WO2014007598A1 - Hybrid catalyst for fischer-tropsch synthesis reaction, and fischer-tropsch synthesis process using same - Google Patents

Hybrid catalyst for fischer-tropsch synthesis reaction, and fischer-tropsch synthesis process using same Download PDF

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WO2014007598A1
WO2014007598A1 PCT/KR2013/006067 KR2013006067W WO2014007598A1 WO 2014007598 A1 WO2014007598 A1 WO 2014007598A1 KR 2013006067 W KR2013006067 W KR 2013006067W WO 2014007598 A1 WO2014007598 A1 WO 2014007598A1
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synthesis
catalyst
zsm5
zeolite
coz
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Korean (ko)
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하경수
강석환
김진호
류재홍
전기원
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한국화학연구원
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00Catalysts comprising molecular sieves
    • B01J29/04Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/40Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74Iron group metals
    • B01J23/75Cobalt
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8933Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/894Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00Catalysts comprising molecular sieves
    • B01J29/04Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J35/40
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02Impregnation, coating or precipitation
    • B01J37/03Precipitation; Co-precipitation
    • B01J37/031Precipitation
    • B01J37/035Precipitation on carriers
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10GCRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G2/00Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/60Synthesis on support
    • B01J2229/64Synthesis on support in or on refractory materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/60Synthesis on support
    • B01J2229/66Synthesis on support on metal supports

Definitions

  • the present invention relates to a Fischer-Tropsch synthesis hybrid catalyst for directly producing intermediate oils from syngas and a Fischer-Tropsch synthesis reaction process using the same.
  • zeolites collectively refer to crystalline aluminosilicate. Since the site of aluminum in the skeleton of the aluminosilicate is negatively charged, cations for the charge offset exist in the pores and the remaining space in the pores is usually filled with water molecules. The structure, shape, and size of the three-dimensional pores of the zeolite depend on the type of zeolite, but the diameter of the pores usually corresponds to the molecular size. Therefore, zeolites are also called molecular sieves because they have the size selectivity or shape selectivity of the molecules to be taken into the pores depending on the kind.
  • zeotype molecular sieves are known in which a part or all of silicon or aluminum is replaced by various other elements instead of silicon (Si) and aluminum (Al), which constitute the skeletal structure of the zeolite.
  • porous silica sicalite
  • AlPO 4 alpo
  • Ti, Mn, Co, Fe in the skeleton of such zeolite and pseudomolecular sieves
  • pseudomolecules obtained by partially substituting various metal elements such as Zn.
  • zeolites materials derived from zeolites and, according to their original mineralogy, do not belong to zeolites, but all of them are called zeolites in the art. Accordingly, the term zeolite in the present specification means a zeolite having a broad meaning including the above-described pseudomolecular body.
  • zeolites having an MFI structure are among the most actively used zeolites, and their kinds are as follows:
  • ZSM-5 A zeolite of MFI structure in which silicon and aluminum are formed in a constant ratio.
  • Silicalite-1 Zeolite having a structure composed only of silica.
  • TS-1 Zeolite of MFI structure with titanium (Ti) in some aluminum spots.
  • the MFI structure is shown in FIG.
  • a channel connected in a zigzag form with oval (0.51 x 0.55 nm) pores flows in the a-axis direction, and pores close to a circle (0.54 x 0.56 nm) form a straight line and extend in the b-axis direction to form a straight channel.
  • the channel is not open in the c-axis direction.
  • the shape, size and channel structure of the pores differ depending on the crystal direction.
  • GTL processes using natural gas, particularly stranded gases or associated gases, have recently attracted attention as another method for synthesizing clean fuels and compounds due to the rapid depletion of crude oil.
  • Conversion of syngas to synthetic fuel via FT synthesis is one of the most promising ways to solve this problem.
  • the main products of the FT synthesis reaction are clean diesel, gasoline, food grade paraffin, and special lubricants, which are continuous upgrade processes such as hydrocracking, hydrodewaxing, or isomerization. Can be obtained through.
  • the polymerisation mechanism represented by the Anderson-Schulz-Flory (ASF) distribution produces a wide range of hydrocarbons, from CH 4 to high molecular weight hydrocarbons.
  • product distribution is described by the possibility of chain growth, and chain growth mechanisms can be performed through various pathways such as CH 2 insertion or CO insertion.
  • the CH 2 insertion mechanism causes CC coupling by polymerisation of CH 2 intermediates on the catalyst surface to form higher molecular weight hydrocarbons. It is known that the selectivity of gasoline and heavy hydrocarbons is limited to a maximum of 48 mol%.
  • synthetic oils can be obtained through the Fischer-Tropsch reaction after converting the coal or biomass gas containing carbon containing a large amount of carbon or the reforming of natural gas into a synthesis gas containing mostly carbon monoxide and hydrogen. .
  • Fischer-Tropsch synthesis (FTS) reaction is a reaction for generating hydrocarbon compounds from syngas and is performed by the following main representative reactions on iron-based and cobalt-based catalysts.
  • Such a Fischer-Tropsch synthesis process can be produced with various products depending on the composition of the synthesis gas and the catalyst used.
  • a Fischer-Tropsch synthesis process is performed using a synthesis gas having a H 2 / CO ratio of 2 or more
  • Many hydrocarbons are produced and gasoline (C 5 -C 11 ), diesel (C 12 -C 18 ), wax (C 24 or more) and the like are produced using a synthesis gas having a H 2 / CO ratio of 2 or less.
  • reactors for Fischer-Tropsch synthesis there are three types of reactors for Fischer-Tropsch synthesis, a fixed bed reactor, a slurry bubble column reactor (SBCR), and a fluidized bed reactor.
  • Commercially available reactors are mainly composed of fixed bed reactors and slurry bubble column reactors.
  • FIG. 10 A typical process for preparing synthetic oil is shown in FIG. 10.
  • Coal or biomass (1) is reacted with oxygen (3) in the gasifier (2) to produce a synthesis gas mainly composed of carbon monoxide and hydrogen, dust collection (4), water gas conversion (5), removes carbon dioxide and sulfur compounds
  • Synthetic oil (9) is produced in the FT synthesis process (7) after the acid gas removal process (6).
  • This synthetic oil 9 is reformed and sold as a gaseous fuel / intermediate fraction 10 through the upgrading process 8.
  • Such a process is known as coal to liquids (CTL).
  • the natural gas 11 reacts with steam (H 2 O) or steam + carbon dioxide (H 2 O / CO 2 ) in the reforming reactor 12 after the odorant is removed, and produces a synthesis gas (FT synthesis process ( 7) produces a synthetic oil (9).
  • This synthetic oil 9 is reformed and sold as a gaseous fuel / intermediate fraction 10 through the upgrading process 8.
  • Such a process is known as gas to liquids (GTL).
  • Cracking catalyst unlike FT synthesis catalyst can be prepared by using the following support.
  • Amorphous oxide HFTreated Al 2 O 3 , SiO 2 -Al 2 O 3 , ZrO 2 / SO 4 2-
  • Zeolites Y, beta, mordenite, ZSM-5, ZSM-22
  • the cracking catalyst may be prepared by impregnating a metal such as Pt, Pd, and bimetallic systems (Ni / Co, Ni / W, Ni / Mo, W / Mo) on the support.
  • a metal such as Pt, Pd, and bimetallic systems (Ni / Co, Ni / W, Ni / Mo, W / Mo) on the support.
  • FT synthesis reaction of syngas is generally classified into 260 ⁇ 280 °C (LTFT) and 300 ⁇ 350 °C (HTFT) according to the operating temperature for iron catalyst above 20 atm pressure, and 220 ⁇ 240 for cobalt catalyst. It is operated at °C.
  • the wax produced is then converted to liquid fuel by a cracking catalyst under conditions such as 360 to 396 ° C. and ⁇ 69 atm (SRI report, 2006).
  • the FT synthesis reaction and cracking process are difficult to operate in a sequential continuous process because the operating temperature or pressure is different, and the preheating and supply system of the wax must be established to operate at a higher pressure than the FT synthesis process.
  • the inventors of the present invention have attempted to develop a hybrid catalyst for FT synthesis that can improve the productivity of the intermediate fraction, while simplifying the overall process in which the cracking process or the upgrading process is omitted.
  • Zeolite and Supported Cobalt System For catalyst structures of specific structure with catalyst, CH 4 Medium fraction (C 5 -C 22 The present invention was completed by confirming the effect of greatly improving the selectivity and / or yield of.
  • Another object of the present invention is to provide a method for producing an intermediate oil directly from syngas using the hybrid catalyst.
  • FT Fischer-Tropsch
  • the present invention provides a method for producing intermediate oil directly from syngas using the hybrid catalyst for FT synthesis according to the present invention.
  • the Fischer-Tropsch (FT) process currently has two major problems with gasoline production. First of all, the selectivity of gasoline (C 5 to C 11 ) is theoretically limited, with linear olefins and paraffins being inadequate for use as energy sources. Gasoline produced through the FT process can be converted to isoparaffins and aromatic compounds using acid and Pt catalysts by further processes to increase the octane number.
  • the giant paraffins produced by the FT process are modified using Pt-based catalysts.
  • Pt-based catalysts many metal catalysts such as Ni, Co, Fe, Zn, and La have been applied to isomerization by many research groups, the selectivity of isoparaffin and aromatic compounds of Pt catalyst is reported to be the best.
  • Pt is mainly used around 1% of zeolite or amorphous alumina. In this catalyst, hydrogenation ability, dehydrogenation ability of metal, acid number of carrier, pore size and geometrical form are also important factors.
  • Fe and Co-based catalysts exhibit high activity as catalysts used to directly produce high-octane gasoline by the FT process.
  • a catalyst for improving the octane number of gasoline Fe and Co series catalysts are hybridized with a zeolite (ZSM-5) catalyst having a strong Bronsted acid point to directly generate a high octane hydrocarbon compound from the synthesis gas.
  • ZSM-5 catalyst zeolite
  • hybrid catalyst it is meant that the catalysts are not physically produced by chemical bonding in the process of preparing the catalysts, but are simply physically mixed after each catalyst is prepared. In the case of the hybrid catalyst, the bifunctionality of the catalyst can be expected at the same time, and the process can be simplified in the production of gasoline of high octane number.
  • Catalyst performance could be altered primarily by varying the acidity and reducibility of cobalt oxides on ZSM5-modified Co / SiO 2 catalysts. This is because the degree of olefin cracking reaction is different when the degree of migration of cobalt oxide from SiO 2 to ZSM5 surface is different.
  • ZSM5-modified Co / SiO 2 catalysts with 25 wt% ZSM5 have high CO conversion and C 5 to C because they have a small cobalt crystal size with high reducibility and optimal acid site density. 22 shows the maximum selectivity for hydrocarbons.
  • the good catalytic performance on ZSM5-modified Co / SiO 2 catalysts is mainly due to the modification of the presence of ZSM5 particles adjacent to the Co / SiO 2 surface and the migration of cobalt species from SiO 2 to the ZSM5 surface during hydrothermal synthesis of ZSM5. It confirmed that it did.
  • the present invention is based on this.
  • the present invention relates to a hybrid catalyst for Fischer-Tropsch (FT) synthesis formed by hydrothermally synthesizing zeolite on a porous support loaded with cobalt oxide, wherein the porous support (weight ratio) of zeolite / cobalt oxide is 0.25 to 0.5. Is characteristic. At this time, the porous support (weight ratio) on which the zeolite / cobalt oxide is supported is preferably within a range of 0.25 ⁇ 0.1.
  • catalyst performance can be altered.
  • the Co / porous support surface is characterized in that it is not completely covered by zeolite. As the zeolite content increases, the mesopores of the Co / porous support catalyst are blocked by the zeolite particles, thereby reducing the surface area and pore volume of the catalyst.
  • the hybrid catalyst for FT synthesis according to the present invention may be one in which some or all of the cobalt oxide is transferred from the porous support to the zeolite surface during hydrothermal synthesis of the zeolite on the porous support (Co / porous support) on which the cobalt oxide is supported.
  • the cobalt oxide transferred to the zeolite surface on the porous support during hydrothermal synthesis is preferably exposed to the surface in contact with the zeolite particles (see FIG. 9).
  • the degree of cobalt oxide migration from the Co / porous support to the zeolite surface increases with increasing zeolite content.
  • the fine crystal size of Co 3 O 4 increases as the zeolite / (Co / porous support) ratio increases.
  • the cobalt crystal average particle diameter of the cobalt oxide migrated from the porous support to the zeolite surface during hydrothermal synthesis is preferably from 15 to 20 nm in order to exhibit high reducibility.
  • Hybrid catalysts for FT synthesis according to the present invention include those in which some or all of the cobalt oxide is reduced to cobalt metal. That is, the cobalt based catalyst may be cobalt metal or cobalt oxide.
  • the hybrid catalyst for FT synthesis according to the present invention can exhibit catalytic activity against FT synthesis reaction and olefin cracking reaction. Therefore, the hybrid catalyst for FT synthesis according to the present invention can omit the cracking process or the upgrading process and can greatly improve the selectivity and yield of the intermediate fractions (C 5 to C 22 ).
  • the catalyst according to the invention is well dispersed, with zeolite particles adjacent contacting cobalt oxide on the surface of the Co / porous support during in situ hydrothermal synthesis, the olefins of the FTS products on the zeolite surface even at low temperatures Cracking reactions can occur, which is advantageous for obtaining high selectivity for gasoline and middle distillate range hydrocarbons.
  • Cobalt catalysts are more expensive than iron catalysts and have a higher selectivity of methane at higher temperatures, but have the advantages of high activity, long lifetime, and little WGS (water gas shift reaction), resulting in low carbon dioxide generation.
  • a support having a high specific surface area may be selected or an accelerator may be used to increase dispersion of the active metal.
  • the size of the porous support is preferably a specific surface area of 100 to 400 m 2 / g.
  • Preferred examples of the porous support are porous silica (SiO 2 ) (silicalite).
  • Co is preferably 5 to 40 parts by weight based on 100 parts by weight of the porous support.
  • zeolite refers not only to (i) a generic term for minerals that are aluminum silicate hydrates of alkali or alkaline earth metals, but also to (ii) a variety of alternatives to silicon (Si) and aluminum (Al), It also includes zeotype molecular sieves that have replaced some or all of silicon or aluminum as an element, and in the larger sense includes all porous oxides or sulfides having hydroxyl groups on the surface.
  • zeolite or pseudomolecular sieves of MFI structure examples include ZSM-5, silicalite, TS-1, AZ-1, Bor-C, Boralite C, encilite, FZ-1, LZ-105, monoclinic H-ZSM -5, mutinite, NU-4, NU-5, TSZ, TSZ-III, TZ-01, USC-4, USI-108, ZBH, ZKQ-1B and the like.
  • the zeolite is preferably ZSM-5, ⁇ -zeolite, MCM, SBA, Morsenite, SAPO, Ferrierite, or the like.
  • a porous support on which cobalt oxide is supported may be prepared by impregnating a cobalt precursor in a porous support and then firing.
  • Co precursors are the metal itself, oxides (eg alumina), hydroxides (eg aluminum hydroxide), oxyhydroxides, nitrates, chlorides, carbonates, acetates, oxalates, citrates, or mixtures thereof.
  • the cobalt precursor may be selected from one or two or more selected from the group consisting of cobalt metal, cobalt nitrate, cobalt acetate, cobalt bromide, cobalt chloride, and cobalt iodide.
  • an initial wetness impregnation method may be used.
  • a synthetic gel a gel to which a structure directing agent or an organic template is added is usually used.
  • the structure inducing agent is a material that serves as a template of a specific crystalline structure, and the charge distribution, size, and geometric shape of the structure inducing agent provide structure directing properties.
  • the structural inducing agent may be an amine, an imine or a quaternary ammonium salt, preferably a quaternary ammonium hydroxide or an oligomer thereof.
  • structure inducing agents are tetraproplyammonium hydroxide (TPAOH), tetraethylammonium hydroxide (TEAOH), tetramethylammonium (TMA), tetrabutylammonium (TBA) or mixtures thereof.
  • the solvent of the gel for zeolite synthesis may be water or an organic solvent or a mixture thereof.
  • the gel for zeolite synthesis may include the following raw materials:
  • Aluminum (Al) as an raw material an organic-inorganic hybrid material in which an organic material is bonded to aluminum such as aluminum isopropoxide, a salt form material containing Al such as aluminum sulfate, or powder form of Al only Metallic material in the form of agglomerates and all materials of aluminum oxide such as alumina.
  • organic inorganic hybrid materials in which organic matter is bonded to silicon such as TEOS (tetraethyl orthosilicate), salt form material containing Si element such as sodium silicalite, powder form or lump form made of Si only Material with, all materials of silicon oxide such as glass powder, and quartz.
  • TEOS tetraethyl orthosilicate
  • salt form material containing Si element such as sodium silicalite
  • powder form or lump form made of Si only Material with, all materials of silicon oxide such as glass powder, and quartz.
  • F raw material such as HF, NH4F, NaF, KF, etc.
  • the gel formation temperature for zeolite synthesis is 50 degreeC or more.
  • the reaction temperature for the zeolite hydrothermal synthesis may vary from 50 °C to 250 °C depending on the composition of the synthetic gel used or the material to be made.
  • the reaction temperature is 80 degreeC-200 degreeC, More preferably, it is 120 degreeC-180 degreeC.
  • the reaction temperature is not always fixed, but may react with varying temperatures in several steps.
  • the reaction time can vary from 0.5 hours to 20 days.
  • the reaction time is preferably 2 hours to 15 days, more preferably 6 hours to 2 days, and most preferably 10 hours to 1 day.
  • the porous support on which cobalt oxide is supported further supports a metal selected from Ru, Pt, and La.
  • the at least one metal element selected from Ru, Pt, and La based on 100 parts by weight of the porous support is preferably 0.1 to 5 parts by weight.
  • the porous support on which the oxide of the metal element is supported may be prepared by impregnating the metal element-containing compound in the porous support and then firing.
  • metal element-containing compound selected from Ru, Pt and La include metals themselves, oxides (e.g., alumina), hydroxides (e.g., aluminum hydroxide), oxyhydroxides, nitrates, chlorides, carbonates, acetates, oxalates, citrates, Or mixtures thereof.
  • the present invention experiments, hydrothermal synthesis of zeolite particles, which are catalysts used in cracking or upgrading processes, on the surface of a cobalt-based catalyst for FT synthesis and a porous support on which oxides of metals selected from Ru, Pt, and La are supported.
  • zeolite particles which are catalysts used in cracking or upgrading processes
  • a porous support on which oxides of metals selected from Ru, Pt, and La are supported.
  • Unreacted CO not converted to CO can be recycled to participate in FT synthesis. 2 It is important to suppress the production of it.
  • the zeolite on the surface of the cobalt-based catalyst supported on the support When the particles are synthesized in a structure similar to that of ZSM-5, the product of the intrinsic fraction produced by the chain growth may simultaneously crack on the zeolite particles, thereby increasing the selectivity of the middle fraction.
  • the hybrid catalyst for FT synthesis according to the present invention may be used in a Fischer-Tropsch synthesis reaction process for directly producing intermediate oil in a synthesis gas, but is not limited thereto.
  • the synthesis gas (H 2 / CO) may be prepared through the gasification of turbidity or biomass or reformation of natural gas.
  • the hydrogen / carbon monoxide reaction ratio is preferably carried out while maintaining the molar ratio of 1-2.
  • the synthesis reaction using the hybrid catalyst for FT synthesis of the present invention can significantly improve the selectivity and yield of the intermediate fractions (C 5 to C 22 ) while maintaining high conversion of hydrogen gas and carbon monoxide gas.
  • the reaction for producing the intermediate oil directly from the synthesis gas using the hybrid catalyst for FT synthesis according to the present invention can be carried out in a fixed bed, fluidized bed or slurry reactor.
  • the hybrid catalyst for FT synthesis according to the present invention is preferably used in a catalytic reaction after reduction in a hydrogen atmosphere in the range of 200 to 700 ° C. When the reduction exceeds 700 °C sintering of the catalyst may proceed.
  • the reaction for producing the intermediate fraction directly from the synthesis gas using the hybrid catalyst for FT synthesis according to the present invention can be carried out under reaction conditions similar to the Fischer-Tropsch synthesis reaction.
  • the reaction temperature is 220 ⁇ 400 °C, preferably the reaction temperature lower than the temperature of the general single cracking process
  • the reaction pressure is preferably carried out at 5 ⁇ 60 kg / and the space velocity is 500 to 10000 h -1 , but It is not limited.
  • the hard hydrocarbons 14 in the C 1 to C 4 range of the final product may be recycled as shown in FIG. 12 and introduced into the reforming process 12 together with the natural gas 11 as a raw material.
  • FIG. 3 shows XPS analysis of Co2p 3/2 and Co2p 1/2 on unused ZSM5-modified Co / SiO 2 catalysts.
  • FIG. 4 shows TEM images of unused ZSM5-modified Co / SiO 2 catalysts ((a) CoZ (0.25), (b) CoZ (0.33), and (c) CoZ (0.50)].
  • FIG. 6 shows NH 3 -TPD profile of unused ZSM5-modified Co / SiO 2 catalysts.
  • FIG. 7 is a graph showing catalyst activity over time in ZSM5-modified Co / SiO 2 catalysts.
  • FIG. 8 is a graph showing catalytic performance (CO conversion and product distribution) with acid point density in ZSM5-modified Co / SiO 2 catalysts.
  • FIG. 10 is a simplified process diagram of a middle oil production process using a conventional Fischer-Tropsch synthesis reaction process.
  • FIG. 11 is a simplified process diagram of a middle oil production process using the Fischer-Tropsch synthesis reaction process according to the present invention.
  • FIG. 12 is an improvement of the process diagram of FIG. 11 to recycle C 1 -C 4 light hydrocarbons in the final product of the Fischer-Tropsch synthesis reaction to a natural gas reforming process.
  • FIG. 13 is a diagram schematically showing zeolite crystals of an MFI structure in which a structure inducing agent is inserted.
  • Co / SiO 2 and Co / ZSM5 catalysts were prepared by typical wet-impregnation using SiO 2 and ZSM5 (Si / Al ratio of 25) supports and aqueous cobalt nitrate precursors of the required composition.
  • SiO 2 Davissil grade 645, Aldrich
  • ZSM5 Zerolyst having a surface area of 350 m 2 / g were used as a support.
  • TEOS 10% aqueous TPAOH solution, ethanol, and additional water were thoroughly mixed in a 100 mL Teflon tube.
  • Al (NO 3 ) 3 .H 2 O was carefully added and stirred at 60 ° C. for 2 hours until a sol was formed according to previously known preparation methods.
  • a Co / SiO 2 catalyst was then added to the synthesized sol solution, the tube was capped, placed in a hydrothermal synthesis apparatus heated to 180 ° C. and vigorously stirred at 100 rpm for 12 hours to ensure crystallization.
  • ZSM5 was synthesized in situ on the Co / SiO 2 surface, with cobalt oxide in close contact.
  • the final ZSM5-modified Co / SiO 2 catalyst was separated from the solution and dried at 120 ° C. for 12 hours. It was then calcined at 500 ° C. for 5 hours at a heating rate of 10 ° C./min.
  • the weight ratio of ZSM5 / (Co / SiO 2 ) was varied.
  • ZSM5-modified Co / SiO 2 catalysts were denoted by CoZ (x), where Co means Co / SiO 2 and Z means ZSM5, and the different ZSM5 / (Co / SiO 2 ) weight ratios are x (e.g., 0.25, 0.33, and 0.50).
  • the final compositions of Co, SiO 2 , and ZSM5 in CoZ catalysts are listed in Table 1.
  • the surface area, pore volume, and average pore size and distribution of CoZ catalysts were measured by N 2 -adsorption using a Micromeritics ASAP 2400 apparatus at -196 ° C. Surface concentrations and oxidation states of cobalt oxide on new CoZ catalysts were characterized using XPS instrument (ESCALAB MK-II). AlK ⁇ monochromatic light (1486.6 eV) was employed during the experiment, and the vacuum level was maintained at about 10 ⁇ 7 Pa. The binding energy (BE) was corrected to the reference BE of C1s (284.4 eV).
