WO2018160041A1 - Method for manufacturing multi-wall carbon nanotubes using continuous type process - Google Patents

Method for manufacturing multi-wall carbon nanotubes using continuous type process Download PDF

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Publication number
WO2018160041A1
WO2018160041A1 PCT/KR2018/002548 KR2018002548W WO2018160041A1 WO 2018160041 A1 WO2018160041 A1 WO 2018160041A1 KR 2018002548 W KR2018002548 W KR 2018002548W WO 2018160041 A1 WO2018160041 A1 WO 2018160041A1
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carbon nanotubes
walled carbon
catalyst powder
reactor
producing
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PCT/KR2018/002548
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French (fr)
Korean (ko)
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류상효
성현경
정충헌
김동환
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금호석유화학 주식회사
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Priority claimed from KR1020180024472A external-priority patent/KR102053726B1/en
Application filed by 금호석유화학 주식회사 filed Critical 금호석유화학 주식회사
Priority to US16/490,772 priority Critical patent/US11117803B2/en
Priority to CN201880023603.XA priority patent/CN110494390A/en
Priority to JP2019548043A priority patent/JP6872627B2/en
Publication of WO2018160041A1 publication Critical patent/WO2018160041A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/16—Preparation
    • C01B32/162—Preparation characterised by catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/16—Preparation
    • C01B32/164—Preparation involving continuous processes

Definitions

  • the present invention relates to a method for producing multi-walled carbon nanotubes using a continuous process.
  • Carbon nanotube is a hexagonal honeycomb tubular structure in which one carbon atom is bonded to three other carbon atoms, and its electrical, thermal, and mechanical properties are superior to other materials to be applied to various industrial fields. have.
  • Such carbon nanotubes are generally arc-discharge, pyrolysis, laser vaporization, chemical vapor deposition, plasma chemical vapor deposition, thermal It is prepared by various methods such as thermal chemical vapor deposition, chemical vapor condensation, and the like.
  • the production method of the catalyst is spray drying (spray dry) is made at a low temperature of 200 ⁇ 350 °C, in order to form a hole in the catalyst, it is essential to use a water-soluble polymer as a pore-forming agent, making the catalyst in a form suitable for synthesis
  • spray drying spray dry
  • a water-soluble polymer as a pore-forming agent
  • the present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to improve the conversion of the carbon-based raw material gas and the yield of the multi-walled carbon nanotubes by using the catalyst powder optimized for the fluidized bed reactor It is to provide a method for producing a large amount of nanotubes.
  • One aspect of the invention (a) dissolving the metal precursor in a solvent to prepare a precursor solution; (b) pyrolysing the precursor solution while spraying into the reactor to form a catalyst powder; And (c) synthesizing the multi-walled carbon nanotubes from the catalyst powder by injecting the catalyst powder into a fluidized bed reactor heated to 600 to 900 ° C. and injecting a carbon gas and a carrier gas. Step a) to (c) is carried out continuously, the catalyst powder provides a method for producing a multi-walled carbon nanotubes comprising a metal component according to the following formula (1).
  • Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn and Cu
  • Mb is at least one metal selected from Mg, Al, Si and Zr
  • the catalyst powder may have a hollow structure having a thickness of 0.5 ⁇ 10 ⁇ m.
  • the apparent density of the catalyst powder may be 0.05 ⁇ 0.70 g / mL.
  • the hollow ratio of the hollow structure may be more than 50% by volume.
  • the conversion rate according to Equation 2 may be 80% or more.
  • Conversion rate (%) ⁇ (weight of multi-walled carbon nanotubes (g))-(weight of catalyst powder (g)) ⁇ / ⁇ (carbon-based gas supply (L)) * (of carbon in 1 mol of carbon-based gas) Weight (g / mol)) / (22.4 (L / mol)) ⁇ * 100
  • the carbon-based gas may be one selected from the group consisting of saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, carbon monoxide, benzene, and mixtures of two or more thereof.
  • the carrier gas may be one selected from the group consisting of helium, nitrogen, argon, and mixtures of two or more thereof.
  • the metal precursor may be one selected from the group consisting of nitrates, sulfates, alkoxides, chlorides, acetates, carbonates, and mixtures of two or more thereof.
  • the step (b) comprises the steps of (i) spraying the precursor solution into the reactor by supplying air of 2 to 5 atm as a carrier gas and introducing external air; And (ii) pyrolyzing the sprayed precursor solution at 600 to 1,200 ° C. to form a catalyst powder.
  • the step (c) comprises: (i) heating the fluidized bed reactor to 600 ⁇ 900 °C; (ii) feeding catalyst powder at the top of the reactor and fluidizing in the reactor; (iii) supplying a carbonaceous gas and a carrier gas through a rotary blade at the bottom of the reactor; And (iv) thermally vapor-depositing carbon on the catalyst powder fluidized by an upward air flow by the rotary blades.
  • step (d) recovering the multi-walled carbon nanotubes from the fluidized bed reactor may be further included.
  • the step (d) comprises the steps of: (i) transferring the multi-walled carbon nanotubes to a cyclone using nitrogen gas; And (ii) screening the multi-walled carbon nanotubes by removing impurities from the multi-walled carbon nanotubes in the cyclone.
  • the multi-walled carbon nanotubes may be aggregated to exist as a bundle-type carbon nanotubes.
  • the average bundle diameter of the bundle-type carbon nanotubes may be 0.5 ⁇ 20 ⁇ m
  • the average bundle length (bundle length) may be 10 ⁇ 200 ⁇ m.
  • the Raman spectral intensity ratio (I G / I D ) of the multi-walled carbon nanotubes may be 0.7 ⁇ 1.5.
  • the average diameter of the multi-walled carbon nanotubes may be 5 ⁇ 50nm.
  • the apparent density of the multi-walled carbon nanotubes may be 0.01 ⁇ 0.07g / mL.
  • FIG. 1 is an SEM image of a catalyst for preparing multi-walled carbon nanotubes according to an embodiment of the present invention.
  • FIG. 2 is an SEM image of a catalyst for preparing multi-walled carbon nanotubes according to a comparative example of the present invention.
  • One aspect of the invention (a) dissolving the metal precursor in a solvent to prepare a precursor solution; (b) pyrolysing the precursor solution while spraying into the reactor to form a catalyst powder; And (c) synthesizing the multi-walled carbon nanotubes from the catalyst powder by injecting the catalyst powder into a fluidized bed reactor heated to 600 to 900 ° C. and injecting a carbon gas and a carrier gas. Step a) to (c) is carried out continuously, the catalyst powder provides a method for producing a multi-walled carbon nanotubes comprising a metal component according to the following formula (1).
  • Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn and Cu
  • Mb is at least one metal selected from Mg, Al, Si and Zr
  • the step (a) it can be prepared a precursor solution of each metal element constituting the catalyst powder.
  • the metal precursor may be one selected from the group consisting of nitrates, sulfates, alkoxides, chlorides, acetates, carbonates, and mixtures of two or more thereof, but is not limited thereto.
  • the solvent may be a polar solvent, and water, methanol, ethanol, propanol, isopropanol, butanol, or a mixed solvent of two or more thereof may be used as the polar solvent, preferably, water, more Preferably, deionized water can be used.
  • the precursor solution may be pyrolyzed while being sprayed into the reactor to form a catalyst powder.
  • Step (b) may include: (i) spraying a precursor solution into the reactor by supplying air of 2 to 5 atmospheres as a carrier gas and introducing external air; And (ii) pyrolyzing the sprayed precursor solution at 600 to 1,200 ° C. to form a catalyst powder.
  • the precursor solution may be sprayed into the reactor and converted into finer droplets in order to control the particle diameter, the apparent density, etc. of the catalyst powder.
  • the pressure can be adjusted in the range of 2 to 5 atm.
  • the spray pressure is less than 2 atm, the particle size, apparent density, etc. of the catalyst powder may not be controlled within a predetermined range, thereby lowering the purity of the carbon nanotubes synthesized therethrough.
  • the spray pressure is more than 5 atm, the particle size of the droplets is excessively small, so that the catalysts obtained may aggregate with each other.
  • the droplet size can be more precisely controlled, and thus the particle size and apparent density of the catalyst powder can be precisely controlled.
  • droplets may be formed by spraying a gas simultaneously with spraying the precursor solution, or spray droplets may be formed by spraying a gas after spraying the precursor solution.
  • the method of preparing the catalyst powder may include spraying the gas into the reactor before the step (ii). It may further include.
  • gas air, nitrogen, argon or a mixed gas of two or more thereof may be used, and preferably air may be used.
  • electrostatic attraction may be added to the gas spray to improve the efficiency of the droplet formation.
  • the pressure of the spraying gas can be adjusted within the range of 2 to 5 atmospheres, and the effect of the case out of the above range is described above. It's like that.
  • the catalyst powder may be finally prepared by heating the droplet to evaporate the solvent and decomposing the precursor.
  • the temperature of the reactor may be 600 ⁇ 1,200 °C, preferably, 700 ⁇ 900 °C.
  • the temperature of the reactor is less than 600 °C, the dry state of the catalyst powder is poor, an additional process is required, which is disadvantageous in terms of economics, through which the purity or physical properties of the carbon nanotubes manufactured may be reduced.
  • the temperature of the reactor is more than 1,200 °C excessive cost to build equipment or equipment not only causes economic losses, but also the performance of the catalyst may be degraded due to the formation of solid solution or modification of the crystal structure.
  • the catalyst powder may be introduced into a fluidized bed reactor heated to 600 to 900 ° C., and a carbon-based gas and a carrier gas may be injected to synthesize multi-walled carbon nanotubes from the catalyst powder.
  • step (c) heating the fluidized bed reactor to 600 ⁇ 900 °C; (ii) feeding catalyst powder at the top of the reactor and fluidizing in the reactor; (iii) supplying a carbonaceous gas and a carrier gas through a rotary blade at the bottom of the reactor; And (iv) thermally vapor-depositing carbon on the catalyst powder fluidized by an upward air flow by the rotary blades.
  • the steps (a) to (c) may be carried out continuously, and in particular, the catalyst powder prepared by spray pyrolysis in the steps (a) to (b) may be carried out in a fluidized bed reactor for producing carbon nanotubes. Continuously added, a large amount of carbon nanotubes can be effectively produced.
