Carbon dioxide conversion system having improved liquid fuel yield by using zeolite, and carbon dioxide conversion reactor therefor

Abstract

The present invention relates to a carbon dioxide conversion system having improved liquid fuel yield by using zeolite, and a carbon dioxide conversion reactor therefor, and, specifically, to a carbon dioxide conversion system and a carbon dioxide conversion reactor therefor, the system using silicoaluminophosphate-34 (SAPO-34) zeolite so as to have an improved yield of naphtha and gasoline, which are produced through carbon dioxide hydrogenation.

Description

A carbon dioxide conversion system using zeolite to improve liquid fuel yield and a carbon dioxide conversion reactor thereof

[0001] The present invention relates to a carbon dioxide conversion system and a carbon dioxide conversion reactor thereof, which utilize zeolite to improve the yield of liquid fuel, and more particularly, to a carbon dioxide conversion system and a carbon dioxide conversion reactor therefor, which utilize silicoaluminophosphate (SAPO-34) zeolite to improve the yield of naphtha and gasoline produced by the hydrogenation reaction of carbon dioxide.

[0002]

[0003] Since the Industrial Revolution, the increased use of fossil fuels like coal and oil has led to an excessive increase in carbon dioxide (CO2) emissions. Carbon dioxide absorbs excessive radiant energy, raising the Earth's temperature, a phenomenon known as global warming. Global warming is causing rising temperatures, rising sea levels, droughts, floods, heat waves, heavy snowfall, and earthquakes, and is also causing physical environmental changes such as ecosystem disruption. It is also having a wide-ranging negative impact on our surroundings, including agriculture, livestock farming, and industrial activities, as well as human health and the living environment.

[0004] Recently, as interest in low-carbon and eco-friendly economy, including 'carbon neutrality', is increasing worldwide, technology to capture and process carbon dioxide emitted into the air is attracting attention from academia and industry. Accordingly, there is a high interest in the development of new technologies to separate and recover the generated carbon dioxide and recycle it into the current energy and chemical industry system. One of them is the reaction to convert carbon dioxide into petroleum substitute chemicals through hydrogenation, and through the hydrogenation reaction of carbon dioxide, a large amount of carbon dioxide can be effectively converted into base oil (C2~C4) and liquid transportation fuel (C5~C). 12) can be converted to .

[0005] In particular, flue gas emitted from the refining process contains excessive carbon dioxide, which can be utilized to produce chemicals such as olefins and paraffins, effectively reducing carbon dioxide emissions. However, while the optimal condition for carbon dioxide conversion is a H2 / CO2 molar ratio of 3, the H2 / CO2 molar ratio in the flue gas is less than 2, making carbon dioxide conversion difficult. While additional hydrogen can be added to the flue gas during the refining process to improve the carbon dioxide conversion rate, adding hydrogen at this high price is not cost-effective.

[0006] Zeolites have been used to convert carbon dioxide into liquid fuel under these low hydrogen supply conditions, potentially improving the yield of the fuel. However, ZSM-5, a Si-Al zeolite widely used in the past, produces a large amount of CH4 as a byproduct during carbon dioxide conversion, and produces more aromatic hydrocarbons than linear hydrocarbons.

[0007]

[0008] The present invention is intended to solve the problems of the prior art, and to improve the yield of liquid fuel by utilizing SAPO-34, which is widely known as a Si-P-Al zeolite catalyst for carbon dioxide hydrogenation reaction.

[0009] In addition, the present invention provides a reactor including a carbon dioxide hydrogenation reaction catalyst and a zeolite catalyst as dual beds within one reactor.

[0010]

[0011] A system for converting carbon dioxide with improved liquid fuel yield utilizing the zeolite of the present invention may include a first catalyst section including an Fe-based catalyst and converting carbon dioxide to produce a reaction product; and a second catalyst section including a zeolite and producing a liquid fuel from the reaction product.

[0012] The above first catalyst section and the second catalyst section can be operated as a single process by including a dual bed in one reactor.

[0013] The above liquid fuel has a carbon number of C5~C 12 It could be.

[0014] The above Fe-based catalyst may be a compound represented by the following [chemical formula 1].

[0015] [Chemical Formula 1]

[0016] Fe a Cu b K c Al d (M) e

[0017] The above M includes at least one selected from rare earth metals including Ce, La, and Pr,

[0018] The sum of the composition ratios of a, b, c, d, and e above is 1.

[0019] The above Fe-based catalyst has a pore volume of 0.17 to 0.21 cm in BET analysis. 3 / g may be.

[0020] The above Fe-based catalyst is S BET 80 to 200 m 2 / g may be.

[0021] The above zeolite may include Si-Al zeolite, Si-P-Al zeolite, or a mixture thereof.

[0022] The above Si-P-Al zeolite may be a silicoaluminophosphate-34 (SAPO-34) zeolite.

[0023] The pore size of the above SAPO-34 may be 1 to 5 Å.

[0024] Acidity of the above SAPO-34 is 1 to 1.5 mmol / g cat It could be.