  • Temperature reduced reduction was performed to measure the reducibility of cobalt oxides on CoZ catalysts. Prior to the TPR experiment, samples were pretreated with He fluid up to 400 ° C. and held for 2 hours to remove adsorbed water and other contaminants, then cooled to 50 ° C. A reducing gas containing a 5% H 2 / Ar mixed gas was passed through the sample at a fluid rate of 30 mL / min, heated to 800 ° C. at a heating rate of 10 ° C./min and held at 800 ° C. for 30 minutes. The acidity of the CoZ catalyst was determined by temperature-programmed desorption of ammonia (NH 3 -TPD).
  • Powder X-ray diffraction (XRD) patterns were obtained using a Rigaku diffractometer with Cu-K ⁇ radiation from which the crystalline phases and average size of cobalt oxide on the CoZ catalyst were identified.
  • Co 3 O 4 average crystallite size on the CoZ catalyst was calculated by X-ray line broadening with the aid of Scherrer's equation.
  • Table 1 relates to the physical properties of ZSM5-modified Co / SiO 2 catalysts and the microcrystalline size of Co 3 O 4 on the catalysts.
  • ZSM5 is widely used as a solid acid catalyst because of its adjustable acid site density and acid strength, and due to the regular pore structure of ZSM5, it can contribute to catalytic activity, especially for hydrocracking.
  • different ratios of ZSM 5 / (Co / SiO 2 ) on CoZ catalysts can significantly change physicochemical properties and acidity.
  • the properties of CoZ catalysts prepared by in situ hydrothermal synthesis of ZSM5 in the presence of Co / SiO 2 catalysts, such as surface area, pore volume, average pore diameter, are summarized in Table 1. These values of CoZ catalysts decreased compared to that of Co / SiO 2 catalyst.
  • the surface area of all CoZ is similar.
  • the increase in the ZSM5 content of CoZ catalysts showed a decrease in surface area (244-> 238 m 2 / g) and a decrease in pore volume (1.01-> 0.97 cm 3 / g), the average pore diameter was especially on CoZ (0.50) 8.8-> 6.0 nm. This shows that the mesopores of the Co / SiO 2 catalyst are blocked by the ZSM5 particles, thereby increasing the ZSM5 content in reducing the surface area and pore volume. As shown in FIG.
  • the pore size distribution of the CoZ catalysts shows that it is possible to block the mesopores of Co / SiO 2 during the hydrothermal synthesis of ZSM5.
  • the pore size in the 2-5 nm range on Co / ZSM5 does not change significantly with increasing Si / Al ratio, and we found that about 3 nm mesopores on CoZ catalyst are ZSM5 pores. It is believed to be related to (FIG. 1). This is also supported by a small reduction in the surface area on CoZ when compared to Co / ZSM5 having a surface area of 306 m 2 / g. Increasing the ZSM5 content decreased the average pore diameter in CoZ catalysts.
  • the decrease in surface area by increasing the ZSM5 content on the CoZ catalysts contributes to the formation of ZSM5 particles on the outer surface, as well as the formation of intergranular structures of ZSM5 with large pore sizes of 40 nm or more as well as pore blocking of Co / SiO 2 .
  • An increase may be the cause.
  • the reduction in surface area and average pore size on CoZ catalysts compared to Co / SiO 2 and Co / ZSM5 catalysts mainly results in the formation of two pore size distributions, resulting in the pore blocking of the Co / SiO 2 catalyst with ZSM5 particles.
  • the fine crystal size of Co 3 O 4 increased. That is, as summarized in Table 1, the cobalt fine crystal sizes in CoZ (0.25), CoZ (0.33), and CoZ (0.50) catalysts were 16.8, 19.2, and 23.5 nm, respectively. Interestingly, the cobalt microcrystalline size on CoZ catalysts is larger than Co / SiO 2 catalyst and smaller than Co / ZSM5 catalyst. In order to clarify the line magnification of the corresponding Co 3 O 4 peak, diffraction peaks in the range of 30 ⁇ 2 ⁇ ⁇ 45 in the CoZ catalyst are included in the insert of FIG. 2.
  • the ZSM5 particles are in adjacent contact on the Co / SiO 2 surface during in situ hydrothermal synthesis, the distribution of which may result in the olefin cracking reaction of FTS products on the ZSM5 surface even at low temperatures. This is advantageous for obtaining high selectivity for gasoline and middle distillate range hydrocarbons.
  • SEM-EDS analysis was performed on the CoZ catalysts, the results of which are summarized in Table 1. This shows the preferential presence of cobalt oxide on the CoZ catalyst surface and the content of cobalt oxide on the CoZ catalyst surface also decreases with increasing ZSM5 content (Co / Si atomic ratio changes from 0.855 to 0.128). .
  • TEM images of the CoZ catalyst support that ZSM5 lies adjacent on the Co / SiO 2 catalysts.
  • cobalt oxide was found to be about 20 nm. Dark black points correspond to cobalt oxide and gray points correspond to ZSM5 and SiO 2 supports.
  • TEM images show that ZSM5 particles are well dispersed on CoZ (0.25) with cobalt oxide in close contact on Co / SiO 2 , and that ZSM5 particles are isolated in separate phase on CoZ (0.50) catalyst. . These results support that ZSM5 is in contact with cobalt oxide at low ZSM5 content, such as CoZ (0.25) catalyst.
  • Table 2 relates to H 2 uptake measured by H 2 -TPR in ZSM 5 -modified Co / SiO 2 catalysts.
  • the reduction profile of the calcined CoZ catalysts is shown in FIG. 5, and the reduction degree was calculated by dividing the H 2 consumption from TPR to 400 ° C. by the total H 2 consumption, as summarized in Table 2.
  • the TPR profile on CoZ catalysts shows two distinct reduction peaks and was observed at better temperatures than that of Co / SiO 2 catalysts due to the possibility of cobalt oxide on SiO 2 migration to ZSM5.
  • the first reduction peak is usually by reduction of Co 3 O 4 to CoO and the second peak is by reduction of CoO to metal cobalt.
  • TPR profiles of all CoZ catalysts also show distinct shoulder peaks around 272-295 ° C., with a strong second peak at maximum temperature (T max ) near 325-341 ° C.
  • the second peak is due to the complete reduction of cobalt oxide to metal cobalt.
  • Small peak intensities in the high temperature range above 600 ° C. suggest that cobalt oxide can be converted to inert cobalt silicate on Co / SiO 2 catalysts.
  • the TPR peaks of the CoZ (0.25) catalyst appearing near 272 and 325 ° C. may be due to cobalt microcrystals that can be readily reduced to the metallic state at low temperatures. Cobalt species with a larger surface area and smaller microcrystal size were found to be characteristic of the CoZ (0.25) catalyst.
  • the fine crystal size and T max of cobalt oxide decreases from 341 ° C. to 325 ° C. as the ZSM5 content decreases in CoZ catalysts.
  • the ZSM5 support exhibits strong cobalt-supporter interaction at ZSM5 acid sites (a rather high reduction temperature near 383 ° C.). This phenomenon suggests that the cobalt oxide migration from SiO 2 to ZSM5 surface is not severe because of the low zeolite content in the CoZ (0.25) catalyst.
  • a higher reduction temperature peak near 380 ° C. in the Co / ZSM5 catalyst also supported the possibility of cobalt oxide migration from SiO 2 to the ZSM 5 surface.
  • the degree of reduction on CoZ catalysts was calculated from the H 2 consumption in TPR.
  • the total H 2 consumption (expressed as total H 2 consumption / g cat ) based on the weight of the CoZ catalyst was 2.12, 2.00, and 1.82 mmol H 2 in CoZ (0.25), CoZ (0.33), and CoZ (0.50), respectively. calculated with / g cat .
  • Co / ZSM5 as compared to (3.86 mmol H 2 / g) , and because it is of the H 2 consumption reduction for CoZ catalyst will decrease the absolute amount of the metal species, the total H 2 consumption is a ZSM5 content of at CoZ catalyst Decreased with increase.
  • This tendency is associated with an increase in the content of ion-exchanged Co 2+ species from Co / SiO 2 to ZSM5 surface or small cobalt microcrystals that are rarely reduced (even above 400 ° C.) during the hydrothermal synthesis step of the CoZ catalyst. .
  • These cobalt species can interact strongly in the backbone of the Al sites, with increasing ZSM5 / (Co / SiO 2 ), hydrogen consumption values from 7.3 to 19.9% above 400 ° C, as shown in Table 2. Increasing results and 30.6% in Co / ZSM5.
  • the H 2 consumption values (mmol H 2 / g Co ), recalculated based on cobalt weight below 400 ° C., are about the same in the range 12.1 to 14.6; However, above 400 ° C., the value gradually increases as the ZSM5 content increases. That is, 1.03, 2.85, and 3.62 mmol H 2 / g cat in CoZ (0.25), CoZ (0.33), and CoZ (0.50), respectively, and 5.91 mmol H 2 / g cat in Co / ZSM5. These observations also show the mobility of small sized cobalt species and ion exchange of cobalt species on the scattering points of the ZSM5 surface.
  • Table 3 relates to the surface acidity measured by NH3-TPD in ZSM5-modified Co / SiO 2 catalysts.
  • NH 3 -TPD experiments were performed to investigate the concentration and strength of acid sites in CoZ catalysts.
  • the acid point on the ZSM5 can act as an active site for the olefin cracking reaction of the FTS product even at low reaction temperatures.
  • the NH 3 -TPD pattern of CoZ catalysts is shown in FIG. 6. Three characteristic steps, peaks I, II and III, associated with NH 3 desorption were observed. Peak I is NH 3 desorption temperature, peak II of below 220 °C temperature of NH 3 desorption temperature, peak III at 220 ⁇ 500 °C corresponds to the NH 3 desorption temperature of at least 500 °C. Desorption peak III observed above 500 ° C.
  • the acid point density in CoZ catalysts as NH 3 / gcat as weak and strong acid points. Considering the first peak (weak acid point) and the second peak (strong acid point), which can be active sites for the olefin cracking reaction, we found that the acid point density is higher due to the increased ZSM5 content in the CoZ (0.50) catalyst. .
  • the total scattering density (sum of peaks I and II) varies in the order of CoZ (0.50)> CoZ (0.33)> CoZ (0.25).
  • the acid point density also increases proportionally.
  • the weak and strong acid point density for peaks I and II in NH 3 -TPD was significantly reduced by the addition of cobalt species by acid point blocking on ZSM5 (0.743 of bare ZSM5, 0.450 on Co / ZSM5 catalyst). mmol NH 3 / g).
  • Table 4 is the catalytic performance for the ZSM5-modified Co / SiO 2 catalyst.
  • CO conversion decreases proportionally with increasing ZSM5 / (Co / SiO 2 ) weight ratio, and the trend is related to the fine crystal size of cobalt oxide and its reducing capacity as shown in Table 1.
  • catalysts having a large surface area and large pore diameters are advantageous for obtaining small cobalt microcrystalline size and can easily transport heavy chain hydrocarbons formed during the FTS reaction. It has been suggested that the large pores on the FTS catalyst are linked to less coke or wax deposition.
  • the high content of weak acid sites is associated with high yields of C 5 to C 22 hydrocarbons due to the cracking of the polymer olefins at the acid sites of the zeolites.
  • a composite catalyst in which Co / SiO 2 and ZSM5 are physically mixed cannot be a good catalyst for improving C 5 to C 22 hydrocarbon selectivity.
  • the iron-based FTS catalyst physically mixed with ZSM5 showed high by-product selectivity and low selectivity of olefin hydrocarbons.
  • lower olefin production rates in cobalt based catalysts than iron based catalysts are associated with low cracking catalyst activity of the olefin components causing small changes in product distribution.
  • the CoZ catalyst showed safe catalytic activity at about 40 hours compared to Co / SiO 2 and Co / ZSM5, showing high selectivity for heavy hydrocarbons and low selectivity for CH 4 and CO 2 .
  • CO conversion from CoZ catalyst to heavy hydrocarbons is 82.8% for all FTS catalysts.
  • CO conversion to CO 2 is proportional to CO conversion by the water gas shift reaction. In addition, they decrease with decreasing Co / SiO 2 content in the CoZ catalyst.
  • TOF values are reported to range from 1.6 ⁇ 10 ⁇ 3 to 3.0 ⁇ 10 ⁇ 3 / s on cobalt nanofine crystal phases having approximately 10 nm size.
  • the CO conversion in the CoZ catalyst is somewhat lower than that of the Co / SiO 2 catalyst due to the blocking of active cobalt sites due to the deposition of ZSM5, the yields of C 5 to C 22 hydrocarbons in the CoZ catalyst change significantly and the low CH 4 selectivity Was observed.
  • CoZ (0.25) catalysts show high values of CO conversion and high yields of C 5 to C 22 hydrocarbons. Due to the low content of ZSM5, which indicates low acid density, the CoZ (0.25) catalyst shows low CH 4 selectivity of about 7.8% and C 2 -C 4 hydrocarbons of about 9.2%. The CoZ (0.25) C 5 ⁇ C 22 hydrocarbons, up to the selection of even lower olefin selected from the catalyst and from about 62.8% Fig. (C 5 ⁇ C 22 hydrocarbons yield 49.1%) was observed.
  • CoZ (0.50) catalysts show the highest CH 4 selectivity of 11.3% and C 2 -C 4 hydrocarbons of 13.4%. CH 4 and C 2 -C 4 selectivity increase with increasing ZSM5 content. This is because the acid point of ZSM5 plays an important role as a catalyst in cracking reaction from olefin hydrocarbon to light hydrocarbon even at low temperature.
  • the acid point of ZSM5 is also related to the content of aluminum forming the backbone, which is related to the high selectivity of the olefin hydrocarbons.
  • Cobalt oxide microcrystals or ion exchanged Co 2+ species on CoZ catalysts may also be due to strong interactions with aluminum forming the backbone. This is supported by the CoZ (0.50) catalyst showing high olefin selectivity (expressed as O / (O + P)) of about 32.1% at 240 ° C.
  • CoZ catalyst with an optimal content of ZSM 5 in close contact with cobalt on Co / SiO 2 phase, such as CoZ (0.25), is formed on the ZSM5 support. It is better to simply impregnate Co at.
  • Catalytic performance parameters such as CO conversion and product distribution for acid point density on CoZ catalysts are summarized in FIG. 8. CO conversion decreased with increasing ZSM5 content on the CoZ catalyst due to the low Co / SiO 2 content. High C 5 -C 22 hydrocarbon selectivity was observed in the CoZ (0.25) catalyst.
  • a schematic diagram of Co / SiO 2 modified with ZSM5 is shown in FIG. 9.
  • CoZ (0.25) catalysts allows cobalt microcrystals to migrate from Co / SiO 2 to the acidic point of ZSM5 during hydrothermal synthesis, resulting in small microcrystalline size in close contact with the weak acidic points of ZSM5 on the Co / SiO 2 surface. Mainly related to the formation of cobalt oxide.
  • ZSM5 particles in close contact with the cobalt oxide can also improve the degree of olefin cracking reaction of the FTS product, which enhances the C 5 -C 22 hydrocarbon selectivity in the CoZ (0.25) catalyst.
  • the catalyst was prepared by hydrothermal synthesis of ZSM5 in-situ in a solution containing pre-prepared Co / SiO 2 catalyst. As a result, a maximum yield of C 5 to C 22 hydrocarbons was obtained in ZSM5-modified CoZ (0.25), which is better than Co / SiO 2 and Co / ZSM5.
  • the crystal size of the increased cobalt oxide is due to the cobalt movement to the ZSM5 surface.
  • the adjacent contact of cobalt oxide with ZSM5 is responsible for high catalytic performance. Modification of Co / SiO 2 with ZSM 5 particles during ZSM 5 hydrothermal synthesis can increase the selectivity of C 5 to C 22 hydrocarbons while minimizing C 1 to C 4 hydrocarbons.
  • the solution was dried with a commercially available silica support by stirring using a magnetic bar to mix 20 wt% of cobalt nitrate (Co (NO 3 ) 2 .6H 2 O) aqueous solution. After calcining at 500 ° C. for 5 hours, a 20 wt% Co / silica catalyst was prepared. The prepared catalyst was filtered by 20 to 40 Mesh.
  • Hybrid catalyst for Fischer-Tropsch (FT) synthesis formed by hydrothermal synthesis of zeolite on a porous support loaded with cobalt oxide
  • TPAOH tetrapropyl ammonium hydroxide solution
  • Al (NO 3 ) 3 ⁇ H 2 O (99.5%) and TEOS tetraethyl ortho silicate
  • the gel-forming composition for zeolite synthesis was prepared by sol at 50 ° C. and then mixed with 4 g of the prepared Fischer-Tropsch synthesis catalyst (Co / SiO 2 , Co-Ru / SiO 2 , Co-Pt / SiO 2 ,) 180 Hydrothermal synthesis for 10 hours at °C.
  • Example 1 Zeolite / (Co / SiO 2 ) 88.3 17.2 17.0 / 16.3 / 13.7 / 53.0 66.7 47.4 240
  • Example 2 Zeolite / (Co-Ru / SiO 2 ) a) 38.7 3.1 17.1 / 10.2 / 20.4 / 56.1 76.5 25.9 240
  • Example 3 Zeolite / (Co-Pt / SiO 2 ) b) 49.7 3.0 25.9 / 17.4 / 28.6 / 28.1 56.7 26.5 260 Comparative Example 1 Co / SiO 2 26.8 0.6 6.8 / 10.9 / 10.4 / 71.9 82.3 21.6 220 Comparative Example 2

Abstract

The present invention provides a hybrid catalyst for Fischer-Tropsch (FT) synthesis, formed by hydrothermally synthesizing zeolites on a porous cobalt oxide-supported scaffold, wherein the zeolite/cobalt oxide-supported porous scaffold (weight ratio) = 0.25 to 0.5. The present invention also provides a method for preparing the hybrid catalyst. Further, the present invention provides a method for producing middle distillates directly from synthesis gas using the hybrid catalyst for FT synthesis according to the present invention. With the hybrid catalyst for Fischer-Tropsch synthesis reaction according to the present invention, middle distillates can be directly produced from synthesis gas without a cracking process or an upgrading process, and CH4 can be selectively maintained at a low level and the selectivity and yield of the middle distillates can be increased.

Description

피셔-트롭쉬 합성 반응용 혼성촉매 및 이를 이용한 피셔-트롭쉬 합성 공정Fischer-Tropsch synthesis reaction and Fischer-Tropsch synthesis process
본 발명은 합성가스로부터 중간유분을 직접 생성하기 위한 피셔-트롭쉬 합성용 혼성촉매 및 이를 이용한 피셔-트롭쉬 합성 반응 공정에 관한 것이다.The present invention relates to a Fischer-Tropsch synthesis hybrid catalyst for directly producing intermediate oils from syngas and a Fischer-Tropsch synthesis reaction process using the same.
통상, 제올라이트는 결정성 알루미노실리케이트 (crystalline aluminosilicate) 를 총칭한다. 알루미노실리케이트의 골격에 있어서 알루미늄이 있는 자리는 음전하를 띄고 있기 때문에 전하 상쇄를 위한 양이온들이 세공(pore)속에 존재하며 세공 내의 나머지 공간은 보통 물 분자들로 채워져 있다. 제올라이트가 갖는 3차원적인 세공의 구조, 모양 및 크기는 제올라이트의 종류에 따라 다르나 세공의 지름은 보통 분자 크기에 해당한다. 따라서 제올라이트는 종류에 따라 세공 속으로 받아들이는 분자의 크기 선택성(size selectivity) 또는 형상 선택성(shape selectivity)을 갖기 때문에 분자체(molecular sieve)라고도 불린다.Typically, zeolites collectively refer to crystalline aluminosilicate. Since the site of aluminum in the skeleton of the aluminosilicate is negatively charged, cations for the charge offset exist in the pores and the remaining space in the pores is usually filled with water molecules. The structure, shape, and size of the three-dimensional pores of the zeolite depend on the type of zeolite, but the diameter of the pores usually corresponds to the molecular size. Therefore, zeolites are also called molecular sieves because they have the size selectivity or shape selectivity of the molecules to be taken into the pores depending on the kind.
한편, 제올라이트의 골격 구조를 이루는 원소들인 실리콘(Si)과 알루미늄(Al) 대신에 여러 가지 다른 원소로 실리콘이나 알루미늄의 일부 또는 전체를 대체시킨 제올라이트 유사분자체(zeotype molecular sieves)들이 알려져 있다. 예를 들어, 알루미늄을 완전히 제거시킨 다공성 실리카(silicalite)와 실리콘을 인(P)으로 대체시킨 알포(AlPO4)계 분자체, 그리고 이러한 제올라이트 및 유사분자체의 골격에 Ti, Mn, Co, Fe 및 Zn 등 다양한 금속 원소를 일부 치환시켜 얻은 유사분자체들이 알려져 있다. 이들은 제올라이트에서 파생되어 나온 물질들로서 원래의 광물학적 분류에 의하면 제올라이트에 속하지 않지만, 당업계에서는 이들을 모두 제올라이트라 부른다. 따라서, 본 명세서에서 제올라이트라 함은 상술한 유사분자체를 포함하는 넓은 의미의 제올라이트를 의미한다.Meanwhile, zeotype molecular sieves are known in which a part or all of silicon or aluminum is replaced by various other elements instead of silicon (Si) and aluminum (Al), which constitute the skeletal structure of the zeolite. For example, porous silica (silicalite) completely removed from aluminum and alpo (AlPO 4 ) -based molecular sieves in which silicon is replaced with phosphorus (P), and Ti, Mn, Co, Fe in the skeleton of such zeolite and pseudomolecular sieves And pseudomolecules obtained by partially substituting various metal elements such as Zn. These are materials derived from zeolites and, according to their original mineralogy, do not belong to zeolites, but all of them are called zeolites in the art. Accordingly, the term zeolite in the present specification means a zeolite having a broad meaning including the above-described pseudomolecular body.
한편, MFI 구조를 갖는 제올라이트는 제올라이트 중에서 가장 활발하게 사용되는 제올라이트 중의 하나이며 그 종류는 다음과 같다:On the other hand, zeolites having an MFI structure are among the most actively used zeolites, and their kinds are as follows:
1) ZSM-5: 실리콘과 알루미늄이 일정비율로 형성된 MFI 구조의 제올라이트.1) ZSM-5: A zeolite of MFI structure in which silicon and aluminum are formed in a constant ratio.
2) 실리카라이트-1: 실리카로만 이루어진 구조의 제올라이트.2) Silicalite-1: Zeolite having a structure composed only of silica.
3) TS-1: 알루미늄 자리 일부에 티타늄(Ti)이 있는 MFI 구조의 제올라이트.3) TS-1: Zeolite of MFI structure with titanium (Ti) in some aluminum spots.
MFI 구조는 도 13과 같다. 이 제올라이트의 경우 타원형(0.51 x 0.55 nm) 세공이 지그재그 형태로 연결된 채널이 a축 방향으로 흐르고, 원형에 가까운(0.54 x 0.56 nm) 세공이 직선을 이루며 b축 방향으로 뻗어있어서 직선형 채널을 형성한다. c축 방향으로는 채널이 열려 있지 않다.The MFI structure is shown in FIG. In the case of this zeolite, a channel connected in a zigzag form with oval (0.51 x 0.55 nm) pores flows in the a-axis direction, and pores close to a circle (0.54 x 0.56 nm) form a straight line and extend in the b-axis direction to form a straight channel. . The channel is not open in the c-axis direction.
상술한 바와 같이, MFI 형 제올라이트의 경우 결정 방향에 따라 세공의 모양, 크기 및 채널 구조가 다르다.As described above, in the case of the MFI zeolite, the shape, size and channel structure of the pores differ depending on the crystal direction.
