide (CO2, 4 sccm) were used as reaction gases, and the flow rates of each gas were precisely controlled via a mass flow controller and injected into the bottom of the reactor. Argon (Ar) was continuously purged at a flow rate of 10 sccm in the upper space of the reactor to suppress incidental gaseous reactions. The reactor temperature was maintained at 800 °C using an external high-temperature electric furnace and thermocouples, and the reaction was performed under atmospheric pressure (approximately 1 atm) without separate pressure control. In some experiments, the reactor inlet pressure was increased to 1.4 atm to evaluate the effect of pressure. A pressure gauge and an electronic pressure controller (EPC) were installed at the reactor inlet and configured to automatically discharge gas for safety if the internal reactor pressure exceeded 1200 torr. The reaction was carried out continuously for a total of 4, 8, or 17 hours.

[0103] The gaseous product discharged from the reactor outlet was transferred to a condenser through a connecting pipe maintained at approximately 290 °C using a heating tape. Cooling water was circulated in the condenser to liquefy or solidify high-boiling point products, including long-chain hydrocarbons in the C7 or higher range, for collection. The collected liquid and waxy products were recovered using 500 μl of CDCl3 solvent after the experiment, and their composition and structure were qualitatively and quantitatively analyzed using gas chromatography-mass spectrometry (GC-MS, Thermo Scientific ISQ LT) and nuclear magnetic resonance spectroscopy (NMR, 850 MHz Avance III HD Bruker). Fluoranthene was used as an internal standard when necessary. The non-condensable gas (unreacted gas, H2, CO, etc.) that passed through the condenser was mixed with nitrogen (N2, 1 sccm, internal standard) and its composition was analyzed in real time through online-connected gas chromatography (GC, Younglin Chrozen GC, TCD detector, Carboxen-1000 column) and mass spectrometry (MS, Pfeiffer Vacuum Thermostar).

[0104] Figure 4 is a comprehensive graph showing the analysis results related to Example 1, where (A) shows the CH4 and CO2 conversion rates for various catalyst combinations, (B) shows the CH4 and CO2 conversion rates for the reference catalyst at different reaction temperatures, (C) shows the overall GC-MS spectrum of the product when using the reference catalyst and the comparison group catalyst, (D) shows the relative amount of long-chain hydrocarbons produced according to reaction time, (E) shows the relative content of major chemical groups in the product according to operating time, and (F) shows the normalized relative abundance of compounds by number of carbon atoms.

[0105] Figure 4A is a bar graph comparing the conversion rates of methane (CH4) and carbon dioxide (CO2) when various catalyst combinations were used under reaction conditions of 800 °C and 17 hours. The X-axis represents the composition of the catalysts used, arranged in the order of Bi (pure bismuth metal layer), GB (GaBi alloy metal layer), MK (MnCl2-KCl salt layer), Bi+MK (Bi metal layer and MK salt layer), GB+K (GB metal layer and KCl salt layer), GB+M (GB metal layer and MnCl2 salt layer), and GB+MK (two-stage structure of GB metal layer and MK salt layer). For each catalyst combination, the methane conversion rate is indicated by blue bars, and the carbon dioxide conversion rate by red bars. Referring to Figure 4A, it can be seen that the GB+M catalyst combination and the GB+MK catalyst combination exhibit significantly higher methane conversion rates (approx. 10%) and carbon dioxide conversion rates (approx. 30%) compared to other combinations. Meanwhile, in initial experiments, the GB 2 cm + M (MnCl2) 0.5 cm catalyst exhibited high methane and carbon dioxide conversion rates; however, stable operation was difficult due to pressure rise caused by clogging of the quartz filter resulting from the collapse of the pure MnCl2 salt layer during the heating and reduction processes. To resolve this issue, KCl was added to prepare an MnCl2-KCl salt, which allowed for the stabilization of operation by controlling the total weight and viscosity of the salt layer while maintaining the gas conversion rate. Consequently, this demonstrates that a two-stage structure utilizing both GaBi alloy and MnCl2 exhibits a synergistic effect in greenhouse gas conversion. In particular, the conversion rate was very low when using the GB+K combination without MnCl2 or MK alone without a metal layer, indicating the importance of using both a metal layer and a salt layer for the conversion of methane and carbon dioxide.