[0025] The (Si+P) / Al ratio of the above SAPO-34 may be 0.6 to 0.65.

[0026] The pressure of the first catalyst section and the second catalyst section may be 1 to 50 bar.

[0027] The temperature of the first catalyst part and the second catalyst part may be 100 to 1000°C.

[0028] The H2 / CO2 molar ratio of the gas flowing into the first catalyst section and the second catalyst section may be 1 to 3.

[0029] The GHSV (Gas Hourly Space Velocity) of the first catalyst part and the second catalyst part may be 1,000 to 10,000 mL / g·h.

[0030] C5~C above 12 The yield can be 20 to 30%.

[0031] The carbon dioxide conversion reactor of the present invention comprises: a columnar body; an inlet formed in a first direction through which gas is introduced from the outside into the columnar body; an outlet formed in a direction opposite to the first direction; and a furnace for applying heat to the columnar body; wherein the interior of the columnar body is connected to the inlet and the outlet, and comprises a first catalyst section for converting carbon dioxide to produce a reaction product; and a second catalyst section for producing a liquid fuel from the reaction product; the first and second catalyst sections may be provided with a dual bed, and the rear ends of the first and second catalyst sections may include silica gel for absorbing and removing moisture; and glass wool for blocking heat energy emission.

[0032] The above first direction may be from top to bottom.

[0033] The above first catalyst part may include an Fe-based catalyst of a carbon dioxide conversion system with improved liquid fuel yield utilizing the zeolite.

[0034] The above second catalyst part may include a zeolite of a carbon dioxide conversion system with improved liquid fuel yield by utilizing the zeolite.

[0035] The molar ratio of H2 / CO2 of the gas introduced from the outside may be 1 to 3.

[0036] The internal pressure of the columnar body may be 1 to 50 bar.

[0037] The internal temperature of the columnar body may be 100 to 1000°C.

[0038] The GHSV (Gas Hourly Space Velocity) of the above columnar body may be 1,000 to 10,000 mL / g·h.

[0039] The above liquid fuel has a carbon number of C5~C 12 It could be.

[0040] C5~C above 12 The yield can be 20 to 30%.

[0041]

[0042] The carbon dioxide conversion system and the carbon dioxide conversion reactor thereof, which utilize the zeolite of the present invention to improve the liquid fuel yield, utilize SAPO-34 zeolite in the carbon dioxide hydrogenation reaction, thereby oligomerizing the base oil (C2~C4) produced by the reverse water gas shift reaction (RWGS) and the Fischer-Tropsch synthesis reaction and converting it into long-chain hydrocarbons (C 13+ ) to crack naphtha and gasoline (C5~C 12 ) yield was improved.

[0043]

[0044] Figure 1 is a schematic diagram showing a reactor for converting carbon dioxide according to one embodiment of the present invention.

[0045] Figure 2 shows a TEM image of an Fe-based catalyst according to the CeO2 content of the present invention.

[0046] Figure 3 shows the XRD results of the Fe-based catalyst according to the CeO2 content of the present invention.

[0047] Figure 4 shows the results of H2-TPR, CO2-TPD, and CO-TPD analysis of the Fe-based catalyst according to the CeO2 content of the present invention.

[0048] Figure 5 shows the results of H2-TPR, CO2-TPD, and CO-TPD analyses of the Fe-based catalyst according to the type of rare earth metal of the present invention.

[0049] Figure 6 shows the reaction activity according to the use of zeolite of the present invention.

[0050] Figure 7 shows the hydrocarbon distribution of the liquid product according to the zeolite of the present invention.

[0051] Figure 8 shows the carbon distribution of the liquid product according to the use of zeolite of the present invention.

[0052]

[0053] The embodiments described herein may be modified in various different forms, and the technology according to one embodiment is not limited to the embodiments described below. In addition, the embodiments of one embodiment are provided to more completely explain the present disclosure to a person with average knowledge in the relevant technical field. In this case, unless there is a different definition for the technical and scientific terms used, they have the meaning commonly understood by a person with ordinary skill in the technical field to which this invention belongs, and in the following description and the attached drawings, descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted.

[0054] Additionally, the singular forms used in this specification and the appended claims are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0055] Additionally, in this specification and the appended claims, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0056] Additionally, in this specification and the appended claims, when a part such as a film (layer), region or component is said to be located “on,” “above,” “upper,” “below,” “lower,” or “lower” another part, this includes not only cases where one part is in contact with another part, but also cases where another part exists between the two parts.

[0057] In addition, the terms "about," "substantially," and the like used in this specification and the appended claims are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly utilizing the disclosure in which exact or absolute values ​​are stated to aid in the understanding of this specification and the appended claims.

[0058] Additionally, the numerical ranges used herein include lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different shapes.

[0059] Furthermore, terms such as “include” or “have” in this specification and the appended claims mean that a feature or component described in the specification is present, and unless specifically limited, do not preclude the possibility that one or more other features or components may be added.