천연가스, 특히 stranded gases or associated gases를 사용하는 GTL 공정은 원유의 급속한 고갈로 인해 청정 연료 및 화합물을 합성하는 다른 방법으로서, 최근 관심이 집중되고 있다. FT 합성을 통해 합성가스를 합성연료로 전환시키는 것은 이러한 문제를 해결하는 가장 유망한 방법 중 하나이다. FT 합성 반응의 주요 생성물들은 청정 디젤, 가솔린, 식품급 파라핀, 및 특수 윤활제가 있으며, 이들은 수소화크래킹(hydrocracking), 수소첨가 탈랍 (hydrodewaxing), 또는 이성체화(isomerization)와 같은 연속적인 업그래딩 공정들을 통해 수득될 수 있다. 그러나, Anderson-Schulz-Flory (ASF) distribution 에 의해 표현되는 고분자화 메커니즘에 의해, CH4로부터 고분자량의 탄화수소에 이르기까지 광범위한 탄화수소들이 생성된다. 또한, 생성물 분포는 사슬 성장 가능성에 의해 설명되고, CH2 삽입 또는 CO 삽입과 같은 다양한 경로를 통해 사슬 성장 메커니즘이 수행될 수 있다. CH2 삽입 메커니즘은 촉매 표면 상에서 CH2 중간체들의 고분자화에 의해 C-C 커플링이 일어나 더 큰 분자량의 탄화수소들을 형성한다. 가솔린 및 중질 탄화수소들의 선택도는 최대값 48 mol %로 제한되는 것으로 알려져 있다.GTL processes using natural gas, particularly stranded gases or associated gases, have recently attracted attention as another method for synthesizing clean fuels and compounds due to the rapid depletion of crude oil. Conversion of syngas to synthetic fuel via FT synthesis is one of the most promising ways to solve this problem. The main products of the FT synthesis reaction are clean diesel, gasoline, food grade paraffin, and special lubricants, which are continuous upgrade processes such as hydrocracking, hydrodewaxing, or isomerization. Can be obtained through. However, the polymerisation mechanism represented by the Anderson-Schulz-Flory (ASF) distribution produces a wide range of hydrocarbons, from CH 4 to high molecular weight hydrocarbons. In addition, product distribution is described by the possibility of chain growth, and chain growth mechanisms can be performed through various pathways such as CH 2 insertion or CO insertion. The CH 2 insertion mechanism causes CC coupling by polymerisation of CH 2 intermediates on the catalyst surface to form higher molecular weight hydrocarbons. It is known that the selectivity of gasoline and heavy hydrocarbons is limited to a maximum of 48 mol%.
한편, 합성유는, 탄소가 다량 포함되어 있는 석탄 또는 바이오매스의 가스화 또는 천연가스의 개질반응으로부터 일산화탄소와 수소가 대부분인 합성가스로 전환 후, 피셔-트롭쉬(Fischer-Tropsch) 반응을 거쳐 얻을 수 있다. On the other hand, synthetic oils can be obtained through the Fischer-Tropsch reaction after converting the coal or biomass gas containing carbon containing a large amount of carbon or the reforming of natural gas into a synthesis gas containing mostly carbon monoxide and hydrogen. .
일반적으로, 피셔-트롭쉬 합성(FTS: Fischer-Tropsch synthesis) 반응은 합성가스로부터 탄화수소 화합물들을 생성하는 반응으로서, 철 계열 및 코발트 계열의 촉매 상에서 다음의 주요 대표적인 반응에 의하여 진행된다. In general, Fischer-Tropsch synthesis (FTS) reaction is a reaction for generating hydrocarbon compounds from syngas and is performed by the following main representative reactions on iron-based and cobalt-based catalysts.
[반응식 1] Scheme 1
Figure PCTKR2013006067-appb-I000001
Figure PCTKR2013006067-appb-I000001
[반응식 2] Scheme 2
Figure PCTKR2013006067-appb-I000002
Figure PCTKR2013006067-appb-I000002
[반응식 3]Scheme 3
Figure PCTKR2013006067-appb-I000003
Figure PCTKR2013006067-appb-I000003
상기 반응식 1과 반응식 3의 FTS 반응과 경쟁반응인 상기 반응식 2의 수성가스 전환(WGS: water-gas shift) 반응은 일산화탄소와 상기 반응식 1로부터 생성되는 물이 반응하여 이산화탄소와 수소를 발생하게 된다. In the water-gas shift (WGS) reaction of Scheme 2, which is a competition with the FTS reactions of Scheme 1 and Scheme 3, carbon monoxide and water generated from Scheme 1 react to generate carbon dioxide and hydrogen.
이와 같은 피셔-트롭쉬 합성공정은 합성가스의 조성 및 사용촉매에 따라 다양한 생성물로 생산할 수 있는데, 일반적으로 H2/CO 비가 2 이상인 합성가스를 사용하여 피셔-트롭쉬 합성공정을 수행할 경우 경질 탄화수소가 많이 생성되며, H2/CO 비가 2 이하인 합성가스를 사용하여 가솔린(C5∼C11), 디젤(C12∼C18), 왁스(C24 이상) 등이 제조된다. 또한, 합성조건을 변화시키거나 직간접적인 방법으로 다양한 화학제품(탄화수소, 알코올, 에텔, 초산 등)을 생산할 수 있다.Such a Fischer-Tropsch synthesis process can be produced with various products depending on the composition of the synthesis gas and the catalyst used. Generally, when the Fischer-Tropsch synthesis process is performed using a synthesis gas having a H 2 / CO ratio of 2 or more, Many hydrocarbons are produced and gasoline (C 5 -C 11 ), diesel (C 12 -C 18 ), wax (C 24 or more) and the like are produced using a synthesis gas having a H 2 / CO ratio of 2 or less. It is also possible to produce a variety of chemicals (hydrocarbons, alcohols, ethers, acetic acid, etc.) by varying the synthetic conditions or by direct or indirect methods.
일반적으로 피셔-트롭쉬 합성을 위한 반응장치 형태로는 고정층 반응기(Fixed bed reactor), 슬러리 기포탑 반응기(Slurry bubble column reactor, SBCR), 그리고 유동층 반응기(Fluidized bed reactor) 세 가지 형태가 있는데, 현재 상용화되어 있는 반응기는 고정층 반응기와 슬러리 기포탑 반응기 두 가지 형태가 주를 이룬다. Generally, there are three types of reactors for Fischer-Tropsch synthesis, a fixed bed reactor, a slurry bubble column reactor (SBCR), and a fluidized bed reactor. Commercially available reactors are mainly composed of fixed bed reactors and slurry bubble column reactors.
전형적인 합성유의 제조방법이 도 10에 도시되어 있다. 석탄이나 바이오매스(1)는 가스화기(2)에서 산소(3)와 반응하여 일산화탄소와 수소가 주성분인 합성가스를 제조하고, 집진(4), 수성가스전환(5), 이산화탄소와 황화합물을 제거하는 산가스제거공정(6)을 거쳐 FT합성공정(7)에서 합성유(9)를 생산한다. 이 합성유(9)는 업그래이딩공정(8)을 통해 가스연료/중간유분(10)으로 개질되어 판매되고 있다. 이와 같은 공정은 CTL(coal to liquids)으로 알려져 있다. A typical process for preparing synthetic oil is shown in FIG. 10. Coal or biomass (1) is reacted with oxygen (3) in the gasifier (2) to produce a synthesis gas mainly composed of carbon monoxide and hydrogen, dust collection (4), water gas conversion (5), removes carbon dioxide and sulfur compounds Synthetic oil (9) is produced in the FT synthesis process (7) after the acid gas removal process (6). This synthetic oil 9 is reformed and sold as a gaseous fuel / intermediate fraction 10 through the upgrading process 8. Such a process is known as coal to liquids (CTL).
한편, 천연가스(11)는 부취제가 제거된 후 개질반응기(12)에서 스팀(H2O)이나 스팀+이산화탄소(H2O/CO2)와 반응하여 합성가스를 생산하고, FT합성공정(7)에서 합성유(9)를 생산한다. 이 합성유(9)는 업그래이딩공정(8)을 통해 가스연료/중간유분(10)으로 개질되어 판매되고 있다. 이와 같은 공정은 GTL(gas to liquids)으로 알려져 있다. Meanwhile, the natural gas 11 reacts with steam (H 2 O) or steam + carbon dioxide (H 2 O / CO 2 ) in the reforming reactor 12 after the odorant is removed, and produces a synthesis gas (FT synthesis process ( 7) produces a synthetic oil (9). This synthetic oil 9 is reformed and sold as a gaseous fuel / intermediate fraction 10 through the upgrading process 8. Such a process is known as gas to liquids (GTL).
합성가스로부터 중간유분을 생성하는 종래의 공정 기술은, 도 10에 나타난 바와 같이 철 또는 코발트계 촉매를 사용한 피셔-트롭쉬 합성 반응을 통해 왁스를 생성한 후 크래킹 촉매에 의해 액상연료로 전환시킨다. Conventional process techniques for producing intermediate fractions from syngas, as shown in FIG. 10, generate wax through a Fischer-Tropsch synthesis reaction using an iron or cobalt based catalyst and then convert it to liquid fuel by a cracking catalyst.
크래킹 촉매는 FT 합성촉매와 달리 아래와 같은 지지체를 사용하여 촉매를 제조할 수 있다.Cracking catalyst, unlike FT synthesis catalyst can be prepared by using the following support.
* 비결정산화물 : HFTreated Al2O3, SiO2-Al2O3, ZrO2/SO4 2- * Amorphous oxide: HFTreated Al 2 O 3 , SiO 2 -Al 2 O 3 , ZrO 2 / SO 4 2-
* 제올라이트 : Y, beta, mordenite, ZSM-5, ZSM-22Zeolites: Y, beta, mordenite, ZSM-5, ZSM-22
* Silicoaluminaphosphates : SAPO 11, SAPO 31, SAPO 41Silicoaluminaphosphates: SAPO 11, SAPO 31, SAPO 41
상기와 같은 지지체에 Pt, Pd, bimetallic systems (Ni/Co, Ni/W, Ni/Mo, W/Mo) 등과 같은 금속을 함침시켜 크래킹 촉매를 제조할 수 있다.The cracking catalyst may be prepared by impregnating a metal such as Pt, Pd, and bimetallic systems (Ni / Co, Ni / W, Ni / Mo, W / Mo) on the support.
합성가스의 FT 합성반응은 일반적으로 20기압의 압력이상에서 철 촉매의 경우에는 운전온도에 따라 260∼280℃(LTFT)와 300∼350℃(HTFT)으로 분류되며, 코발트 촉매의 경우 220∼240℃에서 운전된다. 이후 생성된 왁스는 360∼396℃, ∼69기압 등의 조건에서 크래킹 촉매에 의해 액상연료로 전환된다(SRI report, 2006). FT synthesis reaction of syngas is generally classified into 260 ~ 280 ℃ (LTFT) and 300 ~ 350 ℃ (HTFT) according to the operating temperature for iron catalyst above 20 atm pressure, and 220 ~ 240 for cobalt catalyst. It is operated at ℃. The wax produced is then converted to liquid fuel by a cracking catalyst under conditions such as 360 to 396 ° C. and ˜69 atm (SRI report, 2006).
이와 같이 FT 합성 반응과 크래킹 공정은 운전온도나 압력이 상이하기 때문에 순차적인 연속공정으로 운전하기에는 어려움이 있으며, FT 합성공정보다 높은 압력에서 운전할 수 있도록 왁스의 예열과 공급시스템을 구축해야만 한다.As such, the FT synthesis reaction and cracking process are difficult to operate in a sequential continuous process because the operating temperature or pressure is different, and the preheating and supply system of the wax must be established to operate at a higher pressure than the FT synthesis process.
한편, 합성가스로부터 중간유분을 직접 생산하는 공정에 대한 연구가 진행되고 있으며, 신규한 촉매의 개발 또는 개선 연구가 활발히 진행되고 있다. 특히, FT 합성 생성물의 업그래이딩 없이 FT 합성을 통해 가지형 탄화수소들을 직접 얻기 위해, 특히 고품질의 가솔린을 생성하기 위해, 고체-산 촉매들과 같은 산성 성분들을 코발트계 촉매들에 첨가하는데 심혈을 기울였다. 많은 연구자들은 하기와 같은 다양한 방법으로 제조되고 코발트계 FT 합성 촉매와 크래킹 효소로서 산성 제올라이트로 구성된 하이브리드 또는 복합 효소들의 효과들을 조사하였다: i) 코발트계 FT 합성 촉매를 제올라이트와 물리적으로 혼합, ii) 습식 함침법으로 제조된 제올라이트에 담지된 코발트계 촉매, iii) 제올라이트 멤브레인-코팅된 Co/SiO2 촉매 등. 그러나, 일반적으로 제올라이트 멤브레인으로 코팅된 FT 합성 촉매는, geometrically confined acidic zeolite membrane을 통해, 가능한 수소화크래킹반응과 이성질체화 반응들에 의해 FT 합성 탄화수소들의 생성물 분포를 조절할 수 있음에도 불구하고, 높은 CH4 선택도를 보여준다. On the other hand, the research on the process of producing the intermediate oil directly from the synthesis gas is in progress, the research of the development or improvement of a new catalyst is actively in progress. In particular, branched hydrocarbons can be obtained through FT synthesis without upgrading the FT synthesis product. In order to obtain directly, especially to produce high quality gasoline, devotion has been made to adding acidic components, such as solid-acid catalysts, to cobalt-based catalysts. Many researchers have investigated the effects of hybrid or complex enzymes prepared in a variety of ways, consisting of cobalt-based FT synthesis catalysts and acidic zeolites as cracking enzymes: i) physically mixing cobalt-based FT synthesis catalysts with zeolites, ii) Cobalt based catalyst supported on zeolite prepared by wet impregnation method, iii) Zeolite membrane-coated Co / SiO2 Catalyst and so on. In general, however, FT synthesis catalysts coated with zeolite membranes, although capable of controlling the product distribution of FT synthesis hydrocarbons by means of possible hydrocracking and isomerization reactions via geometrically confined acidic zeolite membranes,4 Show selectivity.
본 발명자들은 크래킹 공정 또는 업그래이딩 공정이 생략된 전체공정의 단순화를 목적으로 하면서 중간유분의 생산성을 향상시킬 수 있는 FT 합성용 혼성촉매를 개발하고자 하였다. 제올라이트 및 담지된 코발트계 촉매를 구비한 특정 구조의 촉매 구조물의 경우, CH4의 선택도를 낮추면서 중간 유분(C5∼C22)의 선택도 및/또는 수율을 크게 향상시키는 효과를 확인함으로써 본 발명을 완성하였다.The inventors of the present invention have attempted to develop a hybrid catalyst for FT synthesis that can improve the productivity of the intermediate fraction, while simplifying the overall process in which the cracking process or the upgrading process is omitted. Zeolite and Supported Cobalt System For catalyst structures of specific structure with catalyst, CH4Medium fraction (C5-C22The present invention was completed by confirming the effect of greatly improving the selectivity and / or yield of.
본 발명의 목적은 합성가스로부터 직접 중간유분을 생산하기 위한 피셔-트롭쉬 합성 반응용 혼성촉매 및 이의 제조방법을 제공하는 것이다.It is an object of the present invention to provide a hybrid catalyst for the Fischer-Tropsch synthesis reaction for producing an intermediate fraction directly from the synthesis gas and a method for preparing the same.
본 발명의 다른 목적은 상기의 혼성촉매를 사용하여 합성가스로부터 직접 중간유분을 생산하는 방법을 제공하는 것이다. Another object of the present invention is to provide a method for producing an intermediate oil directly from syngas using the hybrid catalyst.
본 발명은 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를 수열합성하여 형성된 피셔-트롭쉬(FT) 합성용 혼성촉매로서, 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5인 것이 특징인 FT 합성용 혼성촉매를 제공한다.The present invention is a hybrid catalyst for Fischer-Tropsch (FT) synthesis formed by hydrothermally synthesizing zeolite on a porous support loaded with cobalt oxide, characterized in that the porous support (weight ratio) = 0.25 to 0.5 loaded with zeolite / cobalt oxide A hybrid catalyst for FT synthesis is provided.
또한, 본 발명은 본 발명에 따른 FT 합성용 혼성촉매의 제조방법으로서, 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5이 되도록 하는 조절된 제올라이트 합성용 젤 속에 상기 코발트 산화물이 담지된 다공성 지지체들을 넣은 후 수열합성한 것이 특징인 제조방법을 제공한다.The present invention also provides a method for preparing a hybrid catalyst for FT synthesis according to the present invention, wherein the cobalt oxide is supported in a gel for controlling zeolite synthesis so that the zeolite / cobalt oxide-supported porous support (weight ratio) = 0.25 to 0.5 It provides a manufacturing method characterized in that the hydrothermal synthesis after putting the porous supports.
나아가, 본 발명은 본 발명에 따른 FT 합성용 혼성촉매를 사용하여, 합성가스로부터 직접 중간유분을 생산하는 방법을 제공한다.Furthermore, the present invention provides a method for producing intermediate oil directly from syngas using the hybrid catalyst for FT synthesis according to the present invention.
이하 본 발명을 자세히 설명한다.Hereinafter, the present invention will be described in detail.
피셔-트롭쉬(FT)공정은 현재 가솔린 생산에 있어서 크게 두 가지 문제점을 안고 있다. 우선 가솔린(C5∼C11)의 선택도가 이론적으로 제한되어 있고, 에너지원으로 사용하기에 부적절한 선형 올레핀과 파라핀이 주를 이룬다. FT 공정을 통해 생산된 가솔린은 추가 공정에 의해 산촉매 및 Pt촉매를 이용하여 이소파라핀과 방향족 화합물로 전환시켜 옥탄가를 높일 수 있다.The Fischer-Tropsch (FT) process currently has two major problems with gasoline production. First of all, the selectivity of gasoline (C 5 to C 11 ) is theoretically limited, with linear olefins and paraffins being inadequate for use as energy sources. Gasoline produced through the FT process can be converted to isoparaffins and aromatic compounds using acid and Pt catalysts by further processes to increase the octane number.
FT 공정에 의해 생산되고 있는 거대 파라핀은 Pt계열의 촉매를 이용하여 개질된다. 많은 연구 그룹에 의해 Ni, Co, Fe, Zn, La 등 여러 가지 금속 촉매들이 이성화반응에 응용되어 왔지만, 그 중에서도 Pt 촉매의 이소파라핀과 방향족 화합물의 선택도는 가장 좋은 것으로 보고되고 있다. Pt는 주로 제올라이트나 무정형의 알루미나에 1% 전후로 담지되어 사용되는데, 이런 촉매에서 금속의 수소화 능력, 탈수소화 능력, 담체의 산점 수, 기공크기와 기하학적인 형태도 중요한 인자로 작용한다.The giant paraffins produced by the FT process are modified using Pt-based catalysts. Although many metal catalysts such as Ni, Co, Fe, Zn, and La have been applied to isomerization by many research groups, the selectivity of isoparaffin and aromatic compounds of Pt catalyst is reported to be the best. Pt is mainly used around 1% of zeolite or amorphous alumina. In this catalyst, hydrogenation ability, dehydrogenation ability of metal, acid number of carrier, pore size and geometrical form are also important factors.
한편, FT 공정에 의해 고옥탄가의 가솔린을 직접 생산하는데 사용되는 촉매로 Fe와 Co 계열의 촉매가 높은 활성을 나타낸다고 알려져 있다. 가솔린의 옥탄가를 향상시키기 위한 촉매로, Fe와 Co 계열의 촉매를 강한 Bronsted 산점을 지니는 제올라이트 (ZSM-5) 촉매와 하이브리드시켜, 합성 가스로부터 고옥탄가의 탄화수소 화합물을 직접 생성한다. 하이브리드 촉매라 함은 촉매의 제조 공정에서 촉매를 화학적 결합에 의해 제조하는 것이 아니라 각각의 촉매를 제조 후, 단순히 물리적으로 섞어 놓은 것을 의미한다. 이렇게 하이브리드된 촉매의 경우 촉매의 이원기능(bifunctionality)을 동시에 기대할 수 있으며, 고옥탄가의 가솔린 생산에 있어서 공정을 단순화시킬 수 있다.Meanwhile, it is known that Fe and Co-based catalysts exhibit high activity as catalysts used to directly produce high-octane gasoline by the FT process. As a catalyst for improving the octane number of gasoline, Fe and Co series catalysts are hybridized with a zeolite (ZSM-5) catalyst having a strong Bronsted acid point to directly generate a high octane hydrocarbon compound from the synthesis gas. By hybrid catalyst, it is meant that the catalysts are not physically produced by chemical bonding in the process of preparing the catalysts, but are simply physically mixed after each catalyst is prepared. In the case of the hybrid catalyst, the bifunctionality of the catalyst can be expected at the same time, and the process can be simplified in the production of gasoline of high octane number.
본 발명자들은 낮은 CH4 선택도로 가솔린 및 중간 유분 범위의 탄화수소들을 높은 선택도 및 수율로 직접 생성하기 위해 Co/SiO2 촉매 상의 ZSM5 개질 효과를 연구하였다. ZSM5-개질된 Co/SiO2 FT 합성 촉매를 이용하여, C5 ∼ C22 탄화수소 범위의 가솔린 및 중질 탄화수소를 생산하는 FT 합성을 연구하였다. 이때, Co/SiO2 촉매 상의 ZSM5 입자들의 역할을 설명하기 위해, 함침된 Co/SiO2 촉매들을 다양한 ZSM5 / (Co/SiO2) 무게비로 ZSM5을 in situ 수열합성시켜 개질하였다. 구체적으로, SiO2 슬러리에 코발트 나이트레이트 전구체를 함침시켜 Co/SiO2 촉매를 제조하였고 이어서, 다양한 ZSM5 /(Co/SiO2) 무게비로, Co/SiO2 촉매에 in situ 수열합성법으로 ZSM5 (Si/Al ratio = 40)을 합성하여 ZSM5-개질된 Co/SiO2 촉매를 제조하였다. 주로 ZSM5-개질된 Co/SiO2 촉매들 상에 코발트 산화물들의 산도 및 환원정도(acidity and reducibility) 을 변화시킴으로써 촉매 성능을 변화시킬 수 있었다. 이는 SiO2 으로부터 ZSM5 표면으로 코발트 산화물의 이동 정도가 다르면 올레핀 크래킹 반응의 정도가 상이하기 때문이다. 25 wt% ZSM5을 갖는 ZSM5-개질된 Co/SiO2 촉매는 높은 환원정도(reducibility)와 최적의 산점 밀도(acid site density)를 갖는 작은 코발트 결정 크기를 갖기 때문에, 높은 CO 전환율과 C5∼C22 탄화수소들에 대한 최대 선택도를 보여준다. ZSM5-개질된 Co/SiO2 촉매들 상에서의 우수한 촉매 성능은 주로 Co/SiO2 표면에 인접한 ZSM5 입자들이 존재하도록 개질하는 것과, ZSM5의 수열합성 동안 코발트 종이 SiO2로부터 ZSM5 표면으로의 이동에 기인한 것을 확인하였다. 본 발명은 이에 기초한 것이다.We studied the effect of ZSM5 reforming on Co / SiO 2 catalysts to directly produce gasoline and middle fraction range hydrocarbons with high selectivity and yield with low CH 4 selectivity. Using a ZSM5-modified Co / SiO 2 FT synthesis catalyst, FT synthesis to produce gasoline and heavy hydrocarbons ranging from C 5 to C 22 hydrocarbons was studied. At this time, in order to explain the role of the ZSM5 particles on the Co / SiO 2 catalyst, impregnated Co / SiO 2 catalysts were modified by in situ hydrothermal synthesis of ZSM 5 in various ZSM 5 / (Co / SiO 2 ) weight ratio. Specifically, a Co / SiO 2 catalyst was prepared by impregnating a cobalt nitrate precursor in a SiO 2 slurry, followed by ZSM5 (Si by hydrothermal synthesis in situ in a Co / SiO 2 catalyst at various weight ratios of ZSM5 / (Co / SiO 2 ). / Al ratio = 40) to synthesize ZSM5-modified Co / SiO 2 catalyst. Catalyst performance could be altered primarily by varying the acidity and reducibility of cobalt oxides on ZSM5-modified Co / SiO 2 catalysts. This is because the degree of olefin cracking reaction is different when the degree of migration of cobalt oxide from SiO 2 to ZSM5 surface is different. ZSM5-modified Co / SiO 2 catalysts with 25 wt% ZSM5 have high CO conversion and C 5 to C because they have a small cobalt crystal size with high reducibility and optimal acid site density. 22 shows the maximum selectivity for hydrocarbons. The good catalytic performance on ZSM5-modified Co / SiO 2 catalysts is mainly due to the modification of the presence of ZSM5 particles adjacent to the Co / SiO 2 surface and the migration of cobalt species from SiO 2 to the ZSM5 surface during hydrothermal synthesis of ZSM5. It confirmed that it did. The present invention is based on this.