[0106] Figure 4B is a bar graph showing the methane and carbon dioxide conversion rates when a reaction was carried out for 4 hours using a GB+MK catalyst at varying reaction temperatures of 600 ℃, 700 ℃, 800 ℃, and 900 ℃. The X-axis represents the reaction temperature, and the Y-axis represents the conversion rate (%). As the reaction temperature increases, both the methane and carbon dioxide conversion rates show an upward trend; at 600 ℃, the conversion rates improved to approximately 5% for methane and 12% for carbon dioxide, and at 900 ℃, to approximately 13% for methane and 42% for carbon dioxide. This indicates that the catalyst system of the present invention exhibits higher activity at high temperatures.

[0107] Figure 4C shows the GC-MS analysis results of the products after performing reactions at 800 °C for 17 hours using various catalyst combinations (GB 2 cm, MK 0.5 cm, GB 2 cm+MK 0.5 cm). The X-axis represents the retention time (min) in the GC column, and the Y-axis represents the relative abundance measured by the detector. As shown in Figure 4C, when the GB 2 cm+MK 0.5 cm two-stage catalyst was used, multiple peaks were observed in the range of 7 to 40 minutes, indicating the formation of various hydrocarbon compounds. In contrast, when GB 2 cm or MK 0.5 cm was used alone, hardly any noticeable peaks were observed. This reconfirms that the combination of the GaBi metal layer and the MnCl2-KCl salt layer exerts a synergistic effect on the formation of long-chain hydrocarbons.

[0108] Figure 4D is a graph showing the change in the relative abundance of the product according to reaction time (4, 8, and 17 hours) at 800 °C using a GB 2 cm + MK 0.5 cm catalyst. The Y-axis represents the relative abundance based on an internal standard (fluoranthene). Looking at the graph, it can be seen that the relative abundance of the product increases proportionally as the reaction time increases, which means that the reaction proceeds continuously.

[0109] Figure 4E is a bar graph showing the change in the relative content of major chemical groups in the product according to operating time (4, 8, and 17 hours). The products were broadly classified into cycloalkanes / alkenes (blue), aromatic hydrocarbons (green), ketones (yellow), aldehydes (red), phenols (purple), and esters (gray). At the beginning of the reaction (4 hours), mainly cycloalkanes / alkenes are produced, and as the reaction time increases (8 and 17 hours), the proportion of oxygen-containing compounds such as aromatic hydrocarbons, ketones, and aldehydes tends to gradually increase. This indicates that the distribution of the products changes according to the reaction time, and that compounds with more diverse chemical structures are produced as time progresses.

[0110] Figure 4F is a bar graph comparing the normalized relative abundance of hydrocarbon compounds according to the number of carbon atoms when using the GB 2 cm + MK 0.5 cm, GB 2 cm, and MK 0.5 cm catalysts, respectively. The X-axis represents the number of carbon atoms, and the Y-axis represents the relative abundance normalized relative to an internal standard. When the GB 2 cm + MK 0.5 cm catalyst was used, hydrocarbons in the C7 to C18 range were produced, with compounds in the C8 to C13 range being the most abundant. In contrast, when GB 2 cm or MK 0.5 cm was used alone, hydrocarbon production was very minimal. These results clearly demonstrate that the two-stage catalyst system of the present invention is effective for the production of long-chain hydrocarbons.

[0111]

[0112] Example 2: Characterization of generated hydrocarbons at different temperatures

[0113] In this example, a GB 2 cm + MK 0.5 cm catalyst was used to carry out the reaction for 4 hours at various reaction temperatures (600 ℃, 700 ℃, 800 ℃, 900 ℃), and the chemical characteristics of the resulting hydrocarbon mixture were analyzed.

[0114] Figure 5A shows the chemical structures of the major products that match the NIST mass spectrum library based on GC-MS analysis results. The products were broadly classified into aliphatic hydrocarbons (Al, blue), aromatic hydrocarbons (Ar, green), benzaldehydes (B, red), ketones (K, yellow), and esters (E, gray). Aliphatic hydrocarbons mainly have structures such as cyclohexane, cyclohexadiene, and cyclopentadiene with alkyl groups, and some linear olefins (Al5) were also observed. Aromatic hydrocarbons included various alkylbenzene derivatives, and numerous oxygen-containing compounds, such as aromatic aldehydes, ketones, and esters, were also identified.