[0060]

[0061] Hereinafter, a carbon dioxide conversion system and a carbon dioxide conversion reactor thereof using the zeolite of the present invention with improved liquid fuel yield will be described in detail with reference to the attached drawings.

[0062]

[0063] Hydrogenation is a metal-catalyzed reaction in which hydrogen molecules are added to a compound containing an unsaturated functional group, such as a double or triple bond. This reaction requires an unsaturated compound, hydrogen, and a catalyst. The reaction proceeds at various temperatures and pressures, depending on the activity of the catalyst and the type of reactant (unsaturated compound).

[0064]

[0065] The hydrogenation reaction of carbon dioxide is as follows.

[0066] (1) reverse water gas shift reaction

[0067] CO2+ H2→ CO + H2O

[0068] (2) Carbon chain extension reaction

[0069] nCO + (2n+1)H2→ C n H 2n+2 + nH2O (n > 1)

[0070]

[0071] [Table 1] below shows the uses of products obtained through the hydrogenation reaction of carbon dioxide according to their carbon number range.

[0072]

[0073] Carbon number range classification application C1-C4 gaseous fuel, plastic synthetic raw material C5-C 12 Gasoline car fuel C 12 -C 16 Kerosene jet fuel, diesel oil C 16 -C 18 Diesel fuel, pyrolysis raw material C 18 -C 20 LubricantsLubricants, pyrolysis raw materialsC 20 -C 40 Paraffin Wax Wax C 40 Excess asphalt, asphalt, tar

[0074]

[0075] A crucial element in the carbon dioxide hydrogenation reaction is the catalyst. Without a metal catalyst, hydrogen gas itself barely reacts with organic compounds. Cobalt- and iron-based catalysts are commonly used. Iron-based catalysts are relatively inexpensive, offer a wide range of reactor operating conditions, and produce a high proportion of higher-grade products, such as branched hydrocarbons and lower olefins, making them widely used.

[0076] In the case of FeCuKAl catalysts, which are widely known as iron-based catalysts, there was a problem of relatively low carbon dioxide conversion. Therefore, in the present invention, a rare earth metal was applied as a cocatalyst that facilitates carbon dioxide adsorption and desorption to the FeCuKAl catalyst.

[0077]

[0078] Rare earth metals (REMs) are a group of 15 elements, ranging from lanthnum (atomic number 57) to lutetium (atomic number 71). These elements are chemically very stable, remain stable even in dry air, and conduct heat well. Furthermore, even in small quantities, they can maximize device performance, making them widely used in information technology (IT) electronics such as liquid crystal displays (LCDs), light-emitting diodes (LEDs), and smartphones, as well as military supplies such as missile control systems and fighter jets. Furthermore, they are also used as key elements in various fields, including phosphors, catalysts, abrasives, and alloying elements.

[0079] In particular, cerium (Ce), the most abundant rare earth metal, is a highly electropositive and chemically reactive metal that readily oxidizes to cerium(IV) oxide (CeO2) in air. The surface of cerium oxide is highly hydrophobic, a characteristic of rare earth metals, making it highly adsorbable to organic compounds. This property makes it useful as a variety of catalysts. In particular, CeO2 forms oxygen vacancies at the interface, which not only enhances its oxygen storage capacity but also significantly increases the rate of redox reactions.

[0080]

[0081] The Fe-based catalyst introducing rare earth metal according to the present invention hydrogenates carbon dioxide contained in gas introduced from the outside to produce base oil (C2~C4) and long-chain hydrocarbons (C 13+ ) to produce a reaction product. The Fe-based catalyst includes a rare earth metal and Fe, and any catalyst capable of converting carbon dioxide into a hydrocarbon compound can be used without limitation. As an example, the catalyst may preferably be a compound represented by the following [Chemical Formula 1], but is not limited thereto.

[0082]

[0083] [Chemical Formula 1]

[0084] Fea Cu b K c Al d (M) e

[0085] The above M includes at least one selected from rare earth metals including Ce, La, and Pr,

[0086] The sum of the composition ratios of a, b, c, d, and e above is 1.

[0087]

[0088] The molar ratio of H2 / CO2 in the exhaust gas required for the hydrogenation reaction of carbon dioxide is 3, and the reaction pressure also requires 30 to 40 bar. The hydrogenation reaction activity of carbon dioxide at this time is the carbon dioxide conversion rate of 40%, C, as reported so far. 5+ The maximum ideal yield is 20%.

[0089] Although additional hydrogen supply can improve the carbon dioxide conversion rate and product yield in the hydrogenation reaction of carbon dioxide, this is rather inefficient when considering the process cost issue. Therefore, it is necessary to develop a carbon dioxide conversion system that can achieve the target yield without additional hydrogen supply.

[0090]

[0091] Zeolites are natural and synthetic silicate minerals. Due to their porous structure, in which cavities large enough to adsorb molecules exist regularly within the crystal, zeolites exhibit excellent interfacial activity and possess outstanding catalytic properties. The catalytic properties of zeolites vary depending on the zeolite structure, the nature and structural position of cations, the Si / Al content ratio, and the presence of active metal elements. The catalytic properties of zeolites are utilized in the fields of petroleum refining and petrochemicals. When long-chain hydrocarbons and light olefins are fed as reactants, they can control the carbon chain through cracking and oligomerization, thereby improving the yield of naphtha and gasoline.