본 발명은, 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를 수열합성하여 형성된 피셔-트롭쉬(FT) 합성용 혼성촉매에 관한 것으로, 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5인 것이 특징이다. 이때, 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) 는 0.25 ± 0.1 범위 내인 것이 바람직하다. The present invention relates to a hybrid catalyst for Fischer-Tropsch (FT) synthesis formed by hydrothermally synthesizing zeolite on a porous support loaded with cobalt oxide, wherein the porous support (weight ratio) of zeolite / cobalt oxide is 0.25 to 0.5. Is characteristic. At this time, the porous support (weight ratio) on which the zeolite / cobalt oxide is supported is preferably within a range of 0.25 ± 0.1.
수열합성 동안 다공성 지지체 및 제올라이트 양쪽에 코발트 미세 결정들이 재분포됨으로써, 촉매 성능이 변경될 수 있다.By redistributing cobalt microcrystals to both the porous support and the zeolite during hydrothermal synthesis, catalyst performance can be altered.
본 발명에서, Co/다공성 지지체 표면은 제올라이트에 의해 완전히 뒤덮히지 않은 것이 특징이다. 제올라이트 함량이 증가할수록 Co/다공성 지지체 촉매의 메조기공들이 제올라이트 입자들에 의해 차단됨으로써, 촉매의 표면적과 기공 부피가 감소한다. In the present invention, the Co / porous support surface is characterized in that it is not completely covered by zeolite. As the zeolite content increases, the mesopores of the Co / porous support catalyst are blocked by the zeolite particles, thereby reducing the surface area and pore volume of the catalyst.
본 발명에 따른 FT 합성용 혼성촉매는 코발트 산화물이 담지된 다공성 지지체(Co/다공성 지지체)상에서 제올라이트를 수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 코발트 산화물이 일부 또는 전부 이동되어 있는 것일 수 있다. 이때, 수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 이동된 코발트 산화물은 제올라이트 입자와 접촉된 상태에서 표면에 노출되어 있는 것이 바람직하다(도 9 참조). The hybrid catalyst for FT synthesis according to the present invention may be one in which some or all of the cobalt oxide is transferred from the porous support to the zeolite surface during hydrothermal synthesis of the zeolite on the porous support (Co / porous support) on which the cobalt oxide is supported. At this time, the cobalt oxide transferred to the zeolite surface on the porous support during hydrothermal synthesis is preferably exposed to the surface in contact with the zeolite particles (see FIG. 9).
Co/다공성 지지체로부터 제올라이트 표면으로 코발트 산화물의 이동 정도는 제올라이트 함량 증가에 따라 증가한다. The degree of cobalt oxide migration from the Co / porous support to the zeolite surface increases with increasing zeolite content.
또한, 제올라이트 /(Co/다공성 지지체) 비가 증가함에 따라 Co3O4 의 미세 결정 크기가 증가한다. 수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 이동된 코발트 산화물에서 코발트 결정 평균 입경은 높은 환원정도(reducibility)을 발휘하기 위해 15 내지 20 nm인 것이 바람직하다. In addition, the fine crystal size of Co 3 O 4 increases as the zeolite / (Co / porous support) ratio increases. The cobalt crystal average particle diameter of the cobalt oxide migrated from the porous support to the zeolite surface during hydrothermal synthesis is preferably from 15 to 20 nm in order to exhibit high reducibility.
본 발명에 따른 FT 합성용 혼성촉매는 상기 코발트 산화물의 일부 또는 전부가 코발트 금속으로 환원된 것도 포함한다. 즉, 코발트계 촉매는 코발트 금속 또는 코발트 산화물일 수 있다.Hybrid catalysts for FT synthesis according to the present invention include those in which some or all of the cobalt oxide is reduced to cobalt metal. That is, the cobalt based catalyst may be cobalt metal or cobalt oxide.
본 발명에 따른 FT 합성용 혼성촉매는 FT 합성 반응 및 올레핀 크래킹 반응에 대해 촉매 활성을 발휘할 수 있다. 따라서, 본 발명에 따른 FT 합성용 혼성촉매는 크래킹 공정 또는 업그래이딩 공정을 생략할 수 있으며 중간 유분(C5∼C22)의 선택도 및 수율을 크게 향상시킬 수 있다. The hybrid catalyst for FT synthesis according to the present invention can exhibit catalytic activity against FT synthesis reaction and olefin cracking reaction. Therefore, the hybrid catalyst for FT synthesis according to the present invention can omit the cracking process or the upgrading process and can greatly improve the selectivity and yield of the intermediate fractions (C 5 to C 22 ).
본 발명에 따른 촉매는 in situ 수열 합성 동안 Co/다공성 지지체 표면상에 제올라이트 입자들이 코발트 산화물과 인접하여 접촉(adjacent contact)하여 있으면서, 잘 분산되어 있기 때문에, 저온에서 조차도 제올라이트 표면에서 FTS 생성물들의 올레핀 크래킹 반응이 일어날 수 있어서 가솔린과 중간유분 탄화수소들(middle distillate range hydrocarbons)에 대한 높은 선택성을 수득하는데 유리하다. Since the catalyst according to the invention is well dispersed, with zeolite particles adjacent contacting cobalt oxide on the surface of the Co / porous support during in situ hydrothermal synthesis, the olefins of the FTS products on the zeolite surface even at low temperatures Cracking reactions can occur, which is advantageous for obtaining high selectivity for gasoline and middle distillate range hydrocarbons.
코발트 촉매는 철 촉매에 비해 비싸고 고온에서 메탄의 선택성이 높아진다는 단점이 있지만, 높은 활성과 긴 수명 그리고 WGS(수성가스 전환반응)이 거의 없어 이산화탄소 생성이 적다는 장점을 갖는다. 고가의 코발트를 활성금속으로 사용하기 위해서는 활성금속의 분산을 높여주기 위하여 고 비표면적의 지지체를 선택 사용하거나 촉진제를 첨가 사용할 수 있다.Cobalt catalysts are more expensive than iron catalysts and have a higher selectivity of methane at higher temperatures, but have the advantages of high activity, long lifetime, and little WGS (water gas shift reaction), resulting in low carbon dioxide generation. In order to use expensive cobalt as an active metal, a support having a high specific surface area may be selected or an accelerator may be used to increase dispersion of the active metal.
본 발명에서, 다공성 지지체의 크기는 비표면적이 100 내지 400 m2/g인 것이 바람직하다. 다공성 지지체의 바람직한 예로는 다공성 실리카(SiO2)(silicalite)가 있다.In the present invention, the size of the porous support is preferably a specific surface area of 100 to 400 m 2 / g. Preferred examples of the porous support are porous silica (SiO 2 ) (silicalite).
다공성 지지체 100 중량부를 기준으로 Co는 5 ∼ 40 중량부인 것이 바람직하다.Co is preferably 5 to 40 parts by weight based on 100 parts by weight of the porous support.
본 명세서에서 "제올라이트"는 (i) 알칼리 또는 알칼리토금속의 규산 알루미늄 수화물인 광물의 총칭뿐만 아니라, (ii) 제올라이트의 골격 구조를 이루는 원소들인 실리콘(Si)과 알루미늄(Al) 대신에 여러 가지 다른 원소로 실리콘이나 알루미늄의 일부 또는 전체를 대체시킨 제올라이트 유사 분자체(zeotype molecular sieve)도 포함하며, 큰 의미에서는 표면에 히드록실기를 가지는 모든 다공성 산화물 또는 황화물을 포함한다.As used herein, the term "zeolite" refers not only to (i) a generic term for minerals that are aluminum silicate hydrates of alkali or alkaline earth metals, but also to (ii) a variety of alternatives to silicon (Si) and aluminum (Al), It also includes zeotype molecular sieves that have replaced some or all of silicon or aluminum as an element, and in the larger sense includes all porous oxides or sulfides having hydroxyl groups on the surface.
MFI 구조의 제올라이트 또는 유사 분자체의 예로는 ZSM-5, 실리카라이트, TS-1, AZ-1, Bor-C, 보라라이트 C, 엔시라이트, FZ-1, LZ-105, 모노클리닉 H-ZSM-5, 뮤티나이트, NU-4, NU-5, TSZ, TSZ-III, TZ-01, USC-4, USI-108, ZBH, ZKQ-1B 등이 있다. 상기 제올라이트는, ZSM-5, β-zeolite, MCM, SBA, Morsenite, SAPO, Ferrierite 등이 바람직하다.Examples of zeolite or pseudomolecular sieves of MFI structure include ZSM-5, silicalite, TS-1, AZ-1, Bor-C, Boralite C, encilite, FZ-1, LZ-105, monoclinic H-ZSM -5, mutinite, NU-4, NU-5, TSZ, TSZ-III, TZ-01, USC-4, USI-108, ZBH, ZKQ-1B and the like. The zeolite is preferably ZSM-5, β-zeolite, MCM, SBA, Morsenite, SAPO, Ferrierite, or the like.
본 발명에 따른 FT 합성용 혼성촉매는 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5이 되도록 하는 조절된 제올라이트 합성용 젤 속에 상기 코발트 산화물이 담지된 다공성 지지체들을 넣은 후 수열합성하여 제조될 수 있다.The hybrid catalyst for FT synthesis according to the present invention is hydrothermally synthesized after putting the cobalt oxide-supported porous supports in a gel for controlling zeolite synthesis so that the zeolite / cobalt oxide-supported porous support (weight ratio) = 0.25 to 0.5. Can be prepared.
먼저 코발트 산화물이 담지된 다공성 지지체는 다공성 지지체에 코발트 전구체를 함침시킨 후 소성시켜 제조할 수 있다.First, a porous support on which cobalt oxide is supported may be prepared by impregnating a cobalt precursor in a porous support and then firing.
Co 전구체의 바람직한 예로는 금속 자체, 산화물(예, 알루미나), 수산화물(예, 수산화 알루미늄), 옥시수산화물, 질산염, 염화물, 탄산염, 초산염, 옥살산염, 시트르산염, 또는 이들의 혼합물이 있다. 예컨대 코발트 전구체는 코발트 금속, 코발트 나이트레이트, 코발트 아세테이트, 코발트 브로마이드, 코발트 클로라이드, 및 코발트 아이오다이드로 이루어진 군에서 선택된 1종 또는 2종 이상 선택될 수 있다.Preferred examples of Co precursors are the metal itself, oxides (eg alumina), hydroxides (eg aluminum hydroxide), oxyhydroxides, nitrates, chlorides, carbonates, acetates, oxalates, citrates, or mixtures thereof. For example, the cobalt precursor may be selected from one or two or more selected from the group consisting of cobalt metal, cobalt nitrate, cobalt acetate, cobalt bromide, cobalt chloride, and cobalt iodide.
코발트계 촉매를 다공성 지지체에 담지하기 위하여, 초기 적심 함침법(Incipient Wetness Impregnation)법을 사용할 수 있다. In order to support the cobalt-based catalyst on the porous support, an initial wetness impregnation method may be used.
한편, 합성용 젤로 보통 구조 유도제(Structure directing agent) 또는 유기 템플레이트(organic template)를 첨가한 젤이 사용된다. On the other hand, as a synthetic gel, a gel to which a structure directing agent or an organic template is added is usually used.
구조 유도제는 특정 결정구조(crystalline structure)의 주형(template) 역할을 하는 물질로서, 구조 유도제의 charge distribution, size 및 geometric shape가 구조 유도 특성(structure directing properties)를 제공한다.The structure inducing agent is a material that serves as a template of a specific crystalline structure, and the charge distribution, size, and geometric shape of the structure inducing agent provide structure directing properties.
구조 유도제는 아민, 이민 또는 4차 암모늄 염(quaternary ammonium salt)일 수 있으며, 바람직하게는 4차 암모늄 하이드록사이드 또는 이를 반복단위로 한 올리고머일 수 있다. 구조 유도제의 예로는 테트라프로필암모니움 하이드록사이드 (tetraproplyammonium hydroxide, TPAOH), 테트라에틸암모니움 하이드록사이드 (TEAOH), tetramethylammonium (TMA), tetrabutylammonium (TBA) 또는 이의 혼합물이 있다.The structural inducing agent may be an amine, an imine or a quaternary ammonium salt, preferably a quaternary ammonium hydroxide or an oligomer thereof. Examples of structure inducing agents are tetraproplyammonium hydroxide (TPAOH), tetraethylammonium hydroxide (TEAOH), tetramethylammonium (TMA), tetrabutylammonium (TBA) or mixtures thereof.
제올라이트 합성용 젤의 용매는 물 또는 유기용매 또는 이의 혼합물일 수 있다.The solvent of the gel for zeolite synthesis may be water or an organic solvent or a mixture thereof.
제올라이트 합성용 젤은 구조 유도제 이외에도 하기와 같은 원료 물질을 포함할 수 있다:In addition to the structure inducing agent, the gel for zeolite synthesis may include the following raw materials:
1) 알루미늄(Al) 원료로 알루미늄 이소프로폭사이드와 같은 알루미늄에 유기물이 결합된 유기무기 혼성물질, 황산 알루미늄(aluminium sulfate)과 같은 Al이 포함된 염 형태의 물질, Al으로만 이루어진 분말 형태 또는 덩어리 형태를 가진 금속물질 및 알루미나와 같은 알루미늄 산화물의 모든 물질.1) Aluminum (Al) as an raw material, an organic-inorganic hybrid material in which an organic material is bonded to aluminum such as aluminum isopropoxide, a salt form material containing Al such as aluminum sulfate, or powder form of Al only Metallic material in the form of agglomerates and all materials of aluminum oxide such as alumina.
2) 실리콘 원료로 TEOS(테트라에틸 오쏘실리케이트)와 같은 실리콘에 유기물이 결합된 유기무기 혼성물질, 소듐실리카라이트와 같은 Si 원소가 포함된 염 형태의 물질, Si으로만 이루어진 분말 형태 혹은 덩어리 형태를 가진 물질, 유리 분말, 및 석영과 같은 실리콘 산화물의 모든 물질.2) As a raw material of silicon, organic inorganic hybrid materials in which organic matter is bonded to silicon such as TEOS (tetraethyl orthosilicate), salt form material containing Si element such as sodium silicalite, powder form or lump form made of Si only Material with, all materials of silicon oxide such as glass powder, and quartz.
3) F 원료로 HF, NH4F, NaF, KF 등과 같은 F를 포함한 모든 형태의 물질.3) All types of substances including F as F raw material, such as HF, NH4F, NaF, KF, etc.
4) 알루미늄과 실리콘이외에 골격에 다른 종류의 원소를 삽입하기 위해 사용되는 물질.4) Materials used to insert other kinds of elements into the skeleton, in addition to aluminum and silicon.
제올라이트 합성용 젤 형성 온도는 50 ℃이상에서 유지하는 것이 바람직하다. It is preferable to keep the gel formation temperature for zeolite synthesis at 50 degreeC or more.
본 방법에서, 제올라이트 수열합성을 위한 반응온도는 사용되는 합성젤의 조성 또는 만들고자 하는 물질에 따라 50℃∼250℃까지 다양하게 변화할 수 있다. 바람직하게는 그 반응온도는 80℃∼200℃이고, 보다 바람직하게는 120℃∼180℃이다. 또한, 반응 온도는 항상 고정된 것이 아니라 여러 단계로 온도를 변화시키면서 반응할 수 있다. 반응 시간은 0.5시간에서 20일까지 다양하게 변화할 수 있다. 반응 시간은 바람직하게는 2시간∼15일, 보다 바람직하게는 6시간∼2일, 가장 바람직하게는 10시간∼1일이다.In this method, the reaction temperature for the zeolite hydrothermal synthesis may vary from 50 ℃ to 250 ℃ depending on the composition of the synthetic gel used or the material to be made. Preferably the reaction temperature is 80 degreeC-200 degreeC, More preferably, it is 120 degreeC-180 degreeC. In addition, the reaction temperature is not always fixed, but may react with varying temperatures in several steps. The reaction time can vary from 0.5 hours to 20 days. The reaction time is preferably 2 hours to 15 days, more preferably 6 hours to 2 days, and most preferably 10 hours to 1 day.
한편, CO에서 CO2로의 전환율(카본몰%)을 낮추면서, 중간유분(C5∼C22)의 수율 및 C5∼C9의 선택도를 향상시키기 위해 본 발명의 FT 합성용 혼성촉매에서 코발트 산화물이 담지된 다공성 지지체는 Ru, Pt 및 La 중에서 선택된 금속을 더 담지하는 것이 바람직하다. 이때, 다공성 지지체 100 중량부 기준으로 Ru, Pt 및 La 중에서 선택된 1종 이상의 금속원소는 0.1 내지 5 중량부인 것이 바람직하다. 상기 금속원소의 산화물이 담지된 다공성 지지체는 다공성 지지체에 상기 금속원소 함유 화합물을 함침시킨 후 소성시켜 제조할 수 있다. Ru, Pt 및 La 중에서 선택된 금속원소 함유 화합물의 바람직한 예로는 금속 자체, 산화물(예, 알루미나), 수산화물(예, 수산화 알루미늄), 옥시수산화물, 질산염, 염화물, 탄산염, 초산염, 옥살산염, 시트르산염, 또는 이들의 혼합물이 있다. On the other hand, in the hybrid catalyst for FT synthesis of the present invention in order to improve the yield of the intermediate fraction (C 5 ~ C 22 ) and the selectivity of C 5 ~ C 9 while lowering the conversion ratio (carbon mol%) from CO to CO 2 Preferably, the porous support on which cobalt oxide is supported further supports a metal selected from Ru, Pt, and La. In this case, the at least one metal element selected from Ru, Pt, and La based on 100 parts by weight of the porous support is preferably 0.1 to 5 parts by weight. The porous support on which the oxide of the metal element is supported may be prepared by impregnating the metal element-containing compound in the porous support and then firing. Preferred examples of the metal element-containing compound selected from Ru, Pt and La include metals themselves, oxides (e.g., alumina), hydroxides (e.g., aluminum hydroxide), oxyhydroxides, nitrates, chlorides, carbonates, acetates, oxalates, citrates, Or mixtures thereof.
본 발명은 실험을 통해, FT 합성용 코발트계 촉매와 Ru, Pt 및 La 중에서 선택된 금속의 산화물이 담지된 다공성 지지체의 표면에, 크래킹 공정 또는 업그래이딩 공정에 사용되는 촉매인 제올라이트 입자들을 수열합성으로 형성시킨 결과, 본 발명에 따른 FT 합성용 혼성촉매에서 중간유분의 수율을 향상시키는 것을 확인하였으며, 상기 Ru, Pt 및 La 중에서 선택된 금속의 산화물이 다공성 지지체에 함유되지 아니한 FT 합성용 혼성촉매에 비해 CO에서 CO2로의 전환율(카본몰%)을 낮출 수 있으며, C5∼C9의 선택도가 크게 향상되는 것을 확인하였다.The present invention experiments, hydrothermal synthesis of zeolite particles, which are catalysts used in cracking or upgrading processes, on the surface of a cobalt-based catalyst for FT synthesis and a porous support on which oxides of metals selected from Ru, Pt, and La are supported. As a result, in the hybrid catalyst for FT synthesis according to the present invention It was confirmed that the yield of the intermediate fraction was improved, and CO in CO compared to the hybrid catalyst for FT synthesis in which the oxide of the metal selected from Ru, Pt and La was not contained in the porous support.2Lower the conversion rate to carbon mole%, and C5-C9It was confirmed that the selectivity of was greatly improved.
CO2로 전환되지 않은 미반응의 CO는 재순환하여 FT 합성반응에 참여시킬 수 있으므로 CO2의 생성을 억제하는 것이 중요하다. 특히, 지지체에 담지된 코발트계 촉매 표면에 제올라이트 입자들이 ZSM-5와 유사한 구조로 합성되면 사슬성장으로 생성된 고유분의 생성물이 제올라이트 입자 상에서 크래킹이 동시에 발생하여 중간유분의 선택도를 증가시킬 수 있다. CO2Unreacted CO not converted to CO can be recycled to participate in FT synthesis.2It is important to suppress the production of it. In particular, the zeolite on the surface of the cobalt-based catalyst supported on the support When the particles are synthesized in a structure similar to that of ZSM-5, the product of the intrinsic fraction produced by the chain growth may simultaneously crack on the zeolite particles, thereby increasing the selectivity of the middle fraction.
한편, 본 발명에 따른 FT 합성용 혼성촉매는 합성가스에서 중간유분을 직접생산하기 위한 피셔-트롭쉬 합성 반응 공정에 사용할 수 있으나, 이에 제한되는 것은 아니다. Meanwhile, the hybrid catalyst for FT synthesis according to the present invention may be used in a Fischer-Tropsch synthesis reaction process for directly producing intermediate oil in a synthesis gas, but is not limited thereto.
본 발명에 따른 FT 합성용 혼성촉매를 사용하면 별도의 크래킹 공정 또는 업그래이딩 공정 없이 하나의 반응기에서 합성가스로부터 직접 중간유분을 생산할 수 있으며, 중간 유분(C5∼C22)의 선택도 및 수율을 크게 향상시킬 수 있다.By using the hybrid catalyst for FT synthesis according to the present invention, it is possible to produce intermediate oil directly from the synthesis gas in one reactor without a separate cracking process or an upgrade process, and selectivity of the intermediate oil (C 5 to C 22 ) and Yield can be greatly improved.
CO 전환은 제올라이트 / (Co/SiO2) 무게비가 증가함에 따라 비례적으로 감소하는데(표 1), 이는 코발트 산화물의 미세 결정 크기 및 이의 환원능력과 관련이 있다. CO conversion decreases proportionally with increasing zeolite / (Co / SiO 2 ) weight ratio (Table 1), which is related to the fine crystal size of cobalt oxide and its reducing capacity.
상기 합성가스(H2/CO)는 석탁 또는 바이오매스의 가스화 또는 천연가스의 개질화를 통해 준비할 수 있다.The synthesis gas (H 2 / CO) may be prepared through the gasification of turbidity or biomass or reformation of natural gas.
수소/일산화탄소 반응비는 1 내지 2 몰비를 유지하면서 수행하는 것이 바람직하다. 그 결과, 본 발명의 FT 합성용 혼성촉매를 사용한 합성반응은 수소 기체 및 일산화탄소 기체의 전환율이 높게 유지되면서, 중간 유분(C5∼C22)의 선택도 및 수율을 크게 향상시킬 수 있다.The hydrogen / carbon monoxide reaction ratio is preferably carried out while maintaining the molar ratio of 1-2. As a result, the synthesis reaction using the hybrid catalyst for FT synthesis of the present invention can significantly improve the selectivity and yield of the intermediate fractions (C 5 to C 22 ) while maintaining high conversion of hydrogen gas and carbon monoxide gas.
본 발명에 따른 FT 합성용 혼성촉매를 사용하여 합성가스로부터 직접 중간유분을 생산하기 위한 반응은 고정층, 유동층 또는 슬러리 반응기에서 수행할 수 있다.The reaction for producing the intermediate oil directly from the synthesis gas using the hybrid catalyst for FT synthesis according to the present invention can be carried out in a fixed bed, fluidized bed or slurry reactor.
본 발명에 따른 FT 합성용 혼성촉매는 200∼ 700℃의 영역에서 수소 분위기에서 환원한 후 촉매 반응에 활용하는 것이 바람직하다. 700℃를 초과하여 환원할 경우 촉매의 소결이 진행될 수 있다. The hybrid catalyst for FT synthesis according to the present invention is preferably used in a catalytic reaction after reduction in a hydrogen atmosphere in the range of 200 to 700 ° C. When the reduction exceeds 700 ℃ sintering of the catalyst may proceed.
본 발명에 따른 FT 합성용 혼성촉매를 사용하여 합성가스로부터 직접 중간유분을 생산하기 위한 반응은 피셔-트롭쉬 합성 반응과 유사한 반응 조건에서 수행될 수 있다. 구체적으로 반응 온도는 220 ∼ 400℃, 바람직하게는 일반적인 단독 크래킹 공정의 온도 보다 저온인 반응온도, 반응 압력은 5 ∼ 60 kg/와 공간속도는 500 ∼ 10000 h-1에서 수행하는 것이 좋으나, 이에 한정되는 것은 아니다.The reaction for producing the intermediate fraction directly from the synthesis gas using the hybrid catalyst for FT synthesis according to the present invention can be carried out under reaction conditions similar to the Fischer-Tropsch synthesis reaction. Specifically, the reaction temperature is 220 ~ 400 ℃, preferably the reaction temperature lower than the temperature of the general single cracking process, the reaction pressure is preferably carried out at 5 ~ 60 kg / and the space velocity is 500 to 10000 h -1 , but It is not limited.
