KR102672016B1 - Method and apparatus for manufacturing hydrogen and carbon product using fluidized reactor comprising activation-pretreated catalyst - Google Patents

Abstract

The present invention relates to a manufacturing method and manufacturing device for hydrogen and carbon material, and more specifically, to a manufacturing method and manufacturing device that can continuously produce high-purity hydrogen and high-quality carbon material.

Description

Method and apparatus for producing hydrogen and carbon using a fluidization reactor containing an activated pre-treated catalyst {METHOD AND APPARATUS FOR MANUFACTURING HYDROGEN AND CARBON PRODUCT USING FLUIDIZED REACTOR COMPRISING ACTIVATION-PRETREATED CATALYST}

The present invention relates to a method and apparatus for producing hydrogen and carbon bodies, and more specifically, to the production of hydrogen and carbon bodies using a fluidization reactor containing an activated pre-treated catalyst to continuously produce high-purity hydrogen and high-quality carbon bodies. It relates to methods and manufacturing equipment.

Hydrogen is widely used as a raw material for chemical products and as a process gas in chemical plants, and its demand has recently been increasing as a raw material for fuel cells, a future energy technology. It is considered desirable to produce such hydrogen from renewable energy sources because it does not generate carbon dioxide, but currently, it is preferable to produce hydrogen from coal or natural gas because it is the most economical and contributes to the cleanup of fossil fuels.

Meanwhile, a carbon nanotube is formed by combining one carbon atom with three neighboring carbon atoms to form a hexagonal ring, and the planes of this hexagonal ring are repeated in a honeycomb shape to form a cylinder or tube. Since carbon nanotubes (CNTs) were first discovered by Ijima (1991), they have attracted much research attention from researchers due to their excellent mechanical strength, electrical and thermal properties. Carbon nanotubes have the physical properties of metals or semiconductors depending on the structure in which the molecular chains are rolled, and are used as additives to improve performance in various fields such as batteries, semiconductors, ceramics, paints, coatings, and films.

As a process research for mass production of carbon nanotubes, the methane catalytic decomposition technology of chemical vapor deposition (CCVD) is emerging. Catalytic methane decomposition (CMD) technology decomposes methane directly into hydrogen and carbon species without generating CO _x and is considered an environmentally friendly process. The reaction equation is depicted as follows.

[Scheme 1]

The CMD reaction is a high-temperature endothermic reaction, and due to the strong C-H bond (440 kJ/mol) and high symmetry of the molecular structure, the decomposition of methane can be carried out at temperatures above 1200 °C without a catalyst. On the other hand, the catalytic reaction occurs at temperatures below 1000°C and uses various metal and non-metallic based catalysts alone or in combination to improve active and product carbon selectivity.

The economics of the CMD process are largely determined by the maintenance of catalyst activity and the quality of the filament carbon produced. Therefore, optimization of catalyst-process conditions and understanding of the carbon nanotube growth mechanism are essential for producing high-quality carbon nanotubes. According to several studies on the CMD reaction of methane reported in the literature, a general mechanism for carbon nanotube formation has been described. The main steps of the process are chemisorption of methane on the catalyst metal particles, dissociation of the chemisorbed methane molecules, aggregation and desorption of the chemisorbed atomic hydrogen into molecules, diffusion of atomic carbon through the catalyst bulk, and formation of carbon nuclei and carbon nanostructures. It is a tube formation. At this time, the driving force for bulk diffusion of atomic carbon through metal particles is known as the concentration gradient or temperature gradient. In the nucleation stage, the metal has liquid properties, and the main stages of nucleation are divided into the formation of high carbon coverage on the metal surface, the dissolution of high concentration of carbon into nickel particles, and the generation of CNTs by carbon separation behavior.

The CMD process begins with a catalytic reduction step with a specific ratio of hydrogen balanced with a nitrogen flow, which determines the proportion of metal catalyst to be activated before the reaction and the surface area into which the carbon particles are dissolved. When the catalyst is reduced with hydrogen, the lattice oxygen of the metal oxide is reduced after calcination, and an active metal site where nanocarbon grows is formed. Therefore, considering methane gas, which acts as a reducing agent in the CMD process, it is necessary to derive optimal reduction conditions for maximum carbon yield and high-quality CNT production.

In particular, little research has been reported on the effects of reducing gas concentration (partial pressure) and time, and various reducing conditions on the growth characteristics of carbon nanotubes. Therefore, the present inventors derived the optimal reduction conditions (reduction temperature, reduction time, reduction gas ratio) of the Fe-Mo/MgO catalyst that maximizes CNT yield through catalytic chemical vapor deposition (CCVD) in the methane catalytic decomposition process, and determined the reduction conditions. Through repeated research on the effect of changes on CNT growth characteristics (CNT morphology, diameter, crystallinity), optimal conditions were derived, which led to the present invention.

In addition, the present invention was derived from the need for research on supply methods including appropriate activation and pretreatment of catalysts.

The present invention was devised to solve the above-described problem, and an embodiment of the present invention provides a method for producing hydrogen and carbon body.

In addition, another embodiment of the present invention provides a hydrogen and carbon body manufacturing apparatus.

However, the technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below. It could be.

As a technical means for achieving the above-described technical problem, one aspect of the present invention is,

(S1) pre-activating the catalyst by supplying a gas containing hydrogen; (S2) supplying the catalyst and a hydrocarbon-based source gas to a reactor to produce a gaseous reaction product containing hydrogen and a solid-phase reaction product containing a carbon body; and (S3) recovering the solid-phase reaction product and the gas-phase reaction product, respectively. In the step (S1), the activation pre-treatment time, the pre-treatment temperature, and the concentration of hydrogen in the hydrogen-containing gas are determined. Provided is a method for producing hydrogen and a carbon body, characterized in that the diameter of the carbon body is adjusted by controlling at least one selected from the group consisting of.

The activation pretreatment is to reduce the catalyst by supplying a gas containing hydrogen, and the activation pretreatment temperature may be 450°C or higher and 650°C or lower.

The activation pretreatment time may be 2 to 7 minutes, and the concentration of hydrogen in the gas containing hydrogen may be 25 to 35 mol%.

At this time, the average diameter of the obtained carbon body may be 10 to 12 nm.

At this time, the reaction time in the (S2) step is 25 to 40 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for _ID It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range is 0.55 to 0.75.

At this time, the reaction time in the (S2) step is 55 to 70 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for _ID It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range is 0.75 to 0.85.

The activation pretreatment time may be 45 to 70 minutes, and the concentration of hydrogen in the gas containing hydrogen may be 5 to 15 mol%.

At this time, the obtained carbon body may have an average diameter of 9 to 10.5 nm.

At this time, the reaction time in the (S2) step is 25 to 40 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for _ID It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range is 0.80 to 0.99.

At this time, the reaction time in the (S2) step is 55 to 70 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for _ID It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range is 1.1 to 1.5.

It may further include the step of separating hydrogen from the gaseous reaction product recovered in step (S3) and re-supplying the gaseous reaction product from which the hydrogen has been separated to the reactor.

The reactor may be a fluidized bed reactor, and steps (S1) to (S3) may be performed continuously.

(S4) supplying a portion of the recovered solid reaction product to a combustion unit and burning it; and (S5) supplying heat generated in the combustion unit to the reactor.

In the step (S4), the solid phase to be burned is sensed by sensing one or more conditions selected from the group consisting of the pressure difference between the upper and lower parts of the reactor, the temperature within the reactor, and the concentration of unreacted source gas discharged from the reactor. It may be characterized by controlling the amount of reaction product.

In the step (S1), the catalyst is (Fe), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), cobalt (Co), copper ( Characterized by being any one of metals or alloys of Cu), cadmium (Cd), zinc (Zn), ruthenium (Ru), lead (Pd), silver (Ag), platinum (Pt), and gold (Au). It may be.

The source gas may be characterized as containing methane gas.

It may be characterized in that the average diameter of the obtained carbon body increases as the activation pretreatment temperature increases.

The activation pretreatment temperature is 400°C or higher and 800°C or lower, the reaction time in step (S2) is 25 to 40 minutes, and the average diameter of the obtained carbon body is 8 to 18 nm. It may be.

At this time, in the obtained Raman spectrum of the carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 I _{D is} the ratio of the intensity I _G of the peak appearing in the range of 1570 to 1600 cm ^-1 _D may be characterized as being 0.8 to 2.7.

In step (S2), the reaction time is 25 to 40 minutes, and when the concentration of hydrogen in the gas containing hydrogen is 5 to 60 mol%, the average diameter of the obtained carbon body is 3 to 20 nm. It may be characterized as being .

The reaction time in the (S2) step is 1 to 10 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 In the range of 1570 to 1600 cm ^-1 for I _D It may be characterized in that the ratio I _G / I _D of the intensity I _G of the appearing peak is 0.75 to 1.5.