[0092] Traditionally, zeolites composed of Si-Al have been widely used as catalysts. However, Si-Al zeolites have the disadvantage of producing a large amount of CH4 as a byproduct during the cracking process due to strong acid sites, causing a decrease in catalytic activity due to coke, and forming more aromatic hydrocarbons than linear hydrocarbons due to their large pore size (5-6 Å).

[0093] As a way to improve the problems of such Si-Al zeolites, Si-P-Al zeolites, which are widely known as MTO (Methanol to Olefin) catalysts, can be utilized. The Si-P-Al zeolite may be, as an example, preferably silicon aluminophosphate (Silicoaluminophosphate-34, SAPO-34), but is not limited thereto.

[0094] The above SAPO-34 is a molecular sieve with a unique shape structure and pore structure, appropriate acid properties, and excellent stability under various operating conditions. Unlike Si-Al zeolites, SAPO-34 is a molecular sieve in which the P element exists between Si-Al, and it is characterized by a three-dimensional structure of pores measuring 3.8 x 3.8 Å, forming a unique framework (Chabazite type, CHA). Due to the nests with a diameter of 7.5 x 8.2 Å in the middle of the three-dimensional channels, it has the advantage of suppressing the production of aromatic compounds and heavy olefins, thereby increasing the yield of light olefins (C2-C4). In addition, since the strength of the acid sites is weaker than that of conventional zeolites, it can relatively suppress the production of by-products such as coke and CH4.

[0095]

[0096] Accordingly, the present invention converts carbon dioxide into liquid fuels such as naphtha and gasoline (C5~C) by applying Si-P-Al zeolite as a dual bed to an Fe-based catalyst. 12 ) was intended to improve the yield.

[0097]

[0098]

[0099] The present invention is a system for converting carbon dioxide with improved liquid fuel yield utilizing zeolite, comprising: a first catalyst section including an Fe-based catalyst that converts carbon dioxide to produce a reaction product; and a second catalyst section including zeolite that produces a liquid fuel from the reaction product.

[0100] The above first catalyst section and second catalyst section are operated as a single process including a dual bed in one reactor.

[0101]

[0102] The above first catalyst section includes an Fe-based catalyst to hydrogenate carbon dioxide contained in gas drawn from the outside to produce base oil (C2~C4) and long-chain hydrocarbons (C 13+ ) to produce a reaction product. The Fe-based catalyst includes a rare earth metal and Fe, and any catalyst capable of converting carbon dioxide into a hydrocarbon compound can be used without limitation. As an example, the catalyst may preferably be a compound represented by the following [Chemical Formula 1], but is not limited thereto.

[0103]

[0104] [Chemical Formula 1]

[0105] Fe a Cu b K c Al d (M) e

[0106] The above M includes at least one selected from rare earth metals including Ce, La, and Pr,

[0107] The sum of the composition ratios of a, b, c, d, and e above is 1.

[0108]

[0109] The Fe-based catalyst represented by the above [chemical formula 1] has a pore volume of 0.17 to 0.21 cm in BET analysis. 3 / g and S BET 80 to 200 m 2 / g, 95 to 100 m 2 / g is.

[0110]

[0111] The second catalyst part includes zeolite and oligomerizes the base oil (C2~C4) produced in the first catalyst part to increase the carbon number and long-chain hydrocarbons (C 13+ ) is cracked into molecules with smaller carbon numbers to produce liquid fuel (C5~C 12) is improved. The zeolite includes a Si-Al zeolite, a Si-P-Al zeolite or a mixture thereof, and as an example, it may be preferably silicoaluminophosphate (Silicoaluminophosphate-34, SAPO-34).

[0112] The pore size of the above SAPO-34 is 1 to 5 Å, and the acidity is 1 to 1.5 mmol / g. cat , and the (Si+P) / Al ratio can be 0.6 to 0.65.

[0113]

[0114] The pressure of the first catalyst section and the second catalyst section is 1 to 50 bar, and the temperature is 100 to 1000°C, preferably 20 bar and 300°C, but is not limited thereto. If the pressure and temperature inside the column-shaped body are too low, the conversion reaction of carbon dioxide is insufficient, resulting in a small amount of reaction product produced. In addition, if the pressure and temperature of the reactor are too high, there is a problem of reduced energy efficiency.

[0115] The H2 / CO2 molar ratio of the gas flowing into the first catalyst section and the second catalyst section is 1 to 3, preferably 1.5 to 2, but is not limited thereto.

[0116] In addition, the GHSV (Gas Hourly Space Velocity) of the first catalyst part and the second catalyst part is 1,000 to 10,000 mL / g·h, preferably 3,000 to 8,000 mL / g·h, more preferably 6,000 to 7,000 mL / g·h, but is not limited thereto.