한편, 최종생성물 중 C1∼C4 범위의 경질탄화수소(14)들은 도 12에서와 같이 재순환시켜 원료인 천연가스(11)와 함께 개질공정(12)으로 유입될 수 있다.Meanwhile, the hard hydrocarbons 14 in the C 1 to C 4 range of the final product may be recycled as shown in FIG. 12 and introduced into the reforming process 12 together with the natural gas 11 as a raw material.
본 발명에 따른 피셔-트롭쉬 합성 반응용 혼성촉매를 사용하면, 크래킹 공정 또는 업그래이딩 공정 없이 합성가스로부터 직접 중간유분을 생산할 수 있으며, CH4 선택도를 낮게 유지하면서, 중간유분의 선택도 및 수율을 증가시킬 수 있다. Using the hybrid catalyst for Fischer-Tropsch synthesis reaction according to the present invention, it is possible to produce the intermediate oil directly from the synthesis gas without cracking process or upgrading process, while maintaining the low CH 4 selectivity, And yield can be increased.
도 1은 ZSM5-개질된 Co/SiO2 의 기공크기 분포를 도시한 것이다.1 shows the pore size distribution of ZSM5-modified Co / SiO 2 .
도 2는 미사용된 ZSM5-개질된 Co/SiO2 촉매들 [(a) Co/SiO2, (b) CoZ(0.25), (c) CoZ(0.33), (d)CoZ(0.50), 및 (e) Co/ZSM5 ]의 XRD 패턴들을 도시한 것이다.2 shows unused ZSM5-modified Co / SiO 2 catalysts ((a) Co / SiO 2 , (b) CoZ (0.25), (c) CoZ (0.33), (d) CoZ (0.50), and ( e) XRD patterns of Co / ZSM5].
도 3은 미사용된 ZSM5-개질된 Co/SiO2 촉매들 상에서 Co2p3/2 및 Co2p1/2의 XPS 분석을 도시한 것이다.FIG. 3 shows XPS analysis of Co2p 3/2 and Co2p 1/2 on unused ZSM5-modified Co / SiO 2 catalysts.
도 4는 미사용된 ZSM5-개질된 Co/SiO2 촉매들 [(a) CoZ(0.25), (b) CoZ(0.33), 및 (c) CoZ(0.50) ]의 TEM 이미지들을 도시한 것이다.FIG. 4 shows TEM images of unused ZSM5-modified Co / SiO 2 catalysts ((a) CoZ (0.25), (b) CoZ (0.33), and (c) CoZ (0.50)].
도 5는 미사용된 ZSM5-개질된 Co/SiO2 촉매들의 H2-TPR 프로파일을 도시한 것이다.5 shows the H 2 -TPR profile of unused ZSM5-modified Co / SiO 2 catalysts.
도 6은 미사용된 ZSM5-개질된 Co/SiO2 촉매들의 NH3-TPD 프로파일을 도시한 것이다.FIG. 6 shows NH 3 -TPD profile of unused ZSM5-modified Co / SiO 2 catalysts.
도 7은 ZSM5-개질된 Co/SiO2 촉매들에서 시간에 따른 촉매 활성을 도시한 그래프이다.FIG. 7 is a graph showing catalyst activity over time in ZSM5-modified Co / SiO 2 catalysts.
도 8은 ZSM5-개질된 Co/SiO2 촉매들에서 산점 밀도에 따른 촉매성능(CO 전환 및 생성물 분포)을 도시한 그래프이다.FIG. 8 is a graph showing catalytic performance (CO conversion and product distribution) with acid point density in ZSM5-modified Co / SiO 2 catalysts.
도 9는 ZSM5-개질된 Co/SiO2 및 함침된 코발트계 촉매들의 모식도이다. 9 is a schematic of ZSM5-modified Co / SiO 2 and impregnated cobalt-based catalysts.
도 10은, 종래의 피셔-트롭쉬 합성 반응 공정을 이용한 중간유분 생성 공정의 간략한 공정도이다. 10 is a simplified process diagram of a middle oil production process using a conventional Fischer-Tropsch synthesis reaction process.
도 11는, 본 발명에 따른 피셔-트롭쉬 합성 반응 공정을 이용한 중간유분 생성 공정의 간략한 공정도이다. 11 is a simplified process diagram of a middle oil production process using the Fischer-Tropsch synthesis reaction process according to the present invention.
도 12은, 도 11의 공정도를 개량한 것으로 피셔-트롭쉬 합성 반응의 최종생성물 중 C1∼C4 경질탄화수소들을 천연가스 개질공정에 재순환시킨 것이다.FIG. 12 is an improvement of the process diagram of FIG. 11 to recycle C 1 -C 4 light hydrocarbons in the final product of the Fischer-Tropsch synthesis reaction to a natural gas reforming process.
도 13는, 구조 유도제가 삽입된 MFI 구조의 제올라이트 결정을 개략적으로 도시한 도면이다. FIG. 13 is a diagram schematically showing zeolite crystals of an MFI structure in which a structure inducing agent is inserted.
이하, 본 발명을 다음의 피셔-트롭쉬 합성 반응과 관련하여 실시예와 비교예의 결과를 설명하는 바, 본 발명이 다음 실시예에 의하여 한정되는 것은 아니다. Hereinafter, the present invention will be described with reference to the following Fischer-Tropsch synthesis reaction, and the present invention is not limited by the following examples.
제조예 1. 함침된 Co/SiO2 및 Co/ZSM5 촉매 제조Preparation Example 1 Preparation of Impregnated Co / SiO 2 and Co / ZSM5 Catalysts
SiO2 및 ZSM5 (Si/Al ratio of 25) 지지체, 그리고 필요한 조성의 수성 코발트 니트레이트 전구체를 사용하여 전형적인 습식-함침법으로 Co/SiO2 및 Co/ZSM5 촉매를 제조하였다. 표면적이 336 m2/g이고 기공부피가 1.11 cm3/g 인 SiO2 (Davisil grade 645, Aldrich) 와, 표면적이 350 m2/g 인 ZSM5(Zeolyst)를 지지체로 사용하였다. 상온에서 12시간 교반하면서 SiO2 및 ZSM5 지지체를 기준으로 금속 코발트 20 wt % 를 갖는 코발트 니트레이트 (Co(NO3)2·H2O))로 각각 함침하였다. 이어서, 촉매를 회전식 증발기에서 70℃로 진공시키고, 110℃의 오븐에서 12시간 동안 건조시킨 후, 전기로(muffle furnace)에서 5시간 동안 공기중에 가열속도 10℃/분으로 500℃에서 하소시켰다. 최종 촉매에서 코발트 금속 / SiO2 및 ZSM5의 무게비는 총 촉매 무게를 기준으로 20/80으로 고정하였다.Co / SiO 2 and Co / ZSM5 catalysts were prepared by typical wet-impregnation using SiO 2 and ZSM5 (Si / Al ratio of 25) supports and aqueous cobalt nitrate precursors of the required composition. SiO 2 (Davisil grade 645, Aldrich) having a surface area of 336 m 2 / g and a pore volume of 1.11 cm 3 / g, and ZSM5 (Zeolyst) having a surface area of 350 m 2 / g were used as a support. It was impregnated with cobalt nitrate (Co (NO 3 ) 2 .H 2 O)) having 20 wt% of metal cobalt based on SiO 2 and ZSM5 supports with stirring at room temperature for 12 hours. The catalyst was then evacuated to 70 ° C. in a rotary evaporator, dried for 12 hours in an oven at 110 ° C. and then calcined at 500 ° C. at a heating rate of 10 ° C./min in air for 5 hours in a muffle furnace. The weight ratio of cobalt metal / SiO 2 and ZSM5 in the final catalyst was fixed at 20/80 based on the total catalyst weight.
제조예 2. ZSM5-개질된 Co/SiO2 촉매 제조Preparation Example 2 Preparation of ZSM5-Modified Co / SiO 2 Catalyst
ZSM5-개질된 Co/SiO2 촉매를 제조하기 위해, 탈이온수와 에탄올을 용매로 사용하였다. 템플레이트로 TPAOH (tetrapropylammonium hydroxide solution, ACROS에서 제공)을 사용하였고, Al(NO3)3·H2O (99.5% 순도) 및 TEOS (tetraethyl ortho silicate; Samchun Chemicals에서 제공 99.9% 순도)를 알루미늄 및 실리콘 공급원으로 사용하였다. 하소된 Si/Al = 40에서 몰비는 TEOS/TPAOH/H2O/EtOH/Al(NO3)3 = 1/0.25/60/4/0.025이었다. 구체적으로, 100 mL 테플론 튜브에서 TEOS, 10% TPAOH 수용액, 에탄올, 및 추가 물을 완전히 섞었다. 이어서, Al(NO3)3·H2O을 조심스럽게 추가하여, 이전에 알려진 제조방법에 따라 졸이 형성될 때까지 2시간 동안 60℃에서 교반하였다. 이어서, 상기 합성된 졸 용액에 Co/SiO2 촉매를 첨가하고, 튜브의 뚜껑을 닫고, 180℃로 가열된 수열 합성 장치에 놓고 12시간 동안 100 rpm에서 격렬히 교반하여 확실히 결정화(crystallization)시켰다. 이 단계 동안, ZSM5가 Co/SiO2 표면에서 in situ 합성되었으며, 이때 코발트 산화물이 인접하여 접촉되어 있었다. 최종 ZSM5-개질된 Co/SiO2 촉매를 용액으로부터 분리하고, 120℃에서 12시간 동안 건조시켰다. 이어서, 가열속도 10℃ /분 로 500℃에서 5시간 동안 하소시켰다. ZSM5 / (Co/SiO2)의 무게비를 변화시킴으로써, ZSM5-개질된 Co/SiO2 촉매의 무게 조성을 다양하게 변화시켰다. ZSM5-개질된 Co/SiO2 촉매들을 CoZ(x) 로 표시하였으며, 이때 Co는 Co/SiO2를 의미하고 Z는 ZSM5를 의미하며, 상이한 ZSM5 / (Co/SiO2) 무게비는 x(예, 0.25, 0.33, 및 0.50)로 표시하였다. CoZ 촉매들에서 Co, SiO2, 및 ZSM5의 최종 조성은 표 1에 리스팅되어 있다.To prepare a ZSM5-modified Co / SiO 2 catalyst, deionized water and ethanol were used as solvents. Was used as TPAOH (tetrapropylammonium hydroxide solution, available from ACROS) as a template, Al (NO 3) 3 · H 2 O (99.5% purity) and TEOS; aluminum and silicon to (tetraethyl ortho silicate provides 99.9% purity in Samchun Chemicals) Used as a source. The molar ratio at calcined Si / Al = 40 was TEOS / TPAOH / H 2 O / EtOH / Al (NO 3 ) 3 = 1 / 0.25 / 60/4 / 0.025. Specifically, TEOS, 10% aqueous TPAOH solution, ethanol, and additional water were thoroughly mixed in a 100 mL Teflon tube. Then Al (NO 3 ) 3 .H 2 O was carefully added and stirred at 60 ° C. for 2 hours until a sol was formed according to previously known preparation methods. A Co / SiO 2 catalyst was then added to the synthesized sol solution, the tube was capped, placed in a hydrothermal synthesis apparatus heated to 180 ° C. and vigorously stirred at 100 rpm for 12 hours to ensure crystallization. During this step, ZSM5 was synthesized in situ on the Co / SiO 2 surface, with cobalt oxide in close contact. The final ZSM5-modified Co / SiO 2 catalyst was separated from the solution and dried at 120 ° C. for 12 hours. It was then calcined at 500 ° C. for 5 hours at a heating rate of 10 ° C./min. By varying the weight ratio of ZSM5 / (Co / SiO 2 ), the weight composition of the ZSM5-modified Co / SiO 2 catalyst was varied. ZSM5-modified Co / SiO 2 catalysts were denoted by CoZ (x), where Co means Co / SiO 2 and Z means ZSM5, and the different ZSM5 / (Co / SiO 2 ) weight ratios are x (e.g., 0.25, 0.33, and 0.50). The final compositions of Co, SiO 2 , and ZSM5 in CoZ catalysts are listed in Table 1.
실험예 1. ZSM5-개질된 Co/SiO2 촉매들의 특성화Experimental Example 1. Characterization of ZSM5-Modified Co / SiO 2 Catalysts
CoZ 촉매들의 표면적, 기공 부피, 및 평균 기공 크기 및 이의 분포는 -196℃에서 Micromeritics ASAP 2400장치를 사용하여 N2-흡착법으로 측정하였다. 새로운 CoZ 촉매들 상의 코발트 산화물의 표면 농도 및 산화 상태들은 XPS 기구(ESCALAB MK-II)을 사용하여 특성화하였다. 실험동안 AlKα 단색광 선(1486.6 eV) 을 채용하였고, 진공수준은 약 10-7 Pa 로 유지하였다. 결합에너지(BE) 는 C1s (284.4 eV)의 레퍼런스 BE로 보정하였다. The surface area, pore volume, and average pore size and distribution of CoZ catalysts were measured by N 2 -adsorption using a Micromeritics ASAP 2400 apparatus at -196 ° C. Surface concentrations and oxidation states of cobalt oxide on new CoZ catalysts were characterized using XPS instrument (ESCALAB MK-II). AlKα monochromatic light (1486.6 eV) was employed during the experiment, and the vacuum level was maintained at about 10 −7 Pa. The binding energy (BE) was corrected to the reference BE of C1s (284.4 eV).
CoZ 촉매 상의 코발트 산화물의 입자크기들은 투과 전자 현미경(TEM; TECNAI G2 instrument)으로 특성화하였고, CoZ 촉매 상의 Co/Si 표면 원자비는 주사 전자 현미경(SEM; JEOL (JSM6700F))과 에너지 분산 분광학 (energy dispersive spectroscopy, EDS) 분석으로 특성화하였다. Particle sizes of cobalt oxide on CoZ catalysts were characterized by transmission electron microscopy (TEM; TECNAI G2 instrument), and the Co / Si surface atomic ratio on CoZ catalysts was determined by scanning electron microscopy (SEM; JEOL (JSM6700F)) and energy dispersive spectroscopy (energy). dispersive spectroscopy (EDS) analysis.
온도에 따른 환원특성(Temperature programmed reduction, TPR)을 수행하여 CoZ 촉매들 상에서의 코발트 산화물들의 환원정도(reducibility)를 측정하였다. TPR 실험 이전에, 시료를 400℃까지 He 유체로 전처리하고 2시간 유지하여 흡착된 물 및 다른 오염물을 제거하고, 이어서 50℃로 냉각시켰다. 5% H2/Ar 혼합가스를 함유하는 환원 기체를 30mL/분의 유체 속도로 시료에 통과시키고, 800℃까지 가열 속도 10℃/분로 가열하고 800℃에서 30분간 유지하였다. CoZ 촉매의 산도(acidity)는 온도에 따른 암모니아 탈착(temperature-programmed desorption of ammonia, NH3-TPD)으로 측정하였다. TPD 분석 이전에 시료 100mg 를 2시간 동안 He 유체 내에서 250℃에서 예열하여, 물리흡착된 물을 제거하였다. 상온으로 냉각한 후, 100℃에서 1시간 동안 암모니아를 반응기에 도입하고, 물리흡착된 암모니아를 He 유체 내에서 100℃에서 30분 동안 제거하였다. 이어서, 시료를 100℃에서 800℃로 가열하였으며 승온 속도는 10℃/분이고 He 유체 내에서 동일온도에서 5분동안 유지시켰다. 열전도 검출기(thermal conductivity detector, TCD)가 장착된 기체 크로마토그래피로 유출가스를 분석하였다. Cu-Kα 방사선을 갖는 Rigaku 회절계를 사용하여 분말 X-선 회절(XRD) 패턴들을 수득하고, 이로부터 CoZ 촉매상의 코발트 산화물의 결정 상들(crystalline phases)과 평균크기를 확인하였다. CoZ 촉매상의 Co3O4 평균 미세 결정(crystallite) 크기는 Scherrer식의 도움으로 X-선 라인 확대(X-ray line broadening)를 통해 계산하였다.Temperature reduced reduction (Temperature programmed reduction, TPR) was performed to measure the reducibility of cobalt oxides on CoZ catalysts. Prior to the TPR experiment, samples were pretreated with He fluid up to 400 ° C. and held for 2 hours to remove adsorbed water and other contaminants, then cooled to 50 ° C. A reducing gas containing a 5% H 2 / Ar mixed gas was passed through the sample at a fluid rate of 30 mL / min, heated to 800 ° C. at a heating rate of 10 ° C./min and held at 800 ° C. for 30 minutes. The acidity of the CoZ catalyst was determined by temperature-programmed desorption of ammonia (NH 3 -TPD). Prior to TPD analysis, 100 mg of sample was preheated at 250 ° C. in He fluid for 2 hours to remove physisorbed water. After cooling to room temperature, ammonia was introduced into the reactor at 100 ° C. for 1 hour, and physisorbed ammonia was removed at 100 ° C. for 30 minutes in a He fluid. The sample was then heated from 100 ° C. to 800 ° C. and the rate of temperature rise was 10 ° C./min and held for 5 minutes at the same temperature in the He fluid. The outflow gas was analyzed by gas chromatography equipped with a thermal conductivity detector (TCD). Powder X-ray diffraction (XRD) patterns were obtained using a Rigaku diffractometer with Cu-Kα radiation from which the crystalline phases and average size of cobalt oxide on the CoZ catalyst were identified. Co 3 O 4 average crystallite size on the CoZ catalyst was calculated by X-ray line broadening with the aid of Scherrer's equation.
실험예 2.촉매 활성 측정Experimental Example 2 Measurement of Catalyst Activity
촉매 300mg을 갖는 관형 고정층 반응기(O.D. = 12.7 mm)를 사용하여 촉매 활성을 계산하였다. FTS 반응 이전에, N2로 균형을 이룬 5% H2의 유체로, 촉매를 400℃에서 12시간 동안 환원시켰다. 환원 후, H2/CO = 2 합성가스를 반응기에 주입하였다. 하기 반응 조건하에 반응을 수행하였다: T = 240 ℃, P =2.0 MPa, 및 SV = 4000 mL/gcat/h , 40시간 증기(stream) 상. 탄화수소 분석을 위해 불꽃 이온화 검출기(flame ionized detector)가 연결된 GSGASPRO 모세관 컬럼을 이용한 온라인 기체 크로마토그라피(YoungLin Acme 6000 GC)를 사용하고, 산화 탄소(carbon oxides), H2, CH4, 및 내부 표준 기체 분석을 위해, TCD이 연결된 Porapak Q/분자체(5A) 충진 컬럼을 사용하여 반응기에서 나온 유출가스를 분석하였다. CO 전환 및 탄화수소들의 생성물 분포는 약 20시간의 FTS 반응 이후 안정화 상태(steady-state)에서 수득하였다. CO 전환 및 탄화수소들의 생성물 분포는 하기 식을 이용하는 총 탄소 밸런스에 기초하여 계산하였다. CO 전환은 TCD에서 나온 실험값을 사용하여 내부 표준 기체 Ar와 총 탄소 밸런스와 함께 두번 체크하였다.The catalytic activity was calculated using a tubular fixed bed reactor (OD = 12.7 mm) with 300 mg of catalyst. Prior to the FTS reaction, the catalyst was reduced at 400 ° C. for 12 hours with a 5% H 2 fluid balanced by N 2 . After reduction, H 2 / CO = 2 syngas was injected into the reactor. The reaction was carried out under the following reaction conditions: T = 240 ° C., P = 2.0 MPa, and SV = 4000 mL / g cat / h, 40 hour stream phase. For hydrocarbon analysis, we use on-line gas chromatography (YoungLin Acme 6000 GC) with a GSGASPRO capillary column connected with a flame ionized detector, carbon oxides, H 2 , CH 4 , and internal standard gases. For analysis, the effluent gas from the reactor was analyzed using a Trap-connected Porapak Q / Molecular Sieve (5A) packed column. CO conversion and product distribution of hydrocarbons were obtained at steady-state after about 20 hours of FTS reaction. CO conversion and product distribution of hydrocarbons were calculated based on the total carbon balance using the following formula. CO conversion was checked twice with the internal standard gas Ar and the total carbon balance using experimental values from TCD.
CO conversion (C mol%) = [(moles of inlet CO moles of outlet CO) /moles of inlet CO] * 100CO conversion (C mol%) = [(moles of inlet CO moles of outlet CO) / moles of inlet CO] * 100
Hydrocarbon (Cx; x Hydrocarbon (Cx; x
= 1, 2 ∼ 4, 5 ∼ 22 and 22+ ) selectivity (C mol%)= 1, 2-4, 5-22 and 22+) selectivity (C mol%)
= [moles of Cx produced / (moles of inlet CO - moles of outlet CO)] * 100= [moles of Cx produced / (moles of inlet CO-moles of outlet CO)] * 100
[고찰][Review]
실험을 통해 조사한 다양한 ZSM5-개질된 Co/SiO2 촉매에 대한 다양한 특성은 다음과 같다.Various characteristics of various ZSM5-modified Co / SiO 2 catalysts investigated through the experiment are as follows.
1. ZSM5-개질된 Co/SiO2 촉매의 텍스처 특성1.Texture Characteristics of ZSM5-Modified Co / SiO 2 Catalyst
표 1은 ZSM5-개질된 Co/SiO2 촉매의 물리적 특성 및 상기 촉매상의 Co3O4의 미세결정 크기에 관한 것이다.Table 1 relates to the physical properties of ZSM5-modified Co / SiO 2 catalysts and the microcrystalline size of Co 3 O 4 on the catalysts.