[0115] Figure 5B shows the changes in the appearance and chemical composition of the products according to the reaction temperature (600 °C, 700 °C, 800 °C, 900 °C). The top photograph shows the solution obtained by dissolving the mixture generated at each temperature in 500 μl of CDCl3; it can be observed that the color of the solution gradually changes to a darker yellow as the temperature increases. This is attributed to the increase in the content of aromatic compounds as the temperature rises. The bar graph at the bottom indicates the relative content (area %) of the compounds generated at each temperature. At 600 °C, almost no peaks were detected by GC-MS; however, at 700 °C, cycloalkanes / alkenes were mainly generated, while at 800 °C, cycloalkanes / alkenes, aromatic hydrocarbons, and ketones were generated evenly. At 900 °C, the proportion of aromatic hydrocarbons increased significantly, oxygenated compounds such as aldehydes were observed, and small amounts of acids and phenols were formed.

[0116] Fig. 5C is for the mixture produced at each reaction temperature 1 H- 13 This is the result of the C HSQC (Heteronuclear Single Quantum Coherence) NMR spectrum analysis. This spectrum is hydrogen ( 1 H) and carbon ( 13 C) It shows the correlations between atoms, allowing for a more detailed understanding of the compound's structure. The spectra at the top are δ H 0.5 ~ 2.5 ppm, δ C The aliphatic region in the range of 10 to 40 ppm, and the spectra at the bottom are δ H 2.8 ~ 4.0 ppm, δ C It represents a functional group region in the range of 30 to 70 ppm.

[0117] For the 700 ℃ sample, δ C / δ H A signal is observed in the 40-0 / 2.6-0 ppm range, which is cycloalkane / alkene (Al1 α' , Al3α , Al4 α , Al1 α ) represents the methyl and ethyl groups in the structure. In the 800 ℃ sample, δ C / δ H 35-30 / 3.2-2.8 ppm and δ C / δ H Additional signals in the range of 60-50 / 4.0-3.6 ppm are observed, which are the ethoxy group of the ester (E2) and the ketone (K1 4' , K2 10 It represents the hydrogen and carbon adjacent to the carbonyl group. In the 900 °C sample, δ C / δ H Strong signals are observed in the ranges of 40-20 / 3.6-2.6 ppm and 25-10 / 1.8-0.8 ppm, which corresponds to alkyl aromatic hydrocarbons containing ethyl groups (Ar4 α , Ar5 α , Ar6 α , Ar4 β , Ar5 β , Ar6 β It supports the existence of ). Also, δ C / δ H Signals in the 40-35 / 2.6-2.2 ppm range are aldehydes (B1 β Indicates the existence of ).

[0118] Synthesizing these results, it can be seen that the types and structures of the hydrocarbons produced vary depending on the reaction temperature, and that the proportion of compounds with complex structures and aromatic compounds increases as the temperature rises. The developed catalyst system suggests the potential to selectively produce hydrocarbons of various structures by controlling the reaction temperature.

[0119]

[0120] Example 3: Catalyst Characterization

[0121] In this example, changes in the physical and chemical properties of the catalyst before and after the reaction were investigated through various analysis methods.

[0122] Figure 6A shows scanning electron microscope (SEM) images and energy dispersive X-ray spectroscopy (EDS) elemental mapping results for a catalyst powder sample collected after performing a reaction at 800 °C for 4 hours. The SEM image in the upper left shows the morphology of the sample, while the remaining images show the distribution of each element (O, Cl, Ga, K, Mn, Bi). Through these results, it can be confirmed that phases with various elemental compositions exist, such as (K, Cl), (Mn, Ga, O), (Mn, O), (Ga, O), (Bi), and (Bi, O).

[0123] Figure 6B shows the results of X-ray diffraction (XRD) analysis for samples collected from the top and bottom of the catalyst, respectively, after performing reactions for 4 hours at various reaction temperatures (600 °C, 700 °C, 800 °C, 900 °C). The X-axis represents the diffraction angle (2-Theta, degree), and the Y-axis represents the relative diffraction intensity (Intensity, au). Peaks corresponding to the bismuth (Bi) crystal phase (PDF# 00-005-0519) were predominantly observed in all samples, while Bi2O3 (PDF# 04-011-1986) and Mn were observed in some samples, particularly at the bottom of the metal layer. 0.95 O(PDF# 04-002-8161), MnGa x O y Small amounts of oxide phases such as (PDF# 04-024-7643) were also detected. Gallium or potassium chloride-related peaks were not clearly observed, which is presumed to be because the amount is very small or exists in an amorphous state.