  • the catalyst powder may be used in a gas phase synthesis method for synthesizing carbon nanotubes, wherein Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn, and Cu, and the Mb Is at least one metal selected from Mg, Al, Si and Zr, and therefore may include at least three or more metals, preferably three to five metal components.
  • the Ma is a catalyst component and an active ingredient in the catalyst powder, compared to the case of using a single metal component as the catalyst component and the active ingredient, by mixing two or more metal components during the carbon nanotube synthesis process Impurity can be suppressed to improve purity.
  • catalyst component refers to a substance that substantially lowers the chemical reaction energy of the substance, i.e., the main catalyst
  • active component refers to a substance that aids in the action of the catalyst component, i.e., a promoter. it means.
  • the catalyst component and the active component have a uniform distribution within a certain range, the synthesis yield of carbon nanotubes may be improved.
  • the mole fractions x and y of Ma and Mb may satisfy a relationship of 2.0 ⁇ x ⁇ 7.5 and 2.5 ⁇ y ⁇ 8.0, respectively. If x is less than 2.0, the activity of the catalyst and the resulting synthesis yield of carbon nanotubes may be reduced. If the content is greater than 7.5, the content of Mb, which is a support component, is relatively low, thus reducing the durability of the catalyst powder. There is a problem that is difficult to apply to the continuous fluidized bed chemical vapor deposition method for production.
  • the catalyst powder may have a hollow structure having a thickness of 0.5 to 10 ⁇ m, preferably 1 to 8 ⁇ m, and the hollow ratio may be 50% by volume or more.
  • the apparent density of the catalyst powder may be 0.05 ⁇ 0.70 g / mL.
  • the term “hollow structure” refers to a three-dimensional structure with an empty interior, for example, a spherical or polyhedral structure with an empty interior, wherein the hollow structure is a closed structure in which the entire hollow is closed. ), Some of the hollows may be interpreted to include an open structure, or a combination thereof.
  • the apparent density is higher than about 0.7 g / mL, making it difficult to apply to continuous fluidized bed chemical vapor deposition for mass production of carbon nanotubes, and only to the outer surface of the catalyst powder.
  • carbon nanotubes grow, there is a problem that it is difficult to improve the yield to a certain level or more.
  • the catalyst powder has a hollow structure
  • the apparent density is lower than that of the conventional catalyst powder, so that the catalyst powder can be applied to a continuous fluidized bed chemical vapor deposition method, and carbon nanotubes are directed outward from the outer surface of the hollow structure. Not only can it grow, it can also grow inward from the inner surface of the hollow structure can significantly improve the carbon nanotube synthesis yield.
  • the conversion rate of the carbon-based gas according to Equation 2 may be 80% or more.
  • Conversion rate (%) ⁇ (weight of multi-walled carbon nanotubes (g))-(weight of catalyst powder (g)) ⁇ / ⁇ (carbon-based gas supply (L)) * (of carbon in 1 mol of carbon-based gas) Weight (g / mol)) / (22.4 (L / mol)) ⁇ * 100
  • the carbon-based gas may be, for example, one selected from the group consisting of saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, carbon monoxide, benzene, and mixtures of two or more thereof, and preferably, may be ethylene gas. It is not limited to this.
  • the carrier gas may be, for example, one selected from the group consisting of helium, nitrogen, argon, and a mixture of two or more thereof, and preferably, nitrogen, but is not limited thereto.
  • Step (d) recovering the multi-walled carbon nanotubes from the fluidized bed reactor; may further include.
  • Step (d) may include: (i) transferring the multi-walled carbon nanotubes to a cyclone using nitrogen gas; And (ii) screening the multi-walled carbon nanotubes by removing impurities from the multi-walled carbon nanotubes in the cyclone.
  • cyclone refers to a device that separates impurities contained in a certain mixture, and when a mixture containing impurities flows in the tangential direction of the upper circumference of the conical device, a high-speed swirl flow occurs.
  • the impurity in the mixture impinges on the wall and is discharged and removed to the bottom of the apparatus while the kinetic energy is reduced, and the mixture from which the impurity is removed is discharged to the top.
  • the aggregated carbon nanotubes which is a kind of impurities, are discharged and removed to the lower end of the cyclone, and the purified multi-walled carbon nanotubes are discharged through the upper end of the cyclone to pass through the packaging device located at the rear end of the high purity. Uniform products can be produced.
  • the multi-walled carbon nanotubes may be aggregated to exist as bundle-type carbon nanotubes.
  • the bundle type carbon nanotubes may basically exist in a form in which a plurality of carbon nanotubes, preferably, a plurality of multi-walled carbon nanotubes are aggregated with each other.
  • Each carbon nanotube and the aggregate thereof may be straight, curved, or a mixture thereof.
  • An average bundle diameter of the bundled carbon nanotubes may be 0.5 to 20 ⁇ m, and an average bundle length may be 10 to 200 ⁇ m.
  • the Raman spectral intensity ratio (I G / I D ) of the multi-walled carbon nanotubes may be 0.7 ⁇ 1.5, the average diameter may be 5 ⁇ 50nm, the apparent density may be 0.01 ⁇ 0.07g / mL. .
  • the catalyst of Comparative Example 5 is the same in composition and composition as the catalyst of Example 5, but the catalyst is prepared by spray drying, and Example 5 is different from the method of preparing the catalyst. Specifically, in the case of Comparative Example 5 compared to the spray pyrolysis method of Example 5 to prepare a catalyst powder by spraying the precursor solution in the reactor at a temperature of 200 °C relatively low, 700 °C, 1 hour in an air atmosphere heat treatment furnace The solid catalyst powder of the solid shape was prepared by heat treatment for a while.
  • the catalysts of Comparative Examples 6 and 7 were prepared by the co-precipitation method and the combustion method, respectively, and they each had a plate shape as shown in FIG.
  • the catalyst of Comparative Example 8 is a catalyst prepared using alumina (Al 2 O 3 ) powder which is not dissolved in water as a precursor of Al in the catalyst component.
  • Carbon nanotubes were synthesized using the catalyst powder. Specifically, each catalyst powder was introduced into a fluidized bed chemical vapor deposition reactor having a diameter of 350 mm, and maintained at 700-800 ° C. in a nitrogen atmosphere. Thereafter, a mixture of nitrogen and ethylene was supplied at a rate of 150 L per minute for 40 minutes to synthesize carbon nanotubes grown on the respective catalyst powders.
  • the apparent density of the catalyst powder was obtained by measuring the weight by filling the catalyst powder in the mass cylinder, and dividing the measured weight by the volume of the mass cylinder.
  • the apparent density of the carbon nanotubes was measured in the same manner.
  • the synthesis yield of carbon nanotubes was calculated according to the formula "Weight of synthesized carbon nanotubes (g)] / [weight of injected catalyst powder (g)] * 100", and the conversion of ethylene was " ⁇ (multiple Weight of wall carbon nanotubes (g))-(weight of catalyst powder (g)) ⁇ / ⁇ (carbon-based gas supply (L)) * (weight of carbon in 1 mol of carbon-based gas (g / mol)) / (22.4 (L / mol)) ⁇ * 100 ".
  • the measurement results are shown in Table 2 below.
  • Example 1 0.180 1,264 85.7 0.015
  • Example 2 0.060 1,490 90.1 0.022
  • Example 3 0.516 1,400 89.7 0.020
  • Example 4 0.077 1,354 91.2 0.020
  • Example 5 0.072 1,437 93.5 0.022
  • Example 6 0.084 2,600 83.6 0.023
  • Example 7 0.090 1,392 91.4 0.015
  • Example 8 0.215 4,282 93.5 0.027
  • Example 10 0.662 4,030 95.6 0.034
  • Comparative Example 1 0.164 651 68.5 0.008
  • Comparative Example 2 0.470 967 78.6 0.029
  • Comparative Example 3 0.437 826 74.8 0.076 Comparative Example 4 0.906 0 0 - Comparative Example 5 0.815 763 72.3 0.053 Comparative Example 6 0.726 582
  • the catalysts of Comparative Examples 4, 5, 6, and 8 are difficult to float in the fluidized bed chemical vapor deposition method of synthesizing carbon nanotubes while floating the catalyst powder with the reaction gas with an apparent density of 0.70 g / mL or more. there is a problem.

Abstract

An embodiment of the present invention provides a method for manufacturing multi-wall carbon nanotubes, the method comprising the steps of: (a) dissolving a metal precursor in a solvent to prepare a precursor solution; (b) perform thermal decomposition while spraying the precursor solution into a reactor, thereby forming a catalyst powder; and (c) introducing the catalyst powder into a fluidized-bed reactor heated to 600-900°C and spraying a carbon-based gas and a carrier gas to synthesize multi-wall carbon nanotubes from the catalyst powder, wherein steps (a) to (c) are performed in a continuous type and wherein the catalyst powder contains metal components according to equation 1 below. <Equation 1> Ma:Mb = x:y, wherein Ma represents at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn, and Cu; Mb represents at least one metal selected from Mg, Al, Si, and Zr; x and y each represent the molar ratio of Ma and Mb; and x+y = 10, 2.0≤x≤7.5, and 2.5≤y≤8.0.

Description

연속식 공정을 이용한 다중벽 탄소나노튜브의 제조방법Method for manufacturing multi-walled carbon nanotubes using a continuous process
본 발명은 연속식 공정을 이용한 다중벽 탄소나노튜브의 제조방법에 관한 것이다.The present invention relates to a method for producing multi-walled carbon nanotubes using a continuous process.
탄소나노튜브(carbon nanotube)는 1개의 탄소 원자가 3개의 다른 탄소 원자와 결합한 육각형 벌집 모양의 튜브형 구조를 가지는 소재로서, 그 전기적, 열적, 기계적 특성이 타 소재에 비해 우수하여 다양한 산업 분야에 응용되고 있다.Carbon nanotube (carbon nanotube) is a hexagonal honeycomb tubular structure in which one carbon atom is bonded to three other carbon atoms, and its electrical, thermal, and mechanical properties are superior to other materials to be applied to various industrial fields. have.
이러한 탄소나노튜브는 일반적으로 전기방전법(arc-discharge), 열분해법(pyrolysis), 레이저 증착법(laser vaporization), 화학기상증착법(chemical vapor deposition), 플라즈마 화학기상증착법(plasma chemical vapor deposition), 열 화학기상증착법(thermal chemical vapor deposition), 기상합성법(chemical vapor condensation) 등의 다양한 방법에 의해 제조된다.Such carbon nanotubes are generally arc-discharge, pyrolysis, laser vaporization, chemical vapor deposition, plasma chemical vapor deposition, thermal It is prepared by various methods such as thermal chemical vapor deposition, chemical vapor condensation, and the like.