[0117]

[0118] <Reactor for carbon dioxide conversion>

[0119] Figure 1 is a schematic diagram showing a reactor for converting carbon dioxide according to one embodiment of the present invention.

[0120] A columnar body; an inlet formed in a first direction through which gas flows into the columnar body from the outside; an outlet formed in a direction opposite to the first direction; and a furnace for applying heat to the columnar body; wherein the interior of the columnar body is connected to the inlet and the outlet, and includes a first catalyst section that converts carbon dioxide to produce a reaction product; and a second catalyst section that produces a liquid fuel from the reaction product; and a dual bed, and the rear ends of the first catalyst section and the second catalyst section include silica gel that absorbs and removes moisture; and glass wool that blocks heat energy emission.

[0121] The above first direction is not particularly limited, and is preferably from the top to the bottom of the reactor.

[0122]

[0123] Gas flowing in from the outside through the inlet formed in the first direction in the columnar body is transferred to the first catalyst section. The first catalyst section includes an Fe-based catalyst to hydrogenate carbon dioxide to produce base oil (C2~C4) and long-chain hydrocarbons (C 13+ ) to produce a reaction product. The Fe-based catalyst includes a rare earth metal and Fe, and any catalyst capable of converting carbon dioxide into a hydrocarbon compound can be used without limitation. As an example, the catalyst may preferably be a compound represented by the following [Chemical Formula 1], but is not limited thereto.

[0124]

[0125] [Chemical Formula 1]

[0126] Fe a Cu b K c Al d (M) e

[0127] The above M includes at least one selected from rare earth metals including Ce, La, and Pr,

[0128] The sum of the composition ratios of a, b, c, d, and e above is 1.

[0129]

[0130] The Fe-based catalyst represented by the above [chemical formula 1] has a pore volume of 0.17 to 0.21 cm in BET analysis. 3 / g and S BET 80 to 200 m 2 / g, 95 to 100 m 2 / g is.

[0131]

[0132] The reaction product generated in the first catalyst section is supplied to the second catalyst section. The second catalyst section includes zeolite to oligomerize the base oil (C2~C4) generated in the first catalyst section to increase the carbon number and long-chain hydrocarbons (C 13+ ) is cracked into molecules with smaller carbon numbers to produce liquid fuel (C5~C 12 ) is improved. The zeolite includes a Si-Al zeolite, a Si-P-Al zeolite or a mixture thereof, and as an example, it may be preferably silicoaluminophosphate (Silicoaluminophosphate-34, SAPO-34).

[0133] The pore size of the above SAPO-34 is 1 to 5 Å, and the acidity is 1 to 1.5 mmol / g. cat , and the (Si+P) / Al ratio can be 0.6 to 0.65.

[0134]

[0135] The first catalyst section and the rear section of the first catalyst section include silica gel and glass wool. The silica gel removes moisture generated during the process reaction, and the glass wool prevents the release of heat energy from the reverse water gas shift reaction and the Fischer-Tropsch synthesis reaction.

[0136]

[0137] The gas introduced from the outside contains carbon dioxide and hydrogen, and the molar ratio of H2 / CO2 is 1 to 3, preferably 1.5 to 2.

[0138] The internal pressure of the columnar body is 1 to 50 bar, and the temperature is 100 to 1000°C, preferably 20 bar and 300°C, but is not limited thereto. If the pressure and temperature inside the columnar body are too low, the conversion reaction of carbon dioxide is insufficient, resulting in a small amount of reaction product produced. In addition, if the pressure and temperature of the reactor are too high, there is a problem of reduced energy efficiency.

[0139] In addition, the GHSV (Gas Hourly Space Velocity) of the columnar body is 1,000 to 10,000 mL / g·h, preferably 3,000 to 8,000 mL / g·h, more preferably 6,000 to 7,000 mL / g·h, but is not limited thereto.

[0140]

[0141] The liquid fuel produced in the second catalyst section above has a carbon number of C5~C. 12 It is most preferred that the hydrocarbon compound is delivered to the outside of the reactor or to another process through an outlet formed in the columnar body in a direction opposite to the first direction.

[0142]

[0143] Hereinafter, specific examples of experiments will be provided and explained. However, the experimental examples described below are only illustrative, and the technology described in this specification is not limited thereto.

[0144]

[0145] <Experimental Example 1> Effect of CeO2 content in Fe-based catalyst

[0146] The present invention introduces the properties of CeO2 into an Fe-based catalyst for the purpose of increasing the oxygen vacancy of the catalyst. Accordingly, the influence of the CeO2 content in the Fe-based catalyst was investigated.

[0147]

[0148] Figure 2 shows TEM images of Fe-based catalysts according to the CeO2 content of the present invention. (Same magnification 100 nm, 5 nm) (a) is CeO2 10 wt%, (b) is CeO2 20 wt%, (c) is CeO2 50 wt%, and (d) is CeO2 100 wt%.