표 1
Figure PCTKR2013006067-appb-T000001
Table 1
Figure PCTKR2013006067-appb-T000001
ZSM5는 산점(acid site) 밀도 및 산점 강도가 조절가능하기 때문에, 고체 산 촉매로 널리 사용되고 있으며, 또한 ZSM5의 규칙적인 기공 구조로 인해, 특히 수소화크래킹(hydrocracking)을 위한 촉매 활성에 기여할 수 있다. 따라서, CoZ 촉매상에서 ZSM5 /(Co/SiO2)의 상이한 비율은 물리화학적 특성 및 산도를 현저히 변화시킬 수 있다. Co/SiO2 촉매 존재 하에 ZSM5을 in situ 수열합성하여 제조된 CoZ 촉매의 특성, 예컨대 표면적, 기공 부피, 평균 기공 직경이 표 1에 요약되어 있다. CoZ 촉매들의 이들 값들은 Co/SiO2 촉매의 것과 비교하여 감소하였다. ZSM5 /(Co/SiO2)의 무게비와 상관없이 모든 CoZ의 표면적은 유사하다. 비록, CoZ 촉매들의 ZSM5 함량 증가가 표면적 감소 (244 -> 238 m2/g) 및 기공 부피 감소(1.01 -> 0.97 cm3/g)를 보여 주었으나, 평균 기공 직경은 특히 CoZ(0.50) 상에서 8.8 -> 6.0 nm 로 감소하였다. 이는, Co/SiO2 촉매의 메조기공들이 ZSM5 입자들에 의해 차단됨으로써, 표면적과 기공 부피 감소에 ZSM5 함량 증가가 관여함을 보여준다. 도 1에 도시된 바와 같이, CoZ 촉매들의 기공 크기 분포도 ZSM5의 수열 합성 동안 Co/SiO2의 메조기공을 차단할 수 있는 것을 보여준다. 본 발명자들의 이전 연구에서 제시한 바와 같이, Co/ZSM5 상에서 2∼5nm 범위의 기공 크기는 Si/Al 비율이 증가하여도 크게 변하지 않으며, 본 발명자들은 CoZ 촉매 상의 약 3nm의 메소기공들은 ZSM5 기공들과 관련이 있는 것으로 여겨진다(도 1). 이는 또한 표면적이 306 m2/g인 Co/ZSM5와 비교할 때, CoZ 상의 표면적이 소량 감소한 것에 의해 뒷받침된다. ZSM5 함량이 증가하면 기공 평균 직경이 감소하는 것이 CoZ 촉매들에서도 관찰되었다. 흥미롭게도, 2가지 형태의 기공 크기 분포가 CoZ 촉매들에서 관찰되었으며, 작은 기공은 약 20nm이고 큰 기공은 40nm 이상이었으며, 이들은 각각 SiO2 지지체의 입자내(intragrain) 기공, ZSM5 및 Co/SiO2의 입자간(intergrain) 기공에 해당될 수 있다. 또한, 더 큰 평균 입자 크기를 갖는 ZSM5를 형성하여 입자간 구조를 형성함으로써, Co/SiO2 표면의 인접한 부위상에 ZSM5 입자들이 효과적으로 올려진다. 이는 ZSM5 함량이 증가함에 따라 CoZ 촉매들의 기공 크기가 더 커지는 것에 의해 확인될 수 있다. 따라서, CoZ 촉매들 상에 ZSM5 함량이 증가함으로써 표면적이 감소하는 것은, 바깥 표면 상에 ZSM5 입자들이 형성되면서 Co/SiO2의 기공 차단 뿐만 아니라 40nm 이상의 큰 기공 크기를 갖는 ZSM5의 입자간 구조 형성 기여 증가가 원인이 될 수 있다. 요약하면, Co/SiO2와 Co/ZSM5 촉매와 비교할 때 CoZ 촉매 상의 표면적 및 평균 기공 크기가 감소하는 것은 주로 2가지 기공 크기 분포를 형성함으로써 Co/SiO2 촉매가 ZSM5 입자들로 기공 차단되는 것이 원인이다.ZSM5 is widely used as a solid acid catalyst because of its adjustable acid site density and acid strength, and due to the regular pore structure of ZSM5, it can contribute to catalytic activity, especially for hydrocracking. Thus, different ratios of ZSM 5 / (Co / SiO 2 ) on CoZ catalysts can significantly change physicochemical properties and acidity. The properties of CoZ catalysts prepared by in situ hydrothermal synthesis of ZSM5 in the presence of Co / SiO 2 catalysts, such as surface area, pore volume, average pore diameter, are summarized in Table 1. These values of CoZ catalysts decreased compared to that of Co / SiO 2 catalyst. Regardless of the weight ratio of ZSM 5 / (Co / SiO 2 ), the surface area of all CoZ is similar. Although the increase in the ZSM5 content of CoZ catalysts showed a decrease in surface area (244-> 238 m 2 / g) and a decrease in pore volume (1.01-> 0.97 cm 3 / g), the average pore diameter was especially on CoZ (0.50) 8.8-> 6.0 nm. This shows that the mesopores of the Co / SiO 2 catalyst are blocked by the ZSM5 particles, thereby increasing the ZSM5 content in reducing the surface area and pore volume. As shown in FIG. 1, the pore size distribution of the CoZ catalysts shows that it is possible to block the mesopores of Co / SiO 2 during the hydrothermal synthesis of ZSM5. As we have shown in our previous work, the pore size in the 2-5 nm range on Co / ZSM5 does not change significantly with increasing Si / Al ratio, and we found that about 3 nm mesopores on CoZ catalyst are ZSM5 pores. It is believed to be related to (FIG. 1). This is also supported by a small reduction in the surface area on CoZ when compared to Co / ZSM5 having a surface area of 306 m 2 / g. Increasing the ZSM5 content decreased the average pore diameter in CoZ catalysts. Interestingly, two types of pore size distributions were observed in the CoZ catalysts, with small pores of about 20 nm and larger pores of 40 nm or more, each of the intragrain pores of the SiO 2 support, ZSM5 and Co / SiO 2. It may correspond to intergrain pores of. In addition, ZSM5 particles are effectively loaded on adjacent portions of the Co / SiO 2 surface by forming ZSM5 having a larger average particle size to form interparticle structures. This can be confirmed by increasing the pore size of the CoZ catalysts as the ZSM5 content increases. Therefore, the decrease in surface area by increasing the ZSM5 content on the CoZ catalysts contributes to the formation of ZSM5 particles on the outer surface, as well as the formation of intergranular structures of ZSM5 with large pore sizes of 40 nm or more as well as pore blocking of Co / SiO 2 . An increase may be the cause. In summary, the reduction in surface area and average pore size on CoZ catalysts compared to Co / SiO 2 and Co / ZSM5 catalysts mainly results in the formation of two pore size distributions, resulting in the pore blocking of the Co / SiO 2 catalyst with ZSM5 particles. Cause.
2 코발트 산화물의 미세 결정 크기 및 크기 분포 측정2 Determination of microcrystalline size and size distribution of cobalt oxide
Co/SiO2 촉매를 ZSM5로 개질한 후, 코발트 미세 결정 크기의 분포 및 이의 표면 농도를 이해하기 위해, CoZ 촉매들에 대해 XRD, XPS 및 TEM 분석을 하였다. 도 2는 FTS 반응 이전에 CoZ 촉매들의 XRD 패턴을 보여주고 있다. ZSM5의 특징적인 피크들이 CoZ 촉매상에서 관찰되었으며, 이는 CoZ 촉매에서 ZSM5 구조가 발달되는 것을 보여준다. 게다가, 모든 CoZ 촉매들은 Co3O4 존재로 인해 2θ = 36.8°에서 특징적인 회절피크를 보여준다. X선 라인 확대법(즉, Scherrer 식)을 사용하여 Co3O4 의 미세 결정 크기를 계산하였다. ZSM5 /(Co/SiO2) 비가 증가함에 따라 Co3O4 의 미세 결정 크기가 증가하였다. 즉 표 1에 요약한 바와 같이, 각각 CoZ(0.25), CoZ(0.33), 및 CoZ(0.50) 촉매에서 코발트 미세 결정 크기는 16.8, 19.2, 및 23.5 nm이었다. 흥미롭게도, CoZ 촉매들 상에서 코발트 미세 결정 크기는 Co/SiO2 촉매 보다 더 크고 Co/ZSM5 촉매 보다는 작다. 대응되는 Co3O4 피크의 라인 확대 정도를 명확히 하기 위해, CoZ 촉매에서 30 < 2θ < 45 범위의 회절 피크들이 도 2의 삽입물에 포함되어 있다. 이전에 본 연구에서 기록한 함침된 Co/ZSM5 촉매(23.2 nm)와 비교하여 CoZ 촉매 상에서 더 작은 미세 결정 크기의 Co3O4 이 형성되는 것은 촉매 기능 차이를 야기한다. 그러나, CoZ 촉매에서 ZSM5 함량이 증가함에 따라 코발트 산화물의 미세 결정 크기가 증가하였다. 이는 수열 합성동안 Co/SiO2로부터 ZSM5의 외부 표면으로 코발트 산화물이 이동하는 메커니즘 때문일 수 있다. 흥미롭게도, CoZ(0.5) 촉매 상에서 미세 결정 크기는 Co/ZSM5 촉매와 비슷하며, 이는 대부분의 코발트 산화물이 Co/SiO2로부터 ZSM5 표면으로 이동할 수 있다는 것을 제시한다; 이것이 일어나는 정도는 ZSM5 함량 증가에 따라 증가한다. 코발트 산화물의 표면 분포를 확인하기 위한 표면 선택성 XPS 분석(surface sensitive XPS analysis) 결과는 도 3에 도시되어 있다. 특징적인 Co2p3/2 피크들이 결합에너지(BE) 779.1 eV에서 관찰되었으며, 다소 높은 BE 786.4 eV에서 숄더 피크 (shoulder peak)들이 나타났으며, 이는 코발트 산화물의 높은 산화 상태에 기인한 것이다. CoZ 촉매들 상에 ZSM5 함량이 감소함에 따라 CoZ 촉매들 상에 코발트 산화물 함량 증가로 인해, Co2p3/2 의 피크 강도가 증가하였다. 그러나, 이러한 결과는 코발트 산화물이 SiO2 지지체뿐만아니라 ZSM5 표면 상에 동시에 분산되어 있는 것을 제시하고, 표면 선택성 XPS 분석을 통해 모든 CoZ 촉매들 상에서 Co 피크들이 관측되었기 때문에 Co/SiO2 표면이 ZSM5에 의해 완전히 뒤덮힌 것은 아니라는 것을 제시한다. 따라서, in situ 수열 합성 동안 Co/SiO2 표면상에 ZSM5 입자들이 인접하여 접촉(adjacent contact)하여 있다는 것을 유추할 수 있고, 이의 분포는, 저온에서조차도 ZSM5 표면에서 FTS 생성물들의 올레핀 크래킹 반응이 일어날 수 있어서 가솔린과 중질 탄화수소들(middle distillate range hydrocarbons)에 대한 높은 선택성을 수득하는데 유리하다. CoZ 촉매들의 구조를 더 확인하기 위해, CoZ 촉매에 대해 SEM-EDS 분석을 수행하였고, 그 결과는 표 1에 요약하였다. 이는 CoZ 촉매 표면에 코발트 산화물의 우선적인 존재(preferential presence) 및 CoZ 촉매 표면에서의 코발트 산화물의 함량은 또한 ZSM5 함량이 증가함에 따라 감소하는 것(Co/Si 원자비가 0.855에서 0.128 로 변함)을 보여준다.After modifying the Co / SiO 2 catalyst with ZSM5, XRD, XPS and TEM analyzes were performed on CoZ catalysts to understand the distribution of cobalt microcrystal size and its surface concentration. 2 shows the XRD pattern of CoZ catalysts before the FTS reaction. Characteristic peaks of ZSM5 were observed on the CoZ catalyst, which shows the development of the ZSM5 structure in the CoZ catalyst. In addition, all CoZ catalysts show a characteristic diffraction peak at 2θ = 36.8 ° due to the presence of Co 3 O 4 . X-ray line magnification (ie, Scherrer's equation) was used to calculate the fine crystal size of Co 3 O 4 . As the ZSM 5 / (Co / SiO 2 ) ratio increased, the fine crystal size of Co 3 O 4 increased. That is, as summarized in Table 1, the cobalt fine crystal sizes in CoZ (0.25), CoZ (0.33), and CoZ (0.50) catalysts were 16.8, 19.2, and 23.5 nm, respectively. Interestingly, the cobalt microcrystalline size on CoZ catalysts is larger than Co / SiO 2 catalyst and smaller than Co / ZSM5 catalyst. In order to clarify the line magnification of the corresponding Co 3 O 4 peak, diffraction peaks in the range of 30 <2θ <45 in the CoZ catalyst are included in the insert of FIG. 2. The formation of smaller fine crystal size Co 3 O 4 on the CoZ catalyst compared to the impregnated Co / ZSM5 catalyst (23.2 nm) previously recorded in this study results in a catalyst function difference. However, the fine crystal size of cobalt oxide increased with increasing ZSM5 content in CoZ catalyst. This may be due to the mechanism by which cobalt oxides migrate from Co / SiO 2 to the outer surface of ZSM5 during hydrothermal synthesis. Interestingly, the microcrystalline size on the CoZ (0.5) catalyst is similar to the Co / ZSM5 catalyst, suggesting that most of the cobalt oxide can migrate from Co / SiO 2 to the ZSM5 surface; The extent to which this occurs increases with increasing ZSM5 content. Surface selective XPS analysis results for confirming the surface distribution of cobalt oxide are shown in FIG. 3. Characteristic Co2p 3/2 peaks were observed at binding energy (BE) 779.1 eV, and shoulder peaks appeared at rather high BE 786.4 eV due to the high oxidation state of cobalt oxide. As the ZSM5 content on CoZ catalysts decreased, the peak intensity of Co2p 3/2 increased due to the increased cobalt oxide content on CoZ catalysts. However, these results suggest that cobalt oxide is dispersed simultaneously on the ZSM5 surface as well as on the SiO 2 support, and the Co / SiO 2 surface is not affected by ZSM5 because Co peaks were observed on all CoZ catalysts through surface selective XPS analysis. Suggest that it is not completely covered by Thus, it can be inferred that the ZSM5 particles are in adjacent contact on the Co / SiO 2 surface during in situ hydrothermal synthesis, the distribution of which may result in the olefin cracking reaction of FTS products on the ZSM5 surface even at low temperatures. This is advantageous for obtaining high selectivity for gasoline and middle distillate range hydrocarbons. To further confirm the structure of the CoZ catalysts, SEM-EDS analysis was performed on the CoZ catalysts, the results of which are summarized in Table 1. This shows the preferential presence of cobalt oxide on the CoZ catalyst surface and the content of cobalt oxide on the CoZ catalyst surface also decreases with increasing ZSM5 content (Co / Si atomic ratio changes from 0.855 to 0.128). .
도 4에 도시된 바와 같이, CoZ 촉매의 TEM 이미지들은 ZSM5이 Co/SiO2 촉매들 상에서 인접하여 놓여 있다는 것을 지지해 준다. 게다가, 코발트 산화물은 약 20nm인 것을 확인하였다. 어두운 검은 점은 코발트 산화물에 해당하고, 회색 점은 ZSM5 및 SiO2 지지체에 해당한다. TEM 이미지들은 Co/SiO2 상에 코발트 산화물이 인접하여 접촉하고 있으면서 CoZ(0.25) 상에 잘 분산된 ZSM5 입자들을 보여주며, CoZ(0.50) 촉매 상에서는 ZSM5 입자들이 분리된 상으로 격리되어 있는 것을 보여준다. 이들 결과는 CoZ(0.25) 촉매와 같이 낮은 ZSM5 함량에서는 ZSM5이 코발트 산화물과 접촉하고 있다는 것을 지지하여 준다. 요컨대, CoZ(0.25) 촉매의 경우, Co/SiO2 촉매 상에 인접하여 접촉하는 ZSM5가 효과적으로 수득되고 이는 XPS, SEM-EDS, 및 TEM 분석에 의해 확인된다. 이는 올레핀 크래킹 반응의 촉매 활성에 영향을 주며 C5 ∼ C22 탄화수소들에 대한 선택도가 증가하는 것으로 관찰된다.As shown in FIG. 4, TEM images of the CoZ catalyst support that ZSM5 lies adjacent on the Co / SiO 2 catalysts. In addition, cobalt oxide was found to be about 20 nm. Dark black points correspond to cobalt oxide and gray points correspond to ZSM5 and SiO 2 supports. TEM images show that ZSM5 particles are well dispersed on CoZ (0.25) with cobalt oxide in close contact on Co / SiO 2 , and that ZSM5 particles are isolated in separate phase on CoZ (0.50) catalyst. . These results support that ZSM5 is in contact with cobalt oxide at low ZSM5 content, such as CoZ (0.25) catalyst. In short, in the case of CoZ (0.25) catalyst, ZSM5 in close contact with the Co / SiO 2 catalyst is effectively obtained and confirmed by XPS, SEM-EDS, and TEM analysis. This affects the catalytic activity of the olefin cracking reaction and is observed to increase the selectivity for C 5 to C 22 hydrocarbons.
3. 온도에 따른 분석(H2-TPR 및 NH3-TPD)3. Analysis by temperature (H 2 -TPR and NH 3 -TPD)
표 2는 ZSM5-개질된 Co/SiO2 촉매에서 H2-TPR로 측정된 H2 흡수량에 관한 것이다. Table 2 relates to H 2 uptake measured by H 2 -TPR in ZSM 5 -modified Co / SiO 2 catalysts.
표 2
Figure PCTKR2013006067-appb-T000002
TABLE 2
Figure PCTKR2013006067-appb-T000002
금속 코발트 표면 부위들이 FTS 활성에 중요하기 때문에, 코발트 산화물들의 환원 거동을 이해하기 위해 TPR 실험을 수행하였다. 하소된 CoZ 촉매들의 환원 프로파일을 도 5에 도시하였고, 환원 정도는 표 2에 요약한 바와 같이 TPR에서 400℃까지의 H2 소모량을 총 H2 소모량으로 나누어 계산하였다. CoZ 촉매들 상에서의 TPR 프로파일은 2개의 구별되는 환원 피크를 나타내며, SiO2상의 코발트 산화물이 ZSM5으로의 이동 가능성으로 인해 Co/SiO2 촉매들의 것보다 더 나은 온도에서 관측되었다. 첫번째 환원 피크는 통상 Co3O4에서 CoO로의 환원에 의한 것이고, 두번째 피크는 CoO에서 금속 코발트로의 환원에 의한 것이다. 모든 CoZ 촉매들의 TPR 프로파일들도 272∼295℃ 근처에서 구별되는 숄더 피크를 보여주며, 325∼341℃ 근처의 최대 온도(Tmax)에서 강한 두번째 피크가 나타난다. 두번째 피크는 코발트 산화물이 금속 코발트로 완전히 환원되는 것에 기인한 것이다. 600℃ 이상 고온 범위에서 작은 피크 강도는 Co/SiO2 촉매 상에서 코발트 산화물이 불활성 코발트 실리케이트로 변환될 수 있다는 것을 제시한다. 272 및 325 ℃ 근처에서 나타나는 CoZ(0.25) 촉매의 TPR 피크들은 저온에서 금속 상태로 용이하게 환원될 수 있는 코발트 미세 결정들 때문일 수 있다. 표면적이 더 크고 미세 결정 크기가 작은 코발트 종은 CoZ(0.25) 촉매의 특징인 것으로 확인되었다. 코발트 산화물의 미세 결정 크기 및 Tmax 는 CoZ 촉매들에서 ZSM5 함량이 감소함에 따라 341℃에서 325℃로 감소한다. 도 5에 도시된 바와 같이, ZSM5 지지체는 ZSM5 산점에서 강한 코발트-지지체 상호작용(383℃ 근처에서 다소 높은 환원온도 나타남)을 나타낸다. 이러한 현상은 CoZ(0.25) 촉매에서 제올라이트 함량이 적기 때문에 SiO2에서 ZSM5표면으로의 코발트 산화물 이동이 심각하지 않다는 것을 제시한다. Co/ZSM5 촉매에서 380℃ 근처에서 더 높은 환원 온도 피크가 관측되는 것에 의해서도 SiO2에서 ZSM5표면으로의 코발트 산화물의 이동 가능성이 지지되었다. CoZ(0.25), CoZ(0.33), 및 CoZ(0.50)에서 각각 Tmax 값이 325, 334, 및 341℃이고, ZSM5 함량이 증가함에 따라 CoZ 촉매들에서 더 높은 값으로 온도가 이동하는 것은, ZSM5의 수열합성 단계 동안 코발트 산화물의 이동 가능성을 제시한다.Since metal cobalt surface sites are important for FTS activity, TPR experiments were performed to understand the reduction behavior of cobalt oxides. The reduction profile of the calcined CoZ catalysts is shown in FIG. 5, and the reduction degree was calculated by dividing the H 2 consumption from TPR to 400 ° C. by the total H 2 consumption, as summarized in Table 2. The TPR profile on CoZ catalysts shows two distinct reduction peaks and was observed at better temperatures than that of Co / SiO 2 catalysts due to the possibility of cobalt oxide on SiO 2 migration to ZSM5. The first reduction peak is usually by reduction of Co 3 O 4 to CoO and the second peak is by reduction of CoO to metal cobalt. TPR profiles of all CoZ catalysts also show distinct shoulder peaks around 272-295 ° C., with a strong second peak at maximum temperature (T max ) near 325-341 ° C. The second peak is due to the complete reduction of cobalt oxide to metal cobalt. Small peak intensities in the high temperature range above 600 ° C. suggest that cobalt oxide can be converted to inert cobalt silicate on Co / SiO 2 catalysts. The TPR peaks of the CoZ (0.25) catalyst appearing near 272 and 325 ° C. may be due to cobalt microcrystals that can be readily reduced to the metallic state at low temperatures. Cobalt species with a larger surface area and smaller microcrystal size were found to be characteristic of the CoZ (0.25) catalyst. The fine crystal size and T max of cobalt oxide decreases from 341 ° C. to 325 ° C. as the ZSM5 content decreases in CoZ catalysts. As shown in FIG. 5, the ZSM5 support exhibits strong cobalt-supporter interaction at ZSM5 acid sites (a rather high reduction temperature near 383 ° C.). This phenomenon suggests that the cobalt oxide migration from SiO 2 to ZSM5 surface is not severe because of the low zeolite content in the CoZ (0.25) catalyst. A higher reduction temperature peak near 380 ° C. in the Co / ZSM5 catalyst also supported the possibility of cobalt oxide migration from SiO 2 to the ZSM 5 surface. T max values of 325, 334, and 341 ° C. in CoZ (0.25), CoZ (0.33), and CoZ (0.50), respectively, and the temperature shifts to higher values in CoZ catalysts as the ZSM5 content increases, The possibility of migration of cobalt oxide during the hydrothermal synthesis of ZSM5 is presented.