지금까지 다양한 금속 성분의 조합 및 물리적 특성을 가지는 탄소나노튜브 제조용 촉매가 개발되었으나, 대부분이 생산성 및 합성된 탄소나노튜브의 균일성이 낮은 고정층 화학기상증착 반응기를 기반으로 개발되어, 대량 생산 및 균일한 탄소나노튜브의 제조에 유리한 유동층 화학기상증착 반응기에는 적합하지 않은 문제가 있다.Until now, catalysts for carbon nanotube production have been developed that have various metal components and physical properties, but most of them have been developed based on a fixed bed chemical vapor deposition reactor having low productivity and uniformity of synthesized carbon nanotubes. There is a problem with fluidized bed chemical vapor deposition reactors that are advantageous for the production of carbon nanotubes.
또한, 촉매의 제조방법이 분무건조법(spray dry)으로서 200~350℃의 저온에서 이루어지며, 촉매 내부에 홀을 형성하기 위해서는 필수적으로 수용성 고분자를 조공제로 사용해야 하고, 촉매를 합성에 적합한 형태로 만들기 위해 350~1,100℃로 별도의 소성 과정을 거쳐야 하는 문제가 있으며, 이러한 분무건조법으로 제조된 촉매 분말은 높은 겉보기 밀도로 인해 유동층 반응기에는 적합하지 않은 문제가 있다.In addition, the production method of the catalyst is spray drying (spray dry) is made at a low temperature of 200 ~ 350 ℃, in order to form a hole in the catalyst, it is essential to use a water-soluble polymer as a pore-forming agent, making the catalyst in a form suitable for synthesis In order to have a separate firing process to 350 ~ 1,100 ℃, there is a problem, the catalyst powder prepared by the spray drying method is not suitable for the fluidized bed reactor due to the high apparent density.
본 발명은 전술한 종래 기술의 문제점을 해결하기 위한 것으로, 본 발명의 목적은 유동층 반응기에 최적화된 촉매 분말을 이용하여 탄소계 원료가스의 전환율 및 다중벽 탄소나노튜브의 수율을 향상시킴으로써 다중벽 탄소나노튜브를 대량으로 제조할 수 있는 방법을 제공하기 위한 것이다.The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to improve the conversion of the carbon-based raw material gas and the yield of the multi-walled carbon nanotubes by using the catalyst powder optimized for the fluidized bed reactor It is to provide a method for producing a large amount of nanotubes.
본 발명의 일 측면은, (a) 금속 전구체를 용매 중에 용해시켜 전구체 용액을 제조하는 단계; (b) 상기 전구체 용액을 반응기 내부로 분무하면서 열분해시켜 촉매 분말을 형성하는 단계; 및 (c) 상기 촉매 분말을 600~900℃로 가열된 유동층 반응기 내부로 투입하고 탄소계 가스와 운반 가스를 분사하여 상기 촉매 분말로부터 다중벽 탄소나노튜브를 합성하는 단계;를 포함하고, 상기 (a) 내지 (c) 단계가 연속식으로 수행되고, 상기 촉매 분말은 하기 식 1에 따른 금속 성분을 포함하는 다중벽 탄소나노튜브의 제조방법을 제공한다.One aspect of the invention, (a) dissolving the metal precursor in a solvent to prepare a precursor solution; (b) pyrolysing the precursor solution while spraying into the reactor to form a catalyst powder; And (c) synthesizing the multi-walled carbon nanotubes from the catalyst powder by injecting the catalyst powder into a fluidized bed reactor heated to 600 to 900 ° C. and injecting a carbon gas and a carrier gas. Step a) to (c) is carried out continuously, the catalyst powder provides a method for producing a multi-walled carbon nanotubes comprising a metal component according to the following formula (1).
<식 1><Equation 1>
Ma : Mb = x : yMa: Mb = x: y
상기 식에서, Ma는 Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn 및 Cu중에서 선택된 2종 이상의 금속이고, Mb는 Mg, Al, Si 및 Zr 중에서 선택된 1종 이상의 금속이고, x와 y는 각각 Ma와 Mb의 몰 분율을 나타내며, x+y=10, 2.0≤x≤7.5, 2.5≤y≤8.0 이다.Wherein Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn and Cu, Mb is at least one metal selected from Mg, Al, Si and Zr, x And y represent the mole fractions of Ma and Mb, respectively, x + y = 10, 2.0 ≦ x ≦ 7.5 and 2.5 ≦ y ≦ 8.0.
일 실시예에 있어서, 상기 촉매 분말은 두께가 0.5~10㎛ 인 중공 구조를 가질 수 있다.In one embodiment, the catalyst powder may have a hollow structure having a thickness of 0.5 ~ 10㎛.
일 실시예에 있어서, 상기 촉매 분말의 겉보기 밀도가 0.05~0.70g/mL일 수 있다.In one embodiment, the apparent density of the catalyst powder may be 0.05 ~ 0.70 g / mL.
일 실시예에 있어서, 상기 중공 구조의 중공 비율이 50부피% 이상일 수 있다.In one embodiment, the hollow ratio of the hollow structure may be more than 50% by volume.
일 실시예에 있어서, 하기 식 2에 따른 전환율이 80% 이상일 수 있다.In one embodiment, the conversion rate according to Equation 2 may be 80% or more.
<식 2><Equation 2>
전환율(%)={(다중벽 탄소나노튜브의 중량(g))-(촉매 분말의 중량(g))}/{(탄소계 가스 공급량(L))*(탄소계 가스 1몰 중 탄소의 중량(g/mol))/(22.4(L/mol))}*100Conversion rate (%) = {(weight of multi-walled carbon nanotubes (g))-(weight of catalyst powder (g))} / {(carbon-based gas supply (L)) * (of carbon in 1 mol of carbon-based gas) Weight (g / mol)) / (22.4 (L / mol))} * 100
일 실시예에 있어서, 상기 탄소계 가스가 탄소수 1~4의 포화 또는 불포화 탄화수소, 일산화탄소, 벤젠, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있다.In one embodiment, the carbon-based gas may be one selected from the group consisting of saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, carbon monoxide, benzene, and mixtures of two or more thereof.
일 실시예에 있어서, 상기 운반 가스가 헬륨, 질소, 아르곤, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있다.In one embodiment, the carrier gas may be one selected from the group consisting of helium, nitrogen, argon, and mixtures of two or more thereof.
일 실시예에 있어서, 상기 금속 전구체가 금속의 질산염, 황산염, 알콕사이드, 클로라이드, 아세테이트, 카보네이트, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있다.In one embodiment, the metal precursor may be one selected from the group consisting of nitrates, sulfates, alkoxides, chlorides, acetates, carbonates, and mixtures of two or more thereof.
일 실시예에 있어서, 상기 (b) 단계가, (i) 2~5기압의 공기를 운반 가스로 공급하고 외부 공기를 유입시켜 전구체 용액을 반응기 내부로 분무하는 단계; 및 (ii) 분무된 상기 전구체 용액을 600~1,200℃에서 열분해하여 촉매 분말을 형성하는 단계;를 포함할 수 있다.In one embodiment, the step (b) comprises the steps of (i) spraying the precursor solution into the reactor by supplying air of 2 to 5 atm as a carrier gas and introducing external air; And (ii) pyrolyzing the sprayed precursor solution at 600 to 1,200 ° C. to form a catalyst powder.
일 실시예에 있어서, 상기 (c) 단계가, (i) 유동층 반응기를 600~900℃로 가열하는 단계; (ii) 반응기 상부에서 촉매 분말을 공급하고 반응기 내에서 유동화시키는 단계; (iii) 탄소계 가스와 운반 가스를 반응기 하부에서 회전날개를 통해 공급하는 단계; 및 (iv) 상기 회전날개에 의한 상승 기류로 유동화된 상기 촉매 분말 상에 탄소를 열 기상증착시키는 단계;를 포함할 수 있다.In one embodiment, the step (c) comprises: (i) heating the fluidized bed reactor to 600 ~ 900 ℃; (ii) feeding catalyst powder at the top of the reactor and fluidizing in the reactor; (iii) supplying a carbonaceous gas and a carrier gas through a rotary blade at the bottom of the reactor; And (iv) thermally vapor-depositing carbon on the catalyst powder fluidized by an upward air flow by the rotary blades.
일 실시예에 있어서, 상기 (c) 단계 이후에, (d) 상기 다중벽 탄소나노튜브를 상기 유동층 반응기로부터 회수하는 단계;를 더 포함할 수 있다.In one embodiment, after the step (c), (d) recovering the multi-walled carbon nanotubes from the fluidized bed reactor may be further included.
일 실시예에 있어서, 상기 (d) 단계가, (i) 상기 다중벽 탄소나노튜브를 질소 가스를 이용하여 싸이클론으로 이송하는 단계; 및 (ii) 상기 싸이클론에서 상기 다중벽 탄소나노튜브 중 불순물을 제거하여 다중벽 탄소나노튜브를 선별하는 단계;를 포함할 수 있다.In one embodiment, the step (d) comprises the steps of: (i) transferring the multi-walled carbon nanotubes to a cyclone using nitrogen gas; And (ii) screening the multi-walled carbon nanotubes by removing impurities from the multi-walled carbon nanotubes in the cyclone.
일 실시예에 있어서, 상기 다중벽 탄소나노튜브가 응집되어 다발형 탄소나노튜브로 존재할 수 있다.In one embodiment, the multi-walled carbon nanotubes may be aggregated to exist as a bundle-type carbon nanotubes.
일 실시예에 있어서, 상기 다발형 탄소나노튜브의 평균 다발 직경(bundle diameter)이 0.5~20㎛이고, 평균 다발 길이(bundle length)가 10~200㎛일 수 있다.In one embodiment, the average bundle diameter of the bundle-type carbon nanotubes may be 0.5 ~ 20㎛, the average bundle length (bundle length) may be 10 ~ 200㎛.
일 실시예에 있어서, 상기 다중벽 탄소나노튜브의 라만 분광 강도비(IG/ID)가 0.7~1.5일 수 있다.In one embodiment, the Raman spectral intensity ratio (I G / I D ) of the multi-walled carbon nanotubes may be 0.7 ~ 1.5.