[0149] Looking at Fig. 2, CeO2 (111), (200), (220), (311) planes were confirmed. The average particle size was measured to be 89 nm for CeO2 10 wt%, 250 nm for CeO2 20 wt%, 410 nm for CeO2 50 wt%, and over 500 nm for CeO2 100 wt%. When the CeO2 lattice d-spacing value was calculated through the TEM image, it can be seen that as the CeO2 content increases, many CeO2 (111) and (220) planes are formed. In addition, it can be seen that the shape is agglomerated into round particles by CeO2, and it can be seen that as the CeO2 content increases, the metal mixed particles agglomerated by CeO2 gradually grow larger.

[0150] In the case of CeO2 100 wt%, unlike other catalysts, it was confirmed that the CuO (110) phase (CuO d=0.264 nm) was widely distributed. This is thought to be because CeO2 itself has a relatively low specific surface area, so the dispersion of Fe, Cu, and K was low, and therefore it can be assumed that the Cu metal exists in a largely aggregated state.

[0151] In the case of CeO2, the crystal growth state is clearly different depending on the electronic state of Ce, and is generally in the form of Rod (110), Cube (100), and Octahedral (111). Rod is Ce 3+ Wow Ce 4+ It is formed when the middle, Cube is Ce 3+ It is formed a lot when the Octahedral is Ce 4 It is formed when +.

[0152]

[0153] [Table 2] shows the specific surface analysis according to the CeO2 content of the Fe-based catalyst.

[0154]

[0155] CeO2 addition amount, catalyst name, catalyst S BET (m 2 / g)t-plot micropore area (m 2 / g)pore volume (cm 3 / g)Pore size (nm)CeO20 wt%FeCuKeAlFe 0.38 Cu 0.04 K 0.09 Al 0.49 15800.153.4CeO210wt%FeCuK10CeAlFe 0.37 Cu 0.04 K 0.09 Ce 0.02 Al 0.48 9900.14.1CeO220wt%FeCuK20CeAlFe 0.37 Cu 0.04 K 0.09 Ce 0.03 Al 0.47 98.600.195.6CeO250wt%FeCuK50CeAlFe 0.35 Cu 0.04 K 0.09 Ce 0.08 Al 0.45 303.40.088.6CeO2100 wt%FeCuKCeO2Fe 0.5 Cu 0.06 K 0.14 Ce 0.26 9.32.60.0621

[0156]

[0157] As shown in [Table 2], the specific surface area and pore volume of the catalyst decreased as the CeO2 content increased through the BET analysis.

[0158]

[0159] Figure 3 shows the XRD results of the Fe-based catalyst according to the CeO2 content of the present invention. The XRD analysis according to the CeO2 content in the Fe-based catalyst was confirmed. Looking at Figure 2, the peak corresponding to CeO2 was confirmed at 33.3 °, and the peak corresponding to Fe2O3 was confirmed at 35.9 °, and it was confirmed that the CeO2 peak grew as the CeO2 content increased. In addition, when the part of about 32 to 43 of 2 theta / degree was enlarged and confirmed, the phenomenon of the Fe2O3 peak shifting to a low angle was observed. This can be presumed to be due to the substitution by electron transfer between Fe and other transition metals.

[0160]

[0161] Figure 4 shows the results of H2-TPR, CO2-TPD, and CO-TPD analyses of the Fe-based catalyst according to the CeO2 content of the present invention. Through thermal decomposition analysis (H2-TPR, CO, and CO2-TPD), the difference in the gas adsorption analysis results according to the CeO2 content was confirmed. In the case of H2-TPR, it was confirmed that the H2 consumed by reduction increased gradually as the CeO2 content increased, and it was observed that reduction occurred particularly at high temperatures. In the actual CO2 hydrogenation reaction, the reduction is performed at 350 ℃ as a pretreatment, so the FeCuK20CeAl catalyst has the largest reduction amount in the actual reaction. Therefore, the higher the CeO2 content, the higher the need for reduction at a high temperature. However, in the case of the Fe catalyst, if the reduction is performed at 400 ℃ or higher, the Fe 3+ In Fe 0The phase changes, which causes deactivation in the CO2 hydroxide reaction, so appropriate reduction conditions are required.

[0162] CO and CO2-TPD analyses showed that as CeO2 increased, the amount of adsorbed CO and CO2 increased, and the phenomenon of desorption at relatively high temperatures was confirmed. This means that CeO2 strongly adsorbs CO and CO2, which also contributes to the reaction activity. Although the amount of desorbed CO2 was the highest at 300 ℃, CeO2 20 wt%, and the total CO and CO2 adsorption amount was not large, the fact that CO2 is easily adsorbed / desorbed freely within the reaction temperature means that product formation is easier.

[0163]

[0164] [Table 3] shows the evaluation of reaction activity according to the CeO2 content of the Fe-based catalyst. Yield indicates the yield according to the conversion of CO+CO2.