Another aspect of the present invention is,

An active catalyst supply unit that supplies a gas containing hydrogen to the catalyst to pre-activate it and continuously supplies the activated catalyst to a rear reactor; A reactor in which a hydrocarbon-based source gas undergoes an endothermic reaction in the presence of the catalyst to produce a gas-phase reaction product containing hydrogen and a solid-phase reaction product containing a carbon body; a first recovery unit for recovering gaseous reaction products from the reactor; and a second recovery unit for recovering the solid reaction product from the reactor, wherein at least one selected from the group consisting of an activation pre-treatment time, a pre-treatment temperature, and a concentration of hydrogen in the hydrogen-containing gas in the active catalyst supply unit. Provided is a hydrogen and carbon body manufacturing apparatus, characterized in that the diameter of the carbon body is adjusted by controlling the species.

a separation unit that separates a portion of the solid reaction product recovered in the second recovery unit and supplies it to the combustion unit; and a combustion unit that burns the solid reaction product supplied from the separation unit to supply reaction heat to the reactor.

The reactor may be a fluidized bed reactor, and the active catalyst supply unit may be an upflow-reactor.

a hydrogen supply unit that supplies a portion of hydrogen separated from the gaseous reaction product recovered in the first recovery unit to the lower part of the active catalyst supply unit; and a circulation unit that separates and purifies hydrogen from the gaseous reaction product recovered in the first recovery unit and re-supplies the remaining unreacted source gas to the reactor.

A sensing unit located in the reactor and sensing one or more conditions selected from the group consisting of a pressure difference between the upper and lower parts of the reactor, a temperature within the reactor, and a concentration of unreacted source gas discharged from the reactor; and a control unit that controls the amount of reaction product separated in the separation unit by comparing the sensing value measured in the sensing unit with a set design value.

According to an embodiment of the present invention, methane, the main component of natural gas, is directly decomposed (CH ₄ → C + 2H ₂ △H = 75.6 kJ/mol) to produce hydrogen without generating carbon dioxide and at the same time used as an electrode material, etc. It is possible to produce high value-added carbon materials.

Additionally, according to one embodiment of the present invention, the amount and quality of carbon generated on the catalyst surface can be improved by performing a pretreatment process in a high temperature environment within a certain temperature range under a reducing gas atmosphere.

In addition, according to one embodiment of the present invention, it is a process technology consisting of a catalyst pretreatment device, a fluidization reactor, a reaction heat supply device, and a device for separating, purifying, and recirculating the generated gas/solid products, and the unit is manufactured through the present invention. It is possible to design a large-scale process consisting of operations, and by maximizing the efficiency of the catalyst, the economic feasibility of the process can be greatly improved.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 shows a schematic diagram of a hydrogen and carbon body manufacturing apparatus according to an embodiment of the present invention.
Figure 2 is a schematic diagram of control-related matters of a hydrogen and carbon body manufacturing apparatus according to an embodiment of the present invention.
Figure 3 shows the results of analyzing the catalytic reducibility of the hydrogen and carbon body production device according to an embodiment of the present invention through temperature programmed reduction (H2-TPR) characterization.
Figure 4 shows the results of plotting the carbon yield according to the reduction temperature and reduction time of the catalyst in the hydrogen and carbon body production apparatus according to an embodiment of the present invention.
Figure 5 shows the results of elemental diffraction pattern analysis of a fresh catalyst and a Mo-Fe/MgO catalyst reduced at various temperatures in a hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 6 shows the image and diameter distribution of CNTs deposited on a Mo-Fe/MgO catalyst reduced at various temperatures in a hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 7 shows the Raman spectroscopy results and I _G / I _D variation curve of CNT according to reduction temperature in the hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 8 shows the results of plotting the carbon yield according to the hydrogen concentration (partial pressure) and reduction time through the Mo-Fe/MgO catalyst in the hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 9 shows the results of TEM analysis to investigate the effect of reduction partial pressure on CNT diameter distribution in the hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 10 shows the carbon yield according to reaction time (5-60 min) in the hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 11 shows the shape and diameter distribution of CNTs deposited on a catalyst using TEM analysis in a hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 12 shows high-resolution TEM images under various reduction conditions within 10 minutes to investigate the initial stage of CNT growth form in the hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 13 shows the XRD analysis results and crystal size of CNTs grown for a reaction time of 60 min under various reduction conditions of Mo-Fe/MgO catalyst in a hydrogen and carbon body production device according to an embodiment of the present invention.
Figure 14 shows the results of Raman analysis of CNTs produced at a reaction time of 5-60 min in a hydrogen and carbon body production device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail. However, the present invention can be implemented in various different forms, and the present invention is not limited to the embodiments described herein, and the present invention is only defined by the claims to be described later.

Unless otherwise defined, the technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and the gist of the present invention is summarized in the following description and accompanying drawings. Descriptions of known functions and configurations that may unnecessarily obscure are omitted.

In addition, units used without special mention in this specification are based on weight, and as an example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition unless otherwise defined. It refers to the weight percent occupied in the composition.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-defined values, and the upper limit of the numerical range defined in different forms. and all possible combinations of the lower bounds. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

In addition, the terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the entire specification of the present invention, 'including' a certain element means that other elements may be further included rather than excluding other elements, unless specifically stated to the contrary.

In this specification, 'carbon body' refers to nano-sized carbon structures having various shapes such as carbon nanotubes, carbon nanofibers, fullerenes, carbon nanocones, carbon nanohorns, and carbon nanorods.

Hereinafter, the present application will be described in detail.

The first aspect of the present application is,

(S1) pre-activating the catalyst by supplying a gas containing hydrogen; (S2) supplying the catalyst and a hydrocarbon-based source gas to a reactor to produce a gaseous reaction product containing hydrogen and a solid-phase reaction product containing a carbon body; and (S3) recovering the solid-phase reaction product and the gas-phase reaction product, respectively. In the step (S1), the activation pre-treatment time, the pre-treatment temperature, and the concentration of hydrogen in the hydrogen-containing gas are determined. Provided is a method for producing hydrogen and a carbon body, characterized in that the diameter of the carbon body is adjusted by controlling at least one selected from the group consisting of.

Hereinafter, the method for producing hydrogen and carbon body according to the first aspect of the present application will be described in detail.

First, in one embodiment of the present application, (S1) may include pre-activation treatment by supplying a gas containing hydrogen to the catalyst. As the catalyst activated in step (S1) is supplied to the reactor, the endothermic reaction of the hydrocarbon-based source gas that occurs in the presence of the catalyst in step (S2) can be promoted. Accordingly, it is possible to manufacture large quantities of products in a relatively short period of time.

In one embodiment of the present application, activation of the catalyst in step (S1) may be achieved by reducing the catalyst with a reducing gas. The reducing gas is not limited as long as it is a gas capable of reducing the introduced metal catalyst, but is preferably hydrogen, and more preferably, some of the hydrogen separated from the gaseous product recovered in step (S3) can be used.

In one embodiment of the present application, the activation of the catalyst in step (S1) is preferably performed in an upflow reactor in terms of contact efficiency between the catalyst and the reducing gas, and the catalyst activation may be performed for 1 to 60 seconds, but is limited thereto. It doesn't work.

In one embodiment of the present application, the catalyst may be a metal catalyst, specifically iron (Fe), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel ( Any of Ni), cobalt (Co), copper (Cu), cadmium (Cd), zinc (Zn), ruthenium (Ru), lead (Pd), silver (Ag), platinum (Pt), and gold (Au) It may be any one selected from metals or alloys thereof. In addition, of course, the catalyst may further include supports such as silica and zeolite known in the art for supplying the catalyst in the reactor.

In one embodiment of the present application, the activation pretreatment is to reduce the catalyst by supplying a gas containing hydrogen, and the activation pretreatment temperature is 350°C or higher, 400°C or higher, 450°C or higher, or It may be characterized as being 500°C or higher, 900°C or lower, 850°C or lower, 650°C or lower, or 580°C or lower. The reducibility of the catalyst can be confirmed by temperature programmed reduction (H2-TPR) characterization, where multiple peaks may be formed depending on the degree of reduction. At this time, a first peak may be formed between 400 and 550 °C and a wide second peak may be formed between 600 and 900 °C. Considering carbon yield, the activation pretreatment temperature is preferably 450°C or higher and 650°C or lower.

In one embodiment of the present application, the average diameter of the obtained carbon body may increase as the activation pretreatment temperature increases. Specifically, when the activation pretreatment temperature is in the range of 400°C or higher and 800°C or lower, and the reaction time in step (S2) is 25 to 40 minutes, the average diameter of the obtained carbon body is 8 to 800°C. It may increase with temperature in the range of 18 nm.

In one embodiment of the present application, the crystallinity of the carbon body obtained may be increased as the activation pretreatment temperature increases. At this time, the crystallinity of the carbon body is the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 in the obtained Raman spectrum I _G of the peak appearing in the range of 1570 to 1600 cm ^-1 with respect to I _D It can be determined based on the ratio I _G / I _D , where the activation pretreatment temperature is in the range of 400 ℃ or more and 800 ℃ or less, and the reaction time in step (S2) is 25 to 40 minutes. In this case, I _G /I _D may increase with temperature in the range of 0.8 to 2.7.