일 실시예에 있어서, 상기 다중벽 탄소나노튜브의 평균 직경이 5~50nm일 수 있다.In one embodiment, the average diameter of the multi-walled carbon nanotubes may be 5 ~ 50nm.
일 실시예에 있어서, 상기 다중벽 탄소나노튜브의 겉보기 밀도가 0.01~0.07g/mL일 수 있다.In one embodiment, the apparent density of the multi-walled carbon nanotubes may be 0.01 ~ 0.07g / mL.
본 발명의 일 측면에 따르면, 분무열분해 방법으로 유동층 반응기에 최적화된 촉매 분말을 제조하고 이를 이용하여 유동층 반응기에서 다중벽 탄소나노튜브를 연속적으로 제조함으로써, 80% 이상의 전환율을 얻을 수 있어 매우 경제적으로 다중벽 탄소나노튜브를 대량으로 생산할 수 있다.According to an aspect of the present invention, by preparing a catalyst powder optimized for a fluidized bed reactor by spray pyrolysis method and continuously producing multi-walled carbon nanotubes in a fluidized bed reactor, it is possible to obtain a conversion rate of more than 80% very economically Multi-walled carbon nanotubes can be produced in large quantities.
본 발명의 효과는 상기한 효과로 한정되는 것은 아니며, 본 발명의 상세한 설명 또는 청구범위에 기재된 발명의 구성으로부터 추론 가능한 모든 효과를 포함하는 것으로 이해되어야 한다.It is to be understood that the effects of the present invention are not limited to the above effects, and include all effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.
도 1은 본 발명의 일 실시예에 따른 다중벽 탄소나노튜브 제조용 촉매의 SEM 이미지이다.1 is an SEM image of a catalyst for preparing multi-walled carbon nanotubes according to an embodiment of the present invention.
도 2는 본 발명의 일 비교예에 따른 다중벽 탄소나노튜브 제조용 촉매의 SEM 이미지이다.2 is an SEM image of a catalyst for preparing multi-walled carbon nanotubes according to a comparative example of the present invention.
이하에서는 첨부한 도면을 참조하여 본 발명을 설명하기로 한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며, 따라서 여기에서 설명하는 실시예로 한정되는 것은 아니다. 그리고 도면에서 본 발명을 명확하게 설명하기 위해서 설명과 관계없는 부분은 생략하였으며, 명세서 전체를 통하여 유사한 부분에 대해서는 유사한 도면 부호를 붙였다.Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.
명세서 전체에서, 어떤 부분이 다른 부분과 "연결"되어 있다고 할 때, 이는 "직접적으로 연결"되어 있는 경우뿐 아니라, 그 중간에 다른 부재를 사이에 두고 "간접적으로 연결"되어 있는 경우도 포함한다. 또한 어떤 부분이 어떤 구성요소를 "포함"한다고 할 때, 이는 특별히 반대되는 기재가 없는 한 다른 구성요소를 제외하는 것이 아니라 다른 구성요소를 더 구비할 수 있다는 것을 의미한다.Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.
본 발명의 일 측면은, (a) 금속 전구체를 용매 중에 용해시켜 전구체 용액을 제조하는 단계; (b) 상기 전구체 용액을 반응기 내부로 분무하면서 열분해시켜 촉매 분말을 형성하는 단계; 및 (c) 상기 촉매 분말을 600~900℃로 가열된 유동층 반응기 내부로 투입하고 탄소계 가스와 운반 가스를 분사하여 상기 촉매 분말로부터 다중벽 탄소나노튜브를 합성하는 단계;를 포함하고, 상기 (a) 내지 (c) 단계가 연속식으로 수행되고, 상기 촉매 분말은 하기 식 1에 따른 금속 성분을 포함하는 다중벽 탄소나노튜브의 제조방법을 제공한다.One aspect of the invention, (a) dissolving the metal precursor in a solvent to prepare a precursor solution; (b) pyrolysing the precursor solution while spraying into the reactor to form a catalyst powder; And (c) synthesizing the multi-walled carbon nanotubes from the catalyst powder by injecting the catalyst powder into a fluidized bed reactor heated to 600 to 900 ° C. and injecting a carbon gas and a carrier gas. Step a) to (c) is carried out continuously, the catalyst powder provides a method for producing a multi-walled carbon nanotubes comprising a metal component according to the following formula (1).
<식 1><Equation 1>
Ma : Mb = x : yMa: Mb = x: y
상기 식에서, Ma는 Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn 및 Cu중에서 선택된 2종 이상의 금속이고, Mb는 Mg, Al, Si 및 Zr 중에서 선택된 1종 이상의 금속이고, x와 y는 각각 Ma와 Mb의 몰 분율을 나타내며, x+y=10, 2.0≤x≤7.5, 2.5≤y≤8.0 이다.Wherein Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn and Cu, Mb is at least one metal selected from Mg, Al, Si and Zr, x And y represent the mole fractions of Ma and Mb, respectively, x + y = 10, 2.0 ≦ x ≦ 7.5 and 2.5 ≦ y ≦ 8.0.
상기 (a) 단계에서 상기 촉매 분말을 이루는 각각의 금속 원소의 전구체 용액을 제조할 수 있다. 상기 금속 전구체는 금속의 질산염, 황산염, 알콕사이드, 클로라이드, 아세테이트, 카보네이트, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있으나, 이에 한정되는 것은 아니다.In the step (a) it can be prepared a precursor solution of each metal element constituting the catalyst powder. The metal precursor may be one selected from the group consisting of nitrates, sulfates, alkoxides, chlorides, acetates, carbonates, and mixtures of two or more thereof, but is not limited thereto.
상기 (a) 단계에서 상기 용매는 극성 용매일 수 있고, 상기 극성 용매로 물, 메탄올, 에탄올, 프로판올, 이소프로판올, 부탄올, 또는 이들 중 2 이상의 혼합 용매를 사용할 수 있으며, 바람직하게는, 물, 더 바람직하게는, 탈이온수를 사용할 수 있다.In the step (a), the solvent may be a polar solvent, and water, methanol, ethanol, propanol, isopropanol, butanol, or a mixed solvent of two or more thereof may be used as the polar solvent, preferably, water, more Preferably, deionized water can be used.
상기 전구체 용액의 제조를 위해 각 전구체를 용해시킬 때, 탈이온수를 용매로 사용하면 전구체 용액 내 불순물을 최소화할 수 있고, 이에 따라 최종적으로 제조되는 촉매 분말의 순도를 향상시킬 수 있다. 상기 촉매 분말의 순도 향상은 결과적으로 탄소나노튜브의 순도 향상을 의미할 수 있다.When dissolving each precursor for the preparation of the precursor solution, using deionized water as a solvent can minimize impurities in the precursor solution, thereby improving the purity of the catalyst powder finally prepared. Improved purity of the catalyst powder may mean improved purity of the carbon nanotubes as a result.
상기 (b) 단계에서 상기 전구체 용액을 반응기 내부로 분무하면서 열분해시켜 촉매 분말을 형성할 수 있다. 상기 (b) 단계는, (i) 2~5기압의 공기를 운반 가스로 공급하고 외부 공기를 유입시켜 전구체 용액을 반응기 내부로 분무하는 단계; 및 (ii) 분무된 상기 전구체 용액을 600~1,200℃에서 열분해하여 촉매 분말을 형성하는 단계;를 포함할 수 있다.In the step (b), the precursor solution may be pyrolyzed while being sprayed into the reactor to form a catalyst powder. Step (b) may include: (i) spraying a precursor solution into the reactor by supplying air of 2 to 5 atmospheres as a carrier gas and introducing external air; And (ii) pyrolyzing the sprayed precursor solution at 600 to 1,200 ° C. to form a catalyst powder.
상기 (i) 단계에서는 촉매 분말의 입경, 겉보기 밀도 등을 제어하기 위해 상기 전구체 용액을 반응기 내부로 분무하여 보다 미세한 액적(droplet)으로 변환시킬 수 있다.In the step (i), the precursor solution may be sprayed into the reactor and converted into finer droplets in order to control the particle diameter, the apparent density, etc. of the catalyst powder.
상기 전구체 용액의 분무 시, 그 압력은 2~5기압의 범위 내로 조절할 수 있다. 상기 분무 압력이 2기압 미만이면 촉매 분말의 입경, 겉보기 밀도 등이 일정 범위 내로 조절되지 않아 이를 통해 합성되는 탄소나노튜브의 순도가 저하될 수 있다. 반면, 상기 분무 압력이 5기압 초과이면 액적의 입도가 과도하게 작아져 수득된 촉매가 상호 응집될 수 있다.When spraying the precursor solution, the pressure can be adjusted in the range of 2 to 5 atm. When the spray pressure is less than 2 atm, the particle size, apparent density, etc. of the catalyst powder may not be controlled within a predetermined range, thereby lowering the purity of the carbon nanotubes synthesized therethrough. On the other hand, when the spray pressure is more than 5 atm, the particle size of the droplets is excessively small, so that the catalysts obtained may aggregate with each other.
상기 전구체 용액의 표면장력을 극복하고 관성력(inertia force)을 효율적으로 용액에 전달할수록 액적의 크기를 보다 세밀하게 제어할 수 있고, 이를 통해 촉매 분말의 입경, 겉보기 밀도 등을 정밀하게 제어할 수 있다.As the surface tension of the precursor solution is overcome and the inertia force is efficiently transferred to the solution, the droplet size can be more precisely controlled, and thus the particle size and apparent density of the catalyst powder can be precisely controlled. .
이에 따라, 상기 전구체 용액의 분무와 동시에 가스를 분사하여 액적을 형성시킬 수 있고, 상기 전구체 용액의 분무 이후에 가스를 분사하여 액적을 형성시킬 수도 있다.Accordingly, droplets may be formed by spraying a gas simultaneously with spraying the precursor solution, or spray droplets may be formed by spraying a gas after spraying the precursor solution.
다만, 전구체 용액과 가스의 분무를 순차적으로 수행하는 경우 액적의 크기를 보다 세밀하게 제어할 수 있으므로, 상기 촉매 분말의 제조방법이 상기 (ii) 단계 이전에 상기 반응기 내부로 가스를 분무하는 단계를 더 포함할 수 있다.However, when the spraying of the precursor solution and the gas is sequentially performed, the size of the droplet may be more precisely controlled. Thus, the method of preparing the catalyst powder may include spraying the gas into the reactor before the step (ii). It may further include.