[0124] Figure 6C shows the results of in-situ high-temperature XRD analysis of the catalyst, observing changes in the crystal structure as the temperature was gradually increased from room temperature to 310 °C. A distinct peak of the bismuth crystal phase is observed from room temperature to 270 °C, but above 290 °C, all peaks disappear. This indicates that the catalyst completely melts at this temperature and transitions into a homogeneous liquid state. However, a small peak is observed around 2θ=28° even above 290 °C, suggesting the presence of a small amount of bismuth oxide.

[0125] Figure 6D shows the X-ray photoelectron spectroscopy (XPS) analysis results for the catalyst samples, illustrating the binding energy spectra of gallium (Ga 2p3 / 2), manganese (Mn 2p3 / 2), bismuth (Bi 4f), and oxygen (O 1s), respectively. In the Bi 4f spectrum, peaks corresponding to Bi3+ (158.95 eV, 164.2 eV) and metallic Bi (156.67 eV, 162.02 eV) were observed. The Mn 2p3 / 2 spectrum is separated into two peaks at 641.54 eV and 643.35 eV, corresponding to Mn 0.95 O and MnGa x O y It represents manganese in the state. The Ga 2p3 / 2 spectrum consists of two peaks at 1119.06 eV and 1118.07 eV, respectively, Ga 3+ and MnGa x O y It represents gallium in the state. The O 1s spectrum shows peaks at 528.92 eV, 529.67 eV, 530.21 eV, and 531.68 eV, indicating the presence of various metal-oxygen bonding environments.

[0126] Synthesizing these analysis results, it can be seen that the two-stage molten catalyst of the present invention undergoes complex chemical and physical changes during the reaction, and various active phases are formed. In particular, active metal components such as gallium and manganese exist in various oxidation states, and it is determined that they play an important role in the activation of methane and carbon dioxide and the growth of hydrocarbon chains.

[0127]

[0128] Example 4: Analysis of Reaction Mechanism

[0129] In this embodiment, the reaction mechanism by which C1 greenhouse gases are converted into long-chain hydrocarbons was analyzed through various additional experiments.

[0130] First, it was confirmed that no hydrocarbons were produced when the reaction was carried out by injecting only synthesis gas (H2+CO) into the GB 2 cm + MK 0.5 cm catalyst. Figure 7A compares the GC-MS analysis results when methane and carbon dioxide were injected with the results when only synthesis gas was injected. When only synthesis gas was injected, peaks corresponding to C7 or higher hydrocarbons were hardly observed. This suggests that the reaction pathway of the present invention does not simply proceed through synthesis gas to the Fischer-Tropsch reaction.

[0131] In addition, experiments using various reference materials were conducted to verify whether hydrocarbons were generated from materials with various elemental combinations. Figure 7B shows the GC-MS spectrum when the reaction was carried out at 800 °C using pure GaCl3 as the reference material. Surprisingly, it was confirmed that when GaCl3 was used, a large amount of hydrocarbons were generated that were qualitatively similar to those produced when using the GB 2 cm⁻¹ + MK 0.5 cm⁻¹ catalyst. This suggests the possibility that GaCl3 or similar gallium-chlorine compounds act as important intermediates during the reaction.

[0132] In order to verify whether GaCl3 is generated in the actual process of the present invention 71Ga NMR and Cl 2p XPS analyses were performed. Figure 7C shows the catalyst after the reaction. 71 Ga NMR analysis confirmed a peak corresponding to GaCl3. Additionally, the presence of Ga-Cl bonds was confirmed in the Cl 2p XPS analysis results in Fig. 7D. These results support the hypothesis that GaCl3 or a similar gallium-chlorine compound is generated during the reaction and acts as an important catalytic active species.

[0133] Finally, experiments using various combinations of reaction gases were conducted to investigate the effect of reactant composition on reactivity and products. Figure 7E compares the GC-MS analysis results according to various reaction gas combinations (CH4+CO2, synthesis gas+CO2, synthesis gas+CH4, H2O+CO2). When synthesis gas and CO2 were injected together, no hydrocarbons were produced, whereas when synthesis gas and CH4 were injected, hydrocarbons were produced. Additionally, when water (H2O) was injected together with carbon dioxide, hydrocarbons were produced, but as shown in Figure 7F, the production of oxygenates such as ketones was significantly reduced. These results suggest that methane acts as the primary carbon source for the production of long-chain hydrocarbons, while carbon dioxide contributes mainly to the formation of oxygenates.