In one embodiment of the present application, the temperature of the activation pretreatment may also affect the yield of the carbon body produced. The activation pretreatment time may be 1 to 90 minutes, and is preferably 40 to 70 minutes in terms of yield of the carbon body produced.

The biggest feature of the present application that distinguishes it from the prior art is that, in the step (S1), at least one selected from the group consisting of activation pre-treatment time, pre-treatment temperature, and concentration of hydrogen in the hydrogen-containing gas is controlled to remove the carbon. This means that the diameter of the sieve can be adjusted. As mentioned in the above paragraph, the activation pretreatment temperature and pretreatment time of the catalyst are also related to the yield of the carbon body, so the carbon body of the desired diameter is adjusted to the above-mentioned catalyst activation pretreatment conditions (temperature, time, hydrogen concentration). This means that it can be adjusted to ensure high yield.

In one embodiment of the present application, the concentration of hydrogen in the gas containing hydrogen may be adjusted to 5 to 60 mol%. From the perspective of optimizing carbon yield, when the catalyst activation pretreatment time and temperature conditions are fixed and only the hydrogen concentration is adjusted, the temperature is 450°C or higher and 650°C or lower and the activation pretreatment time is 2 to 7 minutes. In terms of carbon yield, it is preferable that the concentration of hydrogen in the hydrogen-containing gas is 25 to 35 mol%. In another example, the temperature is 450°C or higher and 650°C or lower and the activation The pretreatment time is 45 to 70 minutes, and the concentration of hydrogen in the gas containing hydrogen is preferably 5 to 15 mol%.

In one embodiment of the present application, the diameter of the carbon body formed in step (S2) can be controlled by adjusting the concentration of hydrogen in the gas containing hydrogen. Specifically, when the activation pretreatment temperature is 450°C or higher and 650°C or lower, and the reaction time in step (S2) is 25 to 40 minutes, the concentration of hydrogen in the gas containing hydrogen is 5 to 60 When performed under mol% conditions, the average diameter of the obtained carbon body may increase in the range of 3 to 20 nm.

In a preferred embodiment of the present application, the activation pretreatment time is 2 to 7 minutes, and the concentration of hydrogen in the gas containing hydrogen is 25 to 35 mol%. At this time, the average diameter of the obtained carbon body may be 10 to 12 nm. In addition, the reaction time in the (S2) step is 1 to 10 minutes, and in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for I _D The ratio I _G / I _D of the intensity I _G of the peak appearing in the range may be 0.75 to 1.5. In addition, when the reaction time in the (S2) step is 25 to 40 minutes, in the Raman spectrum of the obtained carbon body, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 is 1570 to 1600 cm ^-1 for _ID It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range is 0.55 to 0.75. In addition, when the reaction time in step (S2) is 55 to 70 minutes, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 in the Raman spectrum of the carbon body obtained is 1570 to 1600 cm ^-1 for _ID The intensity of the peak appearing in the range I _G may be characterized in that the ratio I _G / I _D is 0.75 to 0.85.

In another preferred embodiment of the present application, the activation pretreatment time is 45 to 70 minutes, and the concentration of hydrogen in the gas containing hydrogen is 5 to 15 mol%. At this time, the obtained carbon body may have an average diameter of 9 to 10.5 nm. In addition, when the reaction time in the (S2) step is 1 to 10 minutes, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 in the Raman spectrum of the carbon body obtained is 1570 to 1600 cm ^-1 for _ID The ratio I _G / I _D of the intensity I _G of the peak appearing in the range may be 0.75 to 1.5. Also, at this time, when the reaction time in the (S2) step is 25 to 40 minutes, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 in the Raman spectrum of the obtained carbon body is 1570 to 1600 cm for I _D ^- It may be characterized in that the ratio I _G / I _D of the intensity I _G of the peak appearing in the range of ¹ is 0.80 to 0.99. In addition, when the reaction time in step (S2) is 55 to 70 minutes, the intensity of the peak appearing in the range of 1330 to 1370 cm ^-1 in the Raman spectrum of the carbon body obtained is 1570 to 1600 cm ^-1 for _ID The intensity of the peak appearing in the range I _G may be characterized in that the ratio I _G / I _D is 1.1 to 1.5.

Next, in one embodiment of the present application, (S2) includes supplying the catalyst and hydrocarbon-based source gas to the reactor to produce a gaseous reaction product containing hydrogen and a solid-phase reaction product containing a carbon body. can do. This reaction may be a step of obtaining gas and solid phase reaction products by performing an endothermic reaction of the hydrocarbon-based source gas in the presence of a catalyst.

In one embodiment of the present application, the hydrocarbon-based source gas contains a carbon source for producing a carbon body as a product, and specifically, a compound having 6 or less carbon atoms, or a compound with 4 or less carbon atoms, or a compound with 2 or less carbon atoms. It can be included. More specifically, one or two or more selected from the group consisting of carbon monoxide, methane, ethane, ethylene, ethanol, acetylene, propane, propylene, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene, and toluene. It can be included. Preferably, it may contain methane, and in one specific example, it may be natural gas containing methane or exhaust gas from a petrochemical/refinery process. Such hydrocarbon-based source gas undergoes an endothermic reaction in the reactor in the presence of the above-mentioned catalyst, and can be converted into high value-added products of carbon materials such as hydrogen and carbon nanotubes.

In one embodiment of the present application, it is preferable that the reactor in step (S2) is a fluidized bed reactor with excellent contact efficiency between the catalyst and the hydrocarbon-based source gas.

In step (S2) according to an embodiment of the present application, the internal pressure of the reactor may be normal pressure or 0.2 to 20 barg (gauge pressure), and preferably 0.5 to 5 barg. Additionally, in step (S1), the temperature inside the reactor may be 500 to 1200°C, specifically 600 to 900°C, but is not limited thereto. Additionally, the endothermic reaction in the reactor may be performed for 1 to 120 minutes, specifically 30 to 80 minutes, but is not limited thereto. As the reaction time of step (S2) increases, the diameter of the carbon body formed increases and the carbon body yield may tend to increase.

Next, (S3) may include recovering the solid-phase reaction product and the gas-phase reaction product, respectively. The solid-phase reaction product contains carbon, and the gas-phase reaction product contains hydrogen.

Hydrogen may be separated from the gaseous reaction product recovered in step (S3) according to an embodiment of the present application, and the gaseous reaction product from which the hydrogen has been separated may be re-supplied to the reactor. The gaseous reaction product from which the hydrogen is separated is an unreacted source gas, that is, a raw material. By reusing the raw materials, it is possible to obtain a product with a high yield compared to the amount of raw material input, and to increase economic efficiency in the entire process. .

Next, in one embodiment of the present application, (S4) may further include supplying a portion of the recovered solid reaction product to a combustion unit and burning it. The step (S4) is a step in which part of the recovered solid reaction product is supplied to the combustion unit and burned. Heat can be generated by burning the solid-phase reaction product, and the amount of the solid-phase reaction product moved to the combustion unit can be appropriately adjusted in proportion to the amount of heat required for the endothermic reaction occurring in the reactor. At this time, the solid-phase reaction product may include not only the carbon body but also some catalyst.

In one embodiment of the present application, step (S4) is performed by sensing one or more conditions selected from the group consisting of the pressure difference between the upper and lower parts of the reactor, the temperature within the reactor, and the concentration of unreacted source gas discharged from the reactor. The amount of solid-phase reaction product moving to the combustion section can be adjusted, and thus the amount of solid-phase reaction product burning in the combustion section can be adjusted. For example, if the concentration value of unreacted source gas discharged from the reactor is lower than the design value, the amount of reaction product burned can be reduced by reducing the amount of solid reaction product moving to the combustion section, and the concentration value of unreacted source gas can be reduced. If it is higher than the design value, the amount of reaction products burned can be increased by increasing the amount of solid reaction products moving to the combustion section.

Next, in one embodiment of the present application, (S5) may further include supplying heat generated in the combustion unit to the reactor. The step (S5) is a step of supplying the heat generated in the combustion unit to the reactor, which provides the necessary heat in step (S2). In step (S5), the amount of heat required for the endothermic reaction in step (S2) can be directly supplied into the reactor, greatly increasing the efficiency of heat energy use.

Specifically, step (S5) may be performed by supplying a heat medium containing the solid reaction product burned in the combustion unit to the reactor. The heat medium may further include fluid particles for efficient heat supply in addition to a solid reaction product including a carbon body and a catalyst. Specifically, the fluid particles may include layered materials such as alumina, zirconia, and silica.

In one embodiment of the present application, in step (S5), the supply of the heat medium is not specifically limited as long as it is a conventionally known supply method, but as a non-limiting example, it may be supplied through a loop seal. Additionally, in step (S5), a reducing gas may be further supplied as a carrier gas for smooth transfer of the heat medium.

In one embodiment of the present application, the above-described steps (S1) to (S3), (S1) to (S4), or (S1) to (S5) can be performed continuously, producing high value-added products such as carbon nanotubes. It is possible to mass-produce carbon bodies and high-purity hydrogen, so the possibility of industrial use can be very high.