이 때, 상기 가스로는 공기, 질소, 아르곤 또는 이들 중 2 이상의 혼합 가스를 사용할 수 있고, 바람직하게는 공기를 사용할 수 있다. 또한, 상기 액적 형성의 효율성을 향상시키기 위해 상기 가스 분무에 추가로 정전기적 인력을 가할 수도 있다.In this case, as the gas, air, nitrogen, argon or a mixed gas of two or more thereof may be used, and preferably air may be used. In addition, electrostatic attraction may be added to the gas spray to improve the efficiency of the droplet formation.
상기 전구체 용액을 분무한 후 가스를 추가로 분무하는 경우에 있어서, 동시에 분무하는 경우와 마찬가지로 분무 가스의 압력을 2~5기압의 범위 내로 조절할 수 있고, 상기 범위를 벗어난 경우의 영향에 관해서는 전술한 것과 같다.In the case of further spraying the gas after spraying the precursor solution, as in the case of spraying at the same time, the pressure of the spraying gas can be adjusted within the range of 2 to 5 atmospheres, and the effect of the case out of the above range is described above. It's like that.
상기 (ii) 단계에서는 상기 액적을 가열하여 용매를 증발시키고 전구체를 분해함으로써 최종적으로 촉매 분말을 제조할 수 있다. 이 때, 상기 반응기의 온도가 600~1,200℃, 바람직하게는, 700~900℃일 수 있다.In the step (ii), the catalyst powder may be finally prepared by heating the droplet to evaporate the solvent and decomposing the precursor. At this time, the temperature of the reactor may be 600 ~ 1,200 ℃, preferably, 700 ~ 900 ℃.
상기 반응기의 온도가 600℃ 미만이면 촉매 분말의 건조 상태가 불량하여 추가적인 공정이 필요하여 경제성 측면에서 불리하고, 이를 통해 제조되는 탄소나노튜브의 순도나 물성이 저하될 수 있다. 또한, 상기 반응기의 온도가 1,200℃ 초과이면 장비 또는 설비 구축에 과다한 비용이 소요되어 경제적 손실을 초래할 뿐만 아니라 고용체 형성이나 결정 구조의 변형으로 촉매 성능이 저하될 수 있다.When the temperature of the reactor is less than 600 ℃, the dry state of the catalyst powder is poor, an additional process is required, which is disadvantageous in terms of economics, through which the purity or physical properties of the carbon nanotubes manufactured may be reduced. In addition, if the temperature of the reactor is more than 1,200 ℃ excessive cost to build equipment or equipment not only causes economic losses, but also the performance of the catalyst may be degraded due to the formation of solid solution or modification of the crystal structure.
상기 (c) 단계에서 상기 촉매 분말을 600~900℃로 가열된 유동층 반응기 내부로 투입하고 탄소계 가스와 운반 가스를 분사하여 상기 촉매 분말로부터 다중벽 탄소나노튜브를 합성할 수 있다.In the step (c), the catalyst powder may be introduced into a fluidized bed reactor heated to 600 to 900 ° C., and a carbon-based gas and a carrier gas may be injected to synthesize multi-walled carbon nanotubes from the catalyst powder.
구체적으로, 상기 (c) 단계는, (i) 유동층 반응기를 600~900℃로 가열하는 단계; (ii) 반응기 상부에서 촉매 분말을 공급하고 반응기 내에서 유동화시키는 단계; (iii) 탄소계 가스와 운반 가스를 반응기 하부에서 회전날개를 통해 공급하는 단계; 및 (iv) 상기 회전날개에 의한 상승 기류로 유동화된 상기 촉매 분말 상에 탄소를 열 기상증착시키는 단계;를 포함할 수 있다.Specifically, the step (c), (i) heating the fluidized bed reactor to 600 ~ 900 ℃; (ii) feeding catalyst powder at the top of the reactor and fluidizing in the reactor; (iii) supplying a carbonaceous gas and a carrier gas through a rotary blade at the bottom of the reactor; And (iv) thermally vapor-depositing carbon on the catalyst powder fluidized by an upward air flow by the rotary blades.
상기 (a) 내지 (c) 단계는 연속식으로 수행될 수 있고, 특히, 상기 (a) 내지 (b) 단계에서 분무열분해법에 의해 제조된 촉매 분말이 탄소나노튜브를 제조하기 위한 유동층 반응기에 연속적으로 투입되어 대량의 탄소나노튜브를 효과적으로 제조할 수 있다.The steps (a) to (c) may be carried out continuously, and in particular, the catalyst powder prepared by spray pyrolysis in the steps (a) to (b) may be carried out in a fluidized bed reactor for producing carbon nanotubes. Continuously added, a large amount of carbon nanotubes can be effectively produced.
상기 촉매 분말은 탄소나노튜브를 합성하기 위한 기상합성법에 사용될 수 있고, 상기 Ma가 Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn 및 Cu중에서 선택된 2종 이상의 금속이고, 상기 Mb가 Mg, Al, Si 및 Zr 중에서 선택된 1종 이상의 금속이므로, 적어도 3종 이상의 금속, 바람직하게는, 3종 내지 5종의 금속 성분을 포함할 수 있다.The catalyst powder may be used in a gas phase synthesis method for synthesizing carbon nanotubes, wherein Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn, and Cu, and the Mb Is at least one metal selected from Mg, Al, Si and Zr, and therefore may include at least three or more metals, preferably three to five metal components.
특히, 상기 Ma는 상기 촉매 분말에서 촉매 성분 및 활성 성분이며, 상기 촉매 성분 및 활성 성분으로 단일의 금속 성분을 사용하는 경우에 비해, 2종 이상의 금속 성분을 혼합하여 사용함으로써 탄소나노튜브 합성과정 중 불순물 생성을 억제하여 순도를 향상시킬 수 있다.In particular, the Ma is a catalyst component and an active ingredient in the catalyst powder, compared to the case of using a single metal component as the catalyst component and the active ingredient, by mixing two or more metal components during the carbon nanotube synthesis process Impurity can be suppressed to improve purity.
본 명세서에서 사용된 용어, "촉매 성분"은 물질의 화학반응 에너지를 근본적으로 낮추는 물질, 즉 주촉매를 의미하고, "활성 성분"은 상기 촉매 성분의 작용을 보조하는 물질, 즉, 조촉매를 의미한다. 상기 촉매 성분과 활성 성분이 일정 범위 내에서 균일한 분포를 이루고 있는 경우 탄소나노튜브의 합성수율이 향상될 수 있다.As used herein, the term "catalyst component" refers to a substance that substantially lowers the chemical reaction energy of the substance, i.e., the main catalyst, and "active component" refers to a substance that aids in the action of the catalyst component, i.e., a promoter. it means. When the catalyst component and the active component have a uniform distribution within a certain range, the synthesis yield of carbon nanotubes may be improved.
상기 Ma 및 Mb의 몰 분율 x, y는 각각 2.0≤x≤7.5, 2.5≤y≤8.0인 관계를 만족할 수 있다. 상기 x가 2.0 미만이면 촉매의 활성과 그에 따른 탄소나노튜브의 합성수율이 저하될 수 있고, 7.5 초과이면 지지체 성분인 Mb의 함량이 상대적으로 적어 촉매 분말의 내구성이 저하됨에 따라 탄소나노튜브의 대량생산을 위한 연속식 유동층 화학기상증착 방식에 적용하기 어려운 문제가 있다.The mole fractions x and y of Ma and Mb may satisfy a relationship of 2.0 ≦ x ≦ 7.5 and 2.5 ≦ y ≦ 8.0, respectively. If x is less than 2.0, the activity of the catalyst and the resulting synthesis yield of carbon nanotubes may be reduced. If the content is greater than 7.5, the content of Mb, which is a support component, is relatively low, thus reducing the durability of the catalyst powder. There is a problem that is difficult to apply to the continuous fluidized bed chemical vapor deposition method for production.
상기 촉매 분말은 두께가 0.5~10㎛, 바람직하게는, 1~8㎛인 중공 구조를 가질 수 있고, 상기 중공 비율이 50부피% 이상일 수 있다. 또한, 상기 촉매 분말의 겉보기 밀도는 0.05~0.70g/mL일 수 있다.The catalyst powder may have a hollow structure having a thickness of 0.5 to 10 μm, preferably 1 to 8 μm, and the hollow ratio may be 50% by volume or more. In addition, the apparent density of the catalyst powder may be 0.05 ~ 0.70 g / mL.
본 명세서에 사용된 용어, "중공 구조"는 내부가 비어 있는 입체 구조, 예를 들어, 내부가 비어 있는 구형 또는 다면체형 구조를 의미하고, 상기 중공 구조는 중공이 전부 밀폐된 닫힌 구조(closed structrure), 중공 중 일부가 개방된 열린 구조(open structure), 또는 이들의 조합을 포함하는 것으로 해석될 수 있다.As used herein, the term “hollow structure” refers to a three-dimensional structure with an empty interior, for example, a spherical or polyhedral structure with an empty interior, wherein the hollow structure is a closed structure in which the entire hollow is closed. ), Some of the hollows may be interpreted to include an open structure, or a combination thereof.
종래 사용된 속이 꽉 찬 구형의 촉매 분말의 경우, 겉보기 밀도가 약 0.7g/mL 초과로 높아 탄소나노튜브의 대량생산을 위한 연속식 유동층 화학기상증착 방식에 적용하기 어렵고, 촉매 분말의 외표면에만 탄소나노튜브가 성장하여 수율을 일정 수준 이상으로 개선하기 어려운 문제가 있다.In the case of the conventionally used solid catalyst powder, the apparent density is higher than about 0.7 g / mL, making it difficult to apply to continuous fluidized bed chemical vapor deposition for mass production of carbon nanotubes, and only to the outer surface of the catalyst powder. As carbon nanotubes grow, there is a problem that it is difficult to improve the yield to a certain level or more.
이에 대해, 상기 촉매 분말은 중공 구조를 가지므로, 종래의 촉매 분말에 비해 겉보기 밀도가 낮아 연속식 유동층 화학기상증착 방식에 적용될 수 있고, 탄소나노튜브가 상기 중공 구조의 외표면으로부터 바깥쪽 방향으로 성장할 수 있을 뿐만 아니라, 상기 중공 구조의 내표면으로부터 안쪽 방향으로도 성장할 수 있어 탄소나노튜브 합성수율을 현저히 개선할 수 있다.On the other hand, since the catalyst powder has a hollow structure, the apparent density is lower than that of the conventional catalyst powder, so that the catalyst powder can be applied to a continuous fluidized bed chemical vapor deposition method, and carbon nanotubes are directed outward from the outer surface of the hollow structure. Not only can it grow, it can also grow inward from the inner surface of the hollow structure can significantly improve the carbon nanotube synthesis yield.