[0134] Synthesizing these experimental results, the reaction mechanism of the present invention can be proposed as follows. Methane is activated in the molten GaBi catalyst layer to form active intermediates such as CH3, CH2, and CH, while carbon dioxide is simultaneously activated to produce CO and O, and some reacts with hydrogen to form H2O. At the interface between the metal layer and the salt layer, active gallium-chlorine compounds such as GaCl3 are formed, and the activated methane intermediates grow into long-chain hydrocarbons by forming CC bonds through oligomerization reactions by gallium-chlorine compounds and Friedel-Crafts alkylation or Diels-Alder reactions in the molten MnCl2-KCl salt layer. Oxygen species generated from carbon dioxide react with some hydrocarbons to form oxygen compounds such as ketones, aldehydes, and esters, and hydrocarbons with various structures and compositions are produced depending on the reaction temperature, with the proportion of aromatic compounds increasing as the temperature rises.

[0135] The catalytic system of the present invention is significant in that it efficiently converts C1 greenhouse gases into long-chain hydrocarbons through a novel reaction pathway different from conventional Fischer-Tropsch synthesis or other C1 conversion processes, and in particular, enables the simultaneous utilization of methane and carbon dioxide.

[0136]

[0137] Example 5: Synthesis of long-chain hydrocarbons using a catalyst system of various metal combinations

[0138] In this embodiment, the conversion performance of greenhouse gases into long-chain hydrocarbons was evaluated by varying the components of the first molten catalyst layer and the second molten catalyst layer.

[0139] Sn in the same way as in Example 1 0.5 Bi 0.5 + LiCl, Ni 0.25 Bi 0.75 + CaCl2, Cu 0.45 Bi 0.55 + MgCl2, Fe 0.01 Bi 0.99+ CuCl2, Fe 0.01 Sn 0.1 Ni 0.1 Cu 0.1 Bi 0.69 Catalysts of various compositions, such as LiCl-CaCl2-MgCl2-CuCl2-MnCl2-KCl (1:1:9:1:1:1 wt %), were prepared. All catalyst systems were prepared with a height of 2 cm for the metal layer (first molten catalyst layer) and 0.5 cm for the salt layer (second molten catalyst layer), just as in Example 1, and the reaction was carried out using methane (4 sccm) and carbon dioxide (4 sccm) at 800 ℃ for 4 hours.

[0140] Figures 8A-E are GC-MS spectra showing the results of long-chain hydrocarbon production according to various catalyst combinations. Long-chain hydrocarbons with a carbon number range of C7 or higher were produced in all catalyst combinations, but their composition and distribution differed depending on the catalyst combination.

[0141] Sn 0.5 Bi 0.5 In the case of the + LiCl catalyst (Fig. 8A), a hydrocarbon distribution similar to that of the GaBi + MnCl2-KCl catalyst was observed, but the proportion of aromatic hydrocarbons was slightly lower. Ni 0.25 Bi 0.75 The + CaCl2 catalyst (Fig. 8B) promoted the production of aromatic hydrocarbons, particularly producing an abundance of C9-C12 range alkylbenzenes. Cu 0.45 Bi 0.55 The + MgCl2 catalyst (Fig. 8C) showed a predominance of aliphatic hydrocarbon production and a high ratio of cycloalkane to alkene. Fe 0.01 Bi 0.99 + CuCl2 catalyst (Fig. 8D) produced a somewhat lower overall amount of hydrocarbons, but produced C8-C10 range hydrocarbons with high selectivity.

[0142] Of particular note is the high-entropy form of Fe 0.01 Sn 0.1 Ni 0.1 Cu 0.1 Bi0.69 + The LiCl-CaCl2-MgCl2-CuCl2-MnCl2-KCl catalyst (Fig. 8E) operated stably and produced long-chain hydrocarbons despite containing various components. Due to its multi-component composition, this catalyst provided various reaction pathways through the synergistic effects of each component, which enabled the production of a wider range of hydrocarbons.

[0143] These results demonstrate that the two-stage molten catalyst system of the present invention can be composed of various combinations of metals and salts, and that the distribution and characteristics of the hydrocarbons produced can be controlled according to each combination. Therefore, customized hydrocarbon production is possible by selecting the optimal catalyst combination according to the characteristics of the target product.