The method for producing hydrogen and carbon body according to an embodiment of the present application is to determine the amount (yield) and quality (diameter or crystallinity) of carbon generated on the surface of the catalyst when the catalyst is subjected to a reduction pretreatment process in a high temperature environment within a certain temperature range under a reducing gas atmosphere. ) has the advantage of being able to be improved by adjusting. Furthermore, it is possible to design a large-scale process, and by maximizing the efficiency of the catalyst, the economic feasibility of the process can be greatly improved.

In the method for producing hydrogen and carbon body according to an embodiment of the present application, a part of the recovered solid reaction product is supplied to the combustion unit for combustion, and then the generated heat is supplied to the reactor, thereby transferring the amount of heat required for the endothermic reaction into the reactor. Since it can be supplied directly, the efficiency of thermal energy use is very high, and the endothermic reaction of hydrocarbon-based hydrogen gas occurs uniformly, producing high-purity hydrogen and high-quality carbon material.

In addition, since a portion of the product is burned to supply the required amount of heat, there is no need for separate steps for inputting and burning combustion materials, and the preheating step of the source gas and the heating step of the reactor are not required, so the manufacturing method is relatively simple.

The second aspect of the present application is,

An active catalyst supply unit that supplies a gas containing hydrogen to the catalyst to pre-activate it and continuously supplies the activated catalyst to a rear reactor; A reactor in which a hydrocarbon-based source gas undergoes an endothermic reaction in the presence of the catalyst to produce a gas-phase reaction product containing hydrogen and a solid-phase reaction product containing a carbon body; a first recovery unit for recovering gaseous reaction products from the reactor; and a second recovery unit for recovering the solid-phase reaction product from the reactor, wherein at least one selected from the group consisting of an activation pre-treatment time, a pre-treatment temperature, and a concentration of hydrogen in the hydrogen-containing gas in the active catalyst supply unit. Provided is a hydrogen and carbon body manufacturing apparatus, characterized in that the diameter of the carbon body is adjusted by controlling the species.

Detailed description of parts overlapping with the first aspect of the present application has been omitted, but the content described with respect to the first aspect of the present application can be applied equally even if the description is omitted in the second aspect.

Hereinafter, the hydrogen and carbon body manufacturing apparatus according to the second aspect of the present application will be described in detail with reference to the attached drawings.

Figure 1 shows a schematic diagram of a hydrogen and carbon body manufacturing apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the hydrogen and carbon body production device 1 is a reactor ( 10); A first recovery unit (30) that recovers the gaseous reaction product from the reactor (10); A second recovery unit 35 that recovers the solid reaction product from the reactor 10, a separation unit 50 that separates a portion of the solid reaction product recovered from the second recovery unit 35 and supplies it to the combustion unit 70. ); and a combustion unit 70 that burns the solid reaction product supplied from the separation unit 50 to supply heat energy to the reactor 10.

In conventional hydrogen and carbon body production devices, a heater is installed outside the fluidized bed reactor used as a reactor to supply heat energy necessary when the hydrocarbon-based source gas undergoes an endothermic reaction. However, such a manufacturing device uses a heater installed on the outer surface of the reactor 10 to supply heat energy to the inside of the reactor, resulting in a temperature gradient. Accordingly, as the heater must be heated to a temperature exceeding the amount of heat required for the endothermic reaction, the efficiency in using heat energy is reduced. In addition, since the temperature at the center of the reactor and the temperature of the inner wall of the reactor 10 are different, the carbon body cannot grow homogeneously inside the reactor, resulting in the formation of a relatively low-quality carbon body.

However, since the hydrogen and carbon body manufacturing apparatus according to the present invention includes a combustion unit 70, the amount of heat required when the hydrocarbon-based gas undergoes an endothermic reaction in the presence of a catalyst can be directly supplied into the reactor 10. In other words, since only the required amount of heat is supplied directly into the reactor 10, the efficiency of heat energy use is very high. In addition, as the required amount of heat is supplied directly into the reactor 10, there is almost no temperature difference within the reactor 10, so the endothermic reaction of hydrocarbon-based hydrogen gas occurs uniformly at any location in the reactor 10, producing high-purity hydrogen and high quality. can produce carbon bodies. In addition, the present invention supplies the required amount of heat by burning a part of the product separated through the separation unit 50, so there is no need for separate equipment for inputting external materials, and there is no need for a preliminary heating device and heater for the source gas. The manufacturing equipment is relatively simple. In addition, the present invention can control the conversion rate of hydrocarbon-based gas by controlling the amount of heat supplied to the reactor 10, thereby controlling the yield and characteristics of the produced carbon body.

Specifically, the reactor 10 provides an accommodation space in which the catalyst and source gas can be accommodated, and in the presence of the catalyst, the hydrocarbon-based source gas undergoes an endothermic reaction to produce a gaseous reaction product containing hydrogen and a carbon body. A solid reaction product is produced.

The reactor 10 provides an accommodating space within which the hydrocarbon-based source gas can undergo an endothermic reaction, and is a chemical vapor deposition reactor, preferably a fluidized bed reactor 10. reactor).

In order to produce a carbon body by chemical vapor deposition (CVD), the reaction time between the source gas and the catalyst is required to be longer than a certain time, and the residence time of the carbon body and the catalyst to be produced in the reactor 10 is determined by the reaction time of the carbon body. It has a major impact on purity and yield.

In the fluidized bed reactor 10, a gaseous source gas is contacted with a catalyst that is a solid material in the form of fine particles, and the source gas flows at a speed sufficient to suspend the catalyst, so that the solid catalyst can behave similarly to the gaseous source gas. . Accordingly, the source gas and the catalyst can be mixed and contacted relatively homogeneously, and it is possible to secure the growth time of the carbon body in the reactor 10, so that the production rate of the carbon body is high compared to the amount of catalyst input, making it possible to manufacture the carbon body in high yield. You can.

The reactor 10 may have a longitudinal direction perpendicular to the ground, and a catalyst supply port 11 is provided at the top so that catalyst can be supplied into the reactor 10.

The catalyst supplied to the catalyst supply port 11 may be a metal catalyst, specifically iron (Fe), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), and nickel. (Ni), cobalt (Co), copper (Cu), cadmium (Cd), zinc (Zn), ruthenium (Ru), lead (Pd), silver (Ag), platinum (Pt), and gold (Au). It may be one metal or one selected from alloys thereof.

The reactor 10 is provided with a gas supply port 13 at the bottom, so that source gas can be supplied in an upward flow manner from the bottom to the top.

The hydrocarbon-based source gas supplied to the gas supply port 13 contains a carbon source for producing a carbon body as a product, and specifically, a compound with 6 or less carbon atoms, or a compound with 4 or less carbon atoms, or a compound with 2 or less carbon atoms. may include. More specifically, one or two or more selected from the group consisting of carbon monoxide, methane, ethane, ethylene, ethanol, acetylene, propane, propylene, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene, and toluene. It can be included. In one specific example, it may be natural gas containing methane. Such hydrocarbon-based source gas undergoes an endothermic reaction in the reactor 10 in the presence of a catalyst, and can be converted into high value-added products of carbon materials such as hydrogen and carbon nanotubes.

The source gas may further include one or more of an inert gas or a reducing gas. Nitrogen, helium, argon, neon, etc. can be used as inert gases, and hydrogen, etc. can be used as reducing gases. Such an inert or reducing gas prevents the carbon nanotubes from falling in the direction of gravity due to the increase in weight as they grow, and expands the fluidization area within the reactor 10 to activate the endothermic reaction of the catalyst and hydrocarbon-based source gas. there is. In particular, when a reducing gas is included, the yield of carbon products can be further improved by increasing the catalyst activity in the reactor.

In this way, the catalyst and source gas respectively supplied into the reactor 10 through the catalyst supply port 11 located at the top of the reactor 10 and the gas supply port 13 located at the bottom of the reactor 10 are reactor ( 10) When mixed in the internal accommodation space, in the presence of a catalyst, the source gas undergoes an endothermic reaction to produce a gaseous reaction product containing hydrogen and a solid phase reaction product containing carbon.

The receiving space within the reactor 10 can be divided into an upper space and a lower space. Specifically, the lower space is adjacent to the floor, and source gas and thermal energy (quantity of heat), which will be described later, can be supplied. Meanwhile, in the upper space, the source gas that has received sufficient heat energy from the lower space comes into contact with the catalyst, and an endothermic reaction of the source gas can occur. The reactor 10 is located at the boundary between the upper space and the lower space and is installed to partition the upper space and the lower space, and may be provided with a dispersion plate (not shown) having a plurality of holes. The source gas can be dispersed into the upper space through the distribution plate. Additionally, the dispersion plate may serve to prevent the catalyst or the carbon body produced by the reaction from falling to the bottom of the fluidized bed reactor 10.