[0165]

[0166] CeO2 addition amount catalyst name X CO+CO2 (%)X CO2 (%)Yield (%)CH4C 2~4 C 5~12 C 13+ CeO20 wt%FeCuKeAl24.918.11.44.011.87.7CeO23 wt%FeCuK3CeAl26.518.41.64.412.97.6CeO210 wt%FeCuK10CeAl2818.31.56.013.04.0CeO220 wt%FeCuK20CeAl36.825.91.510.618.06.0CeO230 wt%FeCuK30CeAl30.416.73.17.313.03.2CeO250 wt%FeCuK50CeAl2915.52.87.014.54.7CeO2100 wt%FeCuKCeO229.416.81.25.815.37.1

[0167]

[0168] As shown in [Table 3], it was confirmed that the CO2 conversion rate increased as the CeO2 content increased. In particular, when CeO2 was 20 wt%, C2~C4 and C5~C 12 It can be seen that the yields are the highest at 10.7% and 18.0%, respectively.

[0169]

[0170] <Experimental Example 2> Screening of rare earth metal types in Fe-based catalysts

[0171] In order to confirm the same oxygen vacancy effect by adding a rare earth metal along with Ce to an Fe-based catalyst, La and Pr were also added to confirm the catalytic activity.

[0172]

[0173] [Table 4] shows a comparison of the reaction activity of Fe-based catalysts according to the type of rare earth metal. Yield represents the yield according to the conversion of CO+CO2.

[0174]

[0175] Rare earth metal type catalyst name X CO+CO2 (%)X CO2 (%)Yield (%)CH4C 2~4 C 5~12 C 13+ CeFeCuK20CeAl36.825.91.510.618.06.0LaFeCuK20LaAl32.724.82.210.816.96.3PrFeCuK20PrAl31.124.12.64.817.16.6

[0176]

[0177] As shown in [Table 4], the CO2 conversion rate of Ce was measured as 25.9%, La as 24.8%, and Pr as 24.1%.

[0178]

[0179] Figure 5 shows the results of H2-TPR, CO2-TPD and CO-TPD analyses of the Fe-based catalyst according to the type of rare earth metal of the present invention. La exists as La2O3 oxide, while in the case of Pr, Pr 6+ or Pr 5+ Since it exists as a , relatively many reducing sites can be expected. However, in reality, due to the high oxidation number, there are many sites adjacent to Al and Fe, so the sites for CO or CO2 adsorption are relatively reduced, and thus the adsorption amount in CO2-TPD and CO-TPD is lower than that in Ce.

[0180]

[0181] <Experimental Example 3> Comparison by Zeolite Type

[0182] The present invention compares SAPO-34, a Si-P-Al zeolite, with ZSM-5, the most widely used conventional Si-Al zeolite. The average pore size of SAPO-34 is 3.8 Å, and the average pore size of ZSM-5 is 5.5 Å.

[0183]

[0184] The reaction activity was evaluated when only an Fe-based catalyst (FeCuK20CeAl) was used and when an Fe-based catalyst and zeolite (SAPO-34 or ZSM-5) were used as a dual bed. The reaction conditions were as follows.

[0185] - Catalyst: 0.6 g of Fe-based catalyst, 0.6 g of zeolite (1:1 by weight)

[0186] - Reduction conditions: H250 sccm, atmospheric pressure, 350 ℃, 5 h

[0187] - Reaction conditions: H2 / CO2=1.6, 20 bar, 300 ℃

[0188]

[0189] [Table 5] and Fig. 6 show the reaction activity according to the use of zeolite of the present invention. Yield represents the yield according to CO+CO2 conversion.

[0190]

[0191] Catalyst X CO+CO2 (%X CO2 (%)SelectivityC1C 2~4 = C 2~4 C5 = C5C 6+ Fe-based catalyst 36.825.94.124.44.70.30.664.5Fe-based catalyst + ZSM-5 27.017.311.56.09.30.60.369.6Fe-based catalyst + SAPO-34 36.328.96.86.68.20.20.477.8

[0192]

[0193] C when Fe-based catalyst and zeolite were used as a dual bed compared to when Fe-based catalyst alone was used 6+ It was confirmed that the selectivity of CH4 increased. However, when the zeolite was ZSM-5, there was a problem that the selectivity of CH4 increased by about 2.5 times due to the effect of cracking by acid sites. Therefore, it was confirmed that the reaction activity was the best when the Fe-based catalyst and SAPO-34 were used as a dual bed.

[0194]

[0195] Figure 7 shows the hydrocarbon distribution of the liquid product according to the zeolite of the present invention. The liquid product (C4~C 10 ) was analyzed by Reformulyzer for hydrocarbon distribution. (a) is Fe-based catalyst + ZSM-5, and (b) is Fe-based catalyst + SAPO-34. (a) shows 17% of aromatic compounds produced, while (b) shows 4.2%, which is significantly less than ZSM-5. This is thought to be because aromatic compounds were not formed during the oligomerization process due to the pore specificity of SAPO-34.

[0196]

[0197] Figure 8 shows the carbon distribution of the liquid product according to the use of zeolite of the present invention. (a) shows when only an Fe-based catalyst was used, and (b) shows when an Fe-based catalyst and SAPO-34 were used as a dual bed. Among the liquid products in (a), C5~C 12 The specific gravity of (b) is 74.6%, and C5~C among the liquid products 12 The specific gravity of C5~C is 81.5%, which is higher than that of (a) in the liquid product. 12 It was confirmed that the proportion increased by approximately 7%.