CoZ 촉매들 상에서 환원 정도는 TPR에서 H2 소모량으로부터 계산하였다. CoZ 촉매의 무게를 기준으로 한 총 H2 소모량(total H2 consumption/gcat 로 표시)은 CoZ(0.25), CoZ(0.33), 및 CoZ(0.50)에서 각각 2.12, 2.00, 및 1.82 mmol H2/gcat 로 계산되었다. Co/ZSM5 (3.86 mmol H2/g)와 비교할 때, CoZ 촉매의 경우 H2 소모량이 감소하는 것은 금속 종의 절대 함량이 감소한 것 때문이고, 총 H2 소모량은 CoZ 촉매들에서의 ZSM5 함량이 증가함에 따라 감소하였다. 마찬가지로, 상이한 ZSM5/(Co/SiO2) 무게비에서 CoZ 촉매의 H2 소모량 절대값은 400℃까지 각각 1.96, 1.61, 및 1.46 mmol H2/gcat로 관측되었다. 구체적으로, CoZ(0.25) 촉매는 400℃까지 총 H2 소모량 및 H2 소모량이 높은 값이었다. CoZ 촉매들에서 상이한 코발트 함량을 표준화하기 위해, 코발트의 무게를 기준으로 한 총 H2 소모량(total H2 consumption per gCo 로 표시)도 계산하였으며, 표 2에 기재하였다. 이들 값은 14.1 에서 18.2 mmol H2/gCo 로 증가하였으며, 이는 19.3 mmol H2/gCo 근처에서 Co/ZSM5 촉에서 값이 가장 크기 때문에 CoZ 촉매에서 ZSM5 함량이 증가함에 따라 SiO2에서 ZSM5표면으로의 일부 코발트 산화물의 이동 가능성을 제시한다. 총 H2 소모량(mmol H2/gCo)의 증가는 SiO2 지지체와 비교시 ZSM5 상에서 코발트 미세 결정이 더 크게 형성된다는 것을 보여준다. 이러한 경향은, CoZ 촉매의 수열합성 단계동안 Co/SiO2에서 ZSM5표면으로의 이온 교환 Co2+ 종 또는 (400℃ 이상에서도) 좀처럼 환원되지 않는 작은 코발트 미세 결정들의 함량이 증가하는 것과 관련이 있다. 이들 코발트 종들은 Al 부위들의 골격에서 강한 상호작용을 할 수 있으며, 이는 ZSM5/(Co/SiO2) 가 증가함에 따라, 표 2에 나타난 바와 같이 400℃ 이상에서 수소 소비량 값이 7.3 에서 19.9% 로 증가하는 결과 및 Co/ZSM5에서 30.6%인 것을 뒷받침한다. 400℃ 이하에서 코발트 무게를 기준으로 다시 계산된 H2 소모량 값(mmol H2/gCo)은 12.1∼14.6 범위에서 거의 유사하다; 그러나, 400℃ 이상에서는 ZSM5 함량이 증가함에 따라 상기 값은 점차 증가한다. 즉, CoZ(0.25), CoZ(0.33), 및 CoZ(0.50)에서 각각 1.03, 2.85, 및 3.62 mmol H2/gcat 이며, Co/ZSM5에서 5.91 mmol H2/gcat 이었다. 이러한 관측값은 또한 ZSM5 표면의 산점들 상에 작은 크기의 코발트 종들의 이동 가능성 및 코발트 종들의 이온 교환을 보여준다. ZSM5 함량 증가에 따라 환원온도 피크가 더 높은 영역을 이동하는 것은 ZSM5 상에 위치하는 코발트 미세 결정들이 환원되기 어렵다는 것을 뒷받침하며, ZSM5의 수열합성 동안 ZSM5 표면으로 Co3O4의 이동이 강화된다는 것을 뒷받침한다. CoZ 촉매상에서 TPR 동안 총 H2 소모량에 대한 400℃ 이하에서의 H2 소모량의 상대적인 비로 환원정도를 표현하였다. 도 2에 나타난 바와 같이, CoZ(0.25), CoZ(0.33), 및 CoZ(0.50)에서 각각 92.7, 80.9, and 80.1%이었다. Co/SiO2 촉매와 비교시 CoZ(0.25) 촉매에서 코발트 산화물 미세 결정들의 수월한 환원이 관측되었다. 게다가, CoZ 촉매들에서 ZSM5 함량이 증가함에 따라 400℃ 이상에서 환원정도가 7.3 에서 19.9%로 증가하는 것은 Co/ZSM5 촉매에의 값에 인접함으로써, Co/SiO2 로부터 ZSM5 표면상으로 코발트 미세 결정들의 이동 가능성을 보여줄 수 있다. The degree of reduction on CoZ catalysts was calculated from the H 2 consumption in TPR. The total H 2 consumption (expressed as total H 2 consumption / g cat ) based on the weight of the CoZ catalyst was 2.12, 2.00, and 1.82 mmol H 2 in CoZ (0.25), CoZ (0.33), and CoZ (0.50), respectively. calculated with / g cat . Co / ZSM5 as compared to (3.86 mmol H 2 / g) , and because it is of the H 2 consumption reduction for CoZ catalyst will decrease the absolute amount of the metal species, the total H 2 consumption is a ZSM5 content of at CoZ catalyst Decreased with increase. Likewise, absolute values of H 2 consumption of CoZ catalysts at different ZSM5 / (Co / SiO 2 ) weight ratios were observed to 1.96, 1.61, and 1.46 mmol H 2 / g cat , respectively, up to 400 ° C. Specifically, the CoZ (0.25) catalyst had a high total H 2 consumption and H 2 consumption up to 400 ° C. To standardize the different cobalt content in CoZ catalysts, the total H 2 consumption (expressed as total H 2 consumption per g Co ) based on the weight of cobalt was also calculated and listed in Table 2. These values increased from 14.1 to 18.2 mmol H 2 / g Co , which is the largest value at the Co / ZSM5 chuck near 19.3 mmol H 2 / g Co , thus increasing the ZSM5 content of the SiO 2 to ZSM 5 surface in the CoZ catalyst. Suggests the possibility of some cobalt oxide migration. The increase in total H 2 consumption (mmol H 2 / g Co ) shows that larger cobalt microcrystals are formed on ZSM5 compared to SiO 2 support. This tendency is associated with an increase in the content of ion-exchanged Co 2+ species from Co / SiO 2 to ZSM5 surface or small cobalt microcrystals that are rarely reduced (even above 400 ° C.) during the hydrothermal synthesis step of the CoZ catalyst. . These cobalt species can interact strongly in the backbone of the Al sites, with increasing ZSM5 / (Co / SiO 2 ), hydrogen consumption values from 7.3 to 19.9% above 400 ° C, as shown in Table 2. Increasing results and 30.6% in Co / ZSM5. The H 2 consumption values (mmol H 2 / g Co ), recalculated based on cobalt weight below 400 ° C., are about the same in the range 12.1 to 14.6; However, above 400 ° C., the value gradually increases as the ZSM5 content increases. That is, 1.03, 2.85, and 3.62 mmol H 2 / g cat in CoZ (0.25), CoZ (0.33), and CoZ (0.50), respectively, and 5.91 mmol H 2 / g cat in Co / ZSM5. These observations also show the mobility of small sized cobalt species and ion exchange of cobalt species on the scattering points of the ZSM5 surface. Shifting the region with higher reduction temperature peaks with increasing ZSM5 content supports the difficulty of reducing cobalt microcrystals located on ZSM5, and suggests that the migration of Co 3 O 4 to the ZSM5 surface is enhanced during hydrothermal synthesis of ZSM5. Support. The degree of reduction is expressed as the relative ratio of H 2 consumption below 400 ° C. to the total H 2 consumption during TPR on the CoZ catalyst. As shown in FIG. 2, the CoZ (0.25), CoZ (0.33), and CoZ (0.50) were 92.7, 80.9, and 80.1%, respectively. Easy reduction of cobalt oxide microcrystals was observed in CoZ (0.25) catalysts compared to Co / SiO 2 catalysts. In addition, the increase in reduction degree from 7.3 to 19.9% above 400 ° C with increasing ZSM5 content in CoZ catalysts is close to the value for Co / ZSM5 catalysts, thereby cobalt microcrystallization from Co / SiO 2 onto ZSM5 surfaces. It can show the possibility of their movement.
표 3은 ZSM5-개질된 Co/SiO2 촉매에서 NH3-TPD에 의해 측정된 표면 산도에 관한 것이다. Table 3 relates to the surface acidity measured by NH3-TPD in ZSM5-modified Co / SiO 2 catalysts.
표 3
Figure PCTKR2013006067-appb-T000003
TABLE 3
Figure PCTKR2013006067-appb-T000003
CoZ 촉매들에서 산점의 농도 및 강도를 조사하기 위해 NH3-TPD 실험을 수행하였다. ZSM5 상의 산점은 낮은 반응 온도에서 조차도 FTS 생성물의 올레핀 크래킹 반응을 위한 활성부위로 작용할 수 있다. CoZ 촉매들의 NH3-TPD 패턴은 도 6에 도시되어 있다. NH3 탈착과 관련된 3개의 특징적인 단계들, 피크 I, II, III이 관측되었다. 피크 I는 220℃ 이하 온도에서의 NH3 탈착온도, 피크 II는 220∼500℃에서의 NH3 탈착온도, 피크 III은 500℃ 이상에서의 NH3 탈착온도에 해당한다. 500℃ 이상에서 관측되는 탈착피크 III는 제올라이트 골격으로부터의 수분 탈착 또는 NH3 분해와 관련이 있을 수 있으며, 100~220℃에서의 피크 I는 약한 산점 또는 물리적으로 흡착된 암모니아와 관련이 있으며, 220~500℃에서의 피크 II는 강한 산점에 기인한 것이다. 표 3은 CoZ 촉매에서 산점 밀도를 약한 산점 및 강한 산점으로 NH3/ gcat로 표현하였다. 올레핀 크래킹 반응용 활성부위일 수 있는, 첫번째 피크(약한 산점) 및 두번째 피크(강한 산점)을 고려하면, 본 발명자는 산점 밀도가 CoZ(0.50) 촉매에서 증가된 ZSM5 함량으로 인해 더 높다는 것을 발견하였다. 더욱이 총 산점 밀도(피크 I 및 II의 총합)는 CoZ(0.50) > CoZ(0.33) > CoZ(0.25) 순서로 변한다. 표 3에 나타난 바와 같이 촉매(gcat)와 상관없이 또는 ZSM5 (gZSM5)의 값에 대해 CoZ 촉매 상 ZSM5 함량이 증가하면 산점 밀도도 이에 비례하여 증가한다. 흥미롭게도, NH3-TPD에서 피크 I 및 II에 대한 약한 산점 밀도 및 강한 산점 밀도가, 코발트 종이 추가되면 ZSM5 상의 산점 차단에 의해 상당히 감소되었다(bare ZSM5의 0.743이고, Co/ZSM5 촉매상에서의 0.450 mmol NH3/g임). CoZ 촉매들에서 약한 산점 및 강한 산점이 현저히 감소한 것은 수열 합성 동안 Co/SiO2 촉매로부터 ZSM5 표면으로 코발트 미세 결정들의 이동 가능성을 제시한다. 예컨대, CoZ(0.50)에서 계산된 산점은 CoZ 촉매에서 ZSM5의 무게%를 기준으로 0.372 mmol NH3/g 근처일 수 있다. 그러나, 표 3에 나타난 바와 같이, 모든 CoZ 촉매들은 0.067∼0.205 mmol NH3/g 범위에서 더 낮은 값으로 관측되었다. 따라서, 수열합성 동안 SiO2 및 ZSM5 양쪽에서의 재분포에 의해 코발트 미세 결정들은 CoZ 촉매들상에서 재배열될 수 있으며 촉매 성능을 변경시킬 수 있다.NH 3 -TPD experiments were performed to investigate the concentration and strength of acid sites in CoZ catalysts. The acid point on the ZSM5 can act as an active site for the olefin cracking reaction of the FTS product even at low reaction temperatures. The NH 3 -TPD pattern of CoZ catalysts is shown in FIG. 6. Three characteristic steps, peaks I, II and III, associated with NH 3 desorption were observed. Peak I is NH 3 desorption temperature, peak II of below 220 ℃ temperature of NH 3 desorption temperature, peak III at 220~500 ℃ corresponds to the NH 3 desorption temperature of at least 500 ℃. Desorption peak III observed above 500 ° C. may be related to water desorption from the zeolite skeleton or NH 3 decomposition, and peak I at 100 to 220 ° C. is associated with weak acid sites or physically adsorbed ammonia, 220 Peak II at ˜500 ° C. is due to the strong acid point. Table 3 shows the acid point density in CoZ catalysts as NH 3 / gcat as weak and strong acid points. Considering the first peak (weak acid point) and the second peak (strong acid point), which can be active sites for the olefin cracking reaction, we found that the acid point density is higher due to the increased ZSM5 content in the CoZ (0.50) catalyst. . Furthermore, the total scattering density (sum of peaks I and II) varies in the order of CoZ (0.50)> CoZ (0.33)> CoZ (0.25). As shown in Table 3, as the ZSM5 content on the CoZ catalyst increases regardless of the catalyst (g cat ) or for the value of ZSM5 (g ZSM5 ), the acid point density also increases proportionally. Interestingly, the weak and strong acid point density for peaks I and II in NH 3 -TPD was significantly reduced by the addition of cobalt species by acid point blocking on ZSM5 (0.743 of bare ZSM5, 0.450 on Co / ZSM5 catalyst). mmol NH 3 / g). Significant decreases in weak and strong acid points in CoZ catalysts suggest the possibility of migration of cobalt microcrystals from the Co / SiO 2 catalyst to the ZSM5 surface during hydrothermal synthesis. For example, the acid point calculated at CoZ (0.50) may be near 0.372 mmol NH 3 / g based on the weight percent of ZSM5 in the CoZ catalyst. However, as shown in Table 3, all CoZ catalysts were observed at lower values in the range 0.067 to 0.205 mmol NH 3 / g. Thus, by redistribution in both SiO 2 and ZSM5 during hydrothermal synthesis, cobalt microcrystals can be rearranged on CoZ catalysts and alter catalyst performance.
4. ZSM5-개질된 Co/SiO2 촉매에서 CO 전환 및 생성물 분포4. CO Conversion and Product Distribution on ZSM5-Modified Co / SiO 2 Catalysts
표 4는 ZSM5-개질된 Co/SiO2 촉매에 대한 촉매 성능에 대한 것이다.Table 4 is the catalytic performance for the ZSM5-modified Co / SiO 2 catalyst.
표 4
Figure PCTKR2013006067-appb-T000004
Table 4
Figure PCTKR2013006067-appb-T000004
FTS 생성물의 올레핀 크래킹에 대한 ZSM5의 기여를 확인하기 위해, CoZ 촉매의 촉매 성능을 P= 2.0 MPa, SV = 4000 mL/gcat/h, 및 H2/CO = 2에서 40시간 동안 다소 높은 온도 240℃ 에서 측정하였다. CoZ 촉매들상에서 CO 전환 및 생성물 분포는 30시간 이후 CO 전환 및 생성물 분포의 steady-state 평균값으로 표 4에 나타나 있다. CoZ 촉매의 촉매 활성은 도 7에 도시된 바와 같이 CO 전환에 대해 스트림 상에서 약 10 시간 후에 안정화되었으며, 심각한 촉매 불활성화를 나타내지 않으면서 생성물 분포는 steady-state 에서 크게 변경되지 않았다. CO 전환은 ZSM5 / (Co/SiO2) 무게비가 증가함에 따라 비례적으로 감소하고, 경향은 표 1에 나타난 바와 같이 코발트 산화물의 미세 결정 크기 및 이의 환원능력과 관련있다. 일반적으로, 넓은 표면적을 가지면서 큰 기공 직경을 갖는 촉매는 작은 코발트 미세 결정 크기를 얻는데 유리하며 FTS 반응동안 형성된 중쇄 탄화수소들을 수월하게 이동시킬 수 있다. FTS 촉매 상의 큰 기공은 코크 또는 왁스 증착이 덜되는 것과 연결되어 있다는 것이 제시되어 왔다. 약한 산점의 높은 함량은, 제올라이트의 산점에서의 고분자 올레핀의 촉매에 의한 크래킹으로 인해 C5∼C22 탄화수소의 고수율과 관련이 있다. 그러나, Co/SiO2와 ZSM5가 물리적으로 혼합된 복합 촉매는 C5∼C22 탄화수소 선택도를 향상하기 위한 좋은 촉매가 될 수 없다. 본 발명자들의 이전 연구에 따르면, ZSM5와 물리적으로 혼합된 철계 FTS 촉매는 높은 부산물 선택도를 나타내고 올레핀 탄화수소의 선택도는 낮았다. 게다가, 철계 촉매보다 코발트계 촉매에서 올레핀 생산 속도가 낮은 것은, 생성물 분포의 작은 변화를 유발하는 올레핀 성분들의 낮은 크래킹 촉매 활성과 관련이 있다. 흥미롭게도 CoZ 촉매는 Co/SiO2와 Co/ZSM5와 비교시, 약 40시간에서 안전한 촉매활성을 나타내면서 중질 탄화수소에 대한 높은 선택도, CH4 및 CO2에 대한 낮은 선택도를 보여 주었다. 240℃로 상승된 온도에서 수소화 활성이 증가되고 ZSM5의 산점에서 탄화수소의 크래킹 반응이 상당하기 때문에, Co/SiO2와 Co/ZSM5 촉매에서 각각 14.5%, 24.3%로 높은 CH4 선택도가 관찰되었다.In order to confirm the contribution of ZSM5 to olefin cracking of the FTS product, the catalytic performance of the CoZ catalyst was changed to a somewhat higher temperature for 40 hours at P = 2.0 MPa, SV = 4000 mL / g cat / h, and H 2 / CO = 2. It measured at 240 degreeC. CO conversion and product distribution on CoZ catalysts are shown in Table 4 as steady-state averages of CO conversion and product distribution after 30 hours. The catalytic activity of the CoZ catalyst was stabilized after about 10 hours on the stream for CO conversion as shown in FIG. 7 and the product distribution did not change significantly in steady-state without showing significant catalyst deactivation. CO conversion decreases proportionally with increasing ZSM5 / (Co / SiO 2 ) weight ratio, and the trend is related to the fine crystal size of cobalt oxide and its reducing capacity as shown in Table 1. In general, catalysts having a large surface area and large pore diameters are advantageous for obtaining small cobalt microcrystalline size and can easily transport heavy chain hydrocarbons formed during the FTS reaction. It has been suggested that the large pores on the FTS catalyst are linked to less coke or wax deposition. The high content of weak acid sites is associated with high yields of C 5 to C 22 hydrocarbons due to the cracking of the polymer olefins at the acid sites of the zeolites. However, a composite catalyst in which Co / SiO 2 and ZSM5 are physically mixed cannot be a good catalyst for improving C 5 to C 22 hydrocarbon selectivity. According to our previous work, the iron-based FTS catalyst physically mixed with ZSM5 showed high by-product selectivity and low selectivity of olefin hydrocarbons. In addition, lower olefin production rates in cobalt based catalysts than iron based catalysts are associated with low cracking catalyst activity of the olefin components causing small changes in product distribution. Interestingly, the CoZ catalyst showed safe catalytic activity at about 40 hours compared to Co / SiO 2 and Co / ZSM5, showing high selectivity for heavy hydrocarbons and low selectivity for CH 4 and CO 2 . Because of the increased hydrogenation activity at the elevated temperature to 240 ° C. and the hydrocarbon cracking reaction at the acidic point of ZSM5, a high CH 4 selectivity of 14.5% and 24.3% was observed for Co / SiO 2 and Co / ZSM5 catalysts, respectively. .
CoZ 촉매에서 중질 탄화수소로의 CO 전환은 모든 FTS 촉매들의 경우 82.8%이다. CO2로의 CO 전환은 수성가스 시프트 반응에 의한 CO 전환과 비례한다. 또한, 이들은 CoZ 촉매에서 Co/SiO2 함량이 감소함에 따라 감소한다. 일반적으로, 대략 10nm 크기를 갖는 코발트 나노 미세 결정상에서 TOF 값은 1.6 X 10-3 ∼ 3.0 X 10-3/s 범위인 것으로 보고되어 있다. 비록 ZSM5의 증착으로 인해 활성 코발트 부위들의 차단에 의해 CoZ 촉매에서 CO 전환이 Co/SiO2 촉매보다 다소 낮지만, CoZ 촉매에서 C5∼C22 탄화수소의 수율은 크게 변하고, 낮은 CH4 선택도가 관찰되었다. Co/SiO2와 Co/ZSM5 촉매와 비교시, 작은 코발트 미세 결정(코발트의 넓은 금속 표면적), 높은 환원능력(TPR에서 낮은 환원 온도) 및 Co/SiO2 로부터 ZSM5로의 소량 코발트 미세 결정 이동(XPS, TEM, 및 SEM-EDS 분석에 의해 확인)을 갖는 CoZ(0.25) 촉매는 높은 촉매 성능을 보여주는 것으로 여겨진다.CO conversion from CoZ catalyst to heavy hydrocarbons is 82.8% for all FTS catalysts. CO conversion to CO 2 is proportional to CO conversion by the water gas shift reaction. In addition, they decrease with decreasing Co / SiO 2 content in the CoZ catalyst. In general, TOF values are reported to range from 1.6 × 10 −3 to 3.0 × 10 −3 / s on cobalt nanofine crystal phases having approximately 10 nm size. Although the CO conversion in the CoZ catalyst is somewhat lower than that of the Co / SiO 2 catalyst due to the blocking of active cobalt sites due to the deposition of ZSM5, the yields of C 5 to C 22 hydrocarbons in the CoZ catalyst change significantly and the low CH 4 selectivity Was observed. Compared to Co / SiO 2 and Co / ZSM5 catalysts, small cobalt microcrystals (cobalt's wide metal surface area), high reduction capacity (low reduction temperature in TPR) and small cobalt microcrystal transfer from Co / SiO 2 to ZSM5 (XPS CoZ (0.25) catalysts (identified by TEM, and SEM-EDS analysis) are believed to show high catalytic performance.
다른 CoZ 촉매들과 비교하여, CoZ(0.25) 촉매는 높은 값의 CO 전환 및 C5∼C22 탄화수소의 높은 수율을 보여준다. 낮은 산점 밀도를 나타내는 낮은 함량의 ZSM5로 인해, CoZ(0.25) 촉매는 약 7.8%의 낮은 CH4 선택도 및 약 9.2% 의 C2∼C4 탄화수소를 보여준다. CoZ(0.25) 촉매에서 낮은 올레핀 선택도 및 약 62.8%의 C5∼C22 탄화수소의 최대 선택도(C5∼C22 탄화수소 수율 49.1%)가 관측되었다.Compared with other CoZ catalysts, CoZ (0.25) catalysts show high values of CO conversion and high yields of C 5 to C 22 hydrocarbons. Due to the low content of ZSM5, which indicates low acid density, the CoZ (0.25) catalyst shows low CH 4 selectivity of about 7.8% and C 2 -C 4 hydrocarbons of about 9.2%. The CoZ (0.25) C 5 ~C 22 hydrocarbons, up to the selection of even lower olefin selected from the catalyst and from about 62.8% Fig. (C 5 ~C 22 hydrocarbons yield 49.1%) was observed.
한편, CoZ(0.50) 촉매에서는 11.3%의 가장 높은 CH4 로의 선택도 및 13.4%의 C2∼C4 탄화수소를 보여준다. CH4 및 C2∼C4 선택도는, ZSM5 함량이 증가함에 따라 증가한다. 이는 ZSM5의 산점이 저온에서도 올레핀 탄화수소로부터 경질 탄화수소로의 크래킹 반응에 촉매로서 중요한 역할을 하기 때문이다. ZSM5의 산점은 또한 골격을 형성하는 알루미늄의 함량과 관련이 있으며, 이들 산점은 올레핀 탄화수소의 높은 선택도와 관련이 있다. CoZ 촉매상에서 코발트 산화물 미세 결정 또는 이온 교환된 Co2+ 종은 또한 골격을 형성하는 알루미늄과 강한 상호작용에 의한 것일 수 있다. 이는 CoZ(0.50) 촉매가 240 ℃에서 약 32.1%의 높은 올레핀 선택도(O/(O+P)로 표시)를 보여주는 것에 의해 뒷받침된다.CoZ (0.50) catalysts, on the other hand, show the highest CH 4 selectivity of 11.3% and C 2 -C 4 hydrocarbons of 13.4%. CH 4 and C 2 -C 4 selectivity increase with increasing ZSM5 content. This is because the acid point of ZSM5 plays an important role as a catalyst in cracking reaction from olefin hydrocarbon to light hydrocarbon even at low temperature. The acid point of ZSM5 is also related to the content of aluminum forming the backbone, which is related to the high selectivity of the olefin hydrocarbons. Cobalt oxide microcrystals or ion exchanged Co 2+ species on CoZ catalysts may also be due to strong interactions with aluminum forming the backbone. This is supported by the CoZ (0.50) catalyst showing high olefin selectivity (expressed as O / (O + P)) of about 32.1% at 240 ° C.
C2~C4 탄화수소에서의 올레핀 선택도가 증가하는 것이 큰 산점 밀도로 인해 중질 올레핀 탄화수소의 올레핀 크래킹 특성이 증가한 것과 관련이 있다고 하더라고, 이는 CH4 선택도 강화를 수반하고, 이의 생성율은 CoZ 촉매에서의 ZSM5 함량에 비례한다. CoZ 촉매에서 산점이 풍부한 것은 중질 올레핀을 소비하면서 이성질체들 및 C22+ 방향족 화합물들 형성과 관련이 있다. 그러나, 구체적으로 CoZ(0.50) 촉매상에서, 경질 탄화수소의 생성이 증가되기 때문에, 높은 산점 밀도는 원하는 가솔린 및 중간 유분(C5∼C22 탄화수소) 형성에는 이롭지 않다. 따라서, CoZ(0.25) 촉매에서 CO 전환 및 C5∼C22 선택도가 높은 것은, TEM, 및 SEM-EDS 분석에서 확인 된 바와 같이, CoZ(0.50) 촉매에서 ZSM5 입자들의 응집과 비교하여, Co/SiO2 상에서 ZSM5의 인접한 접촉에 기인한 것이다. Although increasing the olefin selectivity in C 2 to C 4 hydrocarbons is associated with an increase in the olefin cracking properties of heavy olefin hydrocarbons due to the large acid density, this entails enhanced CH 4 selectivity, the rate of formation of which is a CoZ catalyst. Proportional to the ZSM5 content at. Acidic richness in CoZ catalysts is associated with the formation of isomers and C 22+ aromatics while consuming heavy olefins. However, especially on CoZ (0.50) catalysts, since the production of light hydrocarbons is increased, high acid point densities are not beneficial for the formation of desired gasoline and intermediate fractions (C 5 -C 22 hydrocarbons). Thus, the high CO conversion and C 5 to C 22 selectivity in the CoZ (0.25) catalyst, as confirmed by TEM and SEM-EDS analysis, compared to the aggregation of ZSM5 particles in the CoZ (0.50) catalyst, This is due to the adjacent contact of ZSM5 on / SiO 2 .