The reactor 10 is provided with an exhaust port 15 at the top so that gaseous reaction products can be discharged to the outside of the reactor 10, and an exhaust port 17 is provided on at least one of the top, bottom, or side. Thus, the solid reaction product can be discharged to the outside of the reactor (10). Additionally, the reactor 10 may be provided with a connection port 19 on another side to receive heat energy from a combustion unit 70, which will be described later.

The gaseous reaction product generated by the endothermic reaction can be discharged to the outside of the reactor 10 through the exhaust port 15 by the first recovery unit 30, and the solid reaction product can be discharged to the outside of the reactor 10 through the second recovery unit 35. It can be discharged to the outside of the reactor 10 through the discharge port 17.

The first recovery unit 30 recovers the gaseous reaction product from the reactor 10, and the recovery line 31 connected to the exhaust port 15 of the reactor 10 and the gas purification located in the recovery line 31 It may include a device (not shown), etc., and high-purity hydrogen generated in the reactor 10 can be recovered through the recovery line 31. In addition, the first recovery unit further includes a cyclone installed at the top of the reactor, so that the gaseous reaction product can be smoothly recovered.

The second recovery unit 35 recovers the solid reaction product from the reactor 10, and is located in the discharge recovery line 36 and the discharge recovery line 36 connected to the discharge port 17 of the reactor 10. It may include a gas phase separator (not shown). The gas phase separator can remove gas components mixed in the solid reaction product recovered through the discharge recovery line 36, such as unreacted source gas.

The separation unit 50 separates a portion of the solid reaction product recovered through the second recovery unit 35 and supplies it to the combustion unit 70. Except for some solid reaction products supplied to the combustion unit 70 by the separation unit 50, the remaining products are final products and can be discharged to the outside.

The combustion unit 70 combusts the solid reaction product supplied from the separation unit 50 and supplies heat energy to the reactor 10. The combustion unit 70 is a conventionally known combustor and can generate heat energy using a solid reaction product including a carbon body and a catalyst as fuel. The combustor may be equipped with an oxygen supply port through which air containing oxygen or oxygen itself can be supplied from the outside, and a carbon dioxide discharge port through which carbon dioxide generated after combustion can be discharged.

The heat energy generated as the solid reaction product containing the carbon body is burned by the combustion unit 70 is supplied to the reactor 10 through the heat medium, and the amount of heat required when the hydrocarbon-based gas undergoes an endothermic reaction in the presence of the catalyst is supplied to the reactor ( 10) Can be supplied directly internally.

Specifically, the heating medium may include combusted solid reaction products and flowing particles, and may be supplied through the heating medium supply pipe 71 connecting the combustor and the reactor 10. The heat medium supply pipe 71 has a loop seal structure, and the discharge portion is inclined downward toward the reactor 10 so that the heat medium supply pipe 71 can be supplied using gravity. At this time, the combustion unit 70 may further include a fluidizing gas supply unit (not shown) capable of supplying a reducing gas to the heating medium supply pipe to ensure smooth supply of the heating medium.

In the prior art, a large amount of heat energy was consumed to supply the required amount of heat by supplying heat energy through a heater and a preliminary heating device installed outside the reactor 10. However, the present invention includes a combustion unit 70, so that the amount of heat required is As much as this amount is supplied directly into the reactor 10, the efficiency of heat energy use is very high. In addition, since there is almost no temperature difference within the reactor 10, the endothermic reaction of hydrocarbon-based hydrogen gas occurs uniformly at any location within the reactor 10, and uniform growth of carbon bodies such as carbon nanotubes occurs, producing high-purity hydrogen and high-quality Carbon bodies can be created. In addition, the combustion unit 70 burns a portion of the product separated through the separation unit 50 to supply the required amount of heat in the reactor 10, so there is no need for separate equipment for inputting external substances, and heat energy is efficiently used. to be able to supply.

In one embodiment of the present application, a circulation unit 90 located in the recovery line 31 may be further included as shown in the drawing. The circulation unit 90 separates and purifies hydrogen from the gaseous reaction product recovered in the first recovery unit 30, and re-supplies the remaining unreacted source gas to the reactor 10. Accordingly, not only can higher purity hydrogen be obtained, but by recycling unreacted source gas, the product can be obtained at a high yield compared to the amount of source gas input. Specifically, the circulation unit 90 can separate and purify hydrogen through pressure swing adsorption (PSA) or a polymer separation membrane. PSA does not require a heat exchanger, which is essential for cooling the reactor 10 when separating mixed gases, thereby reducing facility investment costs and reducing the size of the manufacturing equipment. Additionally, by recirculating the high-temperature reaction product through a recirculation line connected to the reactor 10 without cooling, the amount of heat required and the size of the preheater can be reduced. The PSA device and polymer separation membrane can be made using any means known in the art without limitation.

In one embodiment of the present application, as shown in the drawing, an active catalyst supply unit 20 located at the front of the reactor 10 may be further included. The active catalyst supply unit 20 activates the catalyst and continuously supplies the activated catalyst to the reactor 10. As the activated catalyst is supplied to the reactor 10, an endothermic reaction can be promoted. Accordingly, it is possible to manufacture large quantities of products in a relatively short period of time. Activation of the catalyst can be achieved by reduction with a reducing gas. This has the advantage of being able to control and improve the amount (yield) and quality (diameter or crystallinity) of carbon generated on the catalyst surface by undergoing a reduction pretreatment process for the catalyst in a high temperature environment within a certain temperature range under a reducing gas atmosphere. Furthermore, it is possible to design a large-scale process, and by maximizing the efficiency of the catalyst, the economic feasibility of the process can be greatly improved.

The active catalyst supply unit 20 is not limited to any catalytically active reactor known in the art, but is preferably an upflow-reactor. In an upstream flow reactor, the catalyst flows from the bottom to the top and is reduced and activated by the reducing gas that flows from the bottom to the top. Compared to the down-flow reactor, the up-flow reactor is easier to control the residence time of the catalyst flowing in the reactor (10), so the degree of activation of the catalyst can be easily adjusted, and the physical properties (e.g. For example, conductivity) may be adjustable. In addition, continuous catalyst introduction is easy, making continuous production of products easy. At this time, the upper part of the active catalyst supply unit 20 and the catalyst supply port 11 located at the upper part of the reactor are connected by the catalyst supply line 21, so that the activated catalyst can be supplied into the reactor 10.

In one embodiment of the present application, a hydrogen supply unit 40 located in the recovery line 31 may be further included. The hydrogen supply unit 40 may supply a portion of the hydrogen separated from the gaseous reaction product recovered in the first recovery unit 30 to the lower part of the active catalyst supply unit 20. Specifically, the hydrogen supply unit 40 may include a gas separator 41 and a hydrogen supply line 43 connecting the gas separator 41 and the lower end of the active catalyst supply unit 20. The active catalyst supply unit 20 does not require a separate reducing gas to activate the catalyst, and allows the use of part of the product generated after the reaction to further increase the manufacturing efficiency of the manufacturing device.

In one embodiment of the present application, referring to FIG. 2, a sensing unit 80 located in the reactor 10 and a control unit 85 that controls the amount of the reaction product separated in the separation unit 50 through the sensing unit 80 are further provided. It can be included. The sensing unit 80 is a sensor that senses various conditions within the reactor 10, specifically the pressure difference between the upper and lower parts of the reactor 10, the temperature within the reactor 10, and the unreacted source discharged from the reactor 10. One or more conditions selected from the group consisting of gas concentration are sensed.

The control unit 85 can control the amount of reaction product separated in the separation unit 50 by comparing the sensing value measured by the sensing unit 80 with a set design value.

For example, if the temperature in the reactor 10 sensed through the temperature sensor installed in the reactor 10 is higher than the design value, the amount of reaction products separated from the separation unit 50 and delivered to the combustion unit 70 can be reduced. In addition, when the temperature in the reactor 10 is lower than the design value, the amount of reaction products separated in the separation unit 50 and delivered to the combustion unit 70 can be increased. Accordingly, the amount of reaction product burned by the combustion unit 70 can be adjusted, and the amount of heat ultimately transferred into the reactor 10 can be adjusted.

In this way, the hydrogen and carbon body manufacturing device including the sensing unit 80 and the control unit 85 controls the amount of reaction product delivered to the combustion unit 70 through conditions within the reactor 10 such as temperature, (10) The amount of heat supplied can be easily adjusted.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement it. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Example 1: Preparation of catalyst

The Mo-Fe/MgO catalyst with a 10:2:88 molar ratio used to produce CNTs from methane decomposition was prepared by the combustion method. Preparation of precursor solution included iron nitrate nonahydrate (Fe(NO ₃ )2·9H ₂ O, 98.5%, Samchun chemicals, Republic of Korea), heptamolybdate ((NH ₄ )6Mo ₇ O ₂₄ ·4H ₂ O, 99.0%, Samchun chemicals, Republic of Korea) and magnesium nitrate hexahydrate (Mg(NO ₃ ) ₂ ·6H ₂ O, 98.0%, Samchun chemicals, Republic of Korea) were used. The resulting aqueous precursor solution was dissolved in heated distilled water and burned in a muffle furnace at 550°C for 30 minutes. The solid produced after combustion was ground into fine catalyst powder.