[0198]

[0199] Although the present invention has been described in this specification with specific details and limited examples, these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those skilled in the art to which the present invention pertains can make various modifications and variations based on these descriptions. Therefore, the ideas described in this specification should not be limited to the described examples, and all things that are equivalent or equivalent to the claims below, as well as the claims, are considered to fall within the scope of the ideas described in this specification.

Claims

1. A first catalyst section including an Fe-based catalyst and converting carbon dioxide to generate a reaction product; and A second catalyst section comprising zeolite and generating a liquid fuel from the reaction product; A system for converting carbon dioxide, comprising:

2. In paragraph 1, A system for converting carbon dioxide, wherein the first catalyst section and the second catalyst section are operated as a single process, including a dual bed in one reactor.

3. In paragraph 1, The above liquid fuel has a carbon number of C 5 ~C 12 A system for converting carbon dioxide into hydrogen.

4. In paragraph 1, The above Fe-based catalyst is a carbon dioxide conversion system represented by the following [chemical formula 1]. [Chemical Formula 1] Fe a With b K c the d (M) e The above M includes at least one selected from rare earth metals including Ce, La, and Pr, The sum of the composition ratios of a, b, c, d, and e above is 1.

5. In paragraph 4, The above Fe-based catalyst has a pore volume of 0.17 to 0.21 cm in BET analysis. 3 / g carbon dioxide conversion system.

6. In paragraph 4, The above Fe-based catalyst is S BET 80 to 200 m 2 / g carbon dioxide conversion system.

7. In paragraph 1, The above zeolite is a system for carbon dioxide conversion including Si-Al zeolite, Si-P-Al zeolite or a mixture thereof.

8. In paragraph 7, The above Si-P-Al zeolite is a carbon dioxide conversion system that is a silicon aluminophosphate (SAPO-34) zeolite.

9. In paragraph 8, The above SAPO-34 is a carbon dioxide conversion system with a pore size of 1 to 5 Å.

10. In paragraph 8, The Acidity of the above SAPO-34 is 1 to 1.5 mmol / g cat A system for converting carbon dioxide into hydrogen.

11. In paragraph 8, A system for carbon dioxide conversion having a (Si+P) / Al ratio of the above SAPO-34 of 0.6 to 0.

65.

12. In paragraph 1, A system for converting carbon dioxide, wherein the pressure of the first catalyst section and the second catalyst section is 1 to 50 bar.

13. In paragraph 1, A system for converting carbon dioxide, wherein the temperature of the first catalyst section and the second catalyst section is 100 to 1000°C.

14. In paragraph 1, H of the gas flowing into the first and second catalyst sections 2 / CO 2 A system for carbon dioxide conversion with a molar ratio of 1 to 3.

15. In paragraph 1, A system for converting carbon dioxide, wherein the GHSV (Gas Hourly Space Velocity) of the first catalyst section and the second catalyst section is 1,000 to 10,000 mL / g·h.

16. In paragraph 3, C above 5 ~C 12 A system for carbon dioxide conversion with a yield of 20 to 30%.

17. A columnar body; an inlet formed in a first direction through which gas flows into the columnar body from the outside; an outlet formed in a direction opposite to the first direction; and a furnace for applying heat to the columnar body; The interior of the columnar body is connected to the inlet and outlet, and includes a first catalyst section that converts carbon dioxide to generate a reaction product; and a second catalyst section that generates liquid fuel from the reaction product; as a dual bed. A reactor for converting carbon dioxide, comprising: a rear end of the first catalyst section and the second catalyst section; silica gel for absorbing and removing moisture; and glass wool for preventing heat energy release.

18. In paragraph 17, The above first direction is a reactor for converting carbon dioxide from top to bottom.

19. In paragraph 17, A reactor for converting carbon dioxide, wherein the first catalyst section comprises a catalyst according to any one of claims 4 to 6.

20. In paragraph 17, A reactor for converting carbon dioxide, wherein the second catalyst section comprises a catalyst according to any one of claims 7 to 10.

21. In paragraph 17, H of the gas flowing in from the above external 2 / CO 2 A reactor for carbon dioxide conversion having a molar ratio of 1 to 3.

22. In paragraph 17, A reactor for carbon dioxide conversion having an internal pressure of the columnar body of 1 to 50 bar.

23. In paragraph 17, A reactor for carbon dioxide conversion having an internal temperature of the columnar body of 100 to 1000°C.

24. In paragraph 17, A reactor for carbon dioxide conversion, wherein the GHSV (Gas Hourly Space Velocity) of the column-shaped body is 1,000 to 10,000 mL / g·h.

25. In paragraph 17, The above liquid fuel has a carbon number of C 5 ~C 12 A reactor for carbon dioxide conversion.

26. In paragraph 25, C above 5 ~C 12 A reactor for carbon dioxide conversion having a yield of 20 to 30%.

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