[0144]

[0145] Example 6: Effect of Pressure Change

[0146] In this example, the effect of reaction pressure on greenhouse gas conversion rate and product characteristics was investigated.

[0147] Ga0 .11 Bi 0.89 The reaction was carried out at 800 °C for 4 hours using a catalyst of + MnCl2-KCl (67:33 at %), and the reaction pressure was varied to 1.0 atm (standard atmospheric pressure), 1.1 atm, 1.2 atm, and 1.4 atm. The reaction pressure was controlled via an electronic pressure controller (EPC) connected to the inlet of the reactor.

[0148] Figure 9 is a graph showing the change in methane and carbon dioxide conversion rates according to reaction pressure. As pressure increased, the methane conversion rate (blue bar) increased proportionally from 7.2% (1.0 atm) to 13.5% (1.4 atm), and the carbon dioxide conversion rate (red bar) increased proportionally from 21.5% (1.0 atm) to 38.7% (1.4 atm). This is attributed to the fact that the contact time and solubility of the reactants with the molten catalyst increase with increasing pressure.

[0149] GC-MS analysis results showed that the distribution of carbon numbers of the generated long-chain hydrocarbons changed as pressure increased, and in particular, the production ratio of C12 or higher long-chain hydrocarbons tended to increase. This is interpreted as being due to the promotion of carbon-carbon bond formation and chain growth reactions under high pressure conditions. However, under conditions of 1.4 atm or higher, the production of solid carbon (coke) increased, leading to clogging of the quartz filter; thus, it was confirmed that selecting an appropriate pressure range is important for stable operation over a long period.

[0150] These results demonstrate that the process of the present invention can control the greenhouse gas conversion rate and product distribution through appropriate pressure control. In particular, the ability to operate efficiently even at atmospheric pressure while improving performance with a slight increase in pressure offers a significant advantage over existing high-pressure processes.

[0151]

[0152] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

Claims

1. A step of injecting a reaction gas containing greenhouse gases into a reactor; A step of inducing a reaction by contacting a reaction gas with a molten catalyst having a two-stage structure, comprising a first molten catalyst layer disposed within the reactor and a second molten catalyst layer located above the first molten catalyst layer; and A step of obtaining a product containing hydrocarbons in a single process through the above reaction; comprising, Method for upcycling greenhouse gases into long-chain hydrocarbons.

2. In Paragraph 1, The above hydrocarbon is characterized as being a long-chain hydrocarbon having a carbon number in the range of C7 or higher. Method for upcycling greenhouse gases into long-chain hydrocarbons.

3. In Paragraph 1, The above reaction gas is characterized by comprising at least one selected from the group consisting of methane, carbon dioxide, hydrogen, water, CO, ethane, propane, butane, ethene, propene, and butene. Method for upcycling greenhouse gases into long-chain hydrocarbons.

4. In Paragraph 1, The above reaction is characterized by being carried out at a temperature of 250 ℃ to 1,200 ℃, Method for upcycling greenhouse gases into long-chain hydrocarbons.

5. In Paragraph 1, The above reaction is characterized by being carried out at a pressure of atmospheric pressure to 50 atmospheres. Method for upcycling greenhouse gases into long-chain hydrocarbons.

6. In Paragraph 1, The first molten catalyst layer is an alloy that exists in a liquid state within an operating temperature range and comprises at least one metal component that contributes to the activation of greenhouse gas reactants or the formation of carbon-carbon bonds, and The second molten catalyst layer comprises at least one metal halide, wherein the metal halide is selected from the group consisting of a first metal halide that exhibits Lewis acid properties to promote hydrocarbon chain growth and a second metal halide that forms a eutectic mixture with the first metal halide to improve the stability and fluidity of the molten salt layer. Method for upcycling greenhouse gases into long-chain hydrocarbons.

7. In Paragraph 6, At least one metal component constituting the first molten catalyst layer is characterized by being selected from the group consisting of metal-based materials including gallium (Ga), bismuth (Bi), tin (Sn), nickel (Ni), copper (Cu), and iron (Fe) and their salts. Method for upcycling greenhouse gases into long-chain hydrocarbons.

8. In Paragraph 6, A method for upcycling greenhouse gases into long-chain hydrocarbons, characterized in that at least one metal halide constituting the second molten catalyst layer is selected from the group consisting of metal halides including manganese, potassium, lithium, calcium, magnesium, and copper.