Example 2: Characterization of experimental conditions

Temperature-programmed reduction (TPR) measurement of the catalyst synthesized in Example 1 above was performed using BELCAT-B (Bel Japan Inc.) using a carrier gas (10% H ₂ , Ar balance) flow of 30 ml/min and a thermal conductivity detector. ) was carried out. After the catalyst sample was pretreated to remove impurities and moisture, it was heated to 1000°C at a temperature increase rate of 3°C/min and the change in thermal conductivity detector was measured. X-ray Diffraction (XRD) of the catalyst after calcination, reduction and reaction was measured using D/MAX-2500V (Rigaku Corp.) with Cu Kα radiation at 60 kV and 300 mA. The 2θ angle was measured in the range 10°-80° with a scanning rate of 0.02°/min.

Transmission electron microscope (TEM) (Talos F200X, Thermo Fisher Scientific Ltd.) analysis was conducted to confirm the diameter distribution and structure of the synthesized CNTs. The Raman spectrum of the synthesized CNTs was measured using a Nanophoton Ramanforce Laser Raman Microscope (Nanophoton Co.) in the range of 50-4000 cm ^-1 with 532 nm excitation of an Ar ion laser.

Example 3: Synthesis of carbon body (carbon nanotube)

The carbon nanotube synthesis apparatus was carried out in a horizontal reactor. The quartz tube (L: 22mm, OD: 4mm, ID: 37mm) inside the reactor has a plate on which to place the crucible (OD: 10mm, L: 10mm) and a thermocouple to measure the temperature of the bottom of the crucible. The reaction gas is supplied at room temperature through the MFC, and through the rapid heating section of the IR heater, methane is decomposed and carbon nanotubes are generated. During the reaction, exhaust gases are discharged through the vent line. Prior to the experiment, the catalyst was sieved to 75–100 μm and all methane catalytic decomposition was performed in an atmospheric pressure atmosphere. 50 mg of fresh catalyst was loaded into the crucible and placed on a plate inside the reactor. After purging the inside of the reactor (20 min) in an N ₂ atmosphere, it was rapidly heated to the reduction temperature at a temperature increase rate of 50 °C/sec. Afterwards, a reduction reaction was performed by introducing a mixed gas of hydrogen and nitrogen (99.9% H ₂ , 99.95% N ₂ ). Reduction temperature experiments were performed in the range of 500–800 °C depending on reduction time (5 to 60 min). Hydrogen partial pressure experiments during reduction were performed in the range of 0.1-0.5 atm (total gas flow rate 100 sccm) depending on reduction time (5, 60 min). Afterwards, CNT synthesis was performed according to reduction conditions and reaction time to determine the effect of various reduction conditions on the activity and deactivation of the catalyst. After the reduction step, it was heated to 800°C in an N2 atmosphere at a temperature increase rate of 10°C/sec and then purged (10min). Afterwards, the reaction was performed by injecting a mixed gas of methane and nitrogen (50 vol % CH ₄ /N ₂ ). Methane catalytic cracking was carried out at 800 °C with a gas hourly space velocity (GHSV) of 36,000 ml/gcat·h. Both reduction time and reduction hydrogen partial pressure experiments were conducted for 30 minutes after methane injection, and reduction condition-reaction time experiments were conducted for 5-60 minutes. The obtained samples were tested at Red _temp ( , time)-Rxn(time), where Red _temp ( , time)-Rxn(time) refers to the hydrogen partial pressure and time of the reduction step used in each experiment when the reduction temperature is fixed, and Rxn (time) refers to the time of the reaction step. The weight of the synthesized carbon nanotubes was weighed and the yield was calculated using the following equation.

W _p is the weight of the product after reaction and W _cat is the weight of fresh catalyst.

Experimental Example 1: Analysis of the effect of catalyst reduction pretreatment temperature

The reducibility of fresh Mo-Fe/MgO catalyst in oxidic state was analyzed through temperature programmed reduction (H ₂ -TPR) characterization. The results are displayed in Figure 3. It is known that the reduction of Fe ₂ O ₃ proceeds in 2 to 3 steps as Fe ₂ O ₃ → Fe ₃ O ₄ → FeO → Fe ⁰ . The sharp peak between 400 and 550 ℃ is the stage where bulk Fe ₂ O ₃ (hematite) is reduced to Fe ₃ O ₄ (magnetite). The wide hydrogen absorption peak in the range of 600 to 900 ℃ is believed to be a complex peak caused by the reduction of various iron (Fe) and molybdenum (Mo) series oxides. This peak was reported to be due to reduction of Fe ₃ O ₄ → FeO → Fe ⁰ and reduction of MgFe ₂ O ₄ and MgMoO ₄ species. It may also include a peak in which MoO ₃ is reduced to oxides (MoO ₂ and Mo) with lower chemical valence. The reduction peak at high temperature is due to a decrease in the reducibility of the catalyst due to Mo, a prometer.

The results of plotting the carbon yield according to the reduction temperature and reduction time through the Mo-Fe/MgO catalyst are shown in Figure 4. It can be seen that the carbon yield gradually increases when the reduction temperature increases from 400 ℃ to 600 ℃ at reduction times of 5 and 15 min. Thereafter, at reduction temperatures above 700°C, the carbon yield tends to gradually decrease. In addition, when the reduction temperature increases from 400 ℃ to 500 ℃ at reduction times of 30 and 60 min, the carbon yield increases, and at temperatures above 600 ℃, the carbon yield also tends to gradually decrease. As a result, the optimal reduction temperature and reduction time of the Mo-Fe/MgO catalyst for high-yield CNT production were determined to be 500 °C and 60 min.

To monitor structural changes in the catalyst, XRD analysis was performed on the catalyst before and after reduction. The results of elemental diffraction pattern analysis of the fresh catalyst and the Mo-Fe/MgO catalyst reduced at various temperatures are shown in Figure 5. For both the fresh and reduced catalysts, several diffraction peaks assigned to the MgO rocksalt lattice were detected, with the MgO peaks corresponding to 2θ = 36.59, 42.50, 61.67, 73.89, and 77.77º. The XRD pattern of the fresh catalyst almost matched the peak of MgO because the Fe and Mo oxide peaks did not appear clearly due to the particle size according to the small amount of Fe and Mo, and because MgO was the main component. Small amounts of MgMoO ₄ and FeMoO ₄ peaks were found at 2θ = 23.25, 25.33, 26.37, 27.41º, 2θ = 23.45, 26.54º, respectively. It was confirmed that MgMoO ₄ species can be produced by the reaction of MgO and MoO ₃ , and that they can appear at a sintering temperature of 550 ℃ or higher. In the XRD pattern of the catalyst after reduction at 400 and 500 °C, Mo ₄ O ₇ and MgFe ₂ O ₄ (magnesioferrite) peaks were additionally found at 2θ = 28.59, 29.17º and 2θ = 30.16, 43.17º, respectively. The existence of MgFe ₂ O ₄ with a spinel-structure means that there was a partial solid-state interaction between the Fe ₂ O ₃ precursor and the MgO precursor, and it was confirmed that it could be formed at a calcination temperature of over 500 °C. . The XRD pattern of the 600°C reduction catalyst indicates that various mixed oxides were reduced, which is consistent with the TPR results in Figure 3. Reduction catalysts above 700°C are FeMoO ₃ (2θ = 17.65, 25.14, 32.17, 36,96, 40.23, 45.31, 49,01, 56.03, 64.58º), γ-Fe (2θ = 42.83, 73.20º) and Mo (2θ = 40.52, 58.64, 73.70º) Additional species were discovered. It can be seen that as the reduction temperature increases from 700 ℃ to 800 ℃, the intensity and sharpness of the Mo peak appear more clearly. This means that the crystal structure of Mo develops as the reduction temperature increases. Therefore, the optimal reduction temperature of 500°C derived from Figure 4 corresponds to the first reduction peak from Fe ₂ O ₃ → Fe ₃ O ₄ in the TPR curve of Figure 3, and the state in which various mixed oxides exist in the XRD of Figure 5 it means. The results suggest that in the case of Mo-Fe/MgO catalyst, complete reduction at high temperature is not effective for CNT production.

TEM analysis was performed to investigate the effect of reduction temperature on CNT diameter distribution. Images and diameter distributions of CNTs deposited on reduced Mo-Fe/MgO catalysts at various temperatures are shown in Figure 6. At this time, the diameter distribution of CNTs was derived by measuring the diameters of 50 CNTs per sample. As shown in Figures 6(a)-(e) and (h), the CNT diameter distribution tended to increase as the reduction temperature increased from 400 ℃ to 800 ℃, with the average diameter size being 8.54, 9.49, 11.0, and 12.95, respectively. It was 16.33 nm. In general, it is well known that CNT diameter size and number of walls are determined by metal particle size. Reduction at 400-600 °C shown in Figure 6(a), (b) and (c) leads to the production of CNTs with a narrow diameter distribution in the range of 2-25 nm, whereas reduction at 700-800 °C Shown in Figure 6(d), (e), increasing the size distribution of metal particles on the catalyst produces CNTs with a non-uniform diameter distribution in the range of 5-40 nm. As shown in Figure 6(f)-(g), MWCNTs with about 10-11 walls were formed on the catalyst reduced at 500°C, and MWCNTs with more than 20 walls were formed on the catalyst reduced at 800°C. was able to confirm. Therefore, reduction below the optimal reduction temperature and time leads to low carbon yield, which may be due to insufficient catalyst activation. On the other hand, reduction beyond the optimal reduction temperature and time also reduces the carbon yield, because high reduction temperature can affect the morphology of the catalyst and cause sintering of particles.