구체적으로, 하기 식 2에 따른 탄소계 가스의 전환율이 80% 이상일 수 있다.Specifically, the conversion rate of the carbon-based gas according to Equation 2 may be 80% or more.
<식 2><Equation 2>
전환율(%)={(다중벽 탄소나노튜브의 중량(g))-(촉매 분말의 중량(g))}/{(탄소계 가스 공급량(L))*(탄소계 가스 1몰 중 탄소의 중량(g/mol))/(22.4(L/mol))}*100Conversion rate (%) = {(weight of multi-walled carbon nanotubes (g))-(weight of catalyst powder (g))} / {(carbon-based gas supply (L)) * (of carbon in 1 mol of carbon-based gas) Weight (g / mol)) / (22.4 (L / mol))} * 100
상기 탄소계 가스는, 예를 들어, 탄소수 1~4의 포화 또는 불포화 탄화수소, 일산화탄소, 벤젠, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있고, 바람직하게는, 에틸렌 가스일 수 있으나, 이에 한정되는 것은 아니다. 또한, 상기 운반 가스는, 예를 들어, 헬륨, 질소, 아르곤, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나일 수 있고, 바람직하게는, 질소일 수 있으나, 이에 한정되는 것은 아니다.The carbon-based gas may be, for example, one selected from the group consisting of saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, carbon monoxide, benzene, and mixtures of two or more thereof, and preferably, may be ethylene gas. It is not limited to this. In addition, the carrier gas may be, for example, one selected from the group consisting of helium, nitrogen, argon, and a mixture of two or more thereof, and preferably, nitrogen, but is not limited thereto.
상기 (c) 단계 이후에, (d) 상기 다중벽 탄소나노튜브를 상기 유동층 반응기로부터 회수하는 단계;를 더 포함할 수 있다. 상기 (d) 단계가, (i) 상기 다중벽 탄소나노튜브를 질소 가스를 이용하여 싸이클론으로 이송하는 단계; 및 (ii) 상기 싸이클론에서 상기 다중벽 탄소나노튜브 중 불순물을 제거하여 다중벽 탄소나노튜브를 선별하는 단계;를 포함할 수 있다.After the step (c), (d) recovering the multi-walled carbon nanotubes from the fluidized bed reactor; may further include. Step (d) may include: (i) transferring the multi-walled carbon nanotubes to a cyclone using nitrogen gas; And (ii) screening the multi-walled carbon nanotubes by removing impurities from the multi-walled carbon nanotubes in the cyclone.
본 명세서에서 사용된 용어, "싸이클론"은 일정 혼합물 내에 함유된 불순물을 분리시키는 장치를 의미하는 것으로, 불순물이 함유된 혼합물을 원추형 장치의 상단 원둘레의 접선 방향으로 유입시키면 고속의 선회류가 발생되고, 상기 혼합물 중 불순물이 벽에 충돌하여 운동 에너지가 감소하면서 장치의 하단부로 배출 및 제거되며, 불순물이 제거된 혼합물은 상단부로 배출되는 원리를 이용한다. 즉, 불순물의 일종인 응집된 탄소나노튜브는 상기 싸이클론의 하단부로 배출 및 제거되고, 정제된 다중벽 탄소나노튜브는 상기 싸이클론의 상단부를 통해 배출됨으로써 그 후단에 위치한 포장장치를 거쳐 고순도의 균일한 제품이 생산될 수 있다.As used herein, the term "cyclone" refers to a device that separates impurities contained in a certain mixture, and when a mixture containing impurities flows in the tangential direction of the upper circumference of the conical device, a high-speed swirl flow occurs. The impurity in the mixture impinges on the wall and is discharged and removed to the bottom of the apparatus while the kinetic energy is reduced, and the mixture from which the impurity is removed is discharged to the top. That is, the aggregated carbon nanotubes, which is a kind of impurities, are discharged and removed to the lower end of the cyclone, and the purified multi-walled carbon nanotubes are discharged through the upper end of the cyclone to pass through the packaging device located at the rear end of the high purity. Uniform products can be produced.
상기 다중벽 탄소나노튜브는 응집되어 다발형 탄소나노튜브로 존재할 수 있다. 상기 다발형 탄소나노튜브는 기본적으로 복수의 탄소나노튜브, 바람직하게는, 복수의 다중벽 탄소나노튜브가 상호 응집된 형태로 존재할 수 있다. 각각의 탄소나노튜브 및 그 집합체는 직선형, 곡선형, 또는 이들이 혼합된 형태일 수 있다.The multi-walled carbon nanotubes may be aggregated to exist as bundle-type carbon nanotubes. The bundle type carbon nanotubes may basically exist in a form in which a plurality of carbon nanotubes, preferably, a plurality of multi-walled carbon nanotubes are aggregated with each other. Each carbon nanotube and the aggregate thereof may be straight, curved, or a mixture thereof.
상기 다발형 탄소나노튜브의 평균 다발 직경(bundle diameter)이 0.5~20㎛이고, 평균 다발 길이(bundle length)가 10~200㎛일 수 있다. 또한, 상기 다중벽 탄소나노튜브의 라만 분광 강도비(IG/ID)가 0.7~1.5일 수 있고, 평균 직경은 5~50nm일 수 있으며, 겉보기 밀도는 0.01~0.07g/mL일 수 있다.An average bundle diameter of the bundled carbon nanotubes may be 0.5 to 20 μm, and an average bundle length may be 10 to 200 μm. In addition, the Raman spectral intensity ratio (I G / I D ) of the multi-walled carbon nanotubes may be 0.7 ~ 1.5, the average diameter may be 5 ~ 50nm, the apparent density may be 0.01 ~ 0.07g / mL. .
이하, 본 발명의 실시예를 상세히 설명하기로 한다.Hereinafter, embodiments of the present invention will be described in detail.
실시예Example
Fe(NO3)3·9H2O, Co(NO3)3·6H2O, (NH4)6Mo7O24·4H2O, NH4VO3, (NH4)10H2(W2O7)6·9H2O, Al(NO3)3·9H2O, Mg(NO3)2·6H2O 및 ZrO(NO3)2·2H2O 중 하기 표 1의 촉매 조성에 필요한 각각의 전구체를 탈이온수에 용해시켜 전구체 용액을 제조하였다. 상기 전구체 용액을 시간 당 3L씩 공기와 함께 반응기 내부로 분무하여 열분해함으로써 촉매 분말을 수득하였다. 이 때, 열분해 조건은 공기의 압력은 3기압, 반응기 내부 온도는 750℃이고, 120분 동안 연속적으로 운전하였다.Fe (NO 3 ) 3 · 9H 2 O, Co (NO 3 ) 3 · 6H 2 O, (NH 4 ) 6 Mo 7 O 24 · 4H 2 O, NH 4 VO 3 , (NH 4 ) 10 H 2 (W 2 0 7 ) 6 · 9H 2 O, Al (NO 3 ) 3 · 9H 2 O, Mg (NO 3 ) 2 · 6H 2 O and ZrO (NO 3 ) 2 · 2H 2 O in the catalyst composition of Table 1 below. Each required precursor was dissolved in deionized water to prepare a precursor solution. The precursor solution was pyrolyzed by spraying 3L per hour with air into the reactor to obtain a catalyst powder. At this time, the pyrolysis condition was that the air pressure is 3 atm, the reactor internal temperature is 750 ℃, and operated continuously for 120 minutes.