이전에 보고된 바와 같이 올레핀 및 C5∼C22 탄화수소의 높은 선택도를 얻기 위해서는, CoZ(0.25)와 같이 Co/SiO2 상의 코발트와 인접 접촉하는 ZSM5의 최적 함량을 갖는 CoZ 촉매가 ZSM5 지지체 상에 Co를 단순히 함침하는 것이 더 좋다. CoZ 촉매 상 산점 밀도에 대해 CO 전환 및 생성물 분포와 같은 촉매성능 매개 변수가 도 8에 정리되어 있다. CO 전환은 낮은 Co/SiO2 함량으로 인해 CoZ 촉매 상의 ZSM5 함량이 증가함에 따라 감소하였다. 높은 C5∼C22 탄화수소 선택도가 CoZ(0.25) 촉매에서 관찰되었다. Co/SiO2 이 ZSM5로 개질된 모식도가 도 9에 도시되어 있다. CoZ(0.25) 촉매에서 향상된 촉매 성능은, 수열 합성동안 Co/SiO2로부터 ZSM5의 산점으로 코발트 미세결정들이 이동하여, Co/SiO2 표면상에 ZSM5의 약한 산점들과 인접 접촉하여 작은 미세 결정 크기의 코발트 산화물이 형성된 것과 주로 관련이 있다. 게다가, 코발트 산화물과 인접 접촉한 ZSM5 입자들은 또한 FTS 생성물의 올레핀 크래킹 반응 정도를 향상시킬 수 있고, 이는 CoZ(0.25) 촉매에서 C5∼C22 탄화수소 선택도를 강화시킨다. As previously reported, in order to obtain high selectivity of olefins and C 5 to C 22 hydrocarbons, a CoZ catalyst with an optimal content of ZSM 5 in close contact with cobalt on Co / SiO 2 phase, such as CoZ (0.25), is formed on the ZSM5 support. It is better to simply impregnate Co at. Catalytic performance parameters such as CO conversion and product distribution for acid point density on CoZ catalysts are summarized in FIG. 8. CO conversion decreased with increasing ZSM5 content on the CoZ catalyst due to the low Co / SiO 2 content. High C 5 -C 22 hydrocarbon selectivity was observed in the CoZ (0.25) catalyst. A schematic diagram of Co / SiO 2 modified with ZSM5 is shown in FIG. 9. Improved catalytic performance in CoZ (0.25) catalysts allows cobalt microcrystals to migrate from Co / SiO 2 to the acidic point of ZSM5 during hydrothermal synthesis, resulting in small microcrystalline size in close contact with the weak acidic points of ZSM5 on the Co / SiO 2 surface. Mainly related to the formation of cobalt oxide. In addition, ZSM5 particles in close contact with the cobalt oxide can also improve the degree of olefin cracking reaction of the FTS product, which enhances the C 5 -C 22 hydrocarbon selectivity in the CoZ (0.25) catalyst.
5. 결론5. Conclusion
Co/SiO2 촉매상에서 ZSM5 (Si/Al 몰비= 40) 함량을 25 에서 50 wt%까지 변화시켜, ZSM5-개질된 Co/SiO2 촉매상에서 C5∼C22 탄화수소 선택도 극대화를 연구하였다. 미리준비된 Co/SiO2 촉매를 함유하는 용액에서 ZSM5을 그자리에서(in-situ) 수열합성하여 촉매를 제조하였다. 그 결과, ZSM5-modified CoZ(0.25)에서 C5 ∼ C22 탄화수소의 최대 수율을 얻었으며, 이는 Co/SiO2 및 Co/ZSM5 보다 우수한것이다. 이는주로, 코발트 결정들이 Co/SiO2 로부터 ZSM5 표면으로의 이동 가능성에 의해, 코발트 산화물의 작은 결정크기의 형성 및 ZSM5상 적절한 산점 밀도에 기인한 것이다. Co/SiO2 촉매상에서 ZSM5을 insitu 합성하는 동안 코발트산화물의 이동가능성(possible migration)은 TPR, NH3-TPD, TEM, XPS, 및 XRD분석결과 확인하였다. Co/SiO2촉매상 산성 ZSM5 성분의 증착에 의해 Co/SiO2이 기공폐색(blockage)되기 때문에 ZSM5 함량이 증가하여 CoZ 촉매의 표면적을 감소시켜 환원정도(reducibility)을 감소시킨다. 또한, 증가된 코발트 산화물의 결정크기는 ZSM5 표면으로의 코발트이동에 기인한 것이다. CoZ 촉매상 ZSM5의 최적 함량 (CoZ(0.25) 촉매)에서, 코발트 산화물과 ZSM5의 인접한 접촉은 높은 촉매성능을 책임지고 있다. ZSM5 수열합성동안 ZSM5입자들로 Co/SiO2를 개질하면, C1 ∼ C4 탄화수소들을 최소화하면서 C5 ∼ C22 탄화수소의 선택도를 증가시킬 수 있다.The ZSM5 (Si / Al mole ratio = 40) by changing the content of 25 to 50 wt%, ZSM5- maximize FIG C 5 ~C 22 hydrocarbons selected on the modified Co / SiO 2 catalysts were studied on the Co / SiO 2 catalyst. The catalyst was prepared by hydrothermal synthesis of ZSM5 in-situ in a solution containing pre-prepared Co / SiO 2 catalyst. As a result, a maximum yield of C 5 to C 22 hydrocarbons was obtained in ZSM5-modified CoZ (0.25), which is better than Co / SiO 2 and Co / ZSM5. This is mainly due to the possibility of cobalt crystals moving from Co / SiO 2 to the ZSM5 surface, due to the formation of a small crystal size of cobalt oxide and to an appropriate scattering density on ZSM5. The possible migration of cobalt oxides during insitu synthesis of ZSM5 on Co / SiO 2 catalysts was confirmed by TPR, NH3-TPD, TEM, XPS, and XRD analysis. Since the deposited Co / SiO 2 pore occlusion (blockage) of the acid by the ZSM5 components Co / SiO 2 catalyst by increasing the content of ZSM5 by reducing the surface area of the catalyst CoZ reduces the degree of reduction (reducibility). In addition, the crystal size of the increased cobalt oxide is due to the cobalt movement to the ZSM5 surface. At the optimum content of ZSM5 on the CoZ catalyst (CoZ (0.25) catalyst), the adjacent contact of cobalt oxide with ZSM5 is responsible for high catalytic performance. Modification of Co / SiO 2 with ZSM 5 particles during ZSM 5 hydrothermal synthesis can increase the selectivity of C 5 to C 22 hydrocarbons while minimizing C 1 to C 4 hydrocarbons.
비교예 1: Co/SiO2 촉매 제조Comparative Example 1: Preparation of Co / SiO 2 Catalyst
상용 실리카 지지체에, 20 중량%의 코발트 나이트레이트(Co(NO3)2·6H2O) 수용액이 잘 섞이도록 마그네틱 바를 이용해 교반해주면서 용액을 건조시켰다. 이후 500℃에서 5 시간 동안 소성하여, 20 중량% Co/실리카 촉매를 제조하였다. 제조된 촉매는 20 내지 40 Mesh로 걸러 주었다.The solution was dried with a commercially available silica support by stirring using a magnetic bar to mix 20 wt% of cobalt nitrate (Co (NO 3 ) 2 .6H 2 O) aqueous solution. After calcining at 500 ° C. for 5 hours, a 20 wt% Co / silica catalyst was prepared. The prepared catalyst was filtered by 20 to 40 Mesh.
참조예 1 내지 5: 제올라이트 지지체에 촉매를 함침시킨 FT 합성용 혼성촉매 제조Reference Examples 1 to 5: Preparation of a Hybrid Catalyst for FT Synthesis Impregnated with a Catalyst in a Zeolite Support
제올라이트 100 중량부 기준으로 20 중량부의 코발트(Co-nitrate) 및 선택적으로 0.2 중량부의 Pt-nitrate 또는 La-nitrate를 제올라이트의 표면 및 세공 내 함침시킨 후, 100 ℃ 오븐에서 하루 정도 건조시켰다. 이어서 500℃에서 소성하여, FT 합성용 혼성촉매를 제조하였다.20 parts by weight of cobalt (Co-nitrate) and optionally 0.2 parts by weight of Pt-nitrate or La-nitrate based on 100 parts by weight of zeolite were impregnated into the surface and pores of the zeolite and then dried in a 100 ° C. oven for one day. Subsequently, the mixture was calcined at 500 ° C to prepare a hybrid catalyst for FT synthesis.
실시예 1 ∼ 3: 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를 수열합성하여 형성된 피셔-트롭쉬(FT) 합성용 혼성촉매Examples 1 to 3: Hybrid catalyst for Fischer-Tropsch (FT) synthesis formed by hydrothermal synthesis of zeolite on a porous support loaded with cobalt oxide
우선, 실리카 100 중량부 기준으로 20 중량부의 코발트(Co-nitrate) 및 선택적으로 0.2 중량부의 Pt-nitrate 또는 La-nitrate를 실리카 다공성 지지체에 함침시킨 후 500℃에서 소성하여, 피셔-트롭쉬 합성 촉매를 제조하였다.First, 20 parts by weight of cobalt (Co-nitrate) and optionally 0.2 parts by weight of Pt-nitrate or La-nitrate, based on 100 parts by weight of silica, were impregnated into the silica porous support and then calcined at 500 ° C. to provide a Fischer-Tropsch synthesis catalyst. Was prepared.
사용한 제올라이트 합성용 젤 형성 조성물은 TEOS/TPAOH/H2O/EtOH/Al(NO3)3 = 1:0.25:60:4:0.025(질량비)이었다. 이때, TPAOH (tetrapropyl ammonium hydroxide solution)는 템플렛 역할을 하며, Al(NO3)3·H2O (99.5%)와 TEOS (tetraethyl ortho silicate)는 각각 알루미늄과 실리카의 전구체로 사용하였고, 용매로 물과 에탄올을 사용하였다. The gel forming composition for zeolite synthesis used was TEOS / TPAOH / H 2 O / EtOH / Al (NO 3 ) 3 = 1: 0.25: 60: 4: 0.025 (mass ratio). At this time, TPAOH (tetrapropyl ammonium hydroxide solution) serves as a template, Al (NO 3 ) 3 · H 2 O (99.5%) and TEOS (tetraethyl ortho silicate) were used as precursors of aluminum and silica, respectively, water as a solvent And ethanol were used.
상기 제올라이트 합성용 젤 형성 조성물을 50℃에서 졸을 만든 후 상기 제조된 피셔-트롭쉬 합성 촉매(Co/SiO2, Co-Ru/SiO2, Co-Pt/SiO2,) 4g과 혼합하여 180℃에서 10시간 동안 수열합성하였다. 이때, 형성된 제올라이트 입자의 Si/Al=40이며, Zeolite/(Co/SiO2)=0.25의 무게비로 제올라이트를 합성하였다.The gel-forming composition for zeolite synthesis was prepared by sol at 50 ° C. and then mixed with 4 g of the prepared Fischer-Tropsch synthesis catalyst (Co / SiO 2 , Co-Ru / SiO 2 , Co-Pt / SiO 2 ,) 180 Hydrothermal synthesis for 10 hours at ℃. At this time, Si / Al = 40 of the formed zeolite particles and zeolite were synthesized at a weight ratio of Zeolite / (Co / SiO 2 ) = 0.25.
비교예 2: FT 합성용 촉매와 -제올라이트의 물리적 혼합Comparative Example 2: Physical Mixing of Catalyst for FT Synthesis and Zeolite
실리카 다공성 지지체 100 중량부 기준으로 20 중량부의 코발트(Co-nitrate)를 실리카의 표면 및 세공 내 함침시킨 후, 100℃의 오븐에서 하루 정도 건조시켰다. 이어서 500℃에서 소성하였다. 제조한 FT 촉매와 β-제올라이트를 50:50의 중량비로 혼합하여 FT 합성용 혼성촉매를 제조하였다.20 parts by weight of cobalt (Co-nitrate) based on 100 parts by weight of the silica porous support was impregnated into the surface and pores of the silica, and then dried in an oven at 100 ° C. for about one day. Subsequently, it baked at 500 degreeC. The prepared FT catalyst and β-zeolite were mixed at a weight ratio of 50:50 to prepare a hybrid catalyst for FT synthesis.
실험예 3: 피셔-트롭쉬 합성 반응Experimental Example 3: Fischer-Tropsch Synthesis Reaction
표 5 및 표 6에 기재된 바와 같이 참조예 1 ∼ 5, 실시예 1 ∼ 3 및 비교예 1 및 2의 촉매 0.3g 및 반응온도를 사용하고, 20기압, 2000 ml/g·h의 공간속도, H2/CO=2.0의 조건에서 FT 반응을 고정층 반응기에서 수행하였다.As described in Tables 5 and 6, using 0.3 g of the catalysts of Reference Examples 1 to 5, Examples 1 to 3 and Comparative Examples 1 and 2 and the reaction temperature, a space velocity of 20 atm, 2000 ml / g · h, The FT reaction was carried out in a fixed bed reactor under the condition of H 2 /CO=2.0.
표 5
구분 촉매 CO 전환율(탄소 mol%) CO에서 CO2로 전환율(탄소 mol%) 탄소 선택도C1/C2-C4/C5-C9/C10이상 C5 이상 수율(%) 반응온도(℃)
참조예 1 Co/-제올라이트(Si/Al=25) 79.5 11.1 20.3/14.5/12.2/53.0 44.6 240
참조예 2 Co-ZSM-5(Si/Al=15) 56.2 3.4 25.6/31.2/25.1/18.1 22.8 240
참조예 3 Co-Pt/ZSM-5a(Si/Al=25) 55.2 1.7 17.8/12.4/8.8/61.0 37.3 260
참조예 4 Co-Pt/ZSM-5b(Si/Al=25) 53.1 0.4 10.7/10.8/15.6/62.9 41.4 260
실시예 5 Co-La/ZSM-5c(Si/Al=25) 54.1 1.9 18.8/15.3/12.7/53.2 34.4 260
비교예 1 Co/SiO2 26.8 0.6 6.8/10.9/10.4/71.9 21.6 220
* a: Pt-nitrate, b: Pt-chloride, c: La-nitrate
Table 5
division catalyst CO conversion rate (mol mol of carbon) Conversion from CO to CO 2 (mol mol) Carbon selectivity C 1 / C 2 -C 4 / C 5 -C 9 / C 10 or more C 5 or higher yield (%) Reaction temperature (℃)
Reference Example 1 Co / -zeolite (Si / Al = 25) 79.5 11.1 20.3 / 14.5 / 12.2 / 53.0 44.6 240
Reference Example 2 Co-ZSM-5 (Si / Al = 15) 56.2 3.4 25.6 / 31.2 / 25.1 / 18.1 22.8 240
Reference Example 3 Co-Pt / ZSM-5 a (Si / Al = 25) 55.2 1.7 17.8 / 12.4 / 8.8 / 61.0 37.3 260
Reference Example 4 Co-Pt / ZSM-5 b (Si / Al = 25) 53.1 0.4 10.7 / 10.8 / 15.6 / 62.9 41.4 260
Example 5 Co-La / ZSM-5 c (Si / Al = 25) 54.1 1.9 18.8 / 15.3 / 12.7 / 53.2 34.4 260
Comparative Example 1 Co / SiO 2 26.8 0.6 6.8 / 10.9 / 10.4 / 71.9 21.6 220
a: Pt-nitrate, b: Pt-chloride, c: La-nitrate
참조예 1 ∼ 5의 촉매는 비교예 1의 촉매 대비 CO 전환율(카본몰%) 및 C5∼C9와 C9이상의 수율이 크게 향상되었음을 확인할 수 있다.Reference Example 1-5 The catalyst can be concluded that the catalyst prepared CO conversion (carbon mol%) and a significantly improved C 5 ~C 9 and C 9 more than the yield of Comparative Example 1.
표 6
구분 촉매 CO 전환율(탄소 mol%) CO에서 CO2로 전환율(탄소 mol%) 탄소 선택도C1/C2-C4/C5-C9/C10이상 C5 이상 탄소 선택도(%) C5 이상 수율(%) 반응온도(℃)
실시예 1 제올라이트/(Co/SiO2) 88.3 17.2 17.0/16.3/13.7/53.0 66.7 47.4 240
실시예 2 제올라이트/(Co-Ru/SiO2)a) 38.7 3.1 17.1/10.2/20.4/56.1 76.5 25.9 240
실시예 3 제올라이트/(Co-Pt/SiO2)b) 49.7 3.0 25.9/17.4/28.6/28.1 56.7 26.5 260
비교예 1 Co/SiO2 26.8 0.6 6.8/10.9/10.4/71.9 82.3 21.6 220
비교예 2 Co/SiO2+-제올라이트 64.6 2.9 6.7/10.1/11.1/72.1 83.1 83.1 51.3
* a): 실리카 100 중량부 기준으로 Ru-nitrate 0.2 중량부, b): 실리카 100 중량부 기준으로 Pt-nitrate 0.2 중량부
Table 6
division catalyst CO conversion rate (mol mol of carbon) Conversion from CO to CO 2 (mol mol) Carbon selectivity C 1 / C 2 -C 4 / C 5 -C 9 / C 10 or more C 5 or higher carbon selectivity (%) C 5 or higher yield (%) Reaction temperature (℃)
Example 1 Zeolite / (Co / SiO 2 ) 88.3 17.2 17.0 / 16.3 / 13.7 / 53.0 66.7 47.4 240
Example 2 Zeolite / (Co-Ru / SiO 2 ) a) 38.7 3.1 17.1 / 10.2 / 20.4 / 56.1 76.5 25.9 240
Example 3 Zeolite / (Co-Pt / SiO 2 ) b) 49.7 3.0 25.9 / 17.4 / 28.6 / 28.1 56.7 26.5 260
Comparative Example 1 Co / SiO 2 26.8 0.6 6.8 / 10.9 / 10.4 / 71.9 82.3 21.6 220
Comparative Example 2 Co / SiO 2 + -zeolite 64.6 2.9 6.7 / 10.1 / 11.1 / 72.1 83.1 83.1 51.3
* a): 0.2 parts by weight of Ru-nitrate based on 100 parts by weight of silica, b): 0.2 parts by weight of Pt-nitrate based on 100 parts by weight of silica
실시예 2 및 3의 촉매는 비교예 1의 촉매 대비 CO 전환율(카본몰%) 및 C5∼C9와 C9이상의 수율이 크게 향상되었으며 C5∼C9의 선택도가 크게 향상되었다. 또한, 실시예 1의 촉매 대비 CO에서 CO2로의 전환율 (카본몰%)이 낮고 C5∼C9의 선택도가 크게 향상되었다.Examples 2 and 3 Comparative Examples of the catalyst compared to the catalyst of the first CO conversion was improved (carbon mol%) and C 5 ~C 9 and C 9 yield more significantly improved the selectivity to C 5 ~C 9 significantly. In addition, the conversion rate from carbon to CO 2 (carbon mol%) was lower than that of the catalyst of Example 1, and the selectivity of C 5 to C 9 was greatly improved.

Claims (16)

  1. 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를 수열합성하여 형성된 피셔-트롭쉬(FT) 합성용 혼성촉매로서,Fischer-Tropsch (FT) hybrid catalyst formed by hydrothermal synthesis of zeolite on a porous support loaded with cobalt oxide,
    제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5인 것이 특징인 FT 합성용 혼성촉매.Hybrid catalyst for FT synthesis, characterized in that the porous support (weight ratio) = 0.25 to 0.5 supported by zeolite / cobalt oxide.
  2. 제1항에 있어서, 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를 수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 코발트 산화물이 이동되는 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein the cobalt oxide is transferred from the porous support to the zeolite surface during hydrothermal synthesis of the zeolite on the porous support loaded with the cobalt oxide.
  3. 제2항에 있어서, 코발트 산화물이 담지된 다공성 지지체상에서 제올라이트를수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 이동된 코발트 산화물은 제올라이트 입자와 접촉된 상태에서 표면에 노출되어 있는 것이 특징인 FT 합성용 혼성촉매.3. The hybrid of FT synthesis according to claim 2, wherein the cobalt oxide transferred to the zeolite surface on the porous support during hydrothermal synthesis of the zeolite on the porous support on which the cobalt oxide is supported is exposed on the surface in contact with the zeolite particles. catalyst.
  4. 제1항에 있어서, 제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) 는 0.25 ± 0.1 범위 내인 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein the porous support (weight ratio) loaded with the zeolite / cobalt oxide is in the range of 0.25 ± 0.1.
  5. 제1항에 있어서, 상기 다공성 지지체는 SiO2이고, 제올라이트는 ZSM5인 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst of claim 1, wherein the porous support is SiO 2 and the zeolite is ZSM 5.
  6. 제1항에 있어서, 상기 코발트 산화물이 담지된 다공성 지지체는 Ru, Pt 및 La 중에서 선택된 금속을 더 담지한 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein the cobalt oxide-supported porous support further supports a metal selected from Ru, Pt, and La.
  7. 제1항에 있어서, 상기 코발트 산화물의 일부 또는 전부가 코발트 금속으로 환원된 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein some or all of the cobalt oxide is reduced to cobalt metal.
  8. 제1항에 있어서, FT 합성 반응 및 올레핀 크래킹 반응에 대해 촉매 활성이 있는 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein the FT synthesis hybrid catalyst has catalytic activity against FT synthesis reaction and olefin cracking reaction.
  9. 제1항에 있어서, 수열합성하는 동안 다공성 지지체상에서 제올라이트 표면으로 이동된 코발트 산화물에서 코발트 결정 평균 입경은 15 내지 20 nm인 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 1, wherein the cobalt crystal average particle diameter is 15 to 20 nm in cobalt oxide migrated from the porous support to the zeolite surface during hydrothermal synthesis.
  10. 제6항에 있어서, 다공성 지지체 100 중량부를 기준으로 Co는 5 ∼ 40 중량부이고 Ru, Pt 및 La 중에서 선택된 1종 이상의 금속원소는 0.1 ∼ 5 중량부인 것이 특징인 FT 합성용 혼성촉매.The hybrid catalyst for FT synthesis according to claim 6, wherein Co is 5 to 40 parts by weight based on 100 parts by weight of the porous support, and at least one metal element selected from Ru, Pt, and La is 0.1 to 5 parts by weight.
  11. 제1항 내지 제10항 중 어느 한 항에 기재된 FT 합성용 혼성촉매의 제조방법으로서,As a manufacturing method of the hybrid catalyst for FT synthesis | combination as described in any one of Claims 1-10,
    제올라이트 / 코발트 산화물이 담지된 다공성 지지체 (무게비) = 0.25 내지 0.5이 되도록 하는 조절된 제올라이트 합성용 젤 속에 상기 코발트 산화물이 담지된 다공성 지지체들을 넣은 후 수열합성하는 단계를 포함하는 것이 특징인 제조방법.And a hydrothermal synthesis method after putting the cobalt oxide-supported porous supports into a controlled zeolite synthesis gel such that the zeolite / cobalt oxide-supported porous support (weight ratio) = 0.25 to 0.5.
  12. 제1항 내지 제10항 중 어느 한 항에 기재된 FT 합성용 혼성촉매를 사용하여, 합성가스로부터 직접 중간유분을 생산하는 방법.A process for producing intermediate oil directly from syngas using the hybrid catalyst for synthesis of FT according to any one of claims 1 to 10.
  13. 제12항에 있어서, 중간유분은 탄소수가 C5∼C22 인 것이 특징인 방법.The process according to claim 12, wherein the middle fraction has C 5 to C 22 .
  14. 제12항에 있어서, 반응 온도는 220 ∼ 400 이고, 반응압력은 5 ∼ 60 kg/이고, 공간속도는 500 ∼ 10000 h-1인 것이 특징인 방법.The method according to claim 12, wherein the reaction temperature is 220 to 400, the reaction pressure is 5 to 60 kg /, and the space velocity is 500 to 10000 h −1 .
  15. 제12항에 있어서, FT 합성용 혼성촉매는 수소 분위기에서 환원한 후 촉매반응에 사용하는 것이 특징인 방법.13. The method according to claim 12, wherein the hybrid catalyst for FT synthesis is used for catalysis after reduction in a hydrogen atmosphere.
  16. 제12항에 있어서, 합성가스는 천연가스를 개질하여 형성된 것이고, 최종생성물 중 C1∼C4 범위의 경질탄화수소들은 천연가스와 함께 개질공정으로 재순환시키는 것이 특징인 방법.13. The method of claim 12, wherein the syngas is formed by reforming natural gas, and the light hydrocarbons in the range of C 1 to C 4 in the final product are recycled to the reforming process together with the natural gas.
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