The crystallinity (graphitization) of the produced nanotubes is as follows: in the Raman spectrum, the D-band (approximately 1350 cm ^-1 ) due to the presence of sp ³ hybridized carbon atoms and the G-band (approximately 1585 cm -1 ) due to the presence of sp ² hybridized carbon atoms cm ^-1 ) is determined by the relative intensity ratio I _G /I _D . The Raman spectroscopy results and I _G / I _D fluctuation curve of CNT according to reduction temperature are shown in Figure 7. As shown in Figure 7(a)-(f), as the reduction temperature increases from 400 ℃ to 800 ℃, the peak intensity of the G-band becomes relatively stronger compared to the peak intensity of the D-band, and the I _G / I _D ratio showed a tendency to increase to 0.88, 0.91, 1.35, 1.89, and 2.60, respectively. As a result, this means that the catalyst reduced at a high reduction temperature can produce CNTs with better graphitization.

Experimental Example 2: Analysis of the effect of catalyst reduction pretreatment hydrogen concentration (partial pressure)

The results of plotting the carbon yield according to the hydrogen partial pressure and reduction time through the Mo-Fe/MgO catalyst are shown in Figure 8. Hydrogen partial pressure (Hydrogen partial pressure) under conditions of a relatively short reduction time (5 min) ) An increase from 0.1 to 0.3 leads to an increase in carbon yield, but a hydrogen concentration above 0.4 actually leads to a decrease in carbon yield. Additionally, under the condition of long reduction time (60 min), the increase in hydrogen partial pressure from 0.1 to 0.5 tends to gradually decrease the carbon yield. Therefore, it can be seen that when the reduction temperature is fixed at 500 °C, there is a balance point between the reduction time and hydrogen partial pressure with the maximum carbon yield. At a low hydrogen partial pressure of 0.1, a relatively long reduction time of 60 min was required, while at a high hydrogen partial pressure of 0.3, a carbon yield similar to that at 0.1 could be obtained even with a short reduction time of 5 min. As a result, when the reduction temperature was fixed at 500°C, the optimal reduction partial pressure and reduction time of the Mo-Fe/MgO catalyst were derived under the two conditions of 0.1 atm, 60 min, 0.3 atm, and 5 min with the maximum carbon yield.

To investigate the effect of reduction partial pressure on CNT diameter distribution, the diameters of 50 CNTs per sample were measured through TEM analysis. The CNT diameter distribution tended to broaden as the hydrogen partial pressure increased from 0.1 to 0.5 at a reduction time of 5 min, and the average diameter sizes were 5.15, 10.71, and 12.92 nm, respectively. Also, at a reaction time of 60 min, the CNT diameter distribution tended to increase as the hydrogen partial pressure increased from 0.1 to 0.5, and the average diameter sizes were 9.49, 17.42, and 19.41 nm. Therefore, it can be seen that reduction above a certain partial pressure causes catalyst sintering and produces larger diameter and smaller numbers of CNTs, which leads to a decrease in carbon yield in Figure 8. In the CMD reaction, there is an induction section in which metal carbide is formed through carburization as a step before carbon nucleus formation. At this time, the metal particle size determines the surface area where the decomposed methane is dissolved to form carbide. Therefore, the results in Figures 8 and 9 imply that there is an optimal metal particle size for the growth of metal carbide to CNT when it has a similar active phase at the same reduction temperature, Red ₅₀₀ (0.3, 5) and Red A reduction condition of ₅₀₀ (0.1, 60) was derived as the optimal reduction condition for CNT growth.

Experimental Example 3: Analysis of the effect of reaction time according to catalyst reduction pretreatment conditions

To determine the effect of various reduction conditions on the activity and deactivation of the catalyst, the carbon yield according to reaction time (5-60 min) is shown in Figure 10. The reduction conditions of Red ₅₀₀ (0.3, 5) and Red ₅₀₀ (0.1, 60) previously derived through Figures 8 and 9 and three cases of Red (no reduction) in the case where there is no reduction step were tested. As a result, in the reaction with a reaction time of 5 min, under the reduction conditions of Red (no reduction), no carbon was produced, and a smaller amount of product was produced than the amount of catalyst loaded. This suggests that the weight of the fresh catalyst was reduced due to reduction by methane gas. Afterwards, a carbon yield of 2.68 wt% was obtained at a reaction time of 10 min. On the other hand, under the reduction conditions of Red ₅₀₀ (0.1, 60) and Red ₅₀₀ (0.3, 5), carbon yields of about 6-7 wt% were obtained 5 minutes after the start of the reaction. After a reaction time of 30 min, the reduction conditions for Red (no reduction) gave a yield of 139 wt%, and the reduction conditions for Red ₅₀₀ (0.1, 60) and Red ₅₀₀ (0.3, 5) both yielded about 280-290 wt%. Carbon yield was obtained. In conclusion, the Mo-Fe/MgO catalyst has a large difference in carbon yield depending on the presence or absence of reduction conditions, so the reduction step must be considered to obtain a high carbon yield. In addition, it was confirmed that there was little difference in carbon yield between the two reduction conditions in terms of initial catalyst activity and deactivation in the reaction time range of 5-60 minutes.

To investigate the effect of reducing conditions on CNT diameter distribution, the shape and diameter distribution of CNTs deposited on the catalyst are shown in Figure 11 using TEM analysis. At this time, the diameter distribution of CNTs was derived by measuring the CNT diameter. By measuring the diameter of 30 CNTs per sample at a reaction time of 5 min and 50 CNTs per sample at a reaction time of 60 min. Figures 11(a) and (e) show CNTs deposited on the catalyst during 5 and 60 min reactions of Red ₅₀₀ (0.3, 5), respectively. The CNT diameter distribution slightly increased with increasing reaction time. The average CNT diameters for Red ₅₀₀ (0.3, 5) - Rxn(5), Rxn(30), and Rxn(60) were 10.17, 10.71, and 11.21 nm, respectively. Figures 11(b) and (e) show CNTs deposited on the catalyst during 5 and 60 min reactions under reducing conditions of Red ₅₀₀ (0.1, 60). Similar to Red ₅₀₀ (0.3, 5), the CNT diameter distribution increased slightly but remained smaller. The average CNT diameters were 9.38, 9.49, and 10.03 nm, respectively. Meanwhile, Figure 11(c) shows carbon and CNTs deposited on the catalyst during a 10-minute reaction of Red (no reduction). The TEM image corresponds to the low carbon yield results in Figure 9, indicating that little CNTs are produced without prior reduction by hydrogen. Additionally, Figure 12(a)–(c) shows high-resolution TEM images of various reducing conditions within 10 min to investigate the initial stages of CNT growth morphology. The morphology indicates bamboo-like CNTs, and some metal particles were also observed at the CNT tips.

Therefore, the CNTs growth mechanism of Mo-Fe/MgO catalyst is more suitable for base-growth mechanism than tip-growth for the three reduction conditions. These results are compatible with previous studies of the underlying growth mechanisms. In particular, we note that the catalytic reduction conditions have a dominant effect on the CNT diameter.

The XRD analysis results and crystal size of CNTs grown for a reaction time of 60 min under various reduction conditions of Mo-Fe/MgO catalyst are shown in Figure 13 and Table 1. In Figure 13, depending on the reduction conditions, the broad diffraction peak around 2θ = 26° corresponds to the (0 0 2) peak of the hexagonal graphite structure, and all three cases showed a broad graphite peak. In all three reduction conditions, molybdenum carbide (Mo ₂ C) peaks were detected at 2θ = 34.42, 37.99, 39.47, 52.19, 61.66, 69.63, 74.77, and 75.72° after reaction. This means that molybdenum carbide, like Fe carbide, plays an important role in CNT growth. Unlike iron (Fe), which is a metastable carbide that forms Fe ₃ C, leading to the growth into CNTs, molybdenum (Mo) requires the carbon concentration into the metal to reach a certain saturation value for γ-Fe and Fe ₃ C catalyst species. It has been reported that it promotes diffusion of carbon atoms, but is inactive for CNT growth by generating stable carbide (Mo ₂ C). In Figure 13(b), the Mo ₂ C peak with low intensity and large full width at half maximum (FWHM) was detected, whereas in Figures 13(a) and (c), the Mo ₂ C peak with relatively high intensity and small full width at half maximum (FWHM) was detected. It has been done. The full width at half maximum of the graphite peak at 26°, molybdenum carbide (Mo ₂ C) at 39.47°, and magnesia (MgO) at 42.5° were calculated using the Gaussian function, and the crystal size was calculated using the Scherrer equation. In Table ₁ , the crystal size of C ₀₀₂ (26°) is 2.51, 3.42, and 3.58 nm in the order of (b), (a), and (c). , (c) has 13.16, 19.59, and 20.03 nm in that order. Additionally, the crystal size of the MgO (42.5°) peak is 13.28, 20.63, and 28.97 nm in (b), (a), and (c). As a result of TPR analysis of MgO, it was confirmed that a hydrogen absorption peak was detected around 750°C. Therefore, it is judged that the catalyst with the reduction step underwent structural decomposition of MgO due to the rapid growth of CNTs as shown in Figure 10. The results show that the crystal sizes of C ₀₀₂ (26°) in the three reduction conditions tend to match the average CNT diameter at the reaction time of 60 minutes in Figure 11.