구분division 촉매조성Catalyst composition Ma (몰 수)Ma (number of moles) Mb (몰 수)Mb (number of moles) Ma 합계Ma total Mb 합계Mb total x(몰 분율)x (mole fraction) y(몰 분율)y (mole fraction)
FeFe CoCo MoMo VV WW AlAl MgMg ZrZr
실시예 1Example 1 Fe/Al/MgFe / Al / Mg 71.671.6 -- -- -- -- 148.2148.2 82.382.3 -- 71.671.6 230.5230.5 2.372.37 7.637.63
실시예 2Example 2 Fe/Mo/Al/MgFe / Mo / Al / Mg 88.688.6 -- 5.25.2 -- -- 183.5183.5 4.14.1 -- 93.893.8 187.6187.6 3.333.33 6.676.67
실시예 3Example 3 Co/V/Al/MgCo / V / Al / Mg -- 118.8118.8 -- 9.89.8 -- 148.2148.2 41.141.1 -- 128.6128.6 189.4189.4 4.044.04 5.965.96
실시예 4Example 4 Fe/Co/Mo/AlFe / Co / Mo / Al 47.047.0 14.814.8 5.25.2 -- -- 185.3185.3 -- -- 67.167.1 185.3185.3 2.662.66 7.347.34
실시예 5Example 5 Fe/Co/Mo/AlFe / Co / Mo / Al 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 -- -- 93.693.6 185.3185.3 3.363.36 6.646.64
실시예 6Example 6 Fe/Co/Mo/AlFe / Co / Mo / Al 94.094.0 29.729.7 5.25.2 -- -- 185.3185.3 -- -- 128.9128.9 185.3185.3 4.104.10 5.905.90
실시예 7Example 7 Fe/Co/Mo/Al/MgFe / Co / Mo / Al / Mg 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 4.14.1 -- 93.693.6 189.4189.4 3.313.31 6.696.69
실시예 8Example 8 Fe/Co/Mo/V/AlFe / Co / Mo / V / Al 134.3134.3 42.442.4 5.25.2 0.60.6 -- 185.3185.3 -- -- 182.5182.5 185.3185.3 4.964.96 5.045.04
실시예 9Example 9 Co/V/W/AlCo / V / W / Al -- 118.8118.8 -- 9.89.8 8.28.2 148.2148.2 -- -- 136.8136.8 148.2148.2 4.804.80 5.205.20
실시예 10Example 10 Co/V/Al/ZrCo / V / Al / Zr -- 237.6237.6 -- 17.717.7 -- 74.174.1 -- 21.921.9 255.2255.2 96.096.0 7.277.27 2.732.73
비교예 1Comparative Example 1 Fe/Al/MgFe / Al / Mg 53.753.7 -- -- -- -- 148.2148.2 82.382.3 -- 53.753.7 230.5230.5 1.891.89 8.118.11
비교예 2Comparative Example 2 Fe/Co/Mo/AlFe / Co / Mo / Al 143.2143.2 67.967.9 20.820.8 -- -- 74.174.1 -- -- 231.9231.9 74.174.1 7.587.58 2.422.42
비교예 3Comparative Example 3 Fe/Co/MoFe / Co / Mo 67.167.1 21.221.2 5.25.2 -- -- -- -- -- 93.693.6 0.00.0 10.0010.00 0.000.00
비교예 4Comparative Example 4 Al/MgAl / Mg -- -- -- -- -- 74.174.1 41.141.1 -- 0.00.0 115.3115.3 0.000.00 10.0010.00
비교예 5Comparative Example 5 Fe/Co/Mo/AlFe / Co / Mo / Al 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 -- -- 93.693.6 185.3185.3 3.363.36 6.646.64
비교예 6Comparative Example 6 Fe/Co/Mo/AlFe / Co / Mo / Al 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 -- -- 93.693.6 185.3185.3 3.363.36 6.646.64
비교예 7Comparative Example 7 Fe/Co/Mo/AlFe / Co / Mo / Al 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 -- -- 93.693.6 185.3185.3 3.363.36 6.646.64
비교예 8Comparative Example 8 Fe/Co/Mo/AlFe / Co / Mo / Al 67.167.1 21.221.2 5.25.2 -- -- 185.3185.3 -- -- 93.693.6 185.3185.3 3.363.36 6.646.64
비교예 5의 촉매는 실시예 5의 촉매와 성분 및 조성은 동일하지만 촉매를 분무건조법으로 제조한 것으로서, 실시예 5와 촉매의 제조방법이 상이하다. 구체적으로, 비교예 5의 경우 실시예 5의 분무열분해법에 비해 상대적으로 매우 낮은 200℃ 온도의 반응기 내부에 전구체 용액을 분무하여 촉매 분말을 제조한 후 700℃, 공기 분위기의 열처리로에서 1시간 동안 열처리하여 속이 꽉 찬 구형의 촉매 분말을 제조하였다.비교예 6, 7의 촉매는 각각 공침법과 연소법으로 제조된 것으로서, 이들은 각각 도 2와 같은 판상을 가진다. 비교예 8의 촉매는 촉매 성분 중 Al의 전구체로 물에 전혀 녹지 않는 알루미나(Al2O3) 분말을 사용하여 제조한 촉매이다.The catalyst of Comparative Example 5 is the same in composition and composition as the catalyst of Example 5, but the catalyst is prepared by spray drying, and Example 5 is different from the method of preparing the catalyst. Specifically, in the case of Comparative Example 5 compared to the spray pyrolysis method of Example 5 to prepare a catalyst powder by spraying the precursor solution in the reactor at a temperature of 200 ℃ relatively low, 700 ℃, 1 hour in an air atmosphere heat treatment furnace The solid catalyst powder of the solid shape was prepared by heat treatment for a while. The catalysts of Comparative Examples 6 and 7 were prepared by the co-precipitation method and the combustion method, respectively, and they each had a plate shape as shown in FIG. The catalyst of Comparative Example 8 is a catalyst prepared using alumina (Al 2 O 3 ) powder which is not dissolved in water as a precursor of Al in the catalyst component.
상기 촉매 분말을 이용하여 탄소나노튜브의 합성을 진행하였다. 구체적으로, 각각의 촉매 분말을 직경 350mm의 유동층 화학기상증착 반응기에 투입하고, 질소 분위기에서 700~800℃까지 승온하여 유지시켰다. 이후, 질소 및 에틸렌이 혼합된 가스를 분 당 150L의 속도로 공급하면서 40분 동안 반응시켜 각각의 촉매 분말에 성장된 탄소나노튜브를 합성하였다.Carbon nanotubes were synthesized using the catalyst powder. Specifically, each catalyst powder was introduced into a fluidized bed chemical vapor deposition reactor having a diameter of 350 mm, and maintained at 700-800 ° C. in a nitrogen atmosphere. Thereafter, a mixture of nitrogen and ethylene was supplied at a rate of 150 L per minute for 40 minutes to synthesize carbon nanotubes grown on the respective catalyst powders.
실험예Experimental Example
상기 촉매 분말의 겉보기 밀도는 매스실린더에 촉매 분말을 충진하여 무게를 측정한 후, 측정된 무게를 매스실린더의 부피로 나누어 산출하였고, 이와 동일한 방법으로 탄소나노튜브의 겉보기 밀도를 측정하였다. 또한, 탄소나노튜브의 합성 수율은 "합성된 탄소나노튜브의 무게 (g)]/[투입된 촉매분말의 무게 (g)]*100" 의 식에 따라 계산하였으며, 에틸렌의 전환율은 "{(다중벽 탄소나노튜브의 중량(g))-(촉매 분말의 중량(g))}/{(탄소계 가스 공급량(L))*(탄소계 가스 1몰 중 탄소의 중량(g/mol))/(22.4(L/mol))}*100"의 식에 따라 계산하였다. 측정 결과는 하기 표 2와 같다.The apparent density of the catalyst powder was obtained by measuring the weight by filling the catalyst powder in the mass cylinder, and dividing the measured weight by the volume of the mass cylinder. The apparent density of the carbon nanotubes was measured in the same manner. In addition, the synthesis yield of carbon nanotubes was calculated according to the formula "Weight of synthesized carbon nanotubes (g)] / [weight of injected catalyst powder (g)] * 100", and the conversion of ethylene was "{(multiple Weight of wall carbon nanotubes (g))-(weight of catalyst powder (g))} / {(carbon-based gas supply (L)) * (weight of carbon in 1 mol of carbon-based gas (g / mol)) / (22.4 (L / mol))} * 100 ". The measurement results are shown in Table 2 below.
구분division 촉매 분말겉보기 밀도(g/mL)Catalyst powder apparent density (g / mL) 탄소나노튜브합성수율(%)Carbon Nanotube Synthesis Yield (%) 에틸렌 가스전환율(%)Ethylene Gas Conversion Rate (%) 탄소나노튜브겉보기 밀도(g/mL)Carbon nanotube apparent density (g / mL)
실시예 1Example 1 0.1800.180 1,2641,264 85.785.7 0.0150.015
실시예 2Example 2 0.0600.060 1,4901,490 90.190.1 0.0220.022
실시예 3Example 3 0.5160.516 1,4001,400 89.789.7 0.0200.020
실시예 4Example 4 0.0770.077 1,3541,354 91.291.2 0.0200.020
실시예 5Example 5 0.0720.072 1,4371,437 93.593.5 0.0220.022
실시예 6Example 6 0.0840.084 2,6002,600 83.683.6 0.0230.023
실시예 7Example 7 0.0900.090 1,3921,392 91.491.4 0.0150.015
실시예 8Example 8 0.2150.215 4,2824,282 93.593.5 0.0270.027
실시예 9Example 9 0.3690.369 3,8553,855 96.296.2 0.0310.031
실시예 10Example 10 0.6620.662 4,0304,030 95.695.6 0.0340.034
비교예 1Comparative Example 1 0.1640.164 651651 68.568.5 0.0080.008
비교예 2Comparative Example 2 0.4700.470 967967 78.678.6 0.0290.029
비교예 3Comparative Example 3 0.4370.437 826826 74.874.8 0.0760.076
비교예 4Comparative Example 4 0.9060.906 00 00 --
비교예 5Comparative Example 5 0.8150.815 763763 72.372.3 0.0530.053
비교예 6Comparative Example 6 0.7260.726 582582 61.361.3 0.0130.013
비교예 7Comparative Example 7 0.0280.028 594594 59.859.8 0.0070.007
비교예 8Comparative Example 8 1.0561.056 742742 75.275.2 0.0120.012
상기 표 2를 참고하면, 실시예 1~10의 촉매를 사용하여 유동층 화학기상증착 반응기로 탄소나노튜브를 합성할 경우 1,200% 이상의 높은 합성수율을 얻을 수 있어 탄소나노튜브의 대량생산에 적합함을 확인할 수 있다. 그러나 비교예의 촉매를 사용한 경우에는 탄소나노튜브의 합성수율이 1,000% 미만으로 대량생산에는 적합하지 않으며 이러한 결과로부터 비교예의 촉매는 유동층 화학기상증착 반응기에 적합한 형태의 촉매가 아님을 확인할 수 있다.특히, 비교예 4, 5, 6, 8의 촉매는 촉매 분말의 겉보기 밀도가 0.70g/mL 이상으로 촉매 분말을 반응가스로 부유시키면서 탄소나노튜브를 합성하는 유동층 화학기상증착 방식에서는 촉매를 부유시키기 어렵다는 문제가 있다.Referring to Table 2, when synthesizing carbon nanotubes in a fluidized bed chemical vapor deposition reactor using the catalysts of Examples 1 to 10, a high synthesis yield of 1,200% or more can be obtained, which is suitable for mass production of carbon nanotubes. You can check it. However, when the catalyst of the comparative example is used, the synthesis yield of carbon nanotubes is less than 1,000%, which is not suitable for mass production. From these results, it can be seen that the catalyst of the comparative example is not a catalyst suitable for a fluidized bed chemical vapor deposition reactor. The catalysts of Comparative Examples 4, 5, 6, and 8 are difficult to float in the fluidized bed chemical vapor deposition method of synthesizing carbon nanotubes while floating the catalyst powder with the reaction gas with an apparent density of 0.70 g / mL or more. there is a problem.
또한, 낮은 합성수율과 촉매 분말의 유동화 문제로 인해 비교예의 촉매를 사용한 경우에는 탄소나노튜브의 합성에 사용한 에틸렌 가스의 전환율이 모두 80% 미만으로 대량생산에 사용할 경우 동일한 양의 탄소나노튜브를 제조하기 위해 보다 많은 양의 에틸렌 가스를 투입해야 하므로 생산비용 측면에서도 매우 불리함을 알 수 있다.In addition, due to the low synthesis yield and fluidization problem of the catalyst powder, when the catalyst of the comparative example is used, the conversion of the ethylene gas used for the synthesis of carbon nanotubes is less than 80%. In order to increase the amount of ethylene gas to be added, it can be seen that it is very disadvantageous in terms of production cost.