9. Manufactured by the method of any one of paragraphs 1 to 8, and A hydrocarbon composition characterized by comprising hydrocarbons having a carbon number in a range of C7 or higher, wherein the hydrocarbons comprise a plurality of compound groups selected from aliphatic hydrocarbons, aromatic hydrocarbons, and oxyoxides. A composition comprising a plurality of hydrocarbon compounds having a carbon number in the range of 10.7 or more carbon numbers, The above plurality of hydrocarbon compounds are, (i) one or more aliphatic hydrocarbons selected from cyclohexane derivatives, cyclohexadiene derivatives, cyclopentadiene derivatives having alkyl groups and linear olefins; (ii) one or more aromatic hydrocarbons selected from alkylbenzene derivatives and polycyclic aromatic hydrocarbon derivatives; and (iii) one or more oxygenates selected from aromatic aldehydes, ketones and esters; a hydrocarbon composition characterized by comprising 11. In Paragraph 10, A hydrocarbon composition characterized by being prepared under reaction temperature conditions ranging from 250 ℃ to 1,200 ℃, wherein the relative content ratio of the aliphatic hydrocarbon, the aromatic hydrocarbon, and the oxyoxide changes according to the reaction temperature.

12. In Paragraph 10, A hydrocarbon composition characterized by containing C8-C13 hydrocarbons in a relatively high proportion compared to hydrocarbons in other carbon number ranges among C7-C18 range hydrocarbons in the above composition.

13. A first molten catalyst layer comprising one or more selected from the group consisting of metal-based materials including gallium (Ga) and bismuth (Bi), tin (Sn), nickel (Ni), copper (Cu) and iron (Fe) and salts thereof, and providing a first Lewis acid site; and A molten catalyst for greenhouse gas upcycling comprising: a second molten catalyst layer disposed on top of the first molten catalyst layer, comprising one or more selected from the group consisting of metal halides including manganese, potassium, lithium, calcium, magnesium, and copper, and providing a second Lewis acid site to promote the generation of long-chain hydrocarbons.

14. In Paragraph 13, The first molten catalyst layer comprises an alloy of gallium (Ga) and bismuth (Bi), and the composition ratio thereof is Ga x Bi 1-x A molten catalyst for greenhouse gas upcycling characterized by (where x is the mole fraction of gallium (Ga) in the range of 0.11 to 0.50).

15. In Paragraph 13, A molten catalyst for greenhouse gas upcycling, characterized in that the second molten catalyst layer comprises a mixture of manganese halide and alkali metal halide, and the molar ratio of manganese halide to alkali metal halide is 33:67 to 67:

33.

16. In a molten catalyst system for producing long-chain hydrocarbons from greenhouse gases, (a) A reaction gas supply unit comprising a plurality of mass flow controllers (MFCs) that supply a plurality of reaction gases, each containing a greenhouse gas, at a controlled flow rate; (b) A vertical reactor made of quartz tube material connected to the above reaction gas supply unit, having a two-stage molten catalyst disposed inside, and in which the reaction gas comes into contact with the molten catalyst to cause a chemical reaction; (c) a temperature control unit including a high-temperature electric furnace that surrounds the outside of the reactor and controls the internal temperature; and (d) a product recovery unit connected to the outlet of the reactor to condense long-chain hydrocarbons among the gaseous products discharged and recover them in a liquid or solid state; characterized by comprising: a system for upcycling greenhouse gases into long-chain hydrocarbons.

17. In Paragraph 16, The above molten catalyst comprises a first molten catalyst layer and a second molten catalyst layer located above the first molten catalyst layer, and The first molten catalyst layer is an alloy that exists in a liquid state within an operating temperature range and comprises at least one metal component that contributes to the activation of greenhouse gas reactants or the formation of carbon-carbon bonds, and The second molten catalyst layer comprises at least one metal halide, wherein the metal halide is selected from the group consisting of a first metal halide that exhibits Lewis acid properties to promote hydrocarbon chain growth and a second metal halide that forms a eutectic mixture with the first metal halide to improve the stability and fluidity of the molten salt layer. Upcycling system for greenhouse gases into long-chain hydrocarbons.

18. An upcycling system for greenhouse gases into long-chain hydrocarbons according to claim 16, wherein the reactor is equipped with a quartz filter having pores formed in its central portion to support the molten catalyst, and the reaction gas passes through the quartz filter and is injected into the molten catalyst layer in the form of bubbles.

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