To investigate the effect of various reducing conditions on the degree of graphitization (crystallinity) of CNTs in relation to the CNT growth mechanism, the results of Raman analysis of CNTs produced at a reaction time of 5-60 min are shown in Figure 14. Figure 14(a) shows the Raman analysis results of CNTs produced at a reaction time of 5 min. In the case of Red (no reduction) conditions, it can be confirmed that no carbon was produced due to catalyst activation by methane. 14(b) and (c), D peak and G peak appeared as the reaction time increased, and the I _G /I _D ratio had similar values of 0.78 and 0.87, respectively. In the case of the reduction conditions of Red ₅₀₀ (0.1, 60) and Red ₅₀₀ (0.3, 5), the initial I _G / I _D ratios are 0.89 and 1.35, respectively, and it can be confirmed that the latter case has excellent CNT crystallinity. there was. However, it was confirmed that the I _G / I _D ratio of the CNTs produced at a reaction time of 30 min in Figure 14(b) showed a reverse change in crystallinity to 0.65 and 0.92, respectively. Additionally, when the reaction time in Figure 14(c) increases to 60 min, the I _G /I _D ratio tends to worsen to 1.37 and 0.83, respectively. The CNT diameters at 5 min of initial reaction under the two reduction conditions in Figure 11 are 9.38 and 10.17 nm, respectively, which can be seen to be relatively different. This may be the result of differences in the surface area of the metal particles where nucleation occurs depending on the reduction conditions. Therefore, the difference in metal particle surface area affects the nucleation step, which indicates that the crystallinity of the grown CNT may vary accordingly. Therefore, by controlling the reduction conditions, not only the diameter of the CNT but also the degree of graphitization can be adjusted, and application to future manufacturing processes can be considered.

In conclusion, it was confirmed that changes in the metal surface structure in response to the metal reduction conditions of the catalyst affect the diameter distribution and crystallinity of carbon nanotubes. The optimal reduction temperature for Mo-Fe/MgO was determined to be 500 °C for maximum carbon yield, and increasing the reduction temperature led to the growth of highly crystalline carbon nanotubes with larger diameter distribution. Additionally, an increase in reduction partial pressure also led to the growth of carbon nanotubes with a larger diameter distribution, and it was confirmed that the optimal particle size for carbon nanotube growth exists. As a result of the reaction time experiment according to reduction conditions, the difference in carbon yield depending on the presence or absence of reduction was very large, and there was almost no difference in carbon yield depending on reduction conditions. On the other hand, it was confirmed through transmission electron microscopy and Raman spectroscopic analysis that changes in reducing conditions greatly affected the diameter and crystallinity of carbon nanotubes. Ultimately, because reduction conditions affect the CNT growth mechanism, it was found that an appropriate metal activation method must be derived from the reduction step to form high-quality CNTs.

The present invention is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have knowledge.

10: reactor 11: catalyst supply port
13: gas supply port 15: exhaust port
17: discharge port 19: connection port
20: Catalyst active supply unit 21: Catalyst supply line
30: first recovery unit 31: recovery line
35: second recovery unit 36: discharge recovery line
40: Hydrogen supply unit 41: Gas separator
43: Hydrogen supply line 50: Separation part
70: Combustion unit 71: Heat medium supply pipe
90: Circulation section

Claims (15)

(S1) pre-activating the catalyst by supplying a gas containing hydrogen;
(S2) supplying the catalyst and a hydrocarbon-based source gas to a reactor to produce a gaseous reaction product containing hydrogen and a solid-phase reaction product containing a carbon body; and
(S3) recovering the solid-phase reaction product and the gas-phase reaction product, respectively,
In the step (S1), the diameter of the carbon body is adjusted by controlling at least one selected from the group consisting of activation pretreatment time, pretreatment temperature, and concentration of hydrogen in the hydrogen-containing gas,
The activation pretreatment is to reduce the catalyst by supplying a gas containing hydrogen,
The activation pretreatment temperature is 450°C or higher and 650°C or lower,
The activation pretreatment time is 2 to 7 minutes,
The concentration of hydrogen in the gas containing hydrogen is performed under the condition of 25 to 35 mol%, or
The activation pretreatment time is 45 to 70 minutes,
A method for producing hydrogen and carbon body, characterized in that the concentration of hydrogen in the gas containing hydrogen is carried out under the condition of 5 to 15 mol%.
delete delete delete According to paragraph 1,
Further comprising the step of separating hydrogen from the gaseous reaction product recovered in step (S3) and re-supplying the gaseous reaction product from which the hydrogen has been separated to the reactor. Sieve manufacturing method.
According to paragraph 1,
The reactor is a fluidized bed reactor, and steps (S1) to (S3) are performed continuously.
According to paragraph 1,
(S4) supplying a portion of the recovered solid reaction product to a combustion unit and burning it; and
(S5) supplying the heat generated in the combustion unit to the reactor.
In clause 7,
In the step (S4),
Controlling the amount of the solid reaction product to be burned by sensing one or more conditions selected from the group consisting of the pressure difference between the upper and lower parts of the reactor, the temperature within the reactor, and the concentration of unreacted source gas discharged from the reactor. A method for producing hydrogen and carbon bodies, characterized in that.
◈Claim 9 was abandoned upon payment of the setup registration fee.◈ According to paragraph 1,
In the step (S1), the catalyst is (Fe), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), cobalt (Co), copper ( Characterized by being any one of metals or alloys of Cu), cadmium (Cd), zinc (Zn), ruthenium (Ru), lead (Pd), silver (Ag), platinum (Pt), and gold (Au). Method for producing hydrogen and carbon body.
According to paragraph 1,
Method for producing hydrogen and carbon body, characterized in that the source gas contains methane gas
An active catalyst supply unit that supplies a gas containing hydrogen to the catalyst to pre-activate it and continuously supplies the activated catalyst to a rear reactor;
A reactor in which a hydrocarbon-based source gas undergoes an endothermic reaction in the presence of the catalyst to produce a gas-phase reaction product containing hydrogen and a solid-phase reaction product containing a carbon body;
a first recovery unit for recovering gaseous reaction products from the reactor; and
It includes a second recovery unit for recovering the solid reaction product from the reactor,
In the active catalyst supply unit, the diameter of the carbon body is adjusted by controlling at least one selected from the group consisting of activation pretreatment time, pretreatment temperature, and concentration of hydrogen in the hydrogen-containing gas,
The activation pretreatment is to reduce the catalyst by supplying a gas containing hydrogen,
The activation pretreatment temperature is 450°C or higher and 650°C or lower,
The activation pretreatment time is 2 to 7 minutes,
The concentration of hydrogen in the gas containing hydrogen is performed under the condition of 25 to 35 mol%, or
The activation pretreatment time is 45 to 70 minutes,
A hydrogen and carbon body manufacturing device, characterized in that the concentration of hydrogen in the gas containing hydrogen is carried out under the condition of 5 to 15 mol%.
According to clause 11,
a separation unit that separates a portion of the solid reaction product recovered in the second recovery unit and supplies it to the combustion unit; and
A combustion unit for supplying reaction heat to the reactor by burning the solid reaction product supplied from the separation unit.
According to clause 11,
The reactor is a fluidized bed reactor,
A hydrogen and carbon body production device, wherein the active catalyst supply unit is an upflow-reactor.
According to clause 11,
a hydrogen supply unit that supplies a portion of hydrogen separated from the gaseous reaction product recovered in the first recovery unit to the lower part of the active catalyst supply unit; and
A circulation unit that separates and purifies hydrogen from the gaseous reaction product recovered in the first recovery unit and re-supplies the remaining unreacted source gas to the reactor. .
◈Claim 15 was abandoned upon payment of the setup registration fee.◈ According to clause 12,
A sensing unit located in the reactor and sensing one or more conditions selected from the group consisting of a pressure difference between the upper and lower parts of the reactor, a temperature within the reactor, and a concentration of unreacted source gas discharged from the reactor; and
A control unit that controls the amount of reaction product separated in the separation unit by comparing the sensing value measured in the sensing unit with a set design value.