전술한 본 발명의 설명은 예시를 위한 것이며, 본 발명이 속하는 기술분야의 통상의 지식을 가진 자는 본 발명의 기술적 사상이나 필수적인 특징을 변경하지 않고서 다른 구체적인 형태로 쉽게 변형이 가능하다는 것을 이해할 수 있을 것이다. 그러므로 이상에서 기술한 실시예들은 모든 면에서 예시적인 것이며 한정적이 아닌 것으로 이해해야만 한다. 예를 들어, 단일형으로 설명되어 있는 각 구성 요소는 분산되어 실시될 수도 있으며, 마찬가지로 분산된 것으로 설명되어 있는 구성 요소들도 결합된 형태로 실시될 수 있다.The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.
본 발명의 범위는 후술하는 청구범위에 의하여 나타내어지며, 청구범위의 의미 및 범위 그리고 그 균등 개념으로부터 도출되는 모든 변경 또는 변형된 형태가 본 발명의 범위에 포함되는 것으로 해석되어야 한다.The scope of the invention is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention.

Claims (17)

  1. (a) 금속 전구체를 용매 중에 용해시켜 전구체 용액을 제조하는 단계;(a) dissolving a metal precursor in a solvent to prepare a precursor solution;
    (b) 상기 전구체 용액을 반응기 내부로 분무하면서 열분해시켜 촉매 분말을 형성하는 단계; 및(b) pyrolysing the precursor solution while spraying into the reactor to form a catalyst powder; And
    (c) 상기 촉매 분말을 600~900℃로 가열된 유동층 반응기 내부로 투입하고 탄소계 가스와 운반 가스를 분사하여 상기 촉매 분말로부터 다중벽 탄소나노튜브를 합성하는 단계;를 포함하고,(c) injecting the catalyst powder into a fluidized bed reactor heated to 600 to 900 ° C. and injecting a carbon-based gas and a carrier gas to synthesize multi-walled carbon nanotubes from the catalyst powder.
    상기 (a) 내지 (c) 단계가 연속식으로 수행되고,Steps (a) to (c) are carried out continuously,
    상기 촉매 분말은 하기 식 1에 따른 금속 성분을 포함하는 다중벽 탄소나노튜브의 제조방법:The catalyst powder is a method for producing a multi-walled carbon nanotubes comprising a metal component according to the following formula 1:
    <식 1><Equation 1>
    Ma : Mb = x : yMa: Mb = x: y
    상기 식에서,Where
    Ma는 Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn 및 Cu중에서 선택된 2종 이상의 금속이고,Ma is at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn and Cu,
    Mb는 Mg, Al, Si 및 Zr 중에서 선택된 1종 이상의 금속이고,Mb is at least one metal selected from Mg, Al, Si and Zr,
    x와 y는 각각 Ma와 Mb의 몰 분율을 나타내며,x and y represent the mole fraction of Ma and Mb, respectively
    x+y=10, 2.0≤x≤7.5, 2.5≤y≤8.0 이다.x + y = 10, 2.0 ≦ x ≦ 7.5, 2.5 ≦ y ≦ 8.0.
  2. 제1항에 있어서,The method of claim 1,
    상기 촉매 분말은 두께가 0.5~10㎛ 인 중공 구조를 가지는 다중벽 탄소나노튜브의 제조방법.The catalyst powder is a method for producing a multi-walled carbon nanotube having a hollow structure of 0.5 ~ 10㎛ thickness.
  3. 제1항에 있어서,The method of claim 1,
    상기 촉매 분말의 겉보기 밀도가 0.05~0.70g/mL인 다중벽 탄소나노튜브의 제조방법.Method for producing a multi-walled carbon nanotubes having an apparent density of 0.05 ~ 0.70g / mL of the catalyst powder.
  4. 제2항에 있어서,The method of claim 2,
    상기 중공 구조의 중공 비율이 50부피% 이상인 다중벽 탄소나노튜브의 제조방법.Method for producing a multi-walled carbon nanotubes having a hollow ratio of 50% by volume or more of the hollow structure.
  5. 제1항에 있어서,The method of claim 1,
    하기 식 2에 따른 전환율이 80% 이상인 다중벽 탄소나노튜브의 제조방법:Method for producing a multi-walled carbon nanotube having a conversion rate of 80% or more according to the following formula 2:
    <식 2><Equation 2>
    전환율(%)={(다중벽 탄소나노튜브의 중량(g))-(촉매 분말의 중량(g))}/{(탄소계 가스 공급량(L))*(탄소계 가스 1몰 중 탄소의 중량(g/mol))/(22.4(L/mol))}*100.Conversion rate (%) = {(weight of multi-walled carbon nanotubes (g))-(weight of catalyst powder (g))} / {(carbon-based gas supply (L)) * (of carbon in 1 mol of carbon-based gas) Weight (g / mol)) / (22.4 (L / mol))} * 100.
  6. 제1항에 있어서,The method of claim 1,
    상기 탄소계 가스가 탄소수 1~4의 포화 또는 불포화 탄화수소, 일산화탄소, 벤젠, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나인 다중벽 탄소나노튜브의 제조방법.Wherein the carbon-based gas is one selected from the group consisting of saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, carbon monoxide, benzene, and mixtures of two or more thereof.
  7. 제1항에 있어서,The method of claim 1,
    상기 운반 가스가 헬륨, 질소, 아르곤, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나인 다중벽 탄소나노튜브의 제조방법.Wherein said carrier gas is one selected from the group consisting of helium, nitrogen, argon, and mixtures of two or more thereof.
  8. 제1항에 있어서,The method of claim 1,
    상기 금속 전구체가 금속의 질산염, 황산염, 알콕사이드, 클로라이드, 아세테이트, 카보네이트, 및 이들 중 2 이상의 혼합물로 이루어진 군에서 선택된 하나인 다중벽 탄소나노튜브의 제조방법.And the metal precursor is one selected from the group consisting of nitrates, sulfates, alkoxides, chlorides, acetates, carbonates, and mixtures of two or more of these metals.
  9. 제1항에 있어서,The method of claim 1,
    상기 (b) 단계가,In step (b),
    (i) 2~5기압의 공기를 운반 가스로 공급하고 외부 공기를 유입시켜 전구체 용액을 반응기 내부로 분무하는 단계; 및(i) spraying a precursor solution into the reactor by supplying 2-5 atmospheres of air as a carrier gas and introducing external air; And
    (ii) 분무된 상기 전구체 용액을 600~1,200℃에서 열분해하여 촉매 분말을 형성하는 단계;를 포함하는 다중벽 탄소나노튜브의 제조방법.(ii) pyrolysing the sprayed precursor solution at 600 to 1,200 ° C. to form a catalyst powder.
  10. 제1항에 있어서,The method of claim 1,
    상기 (c) 단계가,In step (c),
    (i) 유동층 반응기를 600~900℃로 가열하는 단계;(i) heating the fluidized bed reactor to 600-900 ° C .;
    (ii) 반응기 상부에서 촉매 분말을 공급하고 반응기 내에서 유동화시키는 단계;(ii) feeding catalyst powder at the top of the reactor and fluidizing in the reactor;
    (iii) 탄소계 가스와 운반 가스를 반응기 하부에서 회전날개를 통해 공급하는 단계; 및(iii) supplying a carbonaceous gas and a carrier gas through a rotary blade at the bottom of the reactor; And
    (iv) 상기 회전날개에 의한 상승 기류로 유동화된 상기 촉매 분말 상에 탄소를 열 기상증착시키는 단계;를 포함하는 다중벽 탄소나노튜브의 제조방법.(iv) thermal vapor deposition of carbon on the catalyst powder fluidized in an upward air stream by the rotary blades.
  11. 제1항에 있어서,The method of claim 1,
    상기 (c) 단계 이후에,After step (c),
    (d) 상기 다중벽 탄소나노튜브를 상기 유동층 반응기로부터 회수하는 단계;를 더 포함하는 다중벽 탄소나노튜브의 제조방법.(d) recovering the multi-walled carbon nanotubes from the fluidized bed reactor.
  12. 제11항에 있어서,The method of claim 11,
    상기 (d) 단계가,In step (d),
    (i) 상기 다중벽 탄소나노튜브를 질소 가스를 이용하여 싸이클론으로 이송하는 단계; 및(i) transferring the multi-walled carbon nanotubes to a cyclone using nitrogen gas; And
    (ii) 상기 싸이클론에서 상기 다중벽 탄소나노튜브 중 불순물을 제거하여 다중벽 탄소나노튜브를 선별하는 단계;를 포함하는 다중벽 탄소나노튜브의 제조방법.(ii) screening the multi-walled carbon nanotubes by removing impurities from the multi-walled carbon nanotubes in the cyclone.
  13. 제1항에 있어서,The method of claim 1,
    상기 다중벽 탄소나노튜브가 응집되어 다발형 탄소나노튜브로 존재하는 다중벽 탄소나노튜브의 제조방법.The method of manufacturing a multi-walled carbon nanotubes in which the multi-walled carbon nanotubes are aggregated to exist as bundle-type carbon nanotubes.
  14. 제13항에 있어서,The method of claim 13,
    상기 다발형 탄소나노튜브의 평균 다발 직경(bundle diameter)이 0.5~20㎛이고, 평균 다발 길이(bundle length)가 10~200㎛인 다중벽 탄소나노튜브의 제조방법.The bundle type of the bundle type carbon nanotubes (bundle) is 0.5 ~ 20㎛, bundle length (bundle length) 10 ~ 200㎛ method for producing multi-walled carbon nanotubes.
  15. 제1항에 있어서,The method of claim 1,
    상기 다중벽 탄소나노튜브의 라만 분광 강도비(IG/ID)가 0.7~1.5인 다중벽 탄소나노튜브의 제조방법.Raman spectral intensity ratio (I G / I D ) of the multi-walled carbon nanotubes of 0.7 ~ 1.5 method for producing a multi-walled carbon nanotubes.
  16. 제1항에 있어서,The method of claim 1,
    상기 다중벽 탄소나노튜브의 평균 직경이 5~50nm인 다중벽 탄소나노튜브의 제조방법.Method for producing a multi-walled carbon nanotubes having an average diameter of 5 to 50nm of the multi-walled carbon nanotubes.
  17. 제1항에 있어서,The method of claim 1,
    상기 다중벽 탄소나노튜브의 겉보기 밀도가 0.01~0.07g/mL인 다중벽 탄소나노튜브의 제조방법.Method for producing a multi-walled carbon nanotubes having an apparent density of 0.01 ~ 0.07g / mL of the multi-walled carbon nanotubes